Even if you don’t cast or forge metal yourself, you’re probably aware that you need to get the material very, very hot to make that happen. While some smiths might still stoke coal fires, that’s a minority taste these days; most, like [mikeandmertle] use gas burners to generate the heat. Tired of expensive burners or finicky DIY options [mikeandmertle] built their own Better Burner out of easily-available parts.
Everything you need to make this burner comes from the hardware store: threaded iron pipes of various sizes, hoses and adapters– except for one key piece: a 3D printer nozzle. The nozzle is used here as the all-important gas jet that introduces flammable gas into the burner’s mixing chamber. A demo video below shows it running with a 0.3mm nozzle, which looks like it is putting out some serious heat, but [mikeandmertle] found that could go out if the breather was opened too wide (allowing too much air in the mixture). Eventually he settled on a 0.4mm nozzle, at least for the LPG that is common down under. If one was to try this with propane, their mileage would differ.
That’s the great thing about using printer nozzles, though: with a tapped M6 hole on the cap of the gas pipe serving as intake, one can quickly and easily swap jets without worrying about re-boring. Printer nozzles are machined to reasonable accuracy and you can get a variety pack with all available sizes (including ones so small you’re probably better off using resin) very cheaply.
These sorts of use-what-you-have-on-hand hacks seem to be [mikeandmertle]’s specialty– we’ve seen their PVC thumb nut and their very simple mostly-wooden wood lathe here before.
Binzel or Tweko style screw-in MIG contact tips are also useful in this application.
They range in orifice size from 0.8mm to 1.6mm, so there should be one suitable for whatever fuel-gas you decide to use.
Stoke coal is still very common with forging. I can get a 50 liter bag of stoke coals for 30 euro’s that provides me the same (or more) forging time as 150 euro’s of propane.
Propane is clean so it doesn’t give any problems when forging damascus steel. Especially with stainless damascus, the cleaner the better. When doing stainless damascus, the initial forging I do is always using propane and when everything is set and you start drawing out the material, then I switch over to stoke coal. It’s cheaper, easier, you can use precise heat where you want it, easier to manipulate, cheaper, easier to look into the fire (especially with propane forges you really need sunglasses to look into it), it’s cheaper and a lot less heat outside the forging area. I can stand right in front of my coal forge, I wouldn’t dare doing that with my propane forge, too afraid my cotton shirt will catch fire.
I’m not casting yet, planning on casting zamak using lost PLA or other method casting soon. All the casting forges I’ve seen are either electric or gas. The electric ones I’ve been looking at seem very impractical. Takes several hours to heat up and will drain my wallet at the end of the month when the bill comes.
This is the first I have heard about propane being more effective than coal for welding. I’m glad you left this comment, as I wonder if I too would have more success this way.
Have you tried forging Damascus with anthracite coal? I have had some success with that (it happens to be all that is easily available in my area), but I have only tried 1084+15N20 laminate. I do not at present have a propane forge.
Anthracite is certainly a cleaner coal than the bituminous commonly used by most smiths. It’s likely sold for heating furnaces if those are in use in your area — that’s how I get mine. I think it’s sold for air quality reasons. Its almost pure carbon.
It’s much harder to burn. Usually I use a small amount of charcoal and/or left over coke to start my forge, and once I have a nice hot core I slowly start adding the coal. It helps to preheat some coal around the new fire. An electric blower is necessary for sustained burn, and then some way to switch between a high and low airflow (high replaces the times when you’d hand crank, lower is needed to sustain the flame at all).
I have not had the opportunity to play with proper bituminous coal, but can say that anthracite CAN work for forging, despite a few smiths disagreeing on YouTube. It just requires some trial and error, managing it is a bit different.
It’s more effective because it’s cleaner. There is always a lot of sud and with normal carbon steels better to use propane, but when forging stainless it’s a must to have a clean fire. I’ve made carbon steel damascus in coal and it does work but there is a bigger chance of separation.
I have never used anthracite nor do I have access to it. I have only used coke coals. Even coke coals are difficult to burn, which is actually a good thing. I make a tiny fire and put the coke’s on it with air pressure building so it stays on. When I turn off the air it takes maybe 15 minutes or so and the fire is out. So it’s the same thing for both so I assume it works in a similar way.
My propane furnace takes about 20-25 min to melt about 2kg of aluminum. It doesn’t take much longer to heat up 4kg, because most of the heat is going into the furnace walls and getting everything up to melting temperature. So it’s pretty quick, but if you can reduce the thermal mass of the furnace insulation, I think it’ll improve the performance a lot. I wish I’d made mine from ceramic wool with a coating, maybe sprayed on boric acid, rather than the castable refractory I chose. Having a somewhat reducing atmosphere is also nice compared to an electric furnace. But those little induction melting setups are pretty sweet for small quantities of metal, WAY faster than a propane furnace if you just need a few dozen grams of silver, for instance.
I’ve been having a lot of fun emulating the ShakeTheFuture person on youtube (he’s been featured here on HaD multiple times) and melting small (<200g) amounts of just about anything in an old microwave. 200g of copper from start to pour in under five minutes!
I don’t think you can buy coal in California any more, at least not in home use quantities.
First results on google: McLellan Blacksmithing and The Horseshoe Barn, both in California, provide blacksmith coal. I can’t find anything about a statewide ban and I can find many sources that sell bbq coal
Didn’t the RepRap project originally use brass gas orifices as printer nozzles?