first forge build.

[conanodraconis]

Hello peeps, new to the forums and thought id toss out my first q.

When firing up my new forge for the fist time I noticed some vapors that burn the eyes and throat. So I took it outside and fired it back up. After it ran for a while I noticed a liquid leaking from the cap where I weilded the lid back on. Didnt weld it solid. Just 1 inch welds along the seam. The liquid is clear and leaving a white powder like substance behind as it drys.

I used perlite mixed with paris and sodium silicate. Then coated with refractory cement rated for 3000 degrees. Any idea what this liquid might be? I know with temps in the ranges they are (1800+) that some chemical processes can happen.

 

[Stacy E. Apelt - Bladesmith]

Welcome to Shop Talk.


The liquid is called water with sodium silicate dissolved in it. If your pearlite is real pearlite ( not all is) it is silica with water in it. Plaster is calcium sulfate with lots of water ( CaSO4-12H2O) with water in it. Sodium silicate is a water solution of silica glass ( various silicates of soda). The liquid coming out is probably very caustic, so be careful cleaning it up. It also may cause some corrosion of the metal.

Why did you use pearlite/plaster/silicate of soda for the refractory? I'm betting you "saw it on you-tube".

A proper forge has an insulating layer with a lining of refractory inside. Normally that is a 1" to 2" layer of high temperature wool ( usually Inswool) covered with a 1/4" layer of refractory ( usually Satanite), and a final thin coating of a highly heat reflective coating called ITC-100.

Your setup has a home made refractory lined with a real refractory ( something like Cast-o-lite 30). You will get OK results with your setup, but first you will have to drive all the water out of the refractory by firing it for at least an hour. You will have a forge that will take a long time to heat up and will get fairly hot on the exterior.

All the materials and info to build a forge can be found at www.hightemptools.com

 

[conanodraconis]

Yeah. What was supposed to be coffee can forge off youtube ended up being a propane tank instead. Inner diameter is about 4 inches. tonight I was playing with it. It got about 1700 degree in about 10 minutes. But yes the outer casing does get a tad warm. But nothing I cant pick up for a few seconds using welding gloves.

I use a fire brick to cover the opening during start up. If I build another ill definatly use kaowool as primary insulator next time. This one was a learning experience.

 

[Stacy E. Apelt - Bladesmith]

FYI, don't cover all the opening, or the forge will have too much back-pressure and not run right. That can also make your burner get glowing hot. You need about 6-10 sq.in. of vent space for a 1" burner.