Lawyer BS to cover my Butt.
WARNING!!!: You got a brain... USE IT! Building and working with a foundry furnace is "NOT" child's play. It can be very dangerous and if 'you' screw-up don't come crying back to me! If you don't know what you're doing and didn't take the time to read and study all the safety procedures that are available on the net, as well as your local library, and you get hurt that's your problem. You are responsible for yourself and your own actions and safety.
--- "NOT ME!" ---
Method #2
- 1.5 parts Portland cement (This is "NOT" a ready
mix stuff. This Pure Cement - no rocks or sand)
- 2 parts silica sand (The same stuff you use for your
GreenSand)
- 1.5 parts perlite (Pure - not a blend of other things
meant for plants. "NOT" Vermiculite either!)
- 2 parts fireclay or Well drillers mud (Bentonite Clay)
You want to mix the dry parts thoroughly, it will take
a while
for the clay to bond to the sand. You could use
a cement
mixer/rolling tumbler/vibrating tumbler, but
this is 'ONLY'
for the dry parts, it's way to thick and
gooey once you start
adding the water.
IMPORTANT: Add as little water as possible. You don't
want
it to be soupy you want more in the line of a
moist cookie dough.
Let dry for several days, (Even a week for bigger furnaces)
then fire up the furnace on as low a setting as possible.
(Remember "LOW AND SLOW"!)
1st. burn for 15 minutes - let it cool down - COMPLETELY COLD!
2nd. burn for 30 minutes - let it cool down - COMPLETELY COLD!
3rd. burn for 45 minutes - let it cool down - COMPLETELY COLD!
4th. burn turn up the heat and if no smoke or steam comes out
you're ready to melt metal.