RE: Re: [VAC] Expanding foam sealant

[Gene Williams <realty@aristotle.net>]

Gerald,
    The plastic kept the foam from sticking to the box and the product. One 
step I need to add to that was that we placed chemical in the bottom with 
sheeting covering the bottom then as the chemicals reacted to make the foam the 
excess plastic was folded over and the unit was pressed into the mixture to 
form a fit. (The unit was also wrapped in a protective cover of which I don't 
recall the material but had to be a non electrical conductor) If the foam got 
on the box it stuck.  It normally did not get on the box or the unit we 
manufactured. These units were encoders for any thing from oil well tachometers 
to Space Shuttle end effector positioning devices (tells where the fingers are 
on the shuttle arm). As I recall it did adhere to the plastic.

Gene