Lost Foam Bull #4

Here is the original in foam. Glued together with hot glue

I add a pour spout to get a mass of metal to fill the mold.

here it is coated in plaster. Note the straw. Any "high" points need to be vented in order to fill. In this case the important point is the tip of the nose. I then drill holes through the plaster. This allows the steam created when the hot metal hits the plaster to escape.

I heat the mold in a fire to burn out the foam in advance. (not the standard method for lost foam) Then I bury the mold in regular play sand.

The metal is heated with this simple diy home casting furnace using regular charcoal and a normal can that food comes in. Zinc can be scraps or from Rotometals.com.

I then pour in the molten zinc into the mold. A video of another pour back when I used a regular fire.


Here it is after pouring the metal. The little spikes are where the mold was drilled

After this the bull is cleaned with a wire brush and given a coat of clearcoat.

lost foam bull #3

Lost wax bull with packaging peanuts

This was another failure where the mold blew out. Just wanted to post the image in wax so you can see what it would have looked like. This was done but making a silicon mold of a few packaging peanuts. making a ton of copies and then assembling. An aside to the whole lost foam bull fiasco.

Lost foam bull #2

Lost foam bull #2

not sure why. much less problems with lost foam bull 1. I think I have it figured out for lost foam bull 3. going to do a "burnout" or washout of the foam with acetone. the other big change is moving away from using any of the more dense pink foam. much harder to burn out. I think that joint to the tail gave me major bubbles.

I have also added a new tag Failure to all the old posts that meet my criteria.

Lost foam with packaging peanuts.

The current system:
Packaging peanuts are glued together with hot glue and pour spouts are made out of pink insulation.I have used both drywall mud and plaster and found that plaster is much better for holding the shape.



After the foam is coated with plaster it is buried in play sand and the metal is pour over burning out the foam.






Concerns:
Cleaning the plaster off is a pain. Currently I do it by soaking the piece and working out the plaster with a fine metal tool and a wire brush. I was thinking a pressure washer or sand blaster might work well.
The hot glue sometimes obstructs the profusion of the metal. In this piece one of the rear legs is not getting the metal.

 buy my ingot from Rotometals. also available through Amazon.