Hello Bob

Its down to the silicone resin used. We use a certain silicone resin for 
our masking boots that does not leach out any harmful contaminants in 
normal processing. You also have to be careful how you clean the boots 
after. Attacking them with solvents can cause some leaching.

Drop me a line if you need further info on this.

Best Regards

Dr Lee Hitchens

SCH Technologies is a Division of SCH Services Limited
Mob: +66 (95) 418 5931

www.conformalcoating.co.uk
Skype: leehitchens
  
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On 21/06/2017 20:55, Bob Wettermann wrote:
> All:
>
> After the last discussion of masking tape I happened to be involved soon
> thereafter in a time study of using re-usable "boots"/"caps"/"plugs" to
> protect components in the conformal coating process.
>
> Like most who perform coating we spend an AWFUL lot of time masking and
> demasking in these projects and are always looking for the best method.
>
> We have used the silicone-based boots and have been successful on larger
> repeated projects to use them 250-300X. They are fine for spray coating for
> medium density boards.
>
> The time to mask and demask ,depending on the complexity of the part and
> coating being applied as well as the application method determines whether
> or not the boots make sense. We are partial to the silicone-based boots
> (though with the caveat described in the previous posting about trying to
> get silicone out of the shop-especially for medical applications).
>
> I am wondering if there have been any favorite materials for these boots
> amongst the coating community other than silicone?  If so how do you find
> the boot matches your process and actually derives the time-savings benefit.
>
> Thanks
>