Week 09 assignments:

  • Review Safety Data Sheets for each of our molding and casting materials.
  • Test cast materials.
  • Design a 3D mold, machine it and use it to cast parts.

Test molding and casting materials.

I tried 2 different silicone products: GLS-50 from Prochima (used by instructor last year) and Elasil 12H by Angeloni.

Angeloni Elasil 12H kit.

With Elasil the pot life is quite long but the set time it's only 60 minutes!

Angeloni Elasil 12H docs.

Elasil it's an A+B silicone (1:1 mixture), this can be useful to speed up mixing procedure.

Mixing Angeloni Elasil 12H components.

Reading the SDS i found that uncured silicone it's not so dangerous to touch, but anyway i prefer to use nitrile gloves.
Safety glasses are a must.

Prochima GLS-50 kit.

GLS-50 use a more conventional catalyzer (20:1 mixture), anyway for small batches is not a big deal.

Prochima GLS-50 docs.

This silicone has a longer pot time and a waaaaay longer set time: 15 hours!

Mixing Prochima GLS-50 components.

I tried to be as smooth as possible mixing up the test batches to not include air bubble.

Test cast.

Both products claimed the same hardness (12 Shore A) but in the end Elasil is way softer.
Also Elasil documentation claimed that this silicone is able to autonomously remove air bubble and, as you can see from the photo, GLS-50 actually has a lot more bubbles.

Test results.

Machinable Wax DIY

Melting old scraps with fresh wax.

Wax cast.

Wax block leveling.

Mold designing

Extruding our fablab logo.

Final mold design (or not?)

Simplified logo CAM.

Mold machining

Milling wax.

Take 1: disaster!

Take 2: semi-disaster.

Fixed wax mold.

Silicone casting

Testing mold volume with water.

Weighing and mixing silicone.

Silicone cast in progress.

Silicone mold hero shot.

Pottery plaster casting

Local sourced pottery plaster.

Just plaster, water and the mold.

Mixing the water paying attention not to include too many bubbles (100:75 ratio).

Plaster is setting up.

Plaster cast hero shot.


Here is the 3d model i designed.
Crunchlab logo mold model