SIMPLE Homemade Metal Melting Furnace (Foundry) for metal casting – by VOG (VegOilGuy)

SIMPLE Homemade Metal Melting Furnace (Foundry) for metal casting – by VOG (VegOilGuy)

Looking for an easy build home metal foundry?
Need it affordable, capable of high temperatures and sturdy enough not to fall apart with every
use? I’m going to show you how.
Hi YouTube, I’m Geoff the VegOilGuy. Today I’m going to be building this stable,
high temperature home metal foundry to work alongside my waste oil burner, for melting
and recycling various metals for other projects. Like so many others out there, I started off
using Grant Thompson’s Mini Metal Foundry recipe and whilst I still think it’s a masterpiece,
brilliant for short term use, anyone wanting something a little more substantial should
think more carefully. You can see mine here, made with Grant’s 50/50 sand and Plaster
of Paris mix specification. The problem is this mix is just too weak. It crumbles and
disintegrates too easily and frankly I’ve got fed up of repairing mine.
Taking inspiration from Myfordboy, I’m going to be using dedicated dense, castable Refractory
mix that’s capable of withstanding temperatures up to 1700 degrees Celsius (3092 Fahrenheit).
This should be much more solid and stable. If you want to build along with me, you’ll
need a couple of bags of this. Thankfully if you shop around, it is affordable.
For the structure of the foundry, you could use Grant’s two-bucket approach or even
Myfordboy’s plastic mould approach, but I’m going to be recycle my old Foundry. It
was originally a second hand vegetable oil container and these tins are an excellent
basis for this purpose. I’ve got a spare on hand and will be using both to strengthen
this home foundry. Originally I took one of these veg oil containers
but it was much too tall. So cut out a slim centre section and used both top and bottom
to great success. Obviously it’s important to check that the
container you choose is going to be big enough to handle your crucibles. Again I’m afraid
Grant’s crucible recipe didn’t work for me, so I purchased a couple of crucibles cheaply
on eBay. Here I’m using the larger of the two to make sure I’ve got clearance. You’ll
need a good couple of inches of refractory in the bottom of your foundry, so take this
into account when measuring up. Once you cut either end from these containers,
they lose a lot of strength and don’t keep their shape. It occurred to me an ideal solution
was to reattach the thick rim I’d previously cut away. Here is an older now discarded lid,
but I’m interested in the rim which is much thicker and more structural. The angle grinder
made quick work of removing the thin top material, leaving the rim and sides intact. It was then
just a matter of sliding this down over the bottom section. To do this I needed to cut
a thin slot, again using the angle grinder. It was a tight fit, but the old lid slid over
the bottom section and could then easily tapped down to an ideal height. The metal began to
bulge where I’d cut the slot, but this could be tapped out later.
A scrap of wood helped me gauge the ideal height all around.
I then drilled and riveted the rim section in four places. Self-tapping screws or small
bolts could also be used instead. Once fixed, the whole section regained considerable
strength and I was able to tap out the slight bulge with several light hammer blows. I only
cut one slot be in hindsight three or four may have prevented this bulge.
As nothing sticks well to loose rust, I used a wire brush in my drill to roughly clean
everything. Looking around for something roughly two inches
tall, I used a hole-saw as a guide to mark a two inch high line around the inside of
the container. This is the height of refractory filling.
As the foundry will be heavy, I decided to later add some castors for easy movement,
so I bolted a simple plywood base to the container. Using the bolt means I can always detach it
if I need to. Now I’ve already cut a hole in my base. This
is the inlet for the waste oil burner, the air supply or in my case both. Grant’s tutorial
recommends using barbecue charcoal to fuel your foundry and for your first few attempts
at metal melting, that’s a good idea. But charcoal is hard to control. I found as soon
as the foundry was hot enough, the charcoal was all but burned out.
A gas or oil burner is a better way to go. The heat source is more controllable and dependable.
If you haven’t already built your burner, you should really do that first so you know
what size hole you need to cut. If you’re looking to burn waste vegetable or motor oil,
check out my waste oil burner design. This is a simple, low tech, easy build design that
generates plenty of heat using recycled waste fuels.
There are three important considerations you need to make when cutting your hole.
Firstly, as I’ve already said, make sure your hole matches the diameter of your burner.
