Welded crucible??

[Woodskevin]

I'm doing my research ahead of time. I plan to one day melt down all my retired brass ammo. My question is has anyone got any experience in welding up your own crucible such as this website. http://www.backyardmetalcasting.com/crucibles.html

[HWooldridge]

Yes, I have made several steel crucibles but they have some disadvantages. They scale (which goes into your melt), they take longer to heat than a ceramic crucible and they eventually spring leaks - might take half dozen or more heats but it's inevitable that leakers always happen at the worst time. A ceramic crucible will always give better results and are not that expensive.

[Woodskevin]

Thanks. My goal is to make mokume for blade fittings. Is there a particular brand/style/company you would suggest purchasing a ceramic crucible from?

[dan_m]

Here are two links to sites you can purchase crucibles from:

http://www.lmine.com/mm5/merchant.mvc?Screen=CTGY&Category_Code=crucibles
http://www.budgetcastingsupply.com/Crucibles.php

The first site seems to have better prices, but they only carry silicon carbide crucibles in a #10 (which holds about 30 pounds) and larger. What size were you looking for? Obviously the way you plan on melting the brass will influence that decision. Do you have or plan on building a furnace, or are you looking for something small you can stick in a gas forge? The second link has very small sizes of silicon carbide crucibles (the type typically used for brass, bronze, etc.), but the first one carries "fused silica" crucibles in small size for very cheap. I have no experience with or knowledge about these, but based on the temperature rating given on the site they should be alright.

Especially if you aren't very experienced with welding, it's definitely a better bet to buy the real thing. If you do decide to make your own, make sure you use heavy enough stock. I've used 1/4" wall pipe on a 3/8" steel plate successfully for a long time with aluminum, but the only time I've ever used a steel crucible for a copper alloy it failed when I was about to pull it from the furnace. If you go that route and want to avoid contamination & inclusions from steel flaking off (which it will do rapidly), there is a product called Marcote 7 available from the second link above that you can coat the interior of the pipe with.

Also, be sure to use a flux—it will form a skin on the surface and prevent the zince & lead in the brass from vaporizing out of the top. Be very careful of the fumes, they are nasty. Good luck!

[Woodskevin]

Thanks for the info. I an to build my own gas furnace in time. My goal is to do things like in this video.

I'm researched this topic and am fully aware of the dangers and need for safety equipment. I'll post my progress in the future. Thanks again.

[dan_m]

That's a cool technique, I've never seen it before. If that's what your doing a steel crucible might even be better since you could make it tall and skinny, just make sure to weld it real well. I'll probably try this at some point too, something neat to do with the leftover bronze before it goes into an ingot mold. Please do post pictures when you're done!

[Bentiron1946]

This is called brazing in my book, not welding, still it does give a very interesting pattern. There is a fellow that uses screws, gears, springs and other water parts in brass and then slices it thin for use in jewelry, also creating a very unique pattern. I don't know that I would want to use a steel crucible more than a couple of times. I have seen fellow make crucibles out of schedule 10 through 40 black pipe and even large diameter screw black and galvanized pipe but a good graphite crucible is hard to beat.

[Glenn]

If you notice the white smoke coming off the melt at a couple of points, I think that may be ZINC fumes. Precautions are needed when this happens, like being upwind AND in another zip code. Been there, done that, no thank you to another helping of zinc.

Just because someone posts a video and says Hey y'all watch this, does NOT mean that it is safe.

[pkrankow]

Another fun point about copper alloy melts in an iron crucible is the copper dissolves the iron, and then you may get a hole. Lots of fun to have a hole suddenly form in your crucible.

[MattBower]

Yeah, be aware that iron is soluble in lots of common metals when they are molten -- including aluminum and copper alloys. That's why steel crucibles don't last that long even if they're being used at relatively low temperatures. The charge dissolves the crucible, and it will indeed contaminate your melt. It's a bit like melting ice in a crucible made of sugar.

These guys have good prices on proper ceramic crucibles, and if you treat them right they'll last a lot longer than homemade steel crucibles:

http://www.lmine.com..._Code=crucibles

A couple notes on melting brass cartridge cases, from experience:

• Dry them really well with a very thorough preheat. The fact that they're hollow makes them especially well suited to holding water, and adding a case with water in it to your molten charge is exciting in all the wrong ways.
• Expect to lose a great deal of material to dross.
• Using a couple tablespoons of crushed glass as a cover flux seems to help minimize the formation of zinc oxide (the white smoke someone else mentioned, which you want to be careful not to inhale). And it gives you a good excuse to empty a beer bottle or two.
• I'm fairly sure I once had a live or partly live primer in a load of fired brass, which I discovered when I added the case to the crucible and something went "bang." It sure sounded like a primer going off, at any rate. It scared the heck out of me and could have done much worse, I'm sure. (I'm certain no one had begun reloading those cases, so if it was in fact a primer that I heard, I have to assume that it was some leftover priming compound that, for some reason, didn't get consumed when the cartridge was fired. I was careful to screen the load of cases for duds, so I'm pretty sure that wasn't the problem.) Again, I think a really thorough preheat would've solved the problem before that case went into the crucible.
  

[pkrankow]

It's a bit like melting ice in a crucible made of sugar.

If you don't mind, I am going to borrow that analogy.

Phil

[Woodskevin]

I'm double checking the deprime process. Great info guys. Thanks.