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THIS is a forum for questions and answers about blacksmithing and general metalworking. Ask the Guru any reasonable question and he or one of his helpers will answer your question, find someone that can, OR research the question for you.

This is an archive of posts from May 19 - 24, 2004 on the Guru's Den
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I was wondering how long it took a medieval blacksmith to craft a sword?
   - crystal - Wednesday, 05/19/04 01:31:11 EDT

   - RON - Wednesday, 05/19/04 03:18:57 EDT

guru, do you have a process where I can convert black iron into spring steel? will carburization work?
   Richard - Wednesday, 05/19/04 03:43:12 EDT

Hi Jim,

Yep Me "VAN" again I sent You the pic,s of my hammer and hope they will be added to the show room,the next project than i have in mind is a rolling press i can remember seeing somthing like that in a blade mag or some knife magezine but seem to have lost track of it is there anybody that have done something like that I would just like to know at what speed it is rolling. The rollers I am going to use is made of a ramrod of a front end loader tha is casehardened and cromed the centre is soft and very easy to machine,The ID of the roller is 87 mm and i wont make it longer than 120 mm to give min flex when rolling. If there is someboddy with more info and willing to help it will be highly appreciated.

cheers to all

   "VAN" Van der Merwe - Wednesday, 05/19/04 06:18:57 EDT

Looks like I was more accurate than I thought last Thursday.

Thanks for the confirmation; the dark recesses of my mind are better storage places than expected.

Early anvil material, I had a verbal report on a bronze age, granite, anvil found on Kes Tor (Dartmoor, Devon, UK). The smith (Beni) said it had been excavated, but he couldn’t find where it was now. The choice of granite was easy, it’s the local stone.

Paw paw
I have seen a frog pattern on-line might have been ‘the blacksmiths journal’. General process was to work the end of a square bar, and have the frog sitting on the diagonal. Sorry I can’t be of more help.
   Nigel - Wednesday, 05/19/04 06:25:14 EDT

Thanks guru. thats a start. I'll gather what info I can and that will have to do.
   Shayne - Wednesday, 05/19/04 09:02:08 EDT

Spring Steel: Richard, No and no (maybe).

However, ALL carbon steel (from mild steel through high carbon) has the SAME springyness. The technical term is modulus of elasticity (E). E = 29.8 million PSI. This value is used to calculate everything from deflection of beams to twisting in shafts as well as springs.

The difference between steels is how far you can deflect the steel before it permenently yeilds (bends). A properly designed mild steel spring can do the same job as a "spring steel" spring in many cases. Mild steel can be quenched and hardened but must also be tempered.

"Spring steels" include 304 which cannot be hardened by heat treating but is sold as work hardened wire.

High performance springs like valve springs and die stripper springs are made from carefully selected alloy steels that are carefully heat treated to have virtualy an infinite life in use.

Case hardening increases the carbon to a maximum of 1/32" (.8mm) from the surface of a piece of steel, usualy much less. The torch applied case hardening compounds produce a hard surface only thousandths of an inch thick (~.05mm). If a spring is made from very thin steel (1/16" - 1.6mm or less) then the case hardening will be enough to change the part's yeild. However, case hardening is not uniform. It is greater on the surface and decreases with the depth. Case hardening is used to create wear resistant surfaces and parts that are hard on the outside and tough on the inside.
   - guru - Wednesday, 05/19/04 10:46:50 EDT

Rolling Mill: Van, The article you saw in Blade Magazine was about the McDonald Rolling Mill. See our book review page for the plans. They are available from Norm larson Books.
   - guru - Wednesday, 05/19/04 10:56:17 EDT

I am looking for the min.-max. temp on babbit bearing. I havd a induced draft fan on a 150# saturated steam boiler. We would liketo save money if we could on the cooling water to the fan bearings. The water only passes once and then to the sewer.If I throttled the water back at what would the oulet(cooling) temp be safe. Thank You Marion Kowalski Shift Leader Ford Motor Co.
   Marion Kowalski - Wednesday, 05/19/04 11:44:32 EDT

II tired to melt some silver coins to use on a knife I`m making. Could not get it to melt in a lead melting pot that goes up to 900 degrees. I tried it in my Tim Lively forge in a cast iron pot. No luck. What is the best way to melt silver coins?
   Stan - Wednesday, 05/19/04 12:07:18 EDT

Silver has a melting point of ~962°C (~1763°F). I assume the Lead pot goes to 900°F. I believe coin siver has ~5% copper and it raises the melting point a bit. Silver is the best conductor of heat of the metals so a rich, direct flame from a torch would probably do better than the forge. I would preheat the pot in the forge, or use a crucible and preheat it, then use the torch. I have seen a jeweler do it this way before with 1oz. silver ingots.
   Shack - Wednesday, 05/19/04 13:57:32 EDT

Thanks for the tip on the roll mill plans i will see if i can get the book or some plans from the book to ship books to South Africa is somewhat of a costly business, but as the saying goes many a way to kill a cat.
cheers and keep well
   "VAN' Van der Merwe - Wednesday, 05/19/04 14:33:34 EDT

Stan, I melt silver in the 1-3 oz range using my coal forge and a stainless steel creamer.

Cast iron will *not* work for high temp metals as it's too near the failure temps when you include localized hot spots! The are also too big for the ammount of heat you need to put into the system.

I generally get a deep bed of coke---you want the fire to be reducing as any O2 will be eroding your melting your creamer. Then build a Mt Fuji firelay around the creamer with the creamer in the bore of the "volcano"---again hot coke is suggested for the inside fresh coal around the outside will coak up and hold it together. Place the silver in the creamer---I like using the 1oz rounds in fine or sterling or coin silver---laying flat in the bottom of the creamer, a little borax or powdered charcoal is suggested to keep O2 out of the metal. Heat, not so fast that a lot of O2 makes it through the fire, not so slow that there is a lot of time for the metal to take up O2. Pour when the surface is swirling.

I take the top of the creamer's off to make it easier to pour but put them loosly on top to reflect heat back in and keep flyash out. Remove before pouring.

The heavier the creamer steel is the better. They will scale thinner and need to be discarded.

SAFETY!!! Molten metal is a lot more dangerous than hot steel even if the steel is at a higher temperature! Any trace of water in the mold can result in an explosion of molten metal back onto yourself. Aprons, gloves, face shields ---all mandatory!

