That dots look fine, good coating around the hole. We use EZ-peel from Caplugs by the way. Are you using a rattle can or mixing it yourself? On Feb 28, 2017 16:58, "Steve Gregory" <[log in to unmask]> wrote: > Hi Phil, > > We've been using Shercon KD Kwiky Dot Discs which are supposed to have an > acrylic adhesive: > > http://www.all-spec.com/Catalog/Adhesives-Sealants-Tapes/Tapes/Dots-Discs/ > KD00312-45075 > > Those aren't the ones you are using are they? > > Steve > > On Tue, Feb 28, 2017 at 2:35 PM, Nutting, Phil <[log in to unmask] > > > wrote: > > > With our acrylic conformal coating I noticed a blooming effect around the > > masking tape dots. It turned out that the tape dots had changed from > > acrylic adhesive to silicon adhesive. > > > > Phil > > > > -----Original Message----- > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory > > Sent: Tuesday, February 28, 2017 4:19 PM > > To: [log in to unmask] > > Subject: Re: [TN] Baking before conformal coating > > > > I don't know what the heck is going on here, but try these links! > > > > Arrrrrrrrrgh! > > > > http://stevezeva.homestead.com/Conformal_dark_spots.jpg > > > > http://stevezeva.homestead.com/Conformal_dark_spots_close.jpg > > > > http://stevezeva.homestead.com/Conformal_dark_spots_ > > close_reflected_light.jpg > > > > Steve > > > > On Tue, Feb 28, 2017 at 2:14 PM, Steve Gregory <[log in to unmask]> > wrote: > > > > > Oh shoot, I sent thumbnail links! Here try these: > > > > > > http://stevezeva.homestead.com/Conformal_dark_spots.jpg > > > <http://stevezeva.homestead.com/Conformal_dark_spots_thumb.jpg> > > > > > > http://stevezeva.homestead.com/Conformal_dark_spots_close.jpg > > > <http://stevezeva.homestead.com/Conformal_dark_spots_close_thumb.jpg> > > > > > > http://stevezeva.homestead.com/Conformal_dark_spots_close_ > > > reflected_light.jpg > > > <http://stevezeva.homestead.com/Conformal_dark_spots_ > > close_reflected_light_thumb.jpg> > > > > > > > > > Steve > > > > > > > > > On Tue, Feb 28, 2017 at 2:07 PM, Steve Gregory <[log in to unmask]> > > wrote: > > > > > >> Hi Doug, Lloyd and everyone, > > >> > > >> Here are some photos: > > >> > > >> Area under UV light (BTW, that's my Ray-O-Vac pet pee-pee detector > light > > >> I bought at Walmart): > > >> > > >> http://stevezeva.homestead.com/Conformal_dark_spots_thumb.jpg > > >> > > >> Close-up of area under UV light: > > >> > > >> http://stevezeva.homestead.com/Conformal_dark_spots_close_thumb.jpg > > >> > > >> Close-up of the same area under reflected light: > > >> > > >> http://stevezeva.homestead.com/Conformal_dark_spots_close_ > > >> reflected_light_thumb.jpg > > >> > > >> So you can see that the area is indeed coated. This is Humiseal > 1B73.... > > >> > > >> Steve > > >> > > >> On Tue, Feb 28, 2017 at 1:51 PM, Douglas Pauls < > > >> [log in to unmask]> wrote: > > >> > > >>> Argggh Steve, we know ye to be a pirate anyways...... > > >>> > > >>> I had the same question come to mind as Lloyd asked. Pinholes or > > >>> dewetting? Pinholes can be due to moisture coming out of the board, > > but is > > >>> most often point sources of contamination, like droplets of oil or > some > > >>> other adulterating contaminant in the coating. A picture would help. > > >>> > > >>> > > >>> Doug Pauls > > >>> Principal Materials and Process Engineer > > >>> Rockwell Collins > > >>> > > >>> On Tue, Feb 28, 2017 at 2:20 PM, Steve Gregory <[log in to unmask]> > > >>> wrote: > > >>> > > >>>> Hi all, > > >>>> > > >>>> I'm not trying to hijack this thread, but since we're talking > > conformal > > >>>> coating here, what could cause an acrylic to appear that there are > > tiny > > >>>> little fisheyes in the coating, but when you hold the board at an > > angle, > > >>>> you can clearly see that the area is coated. I