Secondly, position the hole so that its bottom edge is at around 3 inches above the bottom
of the container. This will allow for 2 inches of refractory and an inch clearance for the
burner. Finally, don’t cut straight on to base.
Ideally you want your burner to enter at an angle to encourage the heat to flow around
the edges of your foundry, evenly heating your crucible. Reflect this angle when you
cut your hole. These containers aren’t very thick so a drill and hole-saw make easy work
of this. A few weeks back I made a new lid, but that
used a mix of my own creation. Whilst this was holding up quite well, it was still cracking
and so I decided to empty out the content and fill it with proper high temperature refractory.
It also struck me as a good idea to add a lower rim to the lid as well. The increased
strength makes the extra effort really worthwhile. And I’ve got the remains of the second container
to hand. So the former lid was cleaned up and the base
of the other container was sliced away with my angle grinder.
Grant’s crucible suggestion of an old fire extinguisher didn’t work for me, but it did
leave me with a nice steel tube to line the hole in the lid. An old food tin would do
just as well. Taking the freshly cut container bottom, I
found the centre, marked it and drilled a pilot hole.
I was then able to use the same hole-saw to cut a large feed-hole in the future lid.
A little work with a file took care of any nasty edges and the tube slid in a treat.
I cut away the flat top of the former lid as I did before and this will become the underside
of the new lid. Now the two sections of the lid need to come together.
This time I cut several slots to make fitting simpler.
Same procedure again. Tapped into place and this time I made sure that I had sufficient
height to allow for a good couple of inches of refractory. I then riveted the two sections
together – just four rivets did the job. At this point I realised the tube wouldn’t
be tall enough – typical – but thankfully an ordinary food can was an almost perfect
fit. I cut a few slots and sure enough it all went together.
I made sure there was plenty of room for a soda can… I do like to melt and recycle
these… The lid needs a couple of handles. You can
use what you like. I had some copper pipe to hand. It might not be the strongest metal
but it won’t rust and it can easily handle this job.
The pipe is flattened then bent over in my vice. It doesn’t need to be pretty, just practical.
Four rivets held edge handle in place and that completed this stage of the lid construction.
Now we come to the refractory. This stuff isn’t cheap though I was able to find a reputable
UK supplier with just a little internet browsing. So shop around folks!
Even so, to avoid waste, I filled the base with a dry mix up to the marked two inch line.
I checked the depth then poured the refractory into a bucket for mixing.
Add water very sparingly. You do NOT want a wet mix. Stir it well, a trowel works best,
and ensure there’s no dry spots. The finished mix should compact well but not be sodden.
The mixed content was poured back into the base and pounded down well. Cocoa my Labrador
took the opportunity to supervise my efforts… Pound it flat and level making sure there’s
no air gaps. Then wait ideally 24 hours. The next morning the base was nice and hard.
An old plastic paint can makes an ideal temporary mould liner. It leaves a good inch and a half
to two inch gap all around, which is ideal. The problem is the paint can wobbles slightly,
so I obviously didn’t do a brilliant job of flattening the refractory. I’ll see to that
shortly. I needed to cut a hole in the plastic paint
can to align my waste burner. Adding plenty of temporary weight held the can securely.
Remember the angle of the burner is important. As the can was plastic, I decided to cut the
hole nice and easily using my oil burner and a blow torch.
With careful placement, with just three or four passes I melted a hole just where I wanted
it. Remember the wobbly base? Our friend plasticine
(or play doe, modelling clay or whatever you want to call it) comes it really handy here.
Rolled into thin sausage shapes and pressed around the outer rim of the paint tin, this
will take out any wobble. I took a tiny amount of vegetable oil on a
paper tissue and rubbed this around the paint can. This should help act as a releasing agent.
You don’t need much as all. Just a sheen. I then wrapped cling film around the tip of
the oil burner. Again, keep this thin. Inside my shed, I secured everything in place.
The paint can rests snugly inside the base. The burner is pushed through at just the right
angle and this is secured firmly in place with a few clamps. Any kind of movement needs
restricting. You can see the burner sticking through there
at a nice angle. To avoid the refractory getting inside this, I packed plasticine around it.
Don’t push too hard or it will poke through the other side.