If you have not worked with molten metal before work through a pour with someone who has!

Clean your work areaa you need room to move smoothly from fire to pour, safe places to deal with hot tools and a safe place to pour that can deal with overflows or mis-pours.

What are you making the molds from?

Foundry work has a series of stages, each stage require more expensive equipment to work safely: low temp metals: lead tin zinc; Intermediate: Al, High temp: brass, bronze, silver copper, Very High Temp: Cast iron and VERY HIGHT TEMP INDEED: steels. it is best to work your way up the stages learning the skills you need to keep yourself from not looking like the phantom of the opera!

If you are near Central NM I'd be happy to do a pour with you.

BTW Coin silver is 90% silver, sterling-92.5%, Fine 99.9999% melting temp goes up with purity. I rather like working with fine myself.

   Thomas P - Wednesday, 05/19/04 14:40:33 EDT

I forgot to mention, I did my first pouring in an out of hours brass casting class taught by a university art department. *Very* good hands on training using simple equipment and at a bargin price! Look into taking something similiar.

   Thomas P - Wednesday, 05/19/04 14:44:50 EDT

Thanks Thomas and Van!! You have both great info! I have made my cast bullets for many years. I know what water or the like will do!! Thanks for the advisement. I was going to pouring the silver into the RCBS cast iron ingot molds that were made for lead. I just want to tap the silver ingot into some kind
   - Stan - Wednesday, 05/19/04 15:40:28 EDT

Thanks Thomas and Van!! You have both great info! I have made my cast bullets for many years. I know what water or the like will do!! Thanks for the advisement. I was going to pouring the silver into the RCBS cast iron ingot molds that were made for lead. I just want to tap the silver ingot into some kind "submission" and make into a workable "pile" for spacers on a knife handel. Thanks Again! Stan
   Stan - Wednesday, 05/19/04 15:41:07 EDT

Mark P: I know what you mean, and meant no disrespect. If someone asked me for a "Green River" knife, I'd point them at the actual thing. If someone asked me for a handmade green river STYLE knife, that's what they would get.

1084 would be the best in my opinion, but it's getting very hard to find. I like 5160 too. If they want historical accuracy, a straight 10XX series steel is called for. I don't like 1095, as in my opinion it's too brittle for a long blade.

Ron: your anvil is marked in english hundredweight system 0 2 25, which equals 81 pounds when new. It may have lost weight over time. I don't know what you mean when you say there is a "4" stamped on the vise; there is no part of an anvil called a vise. As for value, it depends on where you are, if there have been any repairs to the anvil, and so on. The little ones (under 100 lbs) tend to be worth more to collectors because they are not common. It was made between 1854 and 1930-something. Does the word "England" appear on it anywhere? If so, it's made after the 1870s, I think. I'd have to look it up.
   Alan-L - Wednesday, 05/19/04 16:03:09 EDT

Web site's lookin good jock, its been awhile. I've been doing some sculptural work with copper wire from 18 to 8 gauge and ive met with SOME success fuzing pieces together with mapp gas torches ( one fixed, one in the hand) however it's hard to predict how the copper will behave when it already has been heated for annealing or color purposes and sometimes when it looks ready to puddle up it fizzes and begins to break down in what im guessing is a reaction having to do with oxidization. I would appreciate any helpful advice you could give me on the behavior of copper and the use of different parts of a mapp gas torch flame. Thankyou.
   - Adam smith - Wednesday, 05/19/04 16:11:20 EDT

Babbit Bearing Temperature: Marion, The operating temperature is determined by the load and lubrication. The manufacturer of the fan is the one to ask.

Note that throttling water with a valve does some very strange things. We have spent years building and testing flow meters for the nuclear industry and the biggest bug-a-boo has been decaying flow while testing. Given a water source with stable pressure and a valve that does not creep the flow decays often from the set point to as little as 50% in an hour or so (5 to 2 GPM flow). To accurately test meters we had to use timed flow measurements before and after each test and average the two. Finally we devised a method that used time and mass to measure real flow and compared THAT to the meter.

To reduce the water usage to the minimum a temperature based flow control would be best. The simplest valve would be an automotive thermostat. I would add a high temperature alarm.
   - guru - Wednesday, 05/19/04 16:26:02 EDT

Melting Silver In the small amounts you are talking about a small clay jewlers melting bowl and a MAPP torch will do. Oxy-fuel is better. I melt brass (much higher temperature) in a little propane melting furnace (see FAQs, Gas Forges).

   - guru - Wednesday, 05/19/04 16:34:00 EDT

Melting in a Forge: If the forge you are speaking of is one of the galvanized pan, perforated pipe type then forget it unles you have a very small (000) crucible. These forges are too small to support a deep enough fuel bed for a crucible.
   - guru - Wednesday, 05/19/04 16:39:13 EDT

Humidity: Air on a humid day (regardless of our subjective perception) is LESS dense than on a dry day. (Density = Mass/Volume.) I suspect this reduces the combustion efficiency in a gas forge, since a lesser MASS of O2 is available for combustion since the burner is drawing in a consistent VOLUME of air.
   John Lowther - Wednesday, 05/19/04 17:00:29 EDT

Agree with you about the lower density. I think it's because H20 (with a molecular weight of 18) displaces N2(28) and O2(32). So a cubic foot of humid air weighs less, because more of it's H20, and has less O2, well, because less of it's O2.
   Mike B - Wednesday, 05/19/04 18:04:39 EDT


If you have a reasonably high-temperature torch such as MAPP or oxy/fuel, you simply melt the coins on a charcoal block into which you have scraped a shallow depression. Flux with a bit of borax or boric acid and the molten silver alloy will puddle into a shallow oblate spheroid. From there, it can be forged or rolled into billet or sheet.

A store-bought jeweler's charcoal block is preferrable, but you can make your own by baking a piece of untreated 2x4 in an oven or campfire. First seal it in heavy-duty aluminum foil to exclude oxygen and cook it until no more gas is escaping from the foil. This is a bit lower-tech than using a crucible, but will work for amounts up to about an ounce of silver using a MAPP torch. For larger amounts you'll need an oxy/fuel torch. Personally, I prefer using a crucible for amounts larger than a pea, but then I have dozens of crucibles on hand from my silversmithing days.
   vicopper - Wednesday, 05/19/04 18:54:18 EDT

Not to belabour the point BUT I think your calculation of mole weight is off. Oxegen is not 32. we use o2 as a symbol for gassous oxegen but oxegen has a molecular weight of 15.999 and Hydrogen has a weight of 1.008 So water would seem to actually be of a higher density which makes sense seein as how the oceans are on bottom and the air is above.

