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  for Metal Finishing since 1989
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Silicon Sealant and the Powder Coating Process...whats wrong?

2003

I have a problem in that I want to use some sort of sealant between Aluminium plates that won't react with the following powder coating process.

The material is first dipped in Trichloroethylene at a temp of 80C then wiped dry. Then it goes through powder process and into an oven for 10mins at a temp of 200 °C.

We have tried various High Temp (nearly pure) Silicon sealants which reacted with the process that caused the paint to run everywhere and it took four goes until an acceptable finish was achieved. It looked like the Silicon had run onto the body of the material even though it should be able to stay solid through the heating process.

This leads me to think that the silicon reacted with the Trichloroethylene.

I do not want to apply the sealant after the powder coat so what I need is a sealant that will survive the cleaning and the oven process. Any Ideas/solutions would be much appreciated.

Regards,

Gary Safhill
- Isleworth, Middlesex, UK

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Hi Gary
The general trend in the automotive industry is to use a PVC plastisol for this type of application.
These products are available from most the companies that manufacture windscreen sealants and are usually in the same packaging as silicon sealants.

Andrew Farrow
- Gauteng, South Africa
2003