The plasticine stops the paint can wobbling and the refractory getting in, but the filling
process could easily dislodge everything. So I added several scoops of dry sand inside
the paint can. Its weight held everything firmly.
The lid was placed back on the paint can. You’ll see why in a moment.
More plasticine was added to the rear of the burner to prevent any refractory escaping.
This is a wonderful tip from Myfordboy. An ordinary electric sander becomes a fabulous
vibrating tool. I attached a piece of copper pipe to mine with a couple of screws. But
I found this wasn’t enough. With use the screws worked loose. I added a number of cable ties
and this seemed to do the trick. Mixing up the refractory again, this mix was
a little wetter than last time as it needs to move around more. But still, NOT TOO MUCH.
Only enough water to make it move. I’ve seen videos of people making a right
mess trying to fill this narrow slot on a foundry. The paint can lid makes this really
simple. Using a bit of old board and a scraper, just
push the refractory down the slot. Hardly any mess.
Pack the refractory down very well with a stick. Pay particular attention around the
burner as you’ll need to refractory to flow under the pipe. This is where the vibration
tool works wonders. No matter how much you pack it down with a stick, the vibration seem
to make it flow and sink so much more. Eventually the base was filled and this probably
uses more refractory than you’d expect. At this point a scrap of wood made an excellent
striking off tool to level off the refractory. The reinforced rim certainly came in useful.
Don’t rush this stage. Make sure you compact it as well as you can. Work out any air bubbles.
Fill any imperfections and tap out the air again.
When you’re happy, a light hand and a trowel make a nice job on the surface. See how the
repeated beating and vibrating has drawn the moisture upwards?
Now you can see the lid. You’ll notice I’ve screwed the handles down. This holds the structure
flat against a board preventing any unwanted curving and make things more controllable.
And with the lid filled, all we can do is wait for it to dry.
One week on and everything’s looking really good.
We need to take this can out as it’s too weak and won’t survive the heat of the foundry.
Lots and lots of tapping here. It took about 3 minutes of tapping and I gradually got harder
and harder and harder, but it wasn’t shifting. The refractory really grips well.
In the end I had no choice but to grab a pair of pliers.
The scraper removes any dried on material.
A few taps from the hammer help to loosen the lid from the board.
The board is just an old scrap piece. Don’t worry about the marks you’re about to see.
There we are… flip it over… looks quite good doesn’t it?
Now let’s look at the base. As you can see, that dried out a treat as
well. I didn’t to remove the paint can lid now and
hopefully the burner. That’s the right thing to do.
BUT I couldn’t get my burner out. I didn’t put enough cling film on. Please don’t make
the same mistake I did. So I had no choice but to smash the can out. Shame really. I
think it would have pulled out. The vegetable oil really did seem to do the trick.
It’s this pinching and twisting motion that you’ve got to do. It does work but you’ll
probably swear a lot if you have to do it the same way as I did.
Eventually it came free, but the burner is still in the bottom.
You can see the plasticine and a little bit of sand with we can tidy up in a moment.
Here you can see I’ve actually put the castors on to the base. Obviously we need a couple
of lockable ones to stop it from moving. There you go – I managed to get the burner
out. I had to use oil unfortunately which means I have a small oil stain inside my foundry
but other than that it’s not look too bad is it?
And here we have a finished product. I gave it a light sanding, applied some rust killer,
then gave it a few coats of heat resistant paint. All that’s needed now is the light
a small fire inside it to help it dry out properly before introducing it to proper foundry
heat. So I’m going to wrap things up there folks.
I hope you’ll agree with me that this is a nice easy build and you can expect good
things from this design of foundry and if you’ve got any questions, do get in touch.
If you enjoyed watching this video, please like it. If you didn’t like it, then why not
let me know why. I’m always eager to improve my videos.
Your comments and questions are always welcomed as I really love to hear from you so do drop
me a message below. Please do check out my YouTube channel and
of course my other videos. I’ve got about 40 videos out there now and I’m receiving
some fantastic feedback and I’m seeing a real interest from Subscriber, so thank you all
for that, and if you haven’t subscribed yet, please do.
If there’s a subject you’d like me to make a video on, let me know and I’ll do
my best to help. So that’s it for now folks, and thanks very
much for watching.

