epoxy works better

input - November 30th, 2007 - Marloes de Valk - No Comments

After the first disastrous attempt at making a cast, I switched from silicone to epoxy. Epoxy becomes solid very gradually so I would have time to wait until it was semi-solid, then paste it into the mold, push the 2 parts together and let it dry. This way I would not have to pour anything through any holes, and the material would be thick enough to be able to spread it over the mold by hand. The only big disadvantage of epoxy is that it takes AGES to harden completely. I got good advice from the FormX shop in Amsterdam. They told me to use a moderate heat to speed up the process. Epoxy is very heat sensitive and with a temperature of +- 40 degrees Celsius things would go a lot faster.


Indeed! My first attempt went quite well, although it was difficult to get the shape out of the mold without damaging it. I have to take it out before it is completely solid, because then it will be super hard to remove it. The key to the whole process is timing and precision. In my first test it took 2 hours from blending part A and B to putting the mixture in the mold, and another 2,5 hours before I could remove it from the mold. Then another 8 hours before it was completely solid. The second test took much longer, I put the mixture into the mold earlier to see if this would minimize the risk of air bubbles. I also did the test in another space with another heater. All this directly affects the duration and result.

A short step by step of the process:

1. Measure part A
2. Measure part B (1/2 of part A) and mix in white pigment
3. Blend part A+B and put on heater
4. Wait +- 2 hours
5. Grease up the molds with vaseline really carefully (otherwise the epoxy will stick to the mold)
6. Stir the material every now and then
7. Poor or push the paste into the hollow mold
8. Push the convex mold into the hollow one and put some pressure on it to keep them together
9. Wait for 2,5 hour +-
10. Carefully open the mold (with a lot of muscle power)
11. If the material is still too flexible, leave the shape in one part of the mold to harden a bit more
12. Take out the shape and let it rest for +- 8 to 15 hours
13. Fine tune the shape using sandpaper, hammers and a blowtorch :) afterwards, polish the epoxy to let it shine

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