View Full Version : backyard foundries

30th April 2010, 09:19 AM
i have done a little research on this subject, and watched a few videos on youtube, but was curious if anyone here had any input or ideas for resourcing materials for the construction and design of one of these little buggers...


i found this site to be informative, but was hoping to find some people "in the know" to bounce ideas off...

Saul Mine
30th April 2010, 10:48 AM
It's a nice site to get a person started, but plan on chucking everything and finding better ways to do them. For one thing, he is talking about melting ten pounds of aluminum, not ten ounces of precious metal. That torch is ok but it needs a blower, even though he says it doesn't. I drilled out a wood block to match a hair dryer to the pipe. Forget the part about ten feet of gas hose. Five is plenty. The refractory is almost good enough for PM melting temps, but you really need something else. I was thinking sodium acetate and vermiculite, but I haven't done any melting for a long time so I never tried it. You can buy insulation, but it'll cost a bundle. An electric furnace would be much nicer than gas, but you need to know a few things to build one. Such as where to get the heater wire and what size.

Instructions for electric furnace and other equipment (http://www.amazon.com/Handbook-Lost-Investment-Casting-Gembooks/dp/0935182284/ref=sr_1_2?ie=UTF8&s=books&qid=1272647195&sr=8-2)
How to design a furnace (http://prometheus.vndv.com/tutorial.html) Use a popcorn can. I used the one from Kitco. It seemed symbolic somehow.
Silica crucibles (https://qtena.com/crucibles-melting-crucibles-c-1221_1321.html) If you get one of these wet you have to bake it for several hours to be sure it's dry. If it's not dry it will break in the furnace.
Graphite crucibles (https://qtena.com/crucibles-graphite-crucibles-c-1221_1318.html) These are much better for precious metals.
Cheap crucibles (http://www.harborfreight.com/3-piece-jewelers-crucibles-93699.html) Use these for less than 4 oz silver.

I hope you know you need at least one crucible for every different metal you melt. Graphite crucibles are very nice but they go away within a hundred melts or maybe less. Don't bother with the cheap ones, use the one linked above. Nobody makes tongs big enough. The tongs at Qtena are big enough for the 4 oz crucibles, but above that you have to use big goose neck pliers and be very careful not to crush the crucible.

30th April 2010, 11:25 AM
just came across a site (http://www.goldrefiningforum.com/) dedicated to recycling PMs from various scrap, lots of info there too.

Saul Mine
30th April 2010, 07:40 PM
Here's a link I just found today for insulation firebrick. It's cheap, less than the materials to mix your own stuff. I would suggest you try that first.


Type firebrick in the search box.