Graham,

Just an off-the-wall thought...seeing what liquid nitrogen does to rubber
gloves and handballs (lab guys gotta play, too!) I wonder if a localized
application would embrittle the mask and allow its removal.  Don't know
about the vias.
Goo  Luck

Ralph Vaughan
Boeing-Atlanta


> ----------
> From:         Graham Naisbitt[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Graham Naisbitt
> Sent:         Thursday, August 12, 1999 10:43 AM
> To:   [log in to unmask]
> Subject:      [TN] Cooked Latex Mask
>
> Fellow Techies,
>
> Hope someone out there can help with this one:
>
> We have a customer with a number of VERY EXPENSIVE assemblies onto which
> has been put some peelable latex masking material. (NOT OURS BTW!)
>
> These assemblies were then placed into an oven at 80Deg C (175Deg F - 176
> for those who want precision :>) ) overnight. Unfortunately the fan in the
> oven broke so they were exposed to 130 Deg C for some time, estimated at 6
> hours.
>
> As you might imagine, this has not done the latex any good at all. It
> pretty much resembles the gum you leave on the bedpost overnight (for 5
> days!).
>
> We have tried up to and including MEK solvent without success. Of course
> we tried peeling it - but, having lost its molecular bond, it fragments
> too easily.
>
> As if that was not enough of a problem, it is inside through hole vias and
> empty sockets into which they must place some other leaded components and
> then solder them.
>
> Can anyone out there come up with a solution (liquid or metaphysical) that
> will allow total removal? Rudy, you got any suggestions?
>
> Regards,
> Graham Naisbitt
>
> [log in to unmask]
>
> WEB: http://www.concoat.co.uk
>
> CONCOAT Ltd
> Alasan House, Albany Park
> CAMBERLEY GU15 2PL UK
>
> Tel: +44 (0) 1276 691100  Fax: +44 (0) 1276 691227
>

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or
847-509-9700 ext.5365
##############################################################