Hey guys. This week I have been offered a 4kg Devil forge for $100 still in the box by a mate that had grand plans but due to life getting the way he did nothing with it. I was going to build a forge but decided this would be a good way to start as if I purchased one It would cost be approx $350au and I don't think I could even build one for that. For Some time my son (12y) and I had been looking at casting he plays a lot on the 3D printer making trinkets and we spend a lot of time on the mill lathe together working on projects. I have some projects I have in mind that I would like to try I am sure my son will come up with some as well. One of the things my mate doesn't have is a crucible apparently it turned up broken so what's best. We will probably start off small just doing 1kg at a time to have a play I guess start by making some ingots start simple then move on from there, will a 1kg crucible be fine in the forge, I have seen cylindrical type as well can they be used or are they only for the electric forges? PPE is another question so what's everyone using what's required to protect my son and me, won't be kicking off until everything is safe, I work with students daily in school in construction and engineering so WHS is paramount in my books. I would ideally love to bring this into school as well in the future, grand plans Willy
Hi Willy, sounds like you are off to a good start getting a prebuilt furnace for $100, I'm in North Queensland and built my own using premixed refractory concrete which is about $50 per bag to buy from Refractech in Brisbane. I bought Morgan Salamander Super crucibles from Skamol in Victoria and a Vesuvius crucible from Foseco Brisbane. The cheaper crucibles don't last very long so using them is a false economy. If you are casting ingots with steel moulds be sure to heat the mould in the furnace exhaust to drive off any moisture in the surface as they will cause steam explosions and spray metal everywhere. I had a lump of bronze the size of a five cent piece get flung out of a steel mould and get stopped by a common plastic clear full face mask right in front of my left eyeball. It was only there for an instant before disappearing with a loud crack as the dust and moisture on the mask surface blew off the bronze and left a clean undamaged spot on the mask. I wear a cotton T-shirt, long sleeved cotton shirt over that, a leather welding apron with a leather extension sewn on so the bottom just reaches my leather boots, I then use leather welding gloves, a full face mask, glasses under the mask and leather welding spats over the boots. The boots are elastic sided so there's no laces to catch molten splashes and they can be removed easily in an emergency. I have personally seen what molten bronze down the boot causes: a fourth degree burn and lots of skin grafts and a couple of months off work .
Welcome Willy. Yup I’d snap that up for 100. It looks like Mark has the info on supplies. I don’t know how well those cylindrical graphite crucibles would work in that furnace. The type Mark mentioned would probably be the way to go. I’d suggest getting your feet wet with lower melting metals like zinc(zamack) or pewter, then aluminum. Way less risky with a young one as well. As for PPE, cover every square inch, plus face shield and glasses. Water is indeed a real hazard, particularly entrapped water, so preheating tools and ingot molds is a must. 1ml of water turns to 1600ml steam in an instant. Pete
Thanks so much, Mark and Pete for your input, will see how I go my son and I have come to a bit of an agreement that I will look after the hot side with his supervision and he will look after the casting side getting things ready as etc as things progress I will give him a little more responsobility. Will order some other PPE today for us both and look into those crucibles you have mentioned
Hi mark do you have any contact details for Skamol or Foseco looking at their website it's all a bit confusing being an industry site.
There are two main types of crucibles, clay-graphite and silicon carbide which is the more durable of the two and a bit more expensive. Clay graphite is rated to higher temperatures but is less resistant to erosion from fluxes molten oxides and other chemicals. If you're going to be melting non ferrous metals like aluminium and bronzes, a silicon carbide is the way to go. The shape of crucible you'll be needing is an 'A' series for clay graphite or "AX" series for silicon carbide, they both have the same shape for a given size, i.e. A10 and AX10. Skamol's phone number is: 03 9560 4477 freight address: 50 Geddes Street, Melbourne, Victoria, 3032 They sell crucibles as a sideline to their main business so you need to do your research beforehand and see which Morgan crucible type and size you want when you call for a price. They can sell out of the smaller sizes and you have to wait for a new shipment to arrive (last ones were made in India). I have found it cheaper to arrange my own freight and insurance using Transdirect's website: https://www.transdirect.com.au/ you'll need to set up a free account as I found it saves about 30% over getting a quote without an account. Make sure you have insurance option too as I have had crucibles cracked on arrival but was able to get a free replacement. You'll also need the weight and dimensions from Skamol to plug into the freight quote website. Once you pay for the freight you'll get a PDF file with the shipping labels that you'll have to email back to Skamol for them to print and put on the boxes. It sounds a bit complicated but it's the least painless method I've found in Australia so far...some of the other guys insist your tiny crucible box must be strapped to a wooden skid for all orders for an extra $100 or so.