Or do you really calculate molar weight using 2 molecules of O and N ? Curious minds wish to know, and since it has been way too many years since any form of chem schooling for this boy........ I can not remember
   Ralph - Wednesday, 05/19/04 19:13:17 EDT

AlanL if they want historical accuracy I'd be looking for shear steel!

I have a few square inches of 1828 steel from a William Foster Anvil I bout for $5 cause 90+ % of the face was missing. One of these days I want to make a couple of 1820-30's knives from it serene in the knowledge that it *is* the "right stuff"---I want to try forgewelding a new face on the anvil too. I talked with Postman and he advised welding the face plate to some WI and then doing a WI-WI weld to the anvil body---now to assemble a crew of necessary craziness to do it!

   Thomas P - Wednesday, 05/19/04 19:41:26 EDT

my $0.02 on the humidity issue:

the issue is partial pressure of oxygen under specific conditions. water vapor, N2, AR, and O2 are the parts in air. increasing or decreasing any of the parts will change the % of each contribution to the whole. the other variable is the atmospheric pressure. O2 @ sea level has a partial pressure of 152mm HG; in denver it is much less. naturally aspirated gas forges run rich in denver compared to death valley (assuming the same forge is used). this is a function of partial pressure. high humidity would be expected to reduce the partial pressure of O2. i dont know if this is significant enough to influence the performance of a gas forge.

since humidity is saturation of gas (air), and water exists as a vapor and not a "true" gas, i would guess that air in a high humidity environment is MORE dense vs a desert situation.....comments welcome
   - rugg - Wednesday, 05/19/04 20:00:37 EDT

Nitrogen and oxygen are both diatomic gasses, meaning they exist as molecules made up of two atoms under normal conditions. So the molecular weights are twice the atomic weights (or 28 and 32, more or less). Unless you're talking about ozone (O3).
   Mike B - Wednesday, 05/19/04 20:02:26 EDT

All I can chip in here, since I never could understand what Pop was talking about when he got into moles and valences and such, is that every automobile racer operates on the belief that on humid days you need to figure that the air is "richer" than on dry days. Same for cold days. Cold air is denser, therefore you get a better burn. Are they right? I have no idea. They also believe that fancy paint jobs make cars go faster, so who can tell? (grin)
   vicopper - Wednesday, 05/19/04 21:29:04 EDT

As Vicopper noted a store bought crucible is the best way to go for the melting of silver or gold. Both can be melted in suprisingly decent sized melts with a cheap store bought propane torch. I used to melt down scrap jewelery to make new. I would melt about an oz. in a clay crucible, using 20 mule team borax for flux. You get a nice button about an inch in diameter, by perhaps 1/4 to 3/8" thick. When cooled a bit, I would place in Sparex(pickle) to remove the firescale and flux. From there I would cold forge out into sheet. For knife spacers, getting a uniform thickness will be tedious. Did you know that the crucible and pickle, as well as sheet silver and gold are available in small to huge lots from Rio Grande jewelors supply. They are on the web.
Good luck
   ptree - Wednesday, 05/19/04 22:09:31 EDT

   - STAN - Thursday, 05/20/04 05:54:37 EDT

Stan, ALL CAPS is considered yelling on the internet. . . please don't yell.

Working Copper: Adam, copper has a very high affinity for oxygen and is difficult to weld with a torch (in my experiance). It is usualy brazed or silver soldered. To weld with a torch you will need to keep the surface covered with a heavy coating of borax flux.

AND although a MAPP/air flame is quite hot it is nothing like an oxy-acetylene flame. There are many jobs where that very concentrated heat is needed.
   - guru - Thursday, 05/20/04 09:25:33 EDT

Humidity and Forges vs. Piston Engines: In the forge the humidity increases the amount of useless mass that must be heated by the fuel and thus reduces efficiency.

In piston engines it is thought that the wet air expands more than dry air and thus the greater power. This is the logic behind the infamous "water injector". However, if it DID work then every truck and automobile on the planet would come with a water injector and water tank. Or at least race cars would. . . I suspect the problem is the same as the forge, the water takes heat to expand and lowers the overall operating temperature and fuel burning efficiency and thus there is no appreciable gain. PLUS you have to haul around all that consumable water. . added weight, lower effeciency.
   - guru - Thursday, 05/20/04 09:33:20 EDT

Computer Crime: I recieved a nifty piece of mail suposedly from Citi Bank. Had their logo and looked very nice except for the pigeon English. It asked for you to go to the link and "update" your account information. The problem IS, I don't have a Citi bank account. The information wanted was:

Account or ATM number
Password or PIN
expiration date
Checking account number
Savings account number
Social Security number
Mother's Maiden name
Date of Birth.

Now. . This bit of SPAM is not your typical SPAM, it is identity theft with the intent to empty your bank accounts and wreck your life. It is also enough information to break into most of your other personal accounts including domain registrations and others.

This is just one of a dozen I recieve every month supposedly from ebay, a credit card company or others. The links always LOOK legitimate but they divert somewhere else.
Beware of SPAM! It is not just harmless junk. The vast majority is some kind of scam. This is why no legitimate business should use bulk email to people they do not know. It puts them in the same camp with the theives.
   - guru - Thursday, 05/20/04 10:12:37 EDT

Chemistry: Although I know most of the elements and their abreviations and a dozen or so chemical formula and reactions (from my misspent youth) I failed to absorb the parts about moles, valences, Agravagios ??? number and such. SO, I know more than most but less than enough to comment on some details.

