Making a Paint Can Furnace with Accessories, Lost Foam Casting, and More!

When I started to cast aluminum the end goal was to build a lathe from scratch following the dave gingery machine shop from scrap metal series of books. Now that I have the lathe, I won’t necessarily need to cast large parts all the time, and thus it seemed like a good idea to build a smaller furnace that would be quick to setup, would cool down quickly, and would also be portable. I was initially planning on building a small furnace from a big coffee can, but when in the paint section of a hardware store I noticed new empty paint cans for sale ( for $5 each ), and decided these would be the way to go ( more capacity and I wouldn’t have a bunch of instant coffee to drink ).

I also wanted to try my luck with lost foam casting, as it seemed like the perfect method for rapidly prototyping parts in aluminum, and this tutorial and video covers the basic tools required to do some lost foam casting.

Project Tutorial Page:
Paint Can Furnace with Accessories, Lost Foam Casting, and More!

Project Step by Step Video:
Video of Making the Paint Can Furnace with Accessories, Lost Foam Casting, and More!


10 thoughts on “Making a Paint Can Furnace with Accessories, Lost Foam Casting, and More!

  1. Morgan, I would like to build a hot wire machine for my foam cutting and I see you have one that works very well. If you get around to it, would you send me a brief ‘how to do it’ least wise, what is needed? The band saw has worked up to this point, more details are needed in these casting patterns coming up and the hot wire sure would advance these! Geat tutorial on your ‘paint can furnace’ Regards, Steve

    • Hey Steve,

      Glad you liked the tutorial, sorry I didn’t drop you an email when it was up. The hot wire cutter was built off this project ‘5 Minute Foam Factory‘ and that would be the best place to get the details. It is basically two pieces of 2×4, a pegboard sized to 2′x2′, a bent 1/4″ aluminum rod, nichrome wire, a bolt, two nuts, a nail, a model train transformer/power supply, two alligator clip wires.

      Some problems with the foam factory above that I have noticed. If you cut too fast the wire will bend which kills any accuracy you may want to get out of it, if cutting parts for something other than art / fun.

      The top aluminum rod that holds the wire in place will wobble a bit even with the nail preventing it from rotating to some extent. This means again that you will not be able to cut as accurately as you would want for a part that needs to be within certain tolerances.

      Finally, the setup simply cannot tension the wire enough, and you’ll find that the bolt that holds the other end of the nichrome wire down will float around a bit to the extent of the pegboard hole.

      That being said, it was a great little cutter that I threw together in an hour or so ( not 5 minutes haha ). It got the job done for the video, and was proof of concept that lost foam could be a viable option for me to make parts quickly.

      When I have a chance I’ll most likely build a new hot wire cutter with sturdier parts. There needs to be a strong column that will not flex to hold the wire. The top of the wire needs to be attached to something that will allow you to adjust tension – similar to the top wheel on a bandsaw. The bottom needs to be anchored at a fixed point, not tied around a floating bolt, etc…

      Anyways, just a few thoughts but it will get you cutting foam pretty quick if you have the parts lying around. The main things are the nichrome wire and the model railroad power supply… You need about 12V @ 7amps or something like that ( depends on the thickness of the nichrome and the length of the wire – all variables in the wire’s resistance and how many amps it will suck up ).


    • Hey Bob,

      Thank you so much for the link – I wouldn’t say the second part of the project isn’t ‘fine’, but I do love the idea of combining 3d printing tech with casting to produce strong metal parts. I wish I had a 3d printer, and may build one someday to give this method a try.

      Thanks again,

  2. Morgan – Take a look at for a cnc project. You can buy all the hardware and software for the project for $600.00. It even has all the tools needed to complete the project. I then added the print head from here:
    with upgrades listed here: you can have both a subtractive and additive cnc machine. You can not get better than that.


  3. Im 15 and ive been thinking of making a forge for about a year or two, and i have a big boy propane torch and welding gloves for protection. But I dont know what other protection things i needed. How much hotter would the forge get or the temperature rise if there were two torches, because i am thinking of melting copper and i have 27 feet of tubing and other scrap copper items. Copper has a melting point roughly around 1983 degrees fahrenheiht. so would it get 600 degrees hotter or not? please let me know/ post back. thanks

    • Hey Brian, I have not melted copper myself as of yet, and have not really built a furnace with two burners either – so possibly better information available elsewhere, however I think the main issue would be loss of heat from your furnace, etc… In air propane will burn to around 2000 deg F. and you probably need just about all that to melt Copper ( ~1980 deg F. or something like that ). So with a dual burner setup you would probably be more likely to achieve that, though I don’t think you’ll get any increased temperature out of it – just getting to the temp faster, and possibly closer to the peak temp of burning propane in air.

      Anyways, I’m not sure how well the homebrew castable refractory will hold up to those temperatures – possibly good for a few melts and then degraded performance. You might want to look into purchasing a commercial product for the longevity of the furnace.

      Finally, you’ll need more than gloves for melting Copper, and you really should have all the safety gear anyways just to be on the safe side. Full face shield, leather boots with covers, full leather apron, etc… You are young, and don’t want to ruin your life by not taking all necessary precautions ahead of time – it only takes one accident and improper gear, etc…

      Here is some information about casting / foundry work and has the melting temps / recommended safety gear, etc…

      Let me know how it goes, and best of luck,

  4. Hi Morgan…i am planning on making my furnace this coming weekend….your tutorial/video is the best on the net. Thanks. My question for you is if I am making larger parts, do you have any experience or advice on joining 2 cast aluminum pieces together after they are cast?

    thanks in advance

    • Hey Matt,

      Bolting would probably be the best option however you could probably braze, or weld, if you have the proper welding equipment, the aluminum pieces together as well. For the lathe project for instance the lathe feet are bolted to the bed casting, etc… I don’t think you would want to cast the lathe bed in parts and bolt that together however as the top surface needs to be scrapped flat, and anything bolted could be prone to shifting over time, etc… Brazing could be done however you may need to work the top surface a bit more to get it flat due to the effects of heating the aluminum during the brazing process, and it probably being a bit harder to get the pieces lined up exactly.



  5. Hi there.

    I was preparing to make your paint can furnace specifically for aluminium, but I’ve changed direction (because here in the UK it’s impossible to find the Bernzomatic torch you recommended since they discontinued it here) and want to build a small electric kiln for firing metal clay pieces. I have the fireclay and sand and the furnace cement and was wondering if I could use them instead of buying firebrick?

    I don’t want to waste all this material I’ve bought. Do you have any suggestions for me? Hope to hear from you soon!

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