100 thoughts on “SIMPLE Homemade Metal Melting Furnace (Foundry) for metal casting – by VOG (VegOilGuy)

  1. will this work for temps of 3,600f(2,000c) or maybe a little more?I'm looking to melt real metals not just cans.

  2. It's great, I would have saved my time, and just got a sturdy new steel can though. Castors had me a little concerned, but you have used lockable ones.

  3. Aside from water, why didn't you use sodium silicate? A few months back, I made a refractory for a friend much similar to your concept, but without knowing your video existed. By the way, I subscribed because you have a practical sense of thinking, I admire that. I'll be coming back here for references and such. Keep pushing forward.

  4. im looking at using propane for my furnace fuel. do you think there is an ideal air gap between outside edge of crucible and inside edge of furnace for flame to vortex?

  5. hi. can you see any reason not to have a steel sleeve between the fire coals and the sand plaster mix insulation . im thinking a large fire extinguisher surrounded by insulation inside a mettle drum with a smaller heavy cruicable inside all of that .

  6. A ducting crimper will easily shrink the edge of the bottom barrel so the top will easily slide over it. Big box hardware stores have them cheap.

  7. Are you on Alloy Avenue?
    Great video. I'm a chronic recycler/reuser myself, and i truly enjoyed your project. When it comes to refractory cement, there's no better option. My current furnace is a mix of perlite, sand, bentonite & mortar. It's okay for solid fuels, but now that I'm using propane, a rebuild is coming soon.

  8. This is the most helpful foundry tutorial I have found yet, I have been looking for ideas on the subject for months now. I tried The King Of Randoms design but it fell apart and was to small. I have some good ideas now and intend to try again soon.The fuel has been the hardest part to come up with. I now have a useful plan thank you for taking the time to put together an informative and useful video on the subject.

  9. Out of curiosity, are you wishing in hindsight that you had built the burner inlet more tangent to the edge of the bore so the flame follows the wall and swirls? Just out of curiosity. The first furnace I built had a burner inlet in about the same spot as yours. It was not and issue when I used my 3/4" reil propane burner, because the burner tube was oversized and I was able to aim the burner along the wall. But recently, I built a forced air propane burner, and it is the same size as the inlet, now the flame blasts one spot on the crucible and you can tell as plain as day that the crucible glows brighter in that one spot.

  10. Just found you tonight and what a delight! I have learned much from Thekingofrandom and oil burner as well and I have built 2 foundries- one from a propane tank welded to a lawnmower base using grants refractory material and one much larger inspired by Oilburner that uses a large oil barrel with an internal "keg" sized barrel internally filled with a refractory mix from (Fire Clay/Silica sand/Portland cement/Perilight) – sorry I can't remember who the author was but it works well though it crumbles. I am very excited about your oil feed method and plan to augment my design to assimilate yours. Aluminum check. Brass check. Copper melting here we come!

  11. Although my plan is to build a small foundry, your detail works well for me. Especially the detailed information on the refractory mix. I want something that will last beyond one or two melts. Nice job!

    By the way is it best to buy or make a crucible ?

  12. hello! I have found your video to be, just what I have been looking for; I have plans on melting some steel, and I needed to maintain a working temp. of around 2900f  I watched your video, and I've read your answers in the comments. I know steel starts to boil when the temp hit about 31 to 3200f  I was wondering how long do you think your foundry would last or may I ask how many firings would you guess at a working temp of 2900f plus ??? by the way great videos. maybe a 3'' wall will help?

  13. I liked the build and I'm sure I'll t
    Have to build one now, good job, but I had a lot of trouble hearing you

  14. I like this build better than all the rest I've seen. Actually pretty simple and to the point. I built one but mixed my own with cement perlite and silica sand. it was messy and time consuming. After about a couple of dozen lights it became too brittle and started falling apart. I'm going to try your build see how that comes out. Thanks.
    San Diego, CA USA

  15. Does anyone know if you can use CLAY as a lining for a sub 1500Deg mini forge? Once it's been progressively heated to high temperatures the unglazed clay is surely resistent to high Temperatures and cracking, so is this a suitable alternative to fire cement type products?

  16. may be missing it, but I've read down a fair way and I'm not finding it.. so

    what's the rate of consumption (liter per hour) on your burner? and what temperatures do you get? (max, and average operation)

  17. Part of the reason your food tin gave you trouble coming out of the lid were the ribs stamped in its' side, coupled with the refractory expanding as it cured, locked it right in place for you.