I DID warn my chemistry teacher about the danger of the book having us grind sulfur with the mortar and pestle one day and then make potassium nitrate in the same (usualy dirty) mortars the next. There was even a fine print warning in the book. But it did not stop the explosion the following day that took out half the windows in the chem lab. Amazingly no one was hurt beyond a few scratches from the flying shards of ceramic. . .
   - guru - Thursday, 05/20/04 10:30:42 EDT

Water injectors:

The actual effect of water injection is to dramatically increase compression ratios in piston engines. Air can be compressed, water cannot. Thus, when using very high-octane fuel (120 or better), water injection gives a sudden boost in power. This application was used on some WWII-era fighter aircraft. Used with ordinary octane range fuels, it causes detonation and can actually bend valve stems and/or break connecting rods, thus the lack of water injection systems for hot-rodders.

Thomas: Right you are, as usual! A recent craze amongst the knifemaking crowd is shear steel salvaged from OLD circular sawmill blades. Apparently it makes a pretty pattern when etched.
   Alan-L - Thursday, 05/20/04 12:47:18 EDT

I was at my first hammer-in this past weekend. It was up in SW Pennsylvania at the PAABA hammer- in. I have never did any smithing.
The whole thing was great!
One of the demonstrators, Fred Crist, demo showed how to forge and form an object out of one piece of stock. When you first looked at the finished product it looked like a few pieces, especially the collar it had. He said that you could use separate pieces and that it would save time.
My question is; are you any less of a blacksmith by using separate pieces of stock instead of forming pieces out one piece? I know it is not always possible to use one piece of stock.
   tom - Thursday, 05/20/04 13:33:53 EDT

Of course not! (well depends)
people who arcweldcoldbenddistresswithballpeenspraypaintflatblack aren't blacksmiths. At CanironIII Bob Patrick made a doorknocker out of nothing but 1/2" square, I think there were 13 seperate peices forgewelded together. As long as you work the black metal hot your a blacksmith, no such thing as a less of a blacksmith! Of course as in any trade/craft there are some who are more competant than others. Welcome to the world of singed hair and burnholes in your clothes!
   JimG - Thursday, 05/20/04 14:01:51 EDT

Whoa, Jim!

I'm going to argue with you about this one:

> spraypaintflatblack

After either wire brushing (at shows) or sand blasting (at home) this is my preferred method of preserving iron.

In one sense, you can call me a traditionalis. It's called wrought iron black for a reason. (grin)
   Paw Paw - Thursday, 05/20/04 14:13:27 EDT

One thing to think about is that smiths in "olden times" used to piece things up a whole lot more since wrought iron forgewelds so nicely.

We have moved away from their methods cause we are forging a different material. If you read in the old books, welding was considered a common joining and shaping technique. I've seen trivits where the ornamentation was forge welded on with a size differential of at least 4.

   Thomas P - Thursday, 05/20/04 14:24:08 EDT

On water injection in WW11 piston engined aircraft. The actual reason for the water/methanol was not to increase the compression ratio, but rather to forstall detonation at extreme boost. The Rolls Royce Merlin, a V-12 of 1650 cubic inches was equiped with a water/methanol injection that would inject for about 5 minutes only, when war emergency power was selected. The methanol was only there as an anti-freeze. When war emergency power was selected, by ramming the throttle thru the wire stop, the supercharger was forced to overboost, and even with the 145 octane av-gas the engine would detonate to pieces with the water to increase the detonation point even higher. The point was to increase the resistance to instanous explosion of the gas air mix to allow a rapid burn. For reference please refer to Bill Gunston's "The developement of the piston aero engine". When higher octane leaded fuels began to dissapear for cars, many aftermarket water vapor injection systems were developed to help with pinging. My dad had one.
   ptree - Thursday, 05/20/04 14:26:00 EDT

Hi Guys I have noticed in the past posts from Aussie Black Smiths and my problem is I wish to try a coal forge which I am about to build but after doing a google search I cannot find a coal supplier in West Australia I know there is a coal mine in collie but where do I buy coal are there any aussie smiths out there that have a supplier locally I was going to try charcoal but thats even muckier to work with and I'm not sure if its hot enough I use my gas forge for smaller items but would like to broaden my skill level. seems silly doesn't it writng to an america blacksmith site to see if I can buy coal just down the road,any help greatly appreciated.
   derek - Thursday, 05/20/04 15:14:24 EDT

Ptree: I sit corrected! Thank you for keeping me from spreading one less half-truth.

That's what I love about this place, there's always someone who really knows the answer to just about anything.
   Alan-L - Thursday, 05/20/04 15:17:32 EDT


I don't know a thing about obraining coal in Oz, but there are a few Aussies who post here and I'm sure they'll hook you up. As for the charcoal, it will get just as hot as coal. Carbon is carbon, pretty much, whatever form it comes in. Charcoal is less dense than coal, so it takes more volume to develop the same heat, but it comes out pretty even by weight.

Charcoal is actually much cleaner than the best coal. No sulphur, no dirt, no "muck", just carbon. It does make a few more sparks,d the ash is very lightweight and prone to blowing around, but it is much cleaner for forge-welding. You need to build a deeper fire than with mineral coal, and avoid really hard air blasts. A blower that supplies a fairly large volume of air at not too high a velocity is best for charcoal.
   vicopper - Thursday, 05/20/04 15:46:56 EDT

I am about to apply ITC-100 to Kaowool for the first time . My question is this : If I have any ITC-100 left over that has been mixed with water can it be saved and reused at a later date ? Or should I try to mix only the ammount I need for the job at hand ?
Thanks ,
   Harley - Thursday, 05/20/04 20:20:48 EDT


It keeps fine if you don't freeze it. I usually mix just about what I need and then dump any leftovers back in the can when I'm done. If I don't have any leftovers, then I put a few drops of watrer on top of the mud in the can jus tto replace what may have evaporated while I had the can open.

When you prepare to coat the Kaowool, be sure to have it thoroughly moistened prior to putting on the ITC-100. If not, it will immediately suck all the water out of the ITC-100 and reduce it's ability to do it's job.
   vicopper - Thursday, 05/20/04 22:20:06 EDT

Parts and Pieces (Iron McNuggets?): Tom, Making complex items from one piece is both good smithing AND a chalange. Weld joints, rivets, collars and even mortise and tennon joints are used in smithing but they are never as strong as solid metal. As noted it used to be more common to forge weld all kinds of lumps together to build a shape when wrought iron was THE material. Modern mild steel is stronger but does not weld quite as well.

Modern manufacturers have also found that complex parts are cheaper in the long run than multiple parts doing the same job. So the old blacksmith that made items from one piece was also one of the first efficiency experts.

