Hi Steve,

We use CHR M797 for masking prior to spraying with polyurethane. It's
worked well for years in our application with no residues.

http://www.chrtape.com/Data/Element/Document/document_edit.asp?ele_ch_id
=D0000000000000010477 

KennyB

-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]] 
Sent: Monday, February 05, 2007 5:59 AM
To: [log in to unmask]
Subject: Re: [TN] Humiseal Masking Tape Residues/latex peelable

Hi Steve!
 
The tape is new, and all the operators that we have in our conformal
coating area have been with the company for quite some time now and are
very familiar with the process. I've stood and stared over peoples
shoulders so much that they've felt self-conscious and think that I
think they've done something wrong, which is the last thing I want to
do. I have one senior operator that I trust as my "second set of eyes",
and he tells me that the process is being carried out as it always has
been. First a pre-bake after final cleaning, then mask, spray, wait 1/2
- 1 hour and then de-mask. The boards aren't baked with the tape on, nor
are they hot from the pre-bake, they are at room temperature when they
are masked. 
 
For the time being, I'm going to have the few areas on the assemblies
that we mask and see the residues, de-masked immediately after spraying
before the coating has a chance to cure at all, and see if that helps
the situation. I'm going to do this until I am able to try the tape that
Amol Kane recommended to me, the 3M Scotch 4737T which I am ordering
today.
 
I'll let ya'll know how it works out...
 
-Steve Gregory-

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