Kathy,
It depends. 

Was the polyurethane at one time hard and now it is not?  If so, you might 
have attack by an aggressive organic solvent making it tacky. 

Was the material a thermal cure urethane that needed to see a minimum 
temperature to get the cure reaction really going, and perhaps the 
material did not see this temperature?

Was the urethane a two part material, as I suspect?  If so, then it could 
be an improper mixing ratio between resin and hardener, or incomplete 
mixing between resin and hardener.  Potentially, you might have a case of 
"reversion", where a cured two part material reverts into its Part A and 
Part B elements, though I have not seen this for many years.

How deep does tacky go?  If it was me, I would consider it a case for 
rejection since it is clearly not what it is supposed to be, and certainly 
a case for process investigation. 

Doug Pauls




[log in to unmask] 
Sent by: TechNet <[log in to unmask]>
08/14/2007 02:05 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
[log in to unmask]


To
[log in to unmask]
cc

Subject
[TN] Tacking potting material






What causes tacky polyurethane potting material? Is tacky a cause for 
rejection or is it a cosmetic issue only?
Thanks in advance
Kat

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 
847-615-7100 ext.2815
-----------------------------------------------------

[attachment "kkuhlow.vcf" deleted by Douglas O 
Pauls/CedarRapids/RockwellCollins] 

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 15.0
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 847-615-7100 ext.2815
-----------------------------------------------------