Here's what I want to do...

[latzanimal]

I wish they spent more time on the casting, but does it give anyone any ideas?

http://www.youtube.com/watch?v=5aw7rd3Msto&t=16m48s

[Jammer]

Sure, they make it look easy. More time on the mold making would have been helpful. With the shell being metal, I wouldn't think the tensioners would have to be so bulky. Kind of hides the Brass. Maybe add a ring to the mold to allow the tension bolts to screw right to the drum shell. I better apply for a patent before I say any more.

[latzanimal]

That casting looks to be quite thick when they are holding it up on the chain. At least .75" thick....

[Harry]

Sure it looks easy and would be with the right setup. Most of us are single hand casters so that puts us out without some sort of pouring crane or tilting furnace. Rasper I think does some pretty good sized bronze pours but I dont know if they are that big and the only other people would be BobS or Kent that I know has that capacity.

I have been working on my foundry and just about ready to move up to an A20 which is probably still smaller than that and I wont be slinging anything other than aluminum in that without full dress gear and a helper. My current foundry would even be tough to do that but I think I could plot the steps and make it fit.

Whats the $ number you have in mind on this piece that would make you happy? Tossing that out there might stir some interest. have you checked with a local foundry? Seems somebody would love to pour these for you.

[latzanimal]

Whats the $ number you have in mind on this piece that would make you happy? Tossing that out there might stir some interest. have you checked with a local foundry? Seems somebody would love to pour these for you.

Well, I'm not sure. I talked to a local (2 hrs away) that does a lot of sculptures/artwork and he wanted $700 to pour it with me making the plaster mold. He uses the lost wax method. I've thought about asking to just rent the foundry if I were to supply the sand/mold. Then I could help him pour...

[latzanimal]

Here is the place... http://www.harryspell.com/

He is a former music professor from a university, so he was intrigued when I talked to him the first time. I think if I were to talk to him some more, perhaps in person, I could get his price down, and possibly go forth with my idea.

I'd love to build my own foundry, but I really just don't have the time right now....

[dallen]

I've helped do some NiBrAl pours that were 75 pounds of molten metal. Harry I hope you got some really big arms cause that A20 hanging on the end of a pouring shank is gonna feel like a ton doing it by your self.

depending on how thick and how tall the shell is I could probably do it with a helper. but the real problem for a home caster to do it is going to be getting the melt to be gas free so you don't end up with a shell that has a million tiny bubbles like a glass of Champagne.

David

[Harry]

Just going to be aluminum in the A20 David, I am a pretty big guy but I dont think I want 60lbs or more at 2k* handling it single jack, at least not with my current setup. It could be done easily enough with some overhead help.

I dont use a pouring shank, I just lift and pour using my tongs. I put a cross handle on one of the legs I hold as a pivot and use the other hand at the end to hold the two together and for leverage. Works well for me and saves the step of setting the crucible down into the pouring shank then picking it back up to return to the furnace.

[latzanimal]

but the real problem for a home caster to do it is going to be getting the melt to be gas free so you don't end up with a shell that has a million tiny bubbles like a glass of Champagne.

David, can you explain a bit more? What causes the gas bubbles and how do you avoid them?

[dallen]

the bubbles are cause by gas absorption, Brass/Bronze does the same thing that Alumium does, it absorbs gases from the atmosphere like oxygen and it has to be degassed before pouring or you end up with a part that has a million tiny holes in it.

Some Aluminum castings are just put in a vat and pressure is applied to the vat so that a sealer is pressured into the metal which seals the pours. others are cast with a alloy and proper degassing procedures so that there are no bubble or pores in the metal.

The most common degasser for copper based alloys is Phosphorous, real old timers used to use straight Phosphorous that had to be kept under Kerosene to keep it for burning. most now days use a Phos shot, or you can use Brazing rod that has Phos in it and just adjust your alloy to accomidate the added addition of the extra copper if your real picky about the alloy.

Most big foundrys use and Inert gas to flush the melt with, most home casters this is way to expensive to do, same thing works for aluminum and the same thing goes with using it is that for home casters like me its way to expensive. for someone like Harry that does a ton od casting and is selling his product, its a good thing cause all he has to do is stick a wand in the crucibe a couple minutes before pulling and pouring an his melts bubble free.

Aluminum has and affinity for Hydrogen it loves the stuff as copper love oxygen, aluminum will absorb enough hydrogen from the atmosphere on a really humid day to cause the melt to be porous, dirty metal added to a crucible can cause it, the clear coat on car wheels causes it really bad so I melt em into ingots them use the stuff or use it for things that don't matter.

When we did SVSeekers prop blades they had pours in them little tiny all most to small to see bubbles cause from the burner, the atomosphere, who knows, we fluxed with a combination flux and degassing agent but still ended up with it, more then likely from not enough experience in casting the NiBrAl, stuff sure was pretty when finished.

hope that helps, you ever get the Monarch to working saw your post on AA looks great