> I am looking for some feedback.  We use Techform Liquid solder mask (peel
> able) to cover PTH on our PCA's.
> We also use this Mask as a "Tacking" mechanism to hold Loose Loaded
> (unsecured/not bent) components on the top side of the board.  After the
> mask dries, we take it off the board.  This is a Non-Value added activity
> that I would like to eliminate.  I want to leave the dried masking on the
> board.
> My question is.  Can I leave it on the board?  Will it affect the long
> term function of the board?  Do any of you use this, or do this?  Any
> input is appreciated.
> Thanks
> Marie

Marie,
I would say no, you can't leave the material on the board.  Many of these
peelable masks outgas materials such as ammonia or silicone, sometimes
acids or amines.  If you have them under parts, do you know if the CTE of
the material will strain the solder joints in thermal cycling?  Will the
material be swelled in contact with an organic solvent, such as in a
solvent based conformal coating?  These materials, certainly not the
Techform,  are not designed to be left on a board surface.  Bad Karma.  We
use a similar product Kester TC533 (I think) and we remove it from the
boards.

Doug Pauls

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------