Dog’s Head: Metal Casting Mould by Dissolving ABS Print


A while back I modelled my retard dog’s head with an aim to casting it in metal, somehow. The first attempt was a big fail and I have been ruminating on it since. This post is attempt II.

My dog, Honey Doughnut

The model head of Dick’ead Dog

Lego Man

The first attempt, a half-scale of the dog’s head, was printed in PLA. I thought I could set it in plaster of Paris and then stick it in the oven and melt out the PLA to leave the lost form for casting. Didn’t work.

Another approach, maybe, was to dissolve out the 3D print, rather than melt it out.

The Lego Batman. The cast was to be minus the cape, which is made of ‘Lego fabric’ (what is that?) and the bat tool/wing/weapon.

PLA does not really seem to have any solvents. ABS, on the other hand, goes bananas at a sniff of acetone.  Rather than printing another dog head, I bought a (Batman) Lego figurine as my test subject: Could I set the figurine in plaster, dissolve out the plastic and then cast an aluminium lego man? (Which would be cool, right?)

Rather than describe anything more in detail I’ll summarise in saying this attempt was a total fail. Photos with captions below.

Mr Legoman is encapsulated in plaster. Something obviously dissolving. I cut up wired wool and mixed it into plaster – that’s the brown stains.

Molten aluminium poured in. I knew something was wrong as little or none actually went into the mould.

Yep. The result ;( You can JUST make out Lego-Batman’s feet

Endnote

I have since moved on from the idea of dissolving the print. I wonder though, in retrospect, the dissolving technique was that crap, or if it was just my execution of it. I think the massive fail was more due to the mold design and the mold (the Lego man).

As I tried to pour the molten metal in I think it could not fill the mold because of the backpressure of the air trapped inside. Also, the Lego figurines are made a quite a few separate bits so the flow from one bit to the another would be pretty restricted.

This aside mucking around with acetone and the gloop you get from dissolving ABS in acetone is not that nice.

 

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