Mike BR

Copper would probably be safe enough if you silver soldered it, but I still don't see any real advantage. Last forge I made, I mitered and TIG welded black pipe to save money on fittings. Of course, my TIG welding's kind of slow, so I probably blew all my savings (and then some) on argon. But I guess that just shows I needed the practice . . . .

Many propane fittings have pipe threads, so you kind of start out with that standard. Also, some forge designs are based on iron pipe (for example, a piece of 1/8" schedule 80threaded inside to 1/4-28 to accept a MIG nozzle). Many forges have very few fittings between a propane hose and the tube that holds the orifice, so it wouldn't really be worth the trouble switch from threaded to sweated and back. And have you seen the price of copper lately? :)

I've considered naming my forge after the nearest body of water. The only problem is that would make it the Sewerside Forge (grin).

Seeing a supercharger in iron-in-the-hat once made me think of belting it to a washing machine motor, putting a carburetor on top, and ducting it into a forge. Or using the fuel system from an injected vehicle with a regular blower, if I could work out the controls. Of course, gas was under $1.50/gallon then. . .

A few years ago at the Smithsonian Folklife Festival, there was a craftsman (a locksmith from Oman, IIRC) with a charcoal forge in what looked to me like a 7.62 ammo can. It was mostly clayed up, with a small firepot left at the top, and a tuyere of sorts formed in the clay. You wouldn't make many hammer heads in a forge like that, but I thought was kind of neat.

Some folks I know buy charcoal at roofing supply places. Might be worth checking if any near you stock the stuff.

The best idea I've seen for general use is a clamp-type rubber coupler (Fernco, for example) on the PVC with a wooden plug clamped in the open end of the coupler. Still not sure I'd trust it mounted on the roof of a vehicle.

One danger I've been warned about is that the diaphragm in a regulator can tear, resulting in high-pressure propane escaping from the vent hole. One reason to have the regulator outside the shop.

Hand-held power tools generally have universal (brush-type) motors. The speed of these motors is determined by the voltage, and they can be controlled with a dimmer switch. Stationary tools usually have induction motors. The speed of these is determined by the frequency of the AC supply (60 Hz in the U.S. and 50 most other places). The motors slip slightly from their theoretical speed, but get very inefficient if they're overloaded to the point they slow significantly. Running one on reduced voltage from a dimmer switch would in effect overload it from the time you turned it on. It would probably quickly overheat, stall, or both. The speed of an induction motor can be controlled with a variable frequency drive (VFD). This rectifies the AC power to DC, and then "chops" or "inverts" it back to AC at the frequency you choose. You should be able to plug a grinder with a standard induction motor into a VFD and control the speed. But a VFD costs a lot more than a dimmer switch.

I had the same problem with the wing nut (actually a nylon screw) on my 110V Lincoln self tightening. I couldn't figure out what that the actual problem was, so I clamped a small pair of vise grips on the wing-nut-like screw head to stop it from turning. This works well enough that I haven't bothered investigating the underlying problem further.