In a message dated 11/21/00 1:28:35 AM Mid-Atlantic Standard Time,
[log in to unmask] writes:

STEPHAN: We have performed the IPC test using adhesive tape and the mask does
peel off...What can we do to these boards so that we can use them?
ROBERT: Ideally all of the "loose" mask must be removed; the areas under the
loose mask must be cleaned and then touched-up (reapplied) with solder mask.
For cleaning there are a variety of specialty cleansers as well as simple
alcohol, but acidic solutions (even mild) should be avoided in the presence
of components. Areas of the PWB missing solder mask but not exposing copper
need not be touched-up except for cosmetic purposes. The repair labor cost
for simple assemblies may not be justified, however.

STEPHAN: We varnish coat all the boards- will this provide enough protection,
what about if we double coat them?
ROBERT: I'd vote No. Putting good varnish on bad solder mask does not equal
high reliability; your varnish will only be as stable as the underlying mask.

STEPHAN: Any suggestions or helpfull hints would be greatly appreciated.
ROBERT: At this point I wouldn't trust the mask, even once repaired. You've
done the adhesion test but what about scratch resistivity and solvent testing
for full cure? I'd make certain the rest of the mask's integrity is known
before proceeding with repairs or using as-is.

Regards -

Robert Lazzara
Circuit Connect, Inc.
Atlanta Service Bureau
www.CircuitConnectInc.com

---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------