If you’ve ever wanted to do some serious metal working you’re going to need a method of heating the stock. Here’s a build that combines a brake drum and some plumbing fittings into an entry-level forge. It’s a pretty cheap start to see if Blacksmithing is for you.
[Asuka] says that the parts cost him around $40. The brake drum was sourced from a local salvage yard for ten bucks. To that he added a shower floor drain plate to keep the fuel from falling into the air inlet. We have doubts about how long that thin metal screen will last once the coal really gets going, but heat rises to who knows? On the bottom of the drum he mounted a pipe flange with some nuts and bolts. Galvanized pipe fittings connect to this to inject air into the forge. Right now he’s using a compressor and some garden hose to fan the flames, but plans to get a fan from the auto salvage for a more permanent setup.
A note for beginners. Blacksmith work can be dangerous. We’d like to point you to this discussion thread about injuries.
Would this get hot enough to melt aluminum stock for DIY investment casting?
yes. If you pump some air in. I used a large coffee can to hold the charcoal, a bathroom exhaust fan for a blower, and heated the aluminum stock in a smaller coffee can. This would work slightly better ’cause it will hold in the heat.
A second drum on the top would be even better. A clam-shell arrangement. Just have some way of lifting the top drum, or make the can small enough to fit through the hole in the center.
Just be careful, the blower will blow hot embers all over the place. Make sure you’re not around dry grass or anything.
What do you use as fuel? Just BBQ charcoal?
Not briquets – those are creosote-packed sawdust. Instead, you want the natural lump hardwood stuff. it’s sold under different brand names regionally, but it’s the stuff which actually looks like charred piece of wood.
Excellent info. Thanks.
Would aluminum cans be useful as stock, or do they burn up before any decent amount can be poured?
Aluminum cans are waaay too thin to forge. While it is possible to forge aluminum the window where it is possible to is relatively narrow.
You’re thinking of a foundry. Foundries are used for smelting ore, and casting parts. A forge is used for shaping metal below its melting point. Forged parts are typically stronger than cast parts due to the alignment of crystal grains in the metal.
You can melt aluminum in a home made foundry , even with charcoal fuel. to minimize the formation of dross it’s best to start each melt with a small chunk of solid aluminum and then add cans to the molten pool. The high surface area of cans tends to form lots of dross if you melt them alone. You’re also better off using extruded aluminum for machine parts since it’s a different alloy than beverage cans.
I once used a barbecue grill from a little Weber to keep the charcoal from falling into the airflow (generated by a hairdryer) and the influx of oxygen plus the forge heat burned the metal just wonderfully. Now there’s this nice drippy little liquefied part in the grill. It looks cool, but not exactly what was expected.
You’re better off to use something ceramic and fireproof. The whole point is to soften metal, and who knows what that drain is made out of. Probably something softer than carbon steel, I know mine is made out of brass.
Still, I’ve heard about this method and it’s nice to see a post about it here on HaD
Some bricks can melt near air inlet in such forge (that was a surprise for me), so not every ceramic will be enough.
So, a couple of points:
Firstly, if you go this route, you must not use anything galzanized. Zinc fumes are very hazardous to your health. Use black iron pipe fittings and flanges, and use stainless nuts and bolts.
Secondly, andar_b’s point is a great one. You’ll want to line the inside of your brake drum with something suitably refractive. Fireplace cement can be had easily in very small quantities suitable for this kind of project.
Third, you’ll want to engineer some kind of tuyere airflow device. This may not be strictly necessary, but in the long run, it will simplify the task of regulating the fire.
And finally, an old hair dryer works the biz as a blower, or the outlet of a shop vac.
s/galzanized/galvanized/
I built a setup like this when I was in high school. Dad was an appliance repairman and had an old dryer lying about. The only thing that worked was the timer and the blower, so I hooked it in. I never mastered the craft, but I blame the lack of proper blacksmithing tools (the only hammers I had were a 16oz claw hammer and an 8 pound sledge).
Once the zinc has been boiled/burnt off the metal fittings, it will be safe subsequently. Although metal fume fever from zinc will give you a one off dose of chills/fever, metallic taste, sore throat and sore eyes that night, you’ll be OK the next day.
So, re: zinc, get it up to forging heat for a while while standing up wind, and you should be good thereafter.
You should be much more careful though if casting lead or salvaged antimonial lead battery plates, as hand mouth absorption is very effective +/- inhaled vapours in the absence of handwashing and local exhaust/ventilation, and the effects are longlasting and cumulative.
Why not try a leaf blower for the bellows?
A leaf blower is far too powerful. I made a small furnace for melting aluminium a similar size to this and a small hair dryer provides more than enough air as StripeyType mentioned. That furnace also used charcoal.
We did this when I was in 6th form and the school’s gas forge was condemned.
It works really well but if you have your hair dryer on too high and you’re using coal, you end up producing lots of clinker (molten coal).
We also found that the constant airflow was enough to keep most of the pipework and the plate stopping the fuel escaping, cold enough
6th form?
He’s in the UK. Basically translates to a junior or senior in high school.
Age around 16 to 18. Final 2 years of school in the UK.
About 11th grade in US
In the UK, probably in junior year of high school.
I thought clinker was clay that was mixed in with the coal that turns to brick…
Would a propane burner for deep frying a turkey not work? You can get those for less than $30, especially after thanksgiving.
No. I use a propane burner from Bass Pro for melting lead and tin (I cast bullets), but it’ll never get hot enough to soften steel to any significance for forging, which needs at least 2,200 F
there are some very good web sites that detail making your own forge, from basic to advanced. it personally use a propane fired forge and it works real good if you are looking for hammers try junk or thrift stores. for a small gas forge use a old camping type propane tank. i have an anvil from harbor freight (65#) works great for small projects, such as knives, hinges and other hardware.
Heh, any blacksmith will tell you anything from harbor freight is an ASO (anvil shaped object) but for small stuff they work just fine. Usually dent pretty easy though. My dad and some friends made me an anvil from a chunk of railroad track. They tempered it in their big coal forge, then heat treated it in a smaller propane forge. Still dents up but only if I miss with my 5 pound hammer.
Yeah, railroad tracks make a nice anvil, but have someone keep an eye out for trains!
I built a small forge on 20 bucks. I used a pie pan and a stock pot from walmart and a hair dryer from the thrift shop. Angle grinded a hole in the pot drilled some holes in the pan then coated it in refractory cement. It works fine i still use it for smaller projects.
The plumbers in Toronto are going to be growing their companies anytime because they know the market is going to take off. Thanks for sharing this information.