However, joinery is as common in blacksmithing as in carpentry. And as the late great Francis Whitaker said, "its either a joint or its NOT". He was commenting on the quality of joint design and construction.

Joinery is used both for practical purposes AND decoration. Truely good artistic blacksmithing uses the joining methods as part of the visual design. Collars are sized and textured for looks as well as strength. Rivets are hidden or acentuated OR made as part of another piece. Mortise joints are made with a swell to look strong AND to BE strong.

If you look at the projects on our iForge page you will see many items made of one piece that you would swear require more.
   - guru - Friday, 05/21/04 01:21:13 EDT

Finally looked up "humidity" in Encyclopedia Britannica. It says that the amount of water vapor a given space can hold depends *only* on the temperature -- the presence or absence of other gasses makes no appreciable difference. It notes that: "[w]hen a given space contains the maximum amount of water vapour, the space is said to be saturated; air containing saturated vapor is also loosely but commonly referred to as saturated." The article also says that the absolute amount of water vapor in the atmosphere never exceeds 3%, so I guess whatever effect humidity has on forges (and engines) probably isn't huge.

Speaking of which, it doesn't seem to make sense to deliberately introduce water *vapor* into an engine -- it expands under the same rules as any other gas. Liquid water, on the other hand expands something like 800 times when it vaporizes. Of course, it absorbs a commensurate amount of heat, which has to come from somewhere -- there's no free lunch. It seems to make sense that water injection could give the same amount of expansion at lower cylinder temperatures, preventing detonation while preserving efficiency.

   Mike B - Friday, 05/21/04 07:31:51 EDT

Thank You Vic.
   Harley - Friday, 05/21/04 08:09:48 EDT

I would like information on the chemical reactions that take place during blacksmithing, such as the borax used during forging, the types of steel, etc. Does anyone know of good books that delve deeply into the science of metallurgy on the molecular level, or have good advice? thanks
   Jorgenson - Friday, 05/21/04 08:18:10 EDT

Thanks guys on your replies. This is a great site.
   tom - Friday, 05/21/04 09:40:50 EDT

Jorgenson, There is an abundance of good technical books on Metallurgy but you don't say what your educational background is so it is diffucult to recommend any particular book. Try going to www.asminternational.org/. They sell a lot of books but most of them are oriented toward graduate metallurgical engineers. CoSira also has an old text on Metals for Craftsmen that is downloadable for free. Perhaps someone could post the URL of the site. If you have other specific questions, email me.
   quenchcrack - Friday, 05/21/04 09:53:50 EDT

Metalurgy and Chemistry: Jorgenson, Besides what quenchcrack (a metalurgist) had to say many of the scientific properties of metals come under physics and engineering. A complete survey of the subject requires study in many fields.

Welding fluxes are chemical solvents. Depending on temperature they react chemicaly to disolve oxides then hold them in solution. Substances like liquid glass and liquid borax are capable of disolving and holding large amounts of oxides. Glass is considered a more universal solvent than water and I suspect borax is close to the same. Common glass can be nearly doubled in density by disolving lead into it and still be transparent.

See our FAQ on Borax
   - guru - Friday, 05/21/04 10:35:40 EDT

Of course when I talk about "olden times" I'm referring to across the WI/MS discontinuity. IIRC in Richardson's "Practical Blacksmithing" they several times do a weld up as "stronger" than the abrubt manipulation of WI---due entirely to the nature of WI.

I get into it fairly frequently with modern armour makers who try telling folks that they way they do things was they way it was done---I point out that armour was made from WI and *doesn't* work the same way and they get mad---if they tried working WI the same way they do mild steel they'd end up madder still!

   Thomas P - Friday, 05/21/04 11:24:26 EDT

One more questin about ITC-100 :Are multiple coatings recomended ? and is fireing to cure a coating recomended between coats ? Also, how many coats are enough ?
Thanks again,
   Harley - Friday, 05/21/04 11:56:21 EDT

4th Century Steel in the news:

   Bruce Blackistone (Atli) - Friday, 05/21/04 16:48:03 EDT

Speaking of ITC100, I'll be ordering some in the next week or two and I notice in the store it says spraying is the best method of application. Would I need some sort of airbrush setup, or would regular spray bottle (like a cleaned windex bottle) work just as well? If I do need an air brush, I'm not too likely to be getting one any time soon, so what would you suggest instead?
   AwP - Friday, 05/21/04 17:13:25 EDT

Guru, I think you meant to refer to Avagadro's Number. A mole is the molecular weight (sum of atomic weights of all elements in a molecule) in grams, pounds, tons, etc. A gram mole is the molecular weight in grams, etc. Avagadro's number is the number of atoms in a gram-mole and the number is 6.023 x 10^23 or 6023 followed by 23 zeros. Don't ask how long it took Avagadro to actually count all these atoms. Rumors say he lost count at about 5.03 x 10^19th and just took a swag at it......grin.
   quenchcrack - Friday, 05/21/04 19:57:37 EDT

Harley and AwP,

Multiple coatings are much better than a single coating, and less prone to cracking. The first coat of ITC-100 should be air-dried and then fired to about 1200ºF to completely cure it. Then apply additional coats. The first cured coat will stop much of the water absorption, so you will not need as much water to moisten it before applying the ITC-100. The second and third coats will patch any shrinkage cracks that occurred in the first coat. I use a hair dryer to dry the ITC-100 between the second and third coats, then let it sit overnight before a final firing to cure the second, third, etc coats. Once I have brought it up to full heat, I start forging.

A spray bottle works great for moistening the Kaowool prior to applying the ITC-100, but I don't think you'll ever be able to get the ITC-100 to spray out of that bottle.

ITC recommends that ITC-100 be applied by spraying, but to do so requires a gravity-fed cup gun designed for high solid content materials. Similar to the sort of spray gun that is used to apply testured ceiling compound, only smaller. For forge building, a brush works just fine. I prefer the natural boar bristle cheapies that are sold as "chip" brushes.

