Large Scale Central

Putting it here

Not sure where this fits. But I have enjoyed casting. First it was casting lead fishing tackle as a kid and adult. Then came casting resin and pewter in RTV molds. When I was a kid in Jr high I did a little bit of sand casting in shop class and some lost wax casting in arts class. All of it I find very rewarding. I want to step up my game and cast aluminum and brass and do some sand and lost wax casting. In order to do this I need something with a bit more umph than a propane torch. So starting last spring I began researching foundry furnaces. As a DIYer I won’t buy what i can make. And there is a plethora of info on the web about making mini or micro founderies. Here is the one that gave me the basic Idea.

I am going to make mine using an outer coffee can and an inner can qt stain can and the bottom of another coffee can cut down to make a lid. You mix plaster of Paris and sand for your refractory and suspend the inner can in a solid mass of refractory. I will drill a hole through both cans to fit a 3/4 galvanized pipe. Then I will pour the refractory in and around the inner can and the burner tube. Here are the piece of my furnace.

The little stainless tube is siliconed in place only for filling the lid with refractory. It can then either stay there or come fall out. Its just to form the vent hole in the top. I am thinking of redoing it and making the hole larger before I pour it so I can feed in small amounts of metal without removing the lid. But at any rate this will give you the basic idea. Now in the vid they don’t use an inner can. They form it with a plastic cup and then remove it. Not sure if thats necessary. I am thinking the inner can will add some strength and keep the refractory in place even if it decides to crack. At some point the inner can may burn out but if it does it does.

And finally the burner. I am making a different version than the one in the vid. I am using one in another vid that is a little larger and looks as if it puts out more BTU if flame, noise, and fury are any indicator. I took an old propane weed burner and took off the end and then fashioned the burner mechanism to screw on it. I am hoping the burner mechanism with stay poured into the furnace and I can unscrew the weed burner if I need to separate them. These burners that people are making for furnaces and forges are a pretty simple affair whereby an orifice is either made or bought (mig welder feed tip) and is suspended by set screws into a bell reducer and a pipe. As the gas passes out of the orifice and down the tune it creates a venture in the bell reducer pulling in air as well adding to the fury. Propane is supposed to produce enough BTUs to melt brass. We will see.

Here is the one I basically copied I have it started where he fires it up. If you want to build one you have to watch fromt he beginning.

Hopefully by the weekend I will have a nice little foundry for melting brass and aluminum. Stay tuned because I have a recipe for making my own casting “green” sand and plans for a sling caster where by you swing molten metal around your head.

I hope you wear something other than your tinfoil hat when you are slinging molten metal around your head. I can hear the story now …”hold my beer … hey, y’all watch this”

Dan Hilyer said:

I hope you wear something other than your tinfoil hat when you are slinging molten metal around your head. I can hear the story now …”hold my beer … hey, y’all watch this”

Nothing is worth doing if it doesn’t require a trip to ER

When I slung a hand caster, it started near my feet and went up, higher than my head, but not over or around.

Be careful and up your insurance please…

John did you keep it out in front of you like this guy does?

this doesn’t seem so scary if you fling it out in front of you feet to chest level.

Our sling was a lot longer and we used oxy/acet with a rosebud tip, no foot pumping. We cast sterling silver. Oh it was over 40 years ago …(https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)

Yeah the heat source kinda sucks thats why I am building the foundry furnace.

So you use a longer lead on the sling. I saw one video where the length of the lead was about waste high. He put the flask on the ground and was able to stand up fully before whipping it. It then flung basically from ankles to head in a circle off to his side. Does that sound more right.

Also was wondering about burning out wax from the flask. I have seen burnout ovens made from clay pots put on propane camp stoves. I was wondering if my foundry furnace would work. I don’t see why not if its hot enough to melt brass is should be hot enough to burn out wax.

Yes arm extended waist high, don’t want a ground strike!

You need a high heat burnout to burn up the ashes, I have no idea if your set up will work. Try it with cheap base metal and see.

