Aubrey Posted February 17, 2019 Share Posted February 17, 2019 Hello all, I have been looking for some inexpensive methods to make some tools and I ran across this video on the youtube: It seems feasible by what this guy does that this could work, but there are a lot of variables I'm sure he did not put in there. So I have a few questions I'm sure you all can answer... 1. He says in the video that wrapping the thing in clay is not necessary, but what kind of clay should be used? ---What exactly IS "fireclay" and where does a guy find it? 2. Should the clay be allowed to dry before firing? 3. Is case hardening really a viable option? I'll warn you in advance: a lot of your answers will likely breed more questions from me. Quote Link to comment Share on other sites More sharing options...
HojPoj Posted February 17, 2019 Share Posted February 17, 2019 1) any clay that can stand the heat. Fire clay can be gotten at pottery supply places. 2) yes, usually in a slow, controlled manner to avoid cracks as it shrinks. 3) Depends on the application. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 17, 2019 Share Posted February 17, 2019 They did not cover that bloomery material can be anything from extremely low carbon metal to cast iron? (The Japanese swordsmiths spend a lot of time and effort lowering the carbon content in material produced by a bloomery.) So an ancient method even more ancient that they one they used. (Which looks to be based on the one Theophilus described in "Divers Arts" in 1120 AD.) Yes you can make case hardened steel or even blister steel. It will of course be a lot more expensive in time and fuel than just getting free higher carbon steel that abounds everywhere---automotive coil and leaf springs for example. I pay 20 US cents a pound for that at the scrap yard as everytime I visit my mechanic he wants to give me way more than I need or have room to store. Fleamarkets tend to have HC punches, chisels and files that can be reworked faster and cheaper. I've done it several ways trying to replicate earlier methods of work; NOT trying to save money as it's more expensive!----Look Look I've saved a dollar by just spending 4 hours of time and several dollars of fuel! Quote Link to comment Share on other sites More sharing options...
Aubrey Posted February 18, 2019 Author Share Posted February 18, 2019 Okay thanks for the info! What exactly is blister steel? So what exactly would be an applicable application for case hardening? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 18, 2019 Share Posted February 18, 2019 Blister steel was steel made from wrought iron using a case hardening process. Common in the 18th and early 19th century. It could be processes into shear steel; or after Huntsman into crucible/cast steel for a better but more expensive steel. "Steelmaking Before Bessemer, Vol 1 Blister Steel " Kenneth Charles Barraclough goes into it in depth. Use for case hardening is where you want a very hard face for wear resistance but a very tough matrix to avoid breaking. Still used that way today----large bearings often have a case hardened outer race; often AISI 8620 that is only 20 points C and so qualifies as a mild steel. Note that even as late as the American Civil War; Steel could cost 6 times the price of wrought iron and so methods of minimizing the use of steel compared to WI were in use. Quote Link to comment Share on other sites More sharing options...
Aubrey Posted February 18, 2019 Author Share Posted February 18, 2019 Thanks a million! Now that's good stuff! I don't know if ya'll watched, but the guy made some chisels he then used to cut teeth into some hand files -- also case hardened. It was a really interesting video. Thomas, you mentioned about a hard surface but supreme toughness. So the release mechanism for a crossbow trigger would qualify, right? I only ask because I wanted to build a crossbow a few years ago... Now, on fireclay: can you tell, at least to a point, what type of clay it is by the color? In past searches for the stuff I saw red, and white, as well as the dark grey graphite clay that costs an arm and leg. And can all fireclays be used to form temper lines on knives? Quote Link to comment Share on other sites More sharing options...
Thad Posted February 18, 2019 Share Posted February 18, 2019 Great Video!! Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 18, 2019 Share Posted February 18, 2019 Crossbows: Traditionally the nut was a lighter material to make if "faster" and there was an inlet piece of harder material for the tiller to wear against. So: Titanium nut with steel wear plate? (Ivory with a steel inset was used a lot way back when...) Using steel you could case harden the nut as well as the race it spins in. (Everybody knows that the nut does not spin on an axle but rather it's supported by the race---much stronger given some of the humongous forces involved---the MET in NYC had a siege crossbow that was a 1100 pound pull bow, 15 pounds force was needed on the cranniquen; but a LOT of turns!) On the videos; I was a bit perplexed with why he didn't make the types of files that were used back then. Using a modern propane forge, modern mild steel to make modern file shapes----why bother with the case hardening in a traditional manner in the first place? What do you gain---besides making people think things were done that way back then... Quote Link to comment Share on other sites More sharing options...
Frosty Posted February 18, 2019 Share Posted February 18, 2019 Nice theatrical production values, better than the accuracy. Think of it like a program on t he history channel, lots of dramatic stuff and close for accuracy. Buy fire clay at a local sand and gravel or concrete supply. A masonry supply will carry it too but around here anyway they get it from the concrete, aggregate supply. You know, the one with concrete trucks coming and going all day. Yes? Frosty The Lucky. they Quote Link to comment Share on other sites More sharing options...
Aubrey Posted February 20, 2019 Author Share Posted February 20, 2019 All this is fascinating stuff. I have asked around here for it and nobody seems to know what I'm talking about. And since I've never really bought it or used it I don't know what I'm really asking for other than fire clay...Catch 22? Quote Link to comment Share on other sites More sharing options...
HojPoj Posted February 20, 2019 Share Posted February 20, 2019 If you're at a pottery supply place you could just ask for a high-fire clay. Whatever's cheapest will do the job. If there isn't one near you, the only other places I'd check would be a brick yard. Unfortunately fireclay doesn't have the ubiquity of bentonite, so the sources are more limited. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted February 20, 2019 Share Posted February 20, 2019 OTOH the clay is not important. I've case hardened using thin walled steel pipe filled with powdered carbon donors with wrought iron buried into it, One end was sealed and the other folded over a couple times---semi loosely so it wasn't subject to popping---tossed it in the forge and kept count of the hours at heat. Quote Link to comment Share on other sites More sharing options...
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