There is a FAQ available on the Store page regarding the application of ITC products, I believe.

   vicopper - Friday, 05/21/04 21:15:13 EDT

Spraying high solid content, small particulate suspention:
The sprayers for cooking oil work pretty well for this in my exp. They have fairly large nozzles. They have pump to compress air into them.
   Shack - Friday, 05/21/04 22:24:46 EDT

I don't see a FAQ, I see a MSDS, a problem solving and application guide which isn't what I need. I see the directions for application, which is where I saw the spraying reccomendation. I don't have access to a cooking oil sprayer or an air compressor. I'll test both a brush and a bottle when I get it and see what works better. Thanks.
   AwP - Friday, 05/21/04 22:30:29 EDT

Once again, Thank You Vic.
   Harley - Saturday, 05/22/04 06:44:10 EDT

ITC-100 Application: Spraying is recommended by ITC for large areas like walk in kilns and industrial furnaces. Smaller kilns are often sprayed when the equipment is available or multiple kilns are being relined. It is sprayed with a heavy solids gun like used to apply glazes by potters. The better of these have a carbide or saphire nozzle to reduce wear. Plastic spray bottles will clog instantly and it would wreck an air brush. We send application instructions including brushing instructions with the product. More details follow. Much of this is in our forge rebuilding iForge demo (#148) .

There are two brushing methods. For very small areas, touching up chips coating small crucibles or crucible blocks I use a stiff artist's paint brush and make a slurry of ITC in the jar. This requires patience and continous working of the surface with a wet brush like using dry water colors. Although suggested for small areas I coated the insides of a small freon can melter using this method. Note that I have been applying artists's paints like this for 45 years. . .

The second method is to thin as instructed and apply with a suitable brush. I use a ragged old 1" (24mm) fibre brush for new forges plus a 3/8" (10mm) artist's brush in tight places or where I need control. There were places in the Whisper Baby that had to be reached with a long narrow brush through the back port.

The ITC products are all shipped as a heavy paste (about like medium hard ice cream). In fact an ice cream scoop is a very good tool for scooping it out of the jar. When ITC-100 is thined it is a thick slurry like plaster or clay slip. It contains a lot of heavy fine sand like solids that must be kept in solution. I find when mixing that it is best to let set over night and then mix again. This gives the lumps time to break up and the fine solids to become suspended in the mix. If the diluted mix sets for any time it will settle and must be stirred again. When spraying the can must be agitated constantly to keep the solids floating (like using metalic paint).

   - guru - Saturday, 05/22/04 11:21:50 EDT

Thank you for the instructions for aplying ITC-100. I haden't seen the instructions that came with it as I haven't opened the carton yet. I will get to it as soon as I finish up three projects that are being worked on for customers.
   Harley - Saturday, 05/22/04 12:46:22 EDT

I concur with Harley, I haven't seen the written instructins yet (because I haven't ordered it yet), but thanks for the directions, now I won't need to worry about not having a special spray setup.
   AwP - Saturday, 05/22/04 15:48:46 EDT

Detail instruction page has being added to the ITC-100 sales page.
   - guru - Saturday, 05/22/04 16:30:01 EDT

anyone know where I can get "reasonably" priced insurance to do demos in public(ie.,fairs, flea markets, local organizations & clubs) in this day and age of our litigous
society, "don't touch, you will get burned" doesn't seem to work. thanks folks!
   Don Kieffer - Sunday, 05/23/04 11:17:20 EDT

Insurance: Don, this is an often asked question and there is no good answer. In the past there was a company that advertised through ABANA's Anvil's Ring but they no longer service the industry in many parts of the company (they dropped policys regionaly).

The best thing to do is call any insurance company other than the one you have your homeowner's with. If you have homeowners, asking them about your extracuricular activities will stir up all kinds of questions and you may lose your insurance simply because you asked. Yes, it is cruel and unreasonable but we are talking about insurance companies.

Before asking about insurance be ready to answer some tough questions. Do you put up a fence? How far from the anvil and forge is it? In the vast majority of cases *I* would refuse to sell insurance for demos the way the majority are setup.

I prefer the fence to be 6 to 8 feet (10 preferred) from the anvil in all directions. YES, this is a BIG circle and many shows will not give you that much space. In that case, tough, don't do the show.

Your other option is that if you are ASKED to demonstrate that you insist that you come under the site or sponsoring group's policy and that they will cover your legal costs. Have a statement of that fact in hand before the demo. This will not keep you from being sued if someone is injured (nothing will except gobs of cash) but it WILL point to deeper pockets. Always note the amount of space needed for a safe demo.

   - guru - Sunday, 05/23/04 15:33:07 EDT

thanks for the quick response. it sure is scary out there.
I hate hiding in a cave, but it looks like if they won't pay, I won't play.Living the New York State(land of lawyers and taxes) doesn't help much either. Don K., FA/WA Ironwerks
   Don Kieffer - Sunday, 05/23/04 16:45:23 EDT

I was hoping that somebody on this forum happened to know what the name of the vice in the Wyllys and Ramsby image on anvilfires home page?
Thank you.
   Kevin Brown - Sunday, 05/23/04 19:46:31 EDT

Don, you can check out this place. http://www.renfaire.org/index.html It's the Ye Olde World Living History Foundation. They also have the Old West Living History Foundation. Their whole thing is providing insurance coverage for re-enactors. It's pretty resonably priced, and you get a million dollar liability policy. It is a requirement in our group to carry this insurance. There is also an accident policy that covers about $1500 of emergency room costs. Be sure to call & talk to Dusty to explain what you do an make sure it will be covered.
   FredlyFX - Sunday, 05/23/04 19:57:47 EDT


If you mean the vise in the picture of Caleb's grandfather, it is a caulking and heading vise.
   vicopper - Sunday, 05/23/04 23:06:52 EDT

dear guru, i am a real fan of blacksmithing, from brasil.
on the 28th i will be going to denver co, and after that i'm planing a honeymoon with my wife and will have a chance to visit some places in the us. does anybody wants a visit from a brasilian blacksmith?
   rodrigo - Sunday, 05/23/04 23:22:25 EDT

Thanks vicopper, that's the one ^_^
   Kevin Brown - Sunday, 05/23/04 23:43:49 EDT

Rodrigo, I'm sure a few folks wouldn't mind a visitor. Most blacksmiths in the US welcome guests.

Post your message on our Hammer-In page. It is archived monthly rater than weekly as this page is.

Let folks know where you are planning to travel. The US is a big country (like Brazil) and we have a road system that rivals your rivers for complexity. The 28th (of this month?) is next Friday. Not much time to plan!

