A few months ago I started having delamination issues in the ocular prostheses. When we make prosthetic eyes, part of the process involves grinding off some material, painting on this surface, and then curing the same material over the painted surface. Delamination occurs when the two halves of the material are not properly bonded to each other.
In some scenarios it affects the aesthetics of the eye and should be fixed to make the eye look acceptable. When delamination occurs along the edges, it can easily trap fluids and bacteria in the prosthesis. In extreme cases, the two halves of the prosthesis may come apart and the prosthesis needs to be re-made. If you wear a prosthetic eye and see delamination in the prosthesis, you should see your ocularist immediately.
There are many valid causes of delamination. When I spoke to other ocularists, each person suggested a different factor, including:
- the use of oil paint instead of dry pigments
- closing the mold after the mixture has bench-cured too long
- improper curing time and temperature
- rapid cooling of the mold after curing
- combining different brands of the same material
- a bad batch of materials
I looked into most of these options but none of them fixed my problem. I was using the same materials and techniques (or so I thought...) that I had been using for four years, so it didn't make sense.
After two months of trial and error, I noticed that delamination occurred more often when I didn't tighten the press as much as I used to. I had been informed several times in the past not to over-tighten the compensating press (because that's what the springs are for) so I was gradually using less force. I started tightening it more, and the problem completely went away.
Conclusion: Don't over-tighten the press but don't under-tighten it either. I would think about purchasing a desktop hydraulic press and a torque wrench to make sure everything is tightened properly.