Aluminium Casting

[Zerohour]

Are there any fellow eco-modders out there that have experience with DIY / Home Brew aluminium casting? There are projects I want to work on, but it requires custom/one off housings and brackets.

I have some metallurgical experience from an iron foundry along with pattern layouts for the sprues and risers. Also involved with projects on the refractories relining, and sand testing for casting quality. But it was all ductile iron and aluminium. I did have a chance for Brass/Aluminium metal casting in a high school metal shop but my project did not utilize the furnace. I'm only looking at a few cubic inches of cast aluminium so I wouldn't be near more than a small crucible (1 liter-ish to half gallon-ish).

If anyone has any tips, directions, other DIY sites I would love the info!

[redneck]

.

Google "backyard casting"



>

[Zerohour]

Oh I have :-p Been doing quite a bit of reading. But there are so many various methods, I feel it would be best to find someone with actual experience. It's always easier to field questions to someone with experience than to read 30 difference sources and go for it on a hunch. With the the lower temps of aluminum, there is a potential for some serious issues and life changing accidents.

Quite seriously I've watched people, wearing shorts and sneakers, casting outside in a grassy field and it looks like it could open up and rain any second. Obviously these are some poor decisions, but there are probably many more less obvious problems that could arise with back yard casting. Another big issue that I see, people seem to just poor aluminium with a cope and drag, but there is not structure holding the sand mold together. If you ever seen a mold crack (or lift and float), you would understand there is a potential for a run-out. If you're not prepared, or have never considered this situation, you could have molten metal pooling across your garage floor near the ignition source or flexible propane lines.

[autoteach]

Well,
I teach high school autos and metals and I have had only one cope "lift" and it was due to very poor mold making by some kids. If you are worried you can stack some cinder blocks on top of the cope so it doesnt lift. I think the real problem with sand casting is strength. I believe that density is lacking and it would probably help to stack another mold on top to add head to your sprue and riser to increase density. I personally like the quality and density of LFC better than sand, and this can be attributed to the insulating property of the ceramic coating. If you have questions, just shoot.

[RobertSmalls]

A cast product is generally going to need machining anyway. For lots of shapes, it may be easier just to have it made on a CNC router. There are places where you can send a CAD file, and they'll send you a part.

small quantity machine shop - Google Search

[Zerohour]

@Smalls:
I do not have access to a proper 3D CAD system at this time. So sending off a cad design wouldn't be quite that easy.

I'm also working on a few projects at once. One requires a few prototype designs. I really don't think I need the lead time to drawing, submitting, quote, order, and waiting to get something done that I could make an afternoon if I had a furnace setup. If I really need a precision design, I will contact a shop. I'm just not anywhere near that point.

@Auto
I'll keep you in mind when I have questions. :-)

I'm trying to go through and make some estimates of what I need versus what I can build versus what I can/should buy. (sometime wasting away a few weekends to get something started isn't worth it if it can be done in a day!).

What kind of setup do you have at the school? Do you have a small brick open? Open top furnace? I would assume you have gas being a school teacher and not a back yard master of trade :-)

-What type of crucibles do you use?
-Do you have re-line the furnace on an set intervals?
-Is it under service contract?
-With LFC, what type of sand do you pack around the foam mold? They did this in my high school, but I believe it was just some type of green sand.
-Where do you get the metal supply? Ingots?

And I'm considering using a charcoal style furnace for the first setup. Simple, cheap, pretty controllable (blower motors are the main source of intense heat).

[autoteach]

Originally Posted by Zerohour

What kind of setup do you have at the school? Do you have a small brick open? Open top furnace? I would assume you have gas being a school teacher and not a back yard master of trade :-)

-What type of crucibles do you use?
-Do you have re-line the furnace on an set intervals?
-Is it under service contract?
-With LFC, what type of sand do you pack around the foam mold? They did this in my high school, but I believe it was just some type of green sand.
-Where do you get the metal supply? Ingots?

We have a natural gas closed top furnace. Graphite crucible (and we have one for steel, i think). I have not had to reline the furnace (dont know if it has ever been done, but it is in good shape). No service contract. Silica sand. We have a large supply of ingots that I dont know the origins of, but I typically do some recycling. I use pistons, cylinder heads, flywheels, snowmobile clutches, etc. The only problem is the silica content in silicon and it seems to just form a slag on the top of the flask. It gets scooped out, of course, and I am not sure how that effects strength.

[redneck]

As far as a foundry goes you could make your own.

A example of a burrner capable of melting metal would be a Babington Burner.

It uses waste oil to heat with, and very little at that.

I built a heater that uses one of these burners and it works well...

Some videos.

http://www.youtube.com/watch?v=7roGxHwv0A4

http://www.youtube.com/watch?v=CjDeG..._order&list=UL

http://www.youtube.com/watch?v=8BUm2BK3-qw

Anyway, it was just a thought for a inexpensive foundry.

>

[Zerohour]

Managed to get one price of this project for the spring. I picked up a used waste oil burner blower. The type meant to be blow the hot air through duct work. Quite literally in the range of XXX cfm powered by a 3 speed, 110 volt, 1/3hp motor. I will no problem getting the coals to superheat and the aluminium to melt. :-)

Was the originally what I wanted, but for 20 bucks. This baby was well worth the motor alone. TY craiglist :-)

[hamsterpower]

I personally don't know anything about casting, but I found this informative and fascinating.

VWVortex.com - The complete guide on casting parts