   - guru - Monday, 05/24/04 00:58:58 EDT

We use printed circuit board controllers for welding arc dynamics control, in our welding power sources.we need some help in improving the reliability of the circuit- currently, we have failures in some components.
If this is of interest to you, can we post aour specific queries?- regards, Raman Kumar
   RAMAN KUMAR - Monday, 05/24/04 04:13:17 EDT

Guru,I live in Australia and have been making/finishing axes for the past ten years. I now have my own brand of axes made which are used in lumberjack sports. The steel is a water quench (W2) and I have had some problems with good size pieces falling out of the face, with no apparent flaws. Do you think it would be more related to carbon content than anything else? We try to get them treated to between 56 and 59 Rockwell c.

Yours in blacksmithing, Ian S.
   Ian Stewart - Monday, 05/24/04 06:57:46 EDT

FredlyFX, thanks for the information as I do F&I and Rev. War re-enacting also. It's amazing, I got a much better response at anvilfire than at Abana's web site. not one smith responded to my questions there. Don K.
   Don Kieffer - Monday, 05/24/04 09:48:02 EDT

Cracked Steel: Ian, the water quench steels are more likely to do this than others I believe. Often it is from overheating the steel while forging OR working too cold. Heating rates can also be a problem. Tool steels need to be slowly warmed until they are too hot to comfortably hold before being put into the direct heat of the forge. This also applies to heat treating depending on the type of furnace and the temperature. A post forging normalizing may be needed to reduce stresses.

IF the pieces look like a layer then it is probably from a shear tear. These often occur when working steel that is not uniformly heated all the way through.

On these issues our friend Frank Turley says, "Tool steels laugh at you." There is a lot that can go wrong.

Perhaps one of our metalurgists will chime in on this one.
   - guru - Monday, 05/24/04 10:06:11 EDT

Lest anyone be wondering about Brazilian smiths, go to CKDforums.com and look under the Brazilian Bladesmith Association to see what these guys are up to. It helps if you can read Portugese, but the pictures are universal!
   Alan-L - Monday, 05/24/04 11:44:14 EDT

Hi There Paw Paw,

my grand dad use to be a black smith and can recall him using white wash when he heat treated something and he did not want any scale on there was it something in the paint ore was it mere the fact thet the paint kept out the O2 and could whith stand the heat, i have never realy experimented but would like to do so some day what did the old whitewash paint consist off is there anybody that would have an idea maybe i can make it myself and then try it.

cheers to all and thanks for every bit of info you chaps give so freely.

   "VAN" van der Merwe - Monday, 05/24/04 12:14:28 EDT

Re Tool Steels: There is a very good book in print titled "Tool Steels". Can't recall who the author was but it was published some years ago and it is worth finding and reading. Some of the causes of cracking are sharp corners that create notch risers, improper forging, etc. If I were forging axes to sell as competition tools, I would make sure the pieces were completely annealed after forging to release those stresses. After the initial quench I would immediately perform a subzero quench in acetone and dry ice to convert more of the retained austenite to martensite and then promptly temper. As stated above, both quench and temper heats should be soaking so the core of the tool is reached.
   - HWooldridge - Monday, 05/24/04 12:26:13 EDT

Hello, My son is doing a school project on John Deere. He is going to dress up as a blacksmith and I was wondering if you could give us any ideas as to what he should wear?? Thank you!!
   Kerry - Monday, 05/24/04 13:05:08 EDT

maybe I'm missunderstanding you, HWooldridge, but putting hot metal in acetone should make a big boom, and spread little bits of you all over the place, wouldn't it?
   HavokTD - Monday, 05/24/04 13:35:08 EDT

Kerry - what to wear
Go to http://pawpawsforge.com/ and look at what Paw Paw wears. Short sleeved cotton shirt, long cotton jeans, and a leather apron - all for the safety of the smith.

The photos in the upper left of Anvilfire and the Guru's pages show photos of smiths.
   - Conner - Monday, 05/24/04 13:50:35 EDT


I think the Whitewash was simply to seal the surface to prevent scaling. After the piece was quenced, it could be washed off with water. I'm not 100% certain of that, but it seems logical.
   Paw Paw - Monday, 05/24/04 14:41:02 EDT

Steve Parker,

Contact me e-mail, please.
   Paw Paw - Monday, 05/24/04 14:55:25 EDT

Blacksmiths Dress: Kerry, Normally it was whatever was normal working man's clothing plus possibly an apron. Smiths wear regular leather or cotton aprons, farriers (horse shoers) wear a half apron that is split in the middle like chaps.

The clothing of the times has varied greatly. In the early 1900's vests and bow ties were universal wear even for smiths and farriers. If the corner blacksmith shop had held on through the 50 and 60's it would have been a white shirt and tie. DON'T LAUGH! I had a service station in the 1970's and wore a white shirt with red pin stripes and a tie while doing lube jobs, tire changes. . . There is an ART to working and staying clean. This was also the common dress for machinists, engineers and draftsmen as well as office workers. "Blue collar" is a distinction that came about with factory workers and rental uniforms that was not as universal as the common use makes it sound.

So other than carrying a big hammer there was never really a typical blacksmiths dress or uniform.
   - guru - Monday, 05/24/04 16:39:11 EDT

HavokTD, That subzero quench is from room temperature to VERY cold, not from a heated condition.

Most subzero quenches require liquid nitrogen to get cold enough to do any good and it only applies to specific alloys. Quite a few folks brag about using a cryognic quench when it is not cold enough and not on the proper steel to make a difference. . more hype.
   - guru - Monday, 05/24/04 16:48:49 EDT

Van, I do not know how well the white wash would have held up. High refractory clay washes are used to prevent oxidation and so is ITC-213. Today it is common practice to seal parts in stainless steel foil to prevent oxidation during heat treating.
   - guru - Monday, 05/24/04 16:51:31 EDT

ITC-100; i tried to use a "spray bottle", did not work. mixing it into a fairly loose slurry and applying it with a brush worked fine.

tried my hand @ forge welding, again. scarfs looked fine. heat was "sticky", hit gently. failed. the blow, although "easy", still displaced the pieces. tried several times, will try again. any advise on preventing the pieces from separating??...appreciated
   - rugg - Monday, 05/24/04 17:50:14 EDT