I’d have to look up the numbers, but we took it up to red hot 1800Fs and cast in the 850-900F range… big if… IIRC(https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-sealed.gif)

Wear a respirator, that silica can pop with heat…

Devon Sinsley said:

Dan Hilyer said:

I hope you wear something other than your tinfoil hat when you are slinging molten metal around your head. I can hear the story now …”hold my beer … hey, y’all watch this”

Nothing is worth doing if it doesn’t require a trip to ER

Well, if this goes bad, you won’t have to worry about your brain drain getting stopped up anymore, this is going to burn a large enough hole you could run the Snake River through (https://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-tongue-out.gif)

Devon, if your heat with propane and air is not sufficient, look for a DIY burner with additional O2. You will increase the heat to the point where it will cut steel in an appropriate torch.

Getting closer. I have about 3 pounds of scrap brass. I should be melting and at least sand casting by the weekend. The fling casting will have to wait. To much to buy in that dept yet. Need all the wax and flasks and investment and then there is the matter of a maybe needing a burnout oven. But I am hoping the furnace will double for that. I will be buying some kitty litter and sand this weened to make my green sand. Of course there is still the little matter of the MIK project.

One nice thing about working for a water utility is the availability of scrap brass.

Devon Sinsley said:

Getting closer. I have about 3 pounds of scrap brass. I should be melting and at least sand casting by the weekend. The fling casting will have to wait. To much to buy in that dept yet. Need all the wax and flasks and investment and then there is the matter of a maybe needing a burnout oven. But I am hoping the furnace will double for that. I will be buying some kitty litter and sand this weened to make my green sand. Of course there is still the little matter of the MIK project.

One nice thing about working for a water utility is the availability of scrap brass.

And Lead …

No lead. we proved that.

Now ther is lead in old school brass so even though I am not casting lead, I am. Respirator is a must.

You might want to reduce the size of your junk. … a 5’ section of sewer pipe filled with water and molten metal dripped into it to make ‘shot’. Helps to make a uniform melt. Either a quartz or carbon 1/4" rod to stir your melt in the crucible. The carbon rod is good to fish out impurities. Use enough, but of course, not too much, flux. Welders gloves help here…

I find this entire topic to invoke a mixture of horror and excitement. And I feel the need to see videos but hope none of them show Devon losing or marring body parts…

John: you seem to have an amazing amount of experience in this. Devon: I hope you heed all his safety warnings…

John Caughey said:

You might want to reduce the size of your junk. … a 5’ section of sewer pipe filled with water and molten metal dripped into it to make ‘shot’. Helps to make a uniform melt. Either a quartz or carbon 1/4" rod to stir your melt in the crucible. The carbon rod is good to fish out impurities. Use enough, but of course, not too much, flux. Welders gloves help here…

Funny you mention that John. I was just looking at making shot. I was thinking that ingots would not be the best plan. So once I fire this furnace up I will take my brass and aluminum and make shot for future pouring. Plus I will have lots of slag initially ass well to deal with.

Flux? For? I have used flux in soldering but what am I using it for in melting and casting? I have not seen that described yet. Fill me in.

As for stirring what about a stainless steel spoon? Thats what I see almost all these guys using to stir and remove the slag. I have not objections to a quartz or carbon rod where do I get one?

Jim Rowson said:

I find this entire topic to invoke a mixture of horror and excitement. And I feel the need to see videos but hope none of them show Devon losing or marring body parts…

John: you seem to have an amazing amount of experience in this. Devon: I hope you heed all his safety warnings…

John and I have conversed on this topic many time already. He did this as a profession as a jewelry maker. So I am relying heavily on his experience. As for safety, yes I promise to be as safe as possible. I need to get me a face shield. I have heavy welding gloves. i should consider a leather apron as well.

Casting Fluxes

Flux can be used for seasoning crucibles, keeping materials liquefied for easier pouring, and for removing impurities when refining your metals. … Simply add them to your melt to draw out impurities and refine your metals.

https://pmcsupplies.com/casting-supplies/casting-fluxes

We used mostly Borax and Boric acid powder… I used boric acid in denatured alcohol for an anti-oxidation coating and Batterns self pickling

For soldering;

(https://encrypted-tbn0.gstatic.com/shopping?q=tbn:ANd9GcRk5ifxa53Y9reRBpEseFMg2gmeSLVJX-DSMa5_htewb6OG9IHB2ACowRNeeh-y8rlaC0fD9MAq-JdZ-s8iiI3GAzOkx8XW&usqp=CAY)

Works fine with brass and I had it on hand.

What the flux!

Devon Sinsley said:

As for stirring what about a stainless steel spoon?

Stainless is all the rage these days!