This Month I Want To Try Metal Casting

Warning! Metal Casting, especially when done at home without professional equipment, is extremely dangerous. You can get severely burned, injured, or even killed during the process. There are extremely high temperatures, potentially explosive gases and materials, as well as hazardous chemicals and fumes. If you decide to do any of these processes, you should become more familiar with the in-depth process than I will describe here. This is just a very basic overview with many of the in-depth details left out.


I don’t remember exactly when or how I first found out about doing metal casting at home. I’m sure there was someone on YouTube who made a video of the foundry they made for $50 and I thought it would be a cool thing to try. At the time I didn’t really have a place where I could do so safely, but now that I’ve got a house with a bit more land I may be trying this one relatively soon.

I also didn’t have many ideas for what to make, which is why I didn’t try it at my last home where I did have a bit of space outside. For me, it would be less about wanting to get metal to make things and more about reusing metal from things I no longer need. I’d rather reuse as much as possible than send it to a land fill so I would really just have a certain amount of usable materials and decide from there what I want to make out of it.

Personal Protective Equipment

Since this is probably the most dangerous at home thing I’ll write about, certainly the most dangerous so far, the safety equipment is extremely important. Don’t go cheap with this. The money you spend now could be saved later when you don’t have to miss work or pay excessive medical bills.

You’ll want goggles that have sides to cover your entire eye, as well as a full face shield. In the event of splashing, your face is the area you want to have the most protection, as four out of five of your senses are triggered there.

You’ll want to wear fire resistant clothing Make sure you are covered head to toe. On top of that, you’ll want a leather apron and gloves. I’d suggest gloves meant for welding, as they are designed for high temperatures.

Whichever clothing you go with, make sure it is something you get out of quickly. The last thing you want is to have a bit of copper, which melts at 1981 °F / 1083 °C to spill into your boot and have to untie it to get it off while it quickly burns through you.

Never use water to put out a fire when molten metal is involved. You’ll want a big pile of dry sand and a shovel nearby in the event of a spill or fire. Never use water to put out a fire when molten metal is involved.

Building A Foundry

You can find an almost endless amount of DIY foundry ideas online. What you build depends on what you want to make. Most of the ones I’ve found have been made by pouring cement into a bucket, and using a smaller bucket to make a hollow center, then making a cement cover with metal handles. I’ve also seen a couple people use fire brick to build one. Just make sure it is big enough for you to fit a crucible with room to grab it with tongs.

Whichever material you decide to use just remember you want thicker walls if possible. Thicker walls mean better insulation, which not only helps it heat up quicker, but will also help it stay hotter using less energy because it loses less heat. You’ll also want to build your foundry outside somewhere or make it portable enough to move outside. Melting metal releases hazardous fumes which can cause permanent health problems, including death.

To heat the foundry, one of the more common sources is a propane torch. I’ve heard it can be very loud though. Charcoal is another option, but will obviously cause a lot of smoke, as well as having lots of ash, potentially in the air. Another common one is electricity. There are things you can buy which work just like an electric stove to heat up the foundry. This, however, has the added risk of electrical shock if you accidentally touch the heating element.

Metal Choices

There are many different metals that can be used, depending on what you want to make and how hot your furnace can get. Here is a table with the approximate melting points of various metals.

Aluminum1218 °F659 °C
Brass1700 °F927 °C
Bronze1675 °F913 °C
Cast Iron2200 °F1204 °C
Copper1981 °F1083 °C
Gold1945 °F1063 °C
Lead621 °F327 °C
Magnesium1204 °F651 °C
Nickel2646 °F1452 °C
Silver1761 °F951 °C
Steel2500 °F1371 °C
Tungsten6150 °F3399 °C
Wrought Iron2700 °F1482 °C
Zinc787 °F419 °C

Aluminum tends to be the most common to use since it is pretty easy to find. You can collect soda cans and melt them down. Just be sure if you do this, clean them and let them dry completely first. Any liquids, especially water, which come into contact with molten metal can cause an explosion. You can also get scrap aluminum from old computer parts, mainly from heat sinks.

Be aware that if you decide to use magnesium there is an extra bit of danger involved. If you are cutting it and there is a large enough amount of magnesium dust in the air, there is a possibility for spontaneous combustion of the dust.

Moulds

Moulds are, more or less, pretty simple. You have a box that is a few inches bigger in each direction than whatever you are casting. Then you either fill it with whichever material you are making the mould with. I use a general term there because there are so many things you can make a mould out of. A couple common ones are sand, rubber, plaster, and metal (with a higher melting point than you’re using to cast). You place the original which you want to replicate in whichever material you decided to use. Obviously, if it is something semi-solid like sand you would put it in before or during pouring, or you won’t be able to. Rubber and plaster are much more likely to move out of the way before they start to harden.

There are a couple ways to make the molds. You can make a two-piece mould, which you make one half in one box, then the other half in another. Then when you cast something using the mould, you separate the two pieces after it has cooled to remove the finished product. If you are making only one copy, or if it is easy enough to make multiple wax copies of something, you can make a one-piece mould which is then destroyed to get the final product out of it.

You’ll want to heat the mould before you pour any metal into it. The sudden temperature change of pouring molten metal can cause the mould to crack or deform if it is not warmed up already. Then you have the potential for molten metal flowing out of control onto the ground. This can be done with a butane torch.

Things To Make

You can make all kinds of little toys for kids, such as toy soldiers or little cars. You could even make them some building blocks.

There are also many things which you can make replacement parts for. If you have a tool and the handle breaks you can cast a new one. I’ve even seen pictures where people replace some fragile plastic parts in things with stronger metal ones.

If you are into tabletop games, such as Warhammer or Dungeons and Dragons, you could you’re your own mini-figures. You could also make mini-figures for other hobbies, like model trains.

Put your woodworking skills to work and build your own chess board, then cast your own chess pieces. You’ll have a completely custom chess set to show off to everyone.

There are all kinds of rings and other jewelry you could make by casting metal. Due to the detail required, many people use lost wax casting for this.

This seems like a bit of a stretch to me, especially for at home casting due to the size, but many people have made their own furniture.


Disclaimer: Although I have done a significant amount of research before preparing this post, I am not an expert on this subject. My intent is to help people who may be interested find some more information. If you decide you would like to try this yourself, please do some additional research and use common sense.


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2 thoughts on “This Month I Want To Try Metal Casting

  1. Thanks for stopping by my blog!
    I too want to cast alum. and have LOTS of it saved up over the years for just this purpose. I have been looking at building the foundry using the 6 gal. bucket idea. One thing you mention for the foundry is the lining is made from cement. Not so and if you do, it is guaranteed to crack. There are several ways to do this using heat resistant materials that are readily available.
    I don’t want to buy a crucible and will probably use a large steel pipe with a bottom welded on. These go bad pretty quickly but I really don’t want to buy one made from carbon or graphite.
    I will probably use briquets as they are available and cheap. They work fine for alum. Building a regular burner to use propane or natural gas is possible but I want it all more portable than that.
    Yes, the question is what to do with a foundry, something I am still thinking on. I want to learn how to do it but not sure what to cast when I do.
    If you decide to go for it, do post something here!

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