Acetone - Not a hot quench...the normal quench is performed in oil or water and when at room temperature, is placed in the acetone/dry ice mixture.
   - HWooldridge - Monday, 05/24/04 18:23:40 EDT

Last few times at the forge, I've been trying to make myself a set of tongs. I've made two sets, and on both sets I had the same problem happen, the rivet shears off. I was using mild steel. I've read multiple descriptions about making rivets and none of them mention this problem, like it's not something that ever happens.
Should I be using higher carbon steel? It seems to me that higher carbon would be even more likely to break then mild steel. Am I just an idiot for not being able to do something that everyone else can do with ease?
Before trying these my only hands on experience was with copper rivets with a washer for use on leather. I didn't think I needed a washer on steel rivets, am I mistaken on that? It's very frustrating, after all day working on it I ended up throwing the tongs across the yard :(
   AwP - Monday, 05/24/04 19:23:22 EDT

AWP: what size were the rivets? 3/8" is a good size for many tongs. I never use a washer, but you do want to "adjust" the tongs while at a goodly heat so the rivet doesn't bind.
   Ellen - Monday, 05/24/04 20:26:30 EDT

I want to give my helper a list of answers to the frequently asked questions by visitors to my blacksmith shop. I recall seeing an article and hand out of frequently asked questions and good answers. I want to give this to my helper rather than try to recreate it from memory. I think it was in the Anvils Ring and can't find my index. Anybody remember. Thanks

   Steven Bronstein - Monday, 05/24/04 20:34:19 EDT

Rugg, If both pieces are indeed "sticky" they should stick together as soon as they make contact. Our warnings about not striking too hard are often taken too far and not enough blow used. A good solid blow is used, just not a heavy forging blow.

If you are trying to weld in the Whisper Baby you may need a flux like Anti-Borax or Easy-weld. Both contain iron powder which melt into the flux coating and make a stickier surface at lower temperatures.
   - guru - Monday, 05/24/04 20:34:25 EDT

Rivets: IF you heat the entire rivet, set and let cool it will be too tight to turn. When heated in the forge as soon as the head is set and still hot the tongs need to be worked to assure the joint is free. IF it locks up, stop, quench the tongs, reheat so the joint is hot and the rivet cooler, and work again. IF you are shearing the rivet then you are forcing them.

Also note that it is common to punch rivet holes in tongs making a loose hole. IF you drill the hole then be sure to use an oversize drill (at least 1/64" or.4mm). Also chamfer the edges of the drilled hole before riveting.
   - guru - Monday, 05/24/04 20:42:02 EDT

AWP: 3/8" X 1 1/4 rivets are $5.15/ # at Centaur Forge, accessible from the pull down menu top right under advertisers. I used their rivets many times, never had a problem In fact I just ordered 5# since I am low and have several tongs to make.

Rugg: I like E-Z weld in my two burner propane forge, if using clean coke or coal in my solid fuel forge I like borax, 20 Mule Team just fine. Both work great. I find when I hit my forge weld it "squirts" molten flux from the weld area, that helps me to know I am at the right temperature. In my propane forge a "slippery orange" color is good with EZ weld. The solid fuel forge gets the metal a little hotter, sort of an orangish white. It does take a decent hit with your hammer, as Guru said above.
   Ellen - Monday, 05/24/04 20:45:52 EDT

Q&A Steven, I have seen the list on T-shirts. We have two lists of rules on our story page that may apply. I think Paw-Paw's rules might get you started.
   - guru - Monday, 05/24/04 20:49:00 EDT

Guru: I did heat the entire rivet, so that might have been the problem. I didn't let it cool though, I tried to work it back and forth while still hot and it broke almost instantly. It was drilled (1/4"), I didn't chamfer all the edges, just the ones that seemed rough to me (the exit side of each), maybe that was also part of the problem.

Ellen: The rivets were about 1/4"-1/8", I tapered a bar until it fit through the hole, so an exact size is hard to give since it was a cone. I figured the bigger end would stick and the smaller end would be free to move. Maybe I will just buy some instead of tapering rods to fit, it sounds alot easier.

Thanks for the advice both of you, next time I fire up the forge I'll try again.
   AwP - Monday, 05/24/04 21:17:12 EDT

I wanted to know if you have ever heard of a condition that occurs when you turn hot steel. By turning I mean like a horizontal knurl. I am turning a 4" bar of steel in a 9" bar with balls on the end. What happens is it's moving the material toward the end so fast that it sometimes has hollow ends on one end or the other. I hope I explained it well enough. Thank you!
   Gary - Monday, 05/24/04 21:36:53 EDT

AwP, try using 1/4" rod for your rivet stock. Form a head on it, cut it off to length, put it through the holes, and head the other end. Heat the whole joint before working it. Some folks like to put a scrap of brown paper bag between the tong halves before riveting to ensure enough clearance to work.
   Alan-L - Monday, 05/24/04 21:47:59 EDT

Gary, you are moving the 'outside' of the metal. Pehaps due to not a thru and thru heating perhaps due to working just the surface of the metal. ( this last is hard to describe) but it seems to me that what happens is you are only moving the 'skin' of the metal. I suppose it is likely just due to not having the heat in the core of the stock.
   Ralph - Monday, 05/24/04 22:15:26 EDT

More ITC questions:

Would ITC-100 stick to bare metal, or do you need a layer of wool under it?
How much of a difference in efficency would a straight ITC 100 or equivelant coating make to something like a big oven that runs around 500 degrees?
   HavokTD - Monday, 05/24/04 22:29:30 EDT


Whitewash, the kind my Pop used on fences and barns eighty years ago, was just slaked white lime in water. Sometimes they added some milk to make it a bit more durable, I'm told. The lime would act as a fire-resistant coating to resist oxidation, I suppose.
   vicopper - Monday, 05/24/04 23:15:46 EDT

AWP: I think you will be happier with 3/8" rivets, Alan mentioned a trick I forgot to mention with the brown paper from a grocery sack, it does give a bit more clearance, slightly oversize hole, chamfered on all entrances and exits as guru said will also help the longevity of your rivet. No way an 1/8- 1/4" rivet is going to hold a pair of tongs unless they are ***real**** small tongs. Let us know how it works for you.
   Ellen - Tuesday, 05/25/04 00:58:13 EDT

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