3D Printing Aluminum Parts

OK, well not really. But here is what is possible using your 3D printed parts to do 'lost wax' style casting. These parts are for the cooling system on my 1UZ engine. The factory fittings left a lot to be desired for my application.

Two of the fittings with sprue and vents. The plastic cup is the pouring funnel.

A few shots of one of the finished fittings.


The 'line' on this one is from a crack in the plaster mould

Notice the internal diverter to insure water is pulled from both the head and the incoming water line

You can see here the striations from the plastic print show in the aluminum:

Here the fittings are on a mock up engine:

The short of it:

1. Print your parts in PLA
2. Vent & Sprue them using stuff that will melt/burn out (hot glue works great)
3. Embed the parts in a mix of plaster and sand
4. Fire in a kiln to dry, melt/burn out PLA
5. Pull out of the kiln while hot and pour in molten aluminum

Obviously there is more to it than that and there is a steep learning curve. Lots of info on the internet.
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Cool Frank. A few questions:

Got any more info or photos of your sand/plaster molds?
What did you use to melt down the aluminum?
Source for the aluminum you used?


Aluminum came from scrap castings. So something close to A356, but these are not structural. Heat treated to what should be T5, but I have no way to test. But they do machine much better after HT so it is working to some extent.

I’ll post some photos of molds/furnace next time I’m at the office.

Furnace is a cut down 55g drum lined with refractory and with ceramic mat heaters (meant for heat treating in the field). Powered via off the shelf controller/SCR and 50A/240v.

Molds are 2 part plaster/1 part sand/1 part water lined with chicken wire to hold it together. Grit of sand used is important and I’m still experimenting.
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I should add that I used sodium silicate to ‘seal’ the pores since these are water fittings. I am sure modern automotive parts don’t need this, but this casting is a lot closer to old school methods and sodium silicate is the way automotive water fittings where sealed back in the day.
Pretty slick. I haven't sand cast aluminum since junior high and wondered off and on if it would make sense for some parts. Seems like it was the perfect solution for what you needed.
Interestingly I’ve been playing with this lately, I’ve 3D printed custom pedals for my car and am working on the mold now. Nice to know I’m headed the right direction.
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Here are some additional pictures...

When making furnace, this is after refractory was poured:

Controller for Furnace and Kiln. The dials on either side set the 'percentage' of full power that is used. The electronic controllers turn the heaters on/off. If the Kiln and Furnace are run flat out, it will draw about 90A and I only have 50A service run to it.

Furnace when hot...

Kiln. You can see the heater just set in there. The original heaters are toast. Kiln cost me $75.

Kiln loaded with molds.