  18. if you watched a little more of grant's channel he explains that the mini metal foundry is more desired to be and easier, in another video he shows how to make some improvements and another completely different design for a more professional foundry

  19. when professionals are using rebar they actually leave the rust on
    not opnly removes rust the scaling on metal but it helps adhere better to the concrete

  20. I have a couple of questions for my maiden voyage. what kind of container are you actually melting the aluminum in or any metal for that matter. I have a fire extinguisher and an old small propane cylinder. both can be used for any project and just have to cut the tops off. thanks for your help

  21. I think you are professor of making excellent, classic tutorial videos. The subtitles are very good idea for those who have problems with understanding of oral narration – this way it is sure even they do not miss any important information.
    As you shown, you had problems by removing of burner although you wrapped it in cling foil. Next time try to wrap it in double side silconized baking paper. You should use at least two but better if three layers, wich are independent from each other. Silcone gives actually some lubrication between layers and makes easier to remove the tuyere pattern. This is just an idea, I have not tryed, but I suppose it works.

  22. what cement did you use?
    do have a link to it?
    just any cement that says refractory?
    what doe refractory mean?
    what's wrong with just any cement?

  23. Appreciate the fact you've taken the time to share this with us but please factor your audio levels correctly. I turned up the volume to hear you and then all of a sudden the intro theme plays at 3x the volume. Scared the shit out of me and my dog.

  24. Great job sir! I am considering making one of these foundries or an electrical one, do you have any idea how much propane gas it is needed to melt say 1kg of aluminum?

  25. I do not know anything about making a furnace but I am very interested in the video and would like to make an attempt at making one myself.I do have some experience of working with making items in mass concrete and I suggest coating the plastic can in oil and then rolling several layers of aluminium foil around it.This should make it easier to remove even BEFORE the the cast has fully hardened.Similarly for the tin used in the "chimney".Thanks for sharing.

  26. Good evening sir I have a question, after the oven was built, how long must I let it dry to use it, thank you from Venezuela.

  27. what is the max heat you think I could get it to with lump charcoal ? I'm using charcoal because I have allot and not enough cash to make a propane or oil fueled 1 :/

  28. I liked your video. I've seen someone else who used refractory cement to make his. He laments the lack of insulating value. Perhaps some insulating aggregate would help alleviate this problem. For the short term, the current smelter could be wrapped in something like fiberglass.

  29. I plan on making one of these, in a similar fashion with the old man. My biggest concern is safety, primarily regarding molten metal and whatnot. (Not all Yank's are fool hardy) but with the oil fuel system, is there any chance the flame itself could backup into the system, causing some sort of detonation/explosion? Especially if someone were to make the mistake of shutting the airflow first? I'm fairly ignorant in these subjects, only having 8-9 hours of a YouTube education. I just don't want to walk into this blind, I'm sure you understand.

    Gloves, long tongs, maybe an apron, good boots, a form of fire extinguisher (bucket of sand). Am I missing anything?

    Also, it could be the angle of which I saw your video, but it looked as if it was perpendicular to the foundry itself, couldn't that be a potential hazard if your base (I don't know the technical term, but the part that actually holds the molten metal) had some sort of failure, to which molten metal could seep out from the oil burn pipe? (Leaving a decent scare and/or a bloody mess in its' wake?) Or is the depth of your base in your foundry sufficient to contain any molten metal?

    Sorry for the long comment, but it seems to me you definitely are experienced, and educated in all this. And I'll trust your judgement.
    Cheers mate, from the Central US!

  30. great vid, this is going to help me lot for making my first foundry. You got my thumbs up for sure, thankyou

  31. It's important to explain the purpose of the vibrator: It eliminates air bubbles from the cement, making the end result stronger.

  32. Geoff – your instructions were duly followed:




  33. It must be a pretty unknowing guy who came up with the "plaster of paris" idea. It is ordinary gypsum and totally worthless as a refractory material!

  34. 14:27 Ooops, That ''bit of an old board'' your using for cement is VERY nice quarter sawn English Oak. Of more value than the forge! 😀

  35. I haven't seen that foundry at work,but it's a whole lot more sturdy,than most. I need to put one of my own together. Thanks for the video!

