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Subject:
From:
Douglas Pauls <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Douglas Pauls <[log in to unmask]>
Date:
Fri, 14 Sep 2018 09:24:03 -0500
Content-Type:
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text/plain (83 lines)
I don't know Chris, I would consider scrapping the assembly. 1A33 is a
pretty durable urethane.  You can spot strip it OK, but stripping ALL the
coating off of an assembly is going to be pretty tough.  As Les said, the
residues from the stripper can be harmful if not completely removed.

Doug Pauls
Principal Materials and Process Engineer
Rockwell Collins


On Fri, Sep 14, 2018 at 9:19 AM Chris Thierolf <[log in to unmask]>
wrote:

> Humiseal 1A33 UR was applied instead of SR. Vendor suggested removing then
> re-applying SR conformal coating. If residue is a potential issue as you
> say then the Silicone will trap the residue on the PCB. This is a problem.
> I will have to do 100% electrical testing to hopefully rule out this
> condition.
>
> -----Original Message-----
> From: TechNet <[log in to unmask]> On Behalf Of Bogert, Gerald L (Contractor)
> Sent: Friday, September 14, 2018 9:27 AM
> To: [log in to unmask]
> Subject: [EXT] Re: [TN] Humiseal Stripper 1063
>
> September 14, 2018
>
>
> This chemical stripper gel product should only be used as a last resort
> for removing Type UR coating when other methods of removal such as grit
> blast or use of heat are not viable.  If the gel is not completely removed
> or neutralized by cleaning process, it will leave conductive residues that
> can cause improper circuit card operation.
>
>
> ________________________________
> From: TechNet <[log in to unmask]> on behalf of lduso - Diamond-MT.com <
> [log in to unmask]>
> Sent: Thursday, September 13, 2018 9:05 PM
> To: [log in to unmask]
> Subject: Re: [TN] Humiseal Stripper 1063
>
> Yes and yes. I have used this many times to remove urethane coating from
> customers CCAs. It does work but can be dangerous. Success often depends on
> the coating, the thickness, and how much of the board is uncoated. We try
> to use the most mild stripper that will get the job done sufficiently.
>
> Is complete removal necessary?
>
> On Thu, Sep 13, 2018, 19:57 Chris Thierolf <[log in to unmask]> wrote:
>
> > Anyone use this on fully assembled PCBs to remove Urethane conformal
> > coating? Any risk to components?
> >
> >
> > Chris Thierolf
> > Principal Engineer, EE
> >
> > L3 Power Distribution - SPD Electrical Systems
> > 13500 Roosevelt Blvd.
> > Philadelphia, PA 19116
> > Ph. 215-698-6390
> > [log in to unmask]<mailto:[log in to unmask]> /
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> > [cid:[log in to unmask]]
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