Home Foundry

This instructable will take you step by step how to make a home foundry so you can make quick and efficient aluminum melts for casting. Its propane fueled so its easy to set up and easy clean. I hope it's informative and allows you to make castings of your own. This instructable is a result of my own research and trials I hope it benefits all those who wish to follow into the world of the home foundry.

This not the cheapest furnace but i had to buy a lot of my supplies. If you are a good scavenger/bargain hunter then your total price will be less than mine. Also propane compared to other fuels isn't the cheapest either, but it is clean and efficient.

Warning/Disclaimer: Working with molten metal is extremely dangerous. I do not claim any responsibly for any injuries or accidents that may occur during replication of this instructable. Always be safe when working with high temperatures and molten metal (don't do anything stupid and always wear safety equipment). 

Do plenty of research and know what your getting yourself into.

Some references:
http://www.backyardmetalcasting.com/index.html
http://www.engineeringtoolbox.com/melting-temperature-metals-d_860.html
http://www.youtube.com/watch?v=lX6yFQNnk-A (this a charcoal foundry but there is still much to learn from it)
http://www.youtube.com/watch?v=B5wCVI7jCyQ&feature=related
http://www.instructables.com/id/My-Second-Aluminium-Foundry/step4/Refractory-Support/

Step 1 Materials

Materials needed:

Burner:
          -1/8" hex cap
          -1/8" pipe (i used brass but steel would be better)
          -1/8" to 3/8" brass fitting
          -3/8" to 1/2" steel fitting
          -1/2" steel pipe x3
          -1/2"  T pipe
          -1/2"  valve
          -1/2" npt to 3/8" nptf fitting
          - 1/2" to 1/4" reducer fitting
          -1/4" x 2" pipe
          -1/4" ball valve
          -1/4" male quick disconnet
          -3/4" steel pipe about 7" long
          -Gas hose
          -High pressure valve

Refractory:
   -Portland Cement (crucial that its portland not masonry)
   -Silica Sand
   -Perlite (used in planting it is an aerated volcanic rock that doesn't absorb heat readily)
   -Fireclay (i had no supplier of this but i used rutland refractory cement instead)
   -Water

Furnace in general:
   -Steel pots or pails (avoid galvanized apparently if they get to hot the zinc on them will release toxic fumes)
   -1" id Steel pipe for burner inlet
   -Drainage pipe about 2" long (leftover from making the burner inlet)

Crucible:
   -Scrap sheet metal
   -Scrap rod of various sizes (i used 1/4 and 1/8)

Various:
   -Steel rod 
   -Cardboard
   -Gaffers or duct tape
   -Teflon tape
   -Mixing tub
   -Propane tank
   -Set screw

Safety equipment:
   -Welding Gloves
   -Safety Glasses
   -long pants
   -flame retardant shirt or jacket

And of course lots of scrap aluminum to melt

Comments

[TheReplicaz]

Thanks for posting this!
But, why do I need a drainage pipe at the bottom of the foundry?
Please, reply.

[pyrogreasemonkey]

replace pearlite with foam beads, such as from packaging. foam will burn out and makes better insulation, but pearlite melts if you do anything hotter than aluminum melting. portland cement becomes a flux at relatively low temps in a furnance and holds chemically bonded water. use fireclay, sand, foam, and crushed firebrick if you can find it. about 3.5 parts clay by weight, 1.5 parts sand by weight, 3 parts crushed firebrick, and then you want to have about 50% of the refractory as a whole to be foam by volume. first mix together the foam, sand, and crushed brick with a small amount of water. then add the fireclay. mix well. you want to use as little water as posible because clay shinks as it dries. that is the same reason you want sand and crushed brick, it keeps the clay from shrinking and cracking a lot during drying and curing. the first time you fire it, start by making a small charcoal fire in it and then after a few hours turn on the propane to get the clay to sinter. the clay must get as hot as posible for as long as posible, but raise the temp slowly so the water gets cooked off slowly

[Mr. E Meat]

Do you need the sand in the mix or can you just use 3.5 parts perlite (for more insulation, maybe)? If not, what is the purpose of the sand in the mix?

[magicman391]

what your essentially making is a kind of concrete that can withstand the temperatures of the furnace. when making concrete the basic ingredients are cement, aggregate (sand, gravel, or crushed stone), and water. Like i said in the refractory making step, adding more perlite can't hurt as its an insulator, but sand is neccessary in order to get the right chemical reaction for it to cure.

[z.jordan]

Technically, the curing reaction only takes place within the cement.

In other words, sand is not actually required for curring to occur. However, it is recommended because it helps increase the strength of the concrete as well as slightly reduces heat conduction.

[ilikechemicals]

Cool but step 7 pic makes it look like you didn't mix the refactory well enough.

[magicman391]

I did but I took that right after I removed the forms and it wasn't completely dry at that point so what you see is parts of it dry and parts of it still a little wet.

[rimar2000]

Thanks for sharing this project, I like it very much.

A suggest: in step 9 image, add some ordinary object for size comparison.