MattBower

The floor of my vertical welding forge is mostly vermiculite, with enough kaolin to bind it together and keep it from blowing away. The mixture is very cheap, and is intended to be disposable.

Good luck. I'd say that putting the vacuum caster to work on this project would probably be a good idea. The pros say that they use acrylic resin: Wood Stabilizing Specialists, Int'l., LLC | Info, Hints, & Tips! I'm sure it'll need to be thinned.

I'm with Rich. Proper stabilizing doesn't involve just dipping. It involves dipping, then pulling a vacuum and soaking in order to get the stabilizer to penetrate deep into the substrate. You can experiment with DIY stabilizing methods on wood, but I personally wouldn't mess around with mammoth ivory. I'd let someone with experience and the right equipment do a first-class job.

If you look closely, it does look like they forge welded a pattern welded blade to a monosteel handle. I couldn't say exactly when in the forging process that happened, but it certainly wasn't the last thing. Given that it's now one solid piece of steel from end to end, I don't think it's inappropriate to call it an integral. There are some interesting little patterns at the bases of those blades. I wish I could see them more closely. It makes me wonder if they started with a monosteel core, stacked up the billet layers on one end (leaving the other one alone), then started welding and folding. Monosteel end becomes handle, billet end becomes blade?

Frosty, that's true. But steam has to be at about 65 psi to reach 300 degrees F. I don't think there's much superheating going on in wet forging. The moment the pressure rises enough to push the work up off the anvil, the pressure dissipates and the steam drops to 212 F.

I agree with evfreek: there really is no good substitute for fiber blanket in a gas forge. The various homemade recipes are just fine in solid fuel forges. Solid fuel forges really don't need to be insulated, because they're largely self-insulating (charcoal and coke insulate reasonably well) and the work is placed in the heart of the fire. In a gasser you really do want good insulation, unless you want to waste a lot of money on propane and spend a long time getting the forge up to heat. For this purpose, fiber blanket with a hard face of castable refractory or mortar really can't be beat for effectiveness and ease of installation. I say this as someone whose first gasser was lined with a fireclay/sand/styrofoam bead mix. The results were very mediocre. blafen's disposable floor idea is a good one. My current welding forge has a loose mix of kaolin and vermiculite as the floor. It's mean to be scooped out and replaced when it gets nasty. Those ferrules are some kind of ceramic, probably something with a high alumina content. If you had a ball mill, you could probably mill them down to a good grog for high temp ceramics. Or you could do it the hard way, with a hammer. :)

Not to get too far afield from the question, here, but while I know that the soft back/hard edge (however one achieves it) is all the rage, I'm not so convinced that it's useful on a typical knife blade made of suitable, good quality modern steel. Just something else to consider.

There are a lot of things to be said against junkyard steel but, yes, it's certainly possible to make knives from recycled steel. Old files and automotive springs (leaf or coil) typically will make satisfactory blades. So will plow discs, sawmill blades, some smaller circular saw blades, some industrial bandsaw blades, old hand saws and bed frames. But with junkyard steel there are no hard and fast rules except that you won't know for sure if it's usable until you've done a little testing.

I'm not sure I've seen the things you're talking about, Brad, but the nozzles for TIG welders are commonly made of alumina (aluminum oxide), which is probably the single most common refractory going. Good to over 3000 degrees if it's pure. I don't think the nozzles are super-pure, but they're still very heat resistant. Alumina isn't much of an insulator, though, so it's not really a replacement for high temp blankets.

Look, lad, dig a bunch of clay from the back yard or local creek, screen/pick out all the pebbles, mix it with enough water to make stiff mud pies, and line your forge with that. It is FREE and it won't blow up in your face. Even if it doesn't contain clay, the worst that'll happen is that it'll get dry and dusty. That's a lot better than blinding you. I'm not sure why you insist on paying for concrete that WILL NOT work (it will crumble when it gets hot, even if it somehow doesn't spall) and WILL be dangerous.

I think I paid $12.50 for a 50 pound bag of kaolin at the ceramic store, last time I bought some. Kaolin will tolerate in excess of 3000 degrees F. But most of a solid fuel forge lining will never get hot enough to truly vitrify, let alone melt, so the type of clay isn't all that critical. Bentonite is actually pretty low-firing as clays go, but it's fine for this. In fact it's a good choice because it has excellent green (unfired) strength. (The green strength is why it's used as a binder in sand casting.)

Skip the concrete. Use clay. A wheelbarrow will make an awfully large, heavy forge. Portable, yes, but unnecessarily bulky. Just a thought.

A while back I bought a 25' roll of 8 pound, 2' wide fiber blanket from an eBay store and parceled most of it out via flat-rate Express Mail to guys on one of my regular forums at a small markup. My profit covered the cost of the relatively small amount I kept for myself, and it was still a better deal for the other guys (for a small quantity of wool) than they would've gotten anywhere else I've seen. Of course it wasn't as simple as just buying a few feet would've been, but I certainly considered it a win-win. Just a thought.

Lots of chromium, plus sizable amounts of molybdenum and vanadium. It has a lot of silicon, too; I'm not sure how much that contributes as far as air-hardening goes.

Whatever you think of borax, it sure as shootin' ain't as bad as Col. Hrisoulas's "Steel Glue," which contains fluorite (calcium fluoride). I kinda like the smell, though I do my best not to smell it. :)

By the way, I don't know why IFI isn't registering my posts, but that wasn't my first. :)

Your "carbide" bits are very likely a metal matrix composite of tungsten carbide aggregate in a cobalt "cement." I very much doubt that you'll be able to forge them, but if they're free there's no harm in experimenting, is there? I can't guarantee that it's safe, though. You might want to look into that. (Cobalt fumes?)