Wanting to melt some aluminum down and make a mold with sandcasting and was wondering if there was a facility that have the materials to do so.
I don’t know the status of it now, but we did at one time, maybe 5 or 6 years ago do sand casting. We had a forge and crucible that held a about a liter by volume.
We cast aluminum, a saw saw brass cast once, It was done out back where blacksmithing does things. Almost all a saw was done in green sand, although some was done with wax castings, most weren’t.
I’m no even sure where anything is stored, last I saw it was in the closet in 104, NW corner of workshop. Jewelry has some very small capability but anything that had zinc or other toxic gases must be done out doors.
@Team_Blacksmithing may know more
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Last I remember, Fired Arts (now Ceramics) gave the furnace for smelting aluminum and/or pewter (non-lead type) to Blacksmithing, and they stashed it in the back corner of their trailer.
That’s been a few years ago, though.
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From what I know we have some aluminum in the trailer. There was at one time a smelting sig but nothing has happened in a long while. It needs someone to head it up.
I don’t know much more than that.
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John Kuhlenschmidt (@JohnK) has done some aluminum casting. He might be able to help you out.
I think Paul Wilson (@Hardsuit) has done some casting at DMS as well.
AFAIK, @Team_Blacksmithing has not done any official casting.
Cast aluminum has no real grain directionality, right? So if I cast a giant rectangle, allow it to cool, and then face it on the Bridgeport, do I end up with the el cheapo version of mic6 plate? I’m imagining it’d probably have giant Bondo craters in it, but it’d still be pretty cool.
WFT is a mic6 plate?
The type of casting you’d be doing at the space would not have grain direction and depending on the alloy whether it has any temper at all (T-0 or T-4 over time). It would likely have high porosity if it is of any size. Unless you are buying new material it’ll be less than optimal for strength.
You want to gate it so it flows to the bottom first and then sideways and up so hot metal upwards to minimizes the porosity and pushed any slag and as much oxidized metal out. The faster the pour and flow through the mold the better as the effects of cooling are minimized - so get it hot.
If you cool it so the thick and small sections cool more evenly less distortion occurs. The Machinery Handbook should give you estimates of shrinkage rates,
My guess if you get a decent pour you wont have to machine off more than .064"~.125" to get a clean surface free of inclusions and porosity.
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The Googlebeast says:
Is cast aluminum the same as MIC 6?
Overview. Aluminum MIC-6 is cast plateknown for its stability and consistency between plates. It has superior flatness and dimensional tolerances on the thickness which makes it popular for tooling and base plates.
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I looked up some more on it as I wanted to know what class of Alum it is a sort of 7000 series. Another site referred a 6000.
What Are Mic 6 Characteristics & Applications
It appears to be very tightly controlled in it is casting (very controlled cooling, etc). It appears there some references to then be a rolled cast product - which means you aren’t going to do it here or be able to do controlled cooling and hardening, It also appears to be a near net type cast material,which given some of the sizes I’m not sure how the casting is made, I suspect vacuum ovens for porosity control.
I’ve never used it in my aerospace career (a tool room may have - I made parts), which given it is not even heat treated. Air frames wouldn’t have it and jet engines were all super alloys and single crystal types (not AL).
But the characteristics I’m seeing I don’t think you can do it without an oven and a controlled process.
If you try it I’d love to see it done - how large a piece? Sand Casting is fun, my experience is almost all if Lost Wax and vacuum casting, near net type stuff.
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This is the context that I learned about the tooling plate from:
Those printers can display an accurate 3D graphic of the bed’s surface. They probably noticed that the (rolled?) aluminum plate was warping after many cycles heating the bed up to 80°C. For my purposes, I’d basically be making a spoilboard. A successful outcome is a part which allows a grid of coarse 1/4" threaded holes across an area 6" square.
Edit:
There’s an example of something similar to what I wanted to make. The threaded holes require low porosity so it’d be a good starting point. And, it can be pretty bad and still be usable.
Off-topic, but here are some aluminum tools in this video (it should skip directly to 2:02):
