Electronics Forum | Thu Feb 25 10:30:21 EST 2010 | davef
It sounds like your poly dots are secreting something that affects coating thickness. Is this a function of the adhesive used by poly dot supplier?
Electronics Forum | Fri Feb 26 10:34:03 EST 2010 | kpm135
If I had to guess I'd say they're using a silicone based adhesive.
Electronics Forum | Fri Feb 26 15:41:19 EST 2010 | kpm135
sorry jdumont I didn't see your post until after I posted mine for some reason. If I had seen it first I wouldn't have posted because yours covered it.
Electronics Forum | Mon Mar 01 09:17:56 EST 2010 | duso02
Hey....I think it might be the silicone adhesive! LOL Yeah, that'll do it. We use simple Shercon paper dots. Work like a charm. No evidence of "de-wetting".
Electronics Forum | Thu Feb 25 10:21:49 EST 2010 | jdumont
My guess would be that the adhesive used on the dots contains silicone. We use 1B73 which is also acrylic and it hates silicone. We use silicone RTV to permanently mask around some connectors and unless its fully cured before coating it will cause l
Electronics Forum | Thu Feb 25 07:37:42 EST 2010 | pcbrown
We are using Humiseal 1B31 and polyester dots for masking. We are spraying this in a Binks sprayer mixed at almost 1:1 with 521 thinner. Whe are seeing the coating creating thin halos around the poly dots as if the dots are "rejecting" the coating. T
Electronics Forum | Tue May 19 11:56:59 EDT 2020 | philc
Do you buy in the PCB's from a manufacturer? If so, they may well offer such a service for you. We get quite a few different boards that come with either Kapton tape, or liquid masking already applied.
Electronics Forum | Mon May 18 08:34:08 EDT 2009 | davef
It's happened perviously. If that happens, there is a widespread solderabily issue, not just on selected pads.
Electronics Forum | Tue May 12 22:54:46 EDT 2009 | davef
Did the board fabricator forget to apply the nickel undercoat?
Electronics Forum | Thu May 09 13:49:24 EDT 2013 | davef
First, it appears that your solder mask and your coating material appear to be incompatible. Second, IPA leaves a residue that's probably not compatible with your coating material, either. IPC-HDBK-830 - Guidelines for Design, Selection and Applic
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