Thread: Forge insulation question

Hi fellas,

I have been reading a lot online (and searched here) and haven't seen anything exactly answering this question: Is a perlite and sodium silicate (water glass) insulation, followed by 1" ceramic wool, lined with high temp mortar a good solution for a 20 lb propane bottle forge?

I keep reading snipits of references to avoiding perlite, but if it's got ceramic wool protecting it, that should be sufficient, no? I only have a small amount of ceramic wool (not even sure which brand), but I bought a gallon of water glass and two bags of perlite, and just looking for my vessel now.

I'm also building a burner roughly from Zoeller Forge plans. BTW, somebody warn me if it's a bad idea to solder a copper MIG tip to black pipe or brass pipe. I'm struggling to find all the right sizes and wall thicknesses for the pipe (but am smart enough to avoid galvanized).

Cheers,
Atchbo

I used 1 1/2" of Superwool 601 then only about 1/4" of high temp motar for the inner lining for my 6" pipe forge
Most gas bottle forges I see have an 1 - 2" of wool with a bonding spray on it, then a pear lite or other substrate for the base as a barrier.
I found the blade forums like British blades and Australian blade forum most useful when researching forge linings etc

i used 1/4" compression fittings on my burner as the mig tips are 1/4" also and you can swap them out if you want easily.

http://straightrazorpalace.com/forge...shiny-wip.html

My son inlaw is a gas fitter and he said that I could solder a tip and redrill it with what ever jet size i want, but the mig tips work fine, I have a # 26 good for forging & a #35 hotter for welding.

My lining probably won't help you. I use charcoal. My recipe is 1/3 wood ash, 1/3 ceramic kitty litter, 1/3 plain old cement.

Actually, this could be helpful. I have a charcoal brake drum forge in a Mexican chiminea but it takes a while to heat up all that steel. I put some sand and rocks in the pot and lava rock around it to protect the chiminea but I might consider lining that drum while I am working on this gas forge. Maybe a bit of perlite with a cover of this tite bond high temp mortar I bought.

I also bought some fire clay for coating the blades... I could probably mix a handful of that in with the perlite and sodium silicate.

I don't have enough ash to use for this (haven't had enough hours on the forge!).

Your intended materials will work.

For horizontal tube forges, Cerowool/kaowool (ceramic wools brand named) are intended as insulators but will work well in a lightweight forge designed for forging. I recommend some form of hard refractory for the bottom where you are going to rest your steel while waiting for it to warm up. The wool refractories are not durable.

For vertical forges, all you need is a layer of insulation as the material being worked hangs in the heat and does not rest on a shelf or forge bottom.

Pot style forges for charcoal or coal require some sort of refractory liner (clay will do) merely to keep the heat from burning out the metal frame you use to form the shape before its time.

I don't know about pearlite, but my mix is dirt cheap. The cement is plain cement, and kitty litter doesn't cost much either.
It serves the dual purpose of keeping heat inside through insulation, and to keep the fire from burning through the metal.

One nice thing about charcoal is that you aren't tempted to put Teflon anywhere. Nasty stuff. Right up there with galvanized.

The tile that they use for the shelves in pottery kilns works pretty well. if flux is part of the equation, a second piece of tile that you can taken and out and replace when it gets nasty or cracks (which it will) without having to tear up your forge lining is a good idea. My Chile forge has the hard bottom laid over the wool. It may be a slab of castable refractory.

Originally Posted by Mike Blue

Your intended materials will work.

For horizontal tube forges, Cerowool/kaowool (ceramic wools brand named) are intended as insulators but will work well in a lightweight forge designed for forging. I recommend some form of hard refractory for the bottom where you are going to rest your steel while waiting for it to warm up. The wool refractories are not durable.

For vertical forges, all you need is a layer of insulation as the material being worked hangs in the heat and does not rest on a shelf or forge bottom.

Pot style forges for charcoal or coal require some sort of refractory liner (clay will do) merely to keep the heat from burning out the metal frame you use to form the shape before its time.

Originally Posted by Atchbo

I'm also building a burner roughly from Zoeller Forge plans. BTW, somebody warn me if it's a bad idea to solder a copper MIG tip to black pipe or brass pipe. I'm struggling to find all the right sizes and wall thicknesses for the pipe (but am smart enough to avoid galvanized).

For mine I put a brass end cap on the end of the black iron pipe to which I wanted to attach the mig tip. Then drilled and tapped into the brass cap. Seems to work fine.

Got the tank cut open and almost ready for the insulation. Thinking about locating the burner at 12 o'clock... Any major problems with this approach?