Devil Forge users or DIYers.

[COMachinist]

I have been thinking, with the price of metal and things going up so much, I’m considering doing some metal recycling.
Casting some of the softer metals copper, brass/bronze aluminum. I have access to lots of scrap, from my sons auto shop. Being family I get 1st pick of, wheels, AL heads, etc brass parts, Don’t figure oil bronze is worth messing around with. I searched this forum on casting not much available here, mostly welding posts. Any way looking at the Devil Forge line, figuring the 8-10 kg size. I have 3 100# propane bottles, and get them filled from my Co-op up the road, so fuel is readily available, at a good price for now. Any one casting parts?
CH

 

[benmychree]

It is not as easy as one might think to produce clean sound castings, especially in bronze, aluminum can be a bit difficult if permanent mold scrap is used due to shrinkage problems, brass is easy. I used to do a lot of it years ago.

 

[rwm]

I have done much casting. Home cast aluminum machines like crap. There are multiple reasons for this. Bronze/brass are much better if done right.
Robert

 

[ericc]

I do it. It is a lot of fun, but it requires a single minded concentration and a focus on safety. My focus was not so much on saving money as it was to get rid of some of the junk branches sitting around my house. They tend to accumulate, and can become dangerous if they are inside the defensible space zone. My main goals were to get rid of some of this yard waste cleanly without subjecting the neighbors to unsightly burn piles or permanent furnaces. There is not much on the Internet about this angle, so I ended up discovering a lot of things on my own. Shrinkage is not a problem if you are willing to cast oversize and turn a lot of your metal into chips. Casting to size and obtaining a good surface finish is more difficult, but entirely possible.

As for casting aluminum and brass into ingots with a Devil Forge, there is plenty of stuff on the Internet about that, especially on YouTube. I just cannot justify the propane expense. All my propane goes into my blacksmith forge, which has a larger bang ( ) for the buck. Propane is less expensive in the 100 lb tanks, so you will be ahead there. There are a lot of experienced people here who can give you advice. Pay special attention to safety and the use of good safety equipment. I wear welding gloves, safety glasses and a face shield, leather apron, and a hard hat. You don't need the mesh screen for the lower temperature metals, and I have spats, but don't use them for aluminum, although I do have a friend who burned his foot severely by spilling aluminum on it.

 

[benmychree]

Brass is easy because the zinc in it excludes oxygen from the melt, so porosity is not a problem; bronze, on the other hand does not contain zinc, at least most of it does not, so the melt must be protected from oxidation and uptake of furnace gasses; a flux is used and a degassing inoculation is needed, otherwise porosity is seen. Porosity is also common with aluminum castings. Problems with shrinkage when using permanent mold scrap such as pistons and wheels is due to the addition of iron to the alloy to prevent sticking of aluminum to the molds; iron narrows the solidification range of the molten metal, making it necessary to raise the pouring temperature in order to get complete filling of the mold and also getting consequent shrink problems such as cracks or hot tears.

 

[COMachinist]

Robert, I’m just trying to save some on metal parts that can be cast, then machined. I have seen video’s of guys 3d printing models, or making out wood, then casting and machining to finish. I cant see using a new hunk of aluminum for a pulley or a pot metal replacement part when quality or strength isn’t that important.
besides it’s fun to do something yourself.
Thanks for the reply.
CH

 

[benmychree]

I do it. It is a lot of fun, but it requires a single minded concentration and a focus on safety. My focus was not so much on saving money as it was to get rid of some of the junk branches sitting around my house. They tend to accumulate, and can become dangerous if they are inside the defensible space zone. My main goals were to get rid of some of this yard waste cleanly without subjecting the neighbors to unsightly burn piles or permanent furnaces. There is not much on the Internet about this angle, so I ended up discovering a lot of things on my own. Shrinkage is not a problem if you are willing to cast oversize and turn a lot of your metal into chips. Casting to size and obtaining a good surface finish is more difficult, but entirely possible.

As for casting aluminum and brass into ingots with a Devil Forge, there is plenty of stuff on the Internet about that, especially on YouTube. I just cannot justify the propane expense. All my propane goes into my blacksmith forge, which has a larger bang ( ) for the buck. Propane is less expensive in the 100 lb tanks, so you will be ahead there. There are a lot of experienced people here who can give you advice. Pay special attention to safety and the use of good safety equipment. I wear welding gloves, safety glasses and a face shield, leather apron, and a hard hat. You don't need the mesh screen for the lower temperature metals, and I have spats, but don't use them for aluminum, although I do have a friend who burned his foot severely by spilling aluminum on it.

I do not worry about shrinkage for dimensional accuracy, but for casting defects such as cracks and hot tears.

 

[rwm]

Robert, I’m just trying to save some on metal parts that can be cast, then machined. I have seen video’s of guys 3d printing models, or making out wood, then casting and machining to finish. I cant see using a new hunk of aluminum for a pulley or a pot metal replacement part when quality or strength isn’t that important.
besides it’s fun to do something yourself.
Thanks for the reply.
CH

Sure. That is a reasonable application. Initially I though I might be able to cast round stock for the lathe. That does not give an acceptable result in aluminum. I have had good success with brass and silicon bronze. I just sent out some nice gear blanks in brass.
Casting parts that need some machining is fine but the finish will not be as good as extruded stock. Control of porosity is a big issue with aluminum and heat treating is hard to do in a home shop.
Robert

 

[benmychree]

One must be really careful to avoid mixing silicon bronze and other bronze alloys; the result is as brittle as glass and will flake like obsidian.

 

[RJSakowski]

I have two books by Terry Aspin, published in the UK; "Foundrywork for the Amateur" and "The Backyard Foundry". I also have The Metalcaster's Bible" by C.W. Ammen. These were purchased long ago and may be out of print but you may be able to find copies on Amazon.

I have cast white metal, aluminum, and some brass. For the most part, I cast raw material for use in machining. Aluminum tends to be porous but for some projects where I need a lot of mass and I am not particular about ultimate strength or surface finish, it beats spending a bunch of cash.

For raw material molds, I often use cans from soup, vegetables, coffee, etc. For a heat source I will use my coal fired forge. We have wood furnace for winter heat and it is a convenient way to melt aluminum and brass.