DIY Metal Melting Furnace





Introduction: DIY Metal Melting Furnace

In this indestructible I will show you how to make a metal melting furnace that can heat up to 1,500 degrees Fahrenheit.

Step 1: Materials

First here is a list of materials you will need for this project,

  • Steel bucket (with lid would be preferred and it works best with a 10 quart but I couldn't find one and made a 6 gallon bucket work)
  • 8 pounds Plaster of Paris (possibly 12 if you do not have a lid with your bucket)
  • Bag of sand (normal play sand will work fine)
  • A 5 gallon bucket for mixing ingredients
  • 2 1/2 quart bucket for measuring
  • Crucible of your choice(Temperature treated ceramic works best you can use a steel bowl but it oxidizes the aluminum which makes it harder to melt)
  • Steel Tongs
  • Heat proof gloves(I recommend gloves that can handle more than 400 degrees Fahrenheit)
  • A pair of channel locks
  • A steel pipe 1" in diameter by 10"
  • 1" diameter PVC coupling
  • 1" diameter PVC pipe 12" (long will work fine but you can get longer)
  • 1" in diameter hole saw
  • For fuel you need charcoal briquettes
  • Hair dryer for steady oxygen intake for coals to get and keep it hot.
  • Drill
  • 3" hole saw(only if you need to make a lid)

Step 2: Mixing

Use the 2 1/2 quart bucket to measure out the sand and water you will need for this project. Pour 2 4 pound packages of Plaster of Paris then measure 2 of the 2 1/2 quart buckets full of sand. Then you will add water add 1 and 1/2 of the 2 1/2 quart buckets full of water to the mix.


You will have about 15 to 20 minutes before it starts setting. Mix with your hand because you can make sure there is minimal clumps of sand. Once you are confident there is little to no clumps pour into the steel bucket slowly, it will splatter.

Once it is poured into the steel bucket if you have a 10 quart bucket you can use the 2 1/2 quart measuring bucket fill it with water and carefully put it in the middle of the steel bucket with the solution if you spill a little it's okay just try not to.

Make sure you leave a little space at the bottom for insulation or else there could be problems

If you have a 6 gallon bucket you can use a 2 gallon pitcher for the center section (that's what I used)

Note: Make sure if you use the pitcher to make the center part it does not have a handle.

Lid instructions: If you do not have a lid for your bucket here is how to make it.

10 Cups Plaster of Paris

10 Cups sand

7 Cups water

Mix together in the 5 gallon bucket used earlier and after you feel there is minimal clumps carefully put in 2 4" U-bolts and carefully stand them up right in the bucket mix.

After an hour it should be set and you should be able to pull it out easily.

Now to vent pressure use a 3" hole saw to cut a hole in the middle of the lid.

Step 3: Final Pieces

Now to make the hole for the air flow take the 1" hole saw and start drilling into the side of the bucket a couple inches from the bottom once through the metal tilt down and drill down at about a 25 to 30 degree angle so that if a crucible does fail it doesn't spill molten metal all over.

Attach the steel pipe to the PVC coupling and the PVC pipe then slide into air port attach hair dryer to the end of the PVC pipe. Make sure the PVC pipe and hair dryer have support or it could add pressure to the inside walls.

Now just add coals fire it up using lighter fluid to start the coals and once they are mostly all white drop in your crucible and start MELTING SOME METAL!!!!

Note: You can use a muffin pan to pour your molten metal in make sure it is steel and don't worry if it catches on fire it's the non-stick coating cooking away. Also was long as you have something that can handle a lot of heat (concrete will explode from the moisture stuck in it if you spill the molten metal on it) you can use little steel cookie cutters to cast your molten metal.



  • Make it Move Contest

    Make it Move Contest
  • Oil Contest

    Oil Contest
  • Casting Contest

    Casting Contest

We have a be nice policy.
Please be positive and constructive.




My local craft group buy aluminium ingots, I wonder if I took one of these to them, and showed them how easy it is, if they'd start recycling instead

8 replies

I want to point out that the aluminum alloy(?) you get from soda cans is more brittle than what you buy. Also do make sure to degas/flux the melt before you cast else bubbles form when your cast cools ruining what the integrity.

That is a good idea dan3008. I'm glad your interested in recycling, but the molds I made I melted just aluminum cans from home and then later I used some scrap aluminum I found at work. For the mold all I used was a ceramic plate to hold heat and a steel cookie cutter, and the mold ended up pretty good in my opinion.

Took a first prototype to them this morning (not really big enough for their scale, but was just a proof of concept). And our local MP was there. He recons if I get it working, he can get us a pile of cans from the local recycling centre who it turns out just sell the aluminum cans on to someone else to deal with, because it makes "too much slag" for them to bother.

So not only am I saving the group money, I'm actually getting support from the local council... I think that counts as a win in my book

I'd hesitate to say you were saving money, Dan.

The cost of the energy to melt the cans will be far greater than the value of the aluminum you recycle. This is a very inefficient process for recycling- suitable for hobbyist but not for any large effort.

The money saving measure would be to sell the cans to the recycling centre, and then use that money to buy the ingots.

our local recycling centre wont buy cans, they take them for free, but then ship them off elsewhere for recycling, or now they send us a bundle for free.

I've been looking at using electric heating elements too, but that'll cost more.

As for buying the ingots, the only place localy that sells them are charging way over the odds.

Yes, I could actually save money by buying online ect, but staying totally local (which they insist on) its cheaper to do it this way. I spent days costing up

The fresnal lense from a 50" projector tv can melt rock all day.

..measured in cubic millimeters per minute...very difficult to cast at that volume : )

Cans have a LOT of slag in them when you try to ;melt them. Try squeezing the blob of slag against the side of the crucible to push out as much liquid metal as you can.

Better sources of metal are old aluminum furniture, tubing, cast engine parts, parts of old hard drives or heat sinks off electronics. Best is if you can get castings to melt down because the alloy is created to cast very well where cans are almost pure aluminum and are softer when made into something else.

This looks like you just took what Grant Thompson - The King Of Random did and called it your own...

2 replies

He did. The script is almost exactly the same.

No I did not copy this from anyone, yes I did use some of his ideas because they were useful. But the rest is all mine.

If you use plaster of Paris the gypsum in it will release toxic sulphur dioxide when heated above 740°C or 1364°F. It is better to use refractory cement made for this sorta stuff.

1 reply

Thank you for the information very useful.

Do not use a galvanised bucket, if this gets hot enough (cracks etc might allow that) nasty toxic gases will be released. They may not have immediate effect but can cause a whole host of problems in later life, so not worth it.

That's a neat setup, my husband really wants to make one!

1 reply

Nice! I'm glad I have brought in his interest I hope that if he does make one he has fun making it.

Add some vermiculite or pearlite to the mix for insulation

1 reply

You can also use steel wool to increase strength I realized this after my second prototype.