  36. I think 50/50 sand and plaster is used because it's more porous than refractory cement which can explode due to high pressure caused by expanding gases. what refractroy material did you use? is it porous enough to prevent explosion?

  37. Hiya fella, told you that you have got me interested in this stuff! Quick question mate. I don't have an oil drum like this (could prob get one without too much effort though I guess), what I do have is one of the small calor gas tanks, the same type used for home heaters etc. Would this be any good do you think? The valve was removed some 12 months ago and it has been filled with water many times, so gas and vapour wouldn't be an issue by now (although I will fill it with water again). So what's your view buddy yes? No? Let me know what you think. Cheers fella.

  38. small suggestion for an easier removal of the paint can:before u place it inside the furnace,place around the paint can around the external side some pizza box paper or something similar and fix it on the can with something like insulating tape or similar.
    place the can with pizza box around well fixed to the can inside the furnace and start pouring the refractory cement .
    day after u will have a slightly easier life on pulling out the can from foundry.

  39. Nice work, I just may well copy it, as is a convenient Chippy at the top of my road. Possibility of cooking oil cans and used oil in the same place.
    As an addition, just looked through your other projects, I like some of them to have a go at. I have subbed.

  40. Please don't use wood to support things that create this much heat! Get some steel! It's all over the place!
    Also a more robust container to start with is a great idea since critical failure of the refractory is always a possibility. Old water and air tanks are great choices. If you want to use a propane tank, look up how to make them safe before trying to cut or drill into them. Gas, Air, and Spark makes BOOOOM!

  41. just rewatched Goeff, great vid thank you. I wanted to see how you mixed up the refractory (it looks like we have a similar brand). I'm hoping to put refractory in my foundry today… at last! Horray! cheers o/ #edit… Coco is very cute!

  42. For the folks in the states specifically the Midwest, Menards sells a 25lb bucket of refractory cement and it’s just enough to do the king of random way with a 2 inch bottom.

    Just did mine. Curing it currently. Can’t wait! Thanks for the vid vegoilguy

  43. Sir, you are a credit to maker's community! Thank you very much for such informative video! I've got a stainless steel beer keg that I'll be turning into foundry, now I know what materials I need and can get cheaply in UK! I'm making a miniature car, so will be casting different parts for it, now my question would be how well would normal plaster behave in case of lost wax casting? Do you think it would be suitable?

  44. Why you not using kawool for the foundry isulation is more cheper and more isulanting than refratory concrete.

  45. i gotta say its great to have a consistant speed naration and quality things for the average just starting out building my own foundry and belt grinder (bench sander) with a electric drill as the motor as i have a limited space on my outdoor topstory balcony..gonna be funny when i start slamming 1 smaller shedge hammer in2 a bigger1..itl be a manuaul run bupushing down with a counter weight till i can save enough from knife and sword making to upgrade and use my smaller1 as a smelting foundry

  46. Seemingly good content but horrible audio. Could hardly understand a word he was saying and did not watch the whole video for this reason.

  47. Sodium silicate instead of water. Vacuum bubble extraction. Using paper for liner's & leaving the handle part's of the lid ROUND:-P

  48. I got lucky when I made mine. I work in a paper mill and was able to get my hands on some old cores like you would find in the center of a roll of paper. It was 7" inches outside diameter and 6" inside diameter. Was real dense too, so when I fired it the first time, it burned real slowly with the help of some charcoal and a a gentle air stream through the inlet.

  49. You say in the video that you can recycle used motor oil. Is there any smell to it when burned and is it safe for the environment to burn it? Also, how many melts do you reckon this could handle? I want to start stockpiling copper as a side hustle.

  50. The problem with this design is it is too heavy then too slow to heat up. My own uses a thin layer of refractory, say 2cm, and then low density siporex tiles, which have no problem withstanding 700-800C temperatures. This designs heats up quickly and is durable.

  51. I just used sand for the bottom 2 inches (the flat base). It's cheaper. And easier to clean up the mess if a crucible breaks

  52. How many times can I use that furnace? I heard about 4-5 times, and then we have to "destroy" and build new one.

  53. Do you have the full detentions for this? I mainly want to know how big does the inside cavity need to be (I guess the size of the paint can), and how thick are the walls? Looks like a bit over 2 inches.

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