know pictures would > > help, > > >>>> I'll see if I can get some.... > > >>>> > > >>>> Steve > > >>>> > > >>>> On Tue, Feb 28, 2017 at 12:59 PM, lduso - Diamond-MT.com < > > >>>> [log in to unmask]> wrote: > > >>>> > > >>>> > We do not pre-bake as an internal rule and never a complaint. > > Obvious > > >>>> > exceptions: We are washing or cleanliness testing the boards. Then > > we > > >>>> will > > >>>> > bake them dry before masking and coating. Or the customer > > specifically > > >>>> > requires a pre-bake on the drawing. (I always then ask the > question; > > >>>> "How > > >>>> > long after the bake do I have to coat them before they need to be > > >>>> baked > > >>>> > again?" Strangely, only a few have an answer for that.) > > >>>> > > > >>>> > I have visited many facilities that conformal coat and I have > > >>>> witnessed it > > >>>> > both ways but mostly on the "no pre-bake" side. One customer even > > >>>> pre-baked > > >>>> > their boards before coating with a water based acrylic. > > >>>> > > > >>>> > Lloyd Duso > > >>>> > Plant Manager > > >>>> > Diamond-MT > > >>>> > (814) 535-3505 > > >>>> > www.Diamond-mt.com > > >>>> > > > >>>> > On Tue, Feb 28, 2017 at 2:39 PM, Douglas Pauls < > > >>>> > [log in to unmask]> wrote: > > >>>> > > > >>>> > > Lee, > > >>>> > > It Depends. > > >>>> > > > > >>>> > > We have one facility that has never baked prior to coating > > >>>> application. > > >>>> > No > > >>>> > > evidence of any conformal coating related problems. We have > > several > > >>>> > > facilities that bake religiously prior to coating application, > > also > > >>>> for > > >>>> > > acrylic. No evidence of any conformal coating related problems. > > >>>> > > > > >>>> > > I think the biggest factor is how much residual water you > have. I > > >>>> don't > > >>>> > > think your assemblies have to be bone dry before coating. We > do a > > >>>> lot > > >>>> > with > > >>>> > > in-line aqueous cleaners, which have heated air knifes that > remove > > >>>> the > > >>>> > bulk > > >>>> > > of the water. Now, there might still be some entrapment areas, > > but > > >>>> if > > >>>> > so, > > >>>> > > we find them and then blow out those entrapment areas with > ionized > > >>>> air. > > >>>> > > > > >>>> > > > > >>>> > > Doug Pauls > > >>>> > > Principal Materials and Process Engineer > > >>>> > > Rockwell Collins > > >>>> > > > > >>>> > > On Tue, Feb 28, 2017 at 10:20 AM, Lee Hitchens < > > >>>> > > [log in to unmask] > > >>>> > > > wrote: > > >>>> > > > > >>>> > > > Hi all > > >>>> > > > > > >>>> > > > I've recently been asked about baking pcbs before conformal > > >>>> coating and > > >>>> > > > whether there is any quantified data on the effect on coating > > >>>> > > performance. > > >>>> > > > > > >>>> > > > Does anyone know of any public studies on this or can shed > some > > >>>> light > > >>>> > on > > >>>> > > > its effectiveness beyond anecdotal experience ? I would be > very > > >>>> > grateful > > >>>> > > to > > >>>> > > > you on this. > > >>>> > > > > > >>>> > > > Best Regards > > >>>> > > > > > >>>> > > > Dr Lee Hitchens > > >>>> > > > > > >>>> > > > SCH Technologies is a Division of SCH Services Limited > > >>>> > > > > > >>>> > > > www.conformalcoating.co.uk > > >>>> > > > Skype: leehitchens > > >>>> > > > > > >>>> > > > > >>>> > > > >>>> > > >>>> -- > > >>>> > > >>>> > > >>>> This email and any attachments are only for use by the intended > > >>>> recipient(s) and may contain legally privileged, confidential, > > >>>> proprietary > > >>>> or otherwise private information. Any unauthorized use, > reproduction, > > >>>> dissemination, distribution or other disclosure of the contents of > > this > > >>>> e-mail or its attachments is strictly prohibited. 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