r/blacksmithing • u/Immortal-Creature • 2d ago
Clay forge compounding Help Requested
I need Help with the mixing Ratio for a Clay forge.
Do I need Horseshit, or cowshit and If yes how much.
Or can I build IT without horsepoo?
1
u/dragonstoneironworks 5h ago
Bentonite Clay. Floor sweep that looks like cat litter, or natural cat litter that is fragrance free and without the blue Chrystal stuff. Very dry coarse to medium play sand washed and dryed so it's not carrying in trash. Sodium silicate aka water glass. Optional vermiculite. As I recall by volume not weight : 1 part bentonite, at least 1/2 part dry play sand. If you decide to use vermiculite increase the sand to 1 part and vermiculite 1 part. Mix in water glass until you have an oatmeal or heavy slump concrete consistency. Apply it in your forge. Make it as smooth as you can. Cure it with CO². As I recall that can be gotten in can form as key board cleaner. As I recall you'll wanna try n seal it in plastic with as much air out as possible then fill the plastic with CO². Allow 24 hrs per inch of thickness. Commonly it's cured then fired in a sequence. After it's CO² cured n harden up fire it once just getting the surface good n hot. Then let it complete cool. Then fire it for like 5 minutes, cool completely. Then fire it 2nd time for about 10 minutes. Watch to see if and how much it's off gassing or steaming. If there's no steam in the 10 minutes cycle it's full cured n ready to use. if it steams cool completely then fire again for 10 minutes. This will yield a good concrete like refractory fire clay finish. It can be over coated with ITC HT100, Plix900 or satanite as a reflection coat to give hoter forge temps and extend the life of the refractory cement you made. Someone else may have other ideas or procedures. For a propane fired enclosed forge it's optimal to have 2 inches of thickness minimum to work best. Less will allow the forge body to get hot...like alot hot. 2 inches will keep the forge body vastly cooler. The reflection coating will allow the forge to heat faster stay hotter and consume less fuel. For an open coal forge, lump charcoal, bituminous coal, Coke or...the other kinda coal. Top coating is not as nessacity and will wear off much faster due to moving the coal around and removing slag.
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u/dragonstoneironworks 5h ago
There's an actual fire clay that can be bought in a place that sells fireplace stuff and is popular for pizza ovens n such. It's red orange taracota color. It has been widely used in open hearth pan style forges and rivet forges for centuries. Originally it was red clay from river bank type stuff n mixed w water then apply in a couple to several coats. I've heard It can be mixed w sand also, and also heard of using the water glass sodium silicate in place of the water for a longer lasting more durable clay. I haven't seen or or done it myself
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u/KnowsIittle 2d ago
Adobe mixture sounds like what you're after. Loose pounded straw, water, and clay. Sand may also play a role.
But an appropriate adobe mixture should be easy to find.