Also try to use the big freight companies as they are less frustrating to deal with, there are quite a few who deliberately hide their contact information and depot addresses as they are such assholes. One company even rebirths their identity every so often due to bad online reviews, they were the one who broke my supposedly insured crucible and went MIA when it came time to claim.... seems the owner is more interested in horse racing than freight service.
I bought a commercial set that is an aluminized heavy "fire retardant fabric" boot covers, open back pants and gloves. I also have a face shield. They are kind of awkward but would probably protect from splashes. I work outside on concrete. If I spill some molten metal it will cause the concrete to pop the surface off. I have sheets of steel where I pour into the molds to catch any overflows. My biggest challenge in casting aluminum is controlling hydrogen bubbles. I bought some commercial stuff that I wrap in foil and push to the bottom of the melt. Helps but not a cure. Preheating the scrap on top of the furnace helps. Lincoln, NE, USA
I think given the size of the DF furnace and the volume of metal probably needed for your casting projects (less than 1kg) you can at least start off with a steel or iron crucible. I started out using 1lb propane cans with the tops cut off. I’d first puncture the can with a rifle and fill it with water to purge the residual gas, pour the water back out, and then cut the top off. After heating the topless cylinder to red heat to burn off the interior coating, it would be ready to go. With the steel can I could lift and pour with pliers (that’s another topic). They would last for a half dozen melts or so of aluminum in a charcoal furnace which I think is probably a more punishing environment than a propane furnace. Conventional wisdom indicates that molten aluminum degrades and weakens the steel from the inside so you can use a wash of some sort inside the can if you think you need to. Otherwise just let it get rusty. Here’s a simple option from the Navy Foundry Manual: ” Aluminum alloys can be melted in graphite or silicon carbide crucibles. The crucibles must be kept clean to avoid contamination. Sometimes cast iron pots are used, but they require a refractory wash to prevent pickup of iron by the aluminum. The pots must be thoroughly cleaned before the protective coating is applied. A coating for iron pots can be made from seven pounds of whiting (calcium carbonate (chalk)) mixed with one gallon of water. A small amount of sodium silicate may be added to provide a better bond. The pot should be heated to a temperature slightly above the boiling point of water and the wash applied. Care must be taken in charging these pots in order to avoid chipping of the coating; which will expose the iron.” Our member Masteryoda uses a stainless steel milkshake cup with some sort of wash and reports great success. A steel pipe with a cap or a cylinder with a bottom welded on would do. The heavier the gauge the better, within reason. You get the idea. A helpful inexpensive book is The Charcoal Foundry by Dave Gingery. It’s available on Kindle as well as paperback. It is a great primer for the beginner and covers the whole process. Don’t let the name fool you. It covers a lot of territory in simple language. Your interested 12 year old will have no trouble reading it either. Pete
Hi willy I just joined this forum yesterday but I have the smallest devil forge and here's some of the things I have learned. I picked up my crucibles direct from skamol. a smaller 1kg one and a 2kg one and I think it cost me round $65 to 70 each, a year and a half ago. I had success in starting off using the bottom of a mocha coffee pot (thick & stainless) did at least 20 pours from that mainly aluminium but also had success with copper and brass, sadly have only poured into muffin tins and food cans(1 time use only). I have used fibre cement board to protect my concrete from splashes etc, but you can't set a crucible on it though. Cold practice the movements of moving the hot crucible and pouring, You will need at least 1 inch of space round your crucible for removal and correct flame path. (size of crucible matters) Hope this helps Jimjam
Iron contamination in cast aluminum is undesirable. It makes the casting more brittle among other things. Best not to use iron/steel containers as crucibles. Controlling hydrogen bubbles is difficult for home casting and also weakens the casting quite a lot. Make sure your scrap is totally dry by preheating it. Pour as soon as temperature is reached to cut exposure to atmospheric moisture. H2O is the source of much of the hydrogen bubbles. The more often you melt and pour the aluminum the more hydrogen bubbles will be incorporated.
