This is a mini forge that I made out of six firebricks. It is usable to me for the little things that I am trying to do. The nice thing about it is that it is portable and inexpensive and allows me to work cleanly. It was also easy and inexpensive to make and the bricks can be reused. I used Oxy/Acetylene to heat it.
The first test of this forge was restoring a rounded off hexagonal lathe chuck wrench. It was almost fully round instead of hexagonal. To fix it, I heated it up, upset the hex part slightly (made it thicker), and then forged the hex shape again. To make sure that it is the right size (1/2" hex), I inserted it into a 1/2" socket, where it was found to fit snugly after a couple of adjustments.
Iggy I am sure you know that the propane forges are a source of CO2. If you are operating this in your attached garage be mindful of this and use good ventilation and a CO2 detector in the house. Steve
Steve, this is an acetylene forge, which is also no doubt a source of CO2 as well. I believe that people, by nature, are good CO2 detectors and I would feel some extreme discomfort and distress way before CO2 concentration becomes lethal. If you meant CO, I hope that a slightly oxidizing flame should take care of it. In any case, I will try to find that CO detector I had laying around.
As a second thought, I am not sure if I should quench it. This is a lathe chuck wrench. If I make it soft, then in case of overtorquing it, the wrench will be ruined (some $20 loss). If I make it hard, then in case of overtorquing the chuck will be ruined (some $400 loss or whatever it is the chuck costs).
Well, thanks. I am not even sure if I need to proceed with making a propane forge. I do not plan on extensive blacksmithing -- at least yet -- just on using it when appropriate. For example I made a holder to hang a welding torch, from a steel bar, properly twisted and bent to the shape I want. That's useful. The O/A forge is good for this purpose.
Making steel flowers and scarecrows, not my cup of tea. We'll see. I will now go back to my lathe.
You need to CNC your plasma cutter for those. There is a fairly good market for that type of metal art crap, particularly customized with house numbers, names, etc. The good this is you also don't need a big CNC plasma cutter either, a 24" square work area is plenty.
I would quench and then draw it blue or purple, so the square won't round off or twist and jam in the chuck socket. You shouldn't be able to overtorque it with hand pressure on a standard-sized tee handle.
That last part is the tough bit. I've got the plasma cutter and could CNC it in short order, but since I couldn't sell crack in a crack house, I don't bother trying.
I'd imagine an artsy or university town with a crafts fair/Saturday market kind of deal would be a good place to start with items like that. Probably pull in some bucks doing custom ones for the more well-heeled artsy-fartsy types.
I had access to a PlasmaCAM (Fairly inexpensive PC-driven table arrangement) with my 1/4" plasma cutter. The thicker the metal, the more heat-effects bugger the work. There are ways to deal with that, but add to setup and constraints in the image. My buddy was always after "thicker, faster", and got a big plasma cutter, then found he couldn't get as fine a detail, and had repeatability issues with thin stuff for switchplates, etc. And with his 1" cutter, he still decided that the heaviest he ever intends to cut is 1/2 inch plate. Thicker than that, he runs into the stuff I hit at 1/8" - you lose live on the cutter tips, slag and blow-back from intersecting lines and pointy features can plug the tip, and just generally foul the thing before finishing cutting out the current setup or piece.
Sometimes the money isn't worth the wear, tear, and effort. Especially if you try something and find it isn't fun at all.
I figured at one point that it made sense to charge by the drawing. About 5 cents per inch of cut, plus 10 cents per piercing or start. At the time, about $1 per square foot of 16 ga steel, and $25/hour for my shop time. I mostly did craft stuff, and left the slag on, for 'character'. On good days when the humidity worked, when the temp was in a good range, when the power on the power lines held reasonably constant, and the steel scrubbed up nicely before I started cutting, it went well. But that cutter could get miserable, too.
Now the cutting I do is by hand (same cutter), and less decorative than making something to fit, or cutting the nut off a bolt. Or cutting 24" steel pipe length ways for cattle feeders. And it is generally a lot less frustrating. 1/4"x1 1/2" strap for a straight edge rules!
Here's trick I've seen the professional use: The art is submerged in water! The table has to be a pool ofcourse.. The heat distorsions are practically nil. Jukka
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