Mike

Frankly you are going to enter some issues because removing the  
silicone will prove almost impossible.

Unfortunately you will find a significant increase in de-wetting and  
probably some issues with masking materials if this is not dealt with  
thoroughly enough.

Your reply implies that this is a spray booth so:

Replace the complete feed set. New lines, guns, nozzles etc., and then  
try to have all surfaces that are/have been exposed to the coating, re- 
surfaced.

Of course the material behaviour will be different so you may need to  
check over your inspection procedures.

Hope this helps

Graham Naisbitt

On 6 Jun 2008, at 16:04, Mike Johnson wrote:

> We are considering changing our pcb conformal coating process from a  
> silicone base material to a urethane base material.  Other than a  
> thorough cleaning of our machine, replacing material delivery lines,  
> complete disassembly and cleaning of nozzles, ordering new nozzles  
> to meet viscosity requirements of new material if necessary, are  
> there other concerns we should be addressing?
>
> Mike
>
>
>
>
>
>
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