Rich: Two thoughts.
1. If it is a moisture problem, is it possible there is moisture in your
nitrogen tank that over time starts reacting with the urethane?

2. If it is an air entrapment problem either introduced by you or the
material manufacturer, are the pickup tubes drawing from the bottom of the
container and the air bubbles are in the top portion. So you must draw down
some of the material before you begin seeing them?
Do you  transfer from the 5gal container into the 10 gal pressure pots or
just place them inside? If you are transferring it will introduce air.


Regards

Michael Barmuta

Staff Engineer

Fluke Corp.

Everett WA

425-446-6076

-----Original Message-----
From: Rich Lasko [mailto:[log in to unmask]]
Sent: Thursday, July 10, 2003 7:37 AM
To: [log in to unmask]
Subject: [TN] Potting Problems



Good morning all,



Background info...



I am currently faced with a potting problem that I am hoping some of you can
shed some light on.  We are currently using a Hysol US5500 compound.  (1 : 1
resin & catalyst mix)  I am dispensing this from two (2) 5 gal containers
located in 10 gal pressurized tanks (blanketed with Nitrogen only - no shop
air introduced)  (We are using a PVA dispensing system).  We have checked
all the tank and hose fittings/gaskets for any leakage to ensure no outside
air / moisture is getting into these containers.



Now the problem...



Using brand new compound from the vendor, we can achieve the clear - amber
solidified compound with virtually no "bubbles".  However, around the third
day of production we start noticing hundreds of very small bubbles (smaller
than the tip of a ball point pen ) in the compound.  I have had numerous
conversations with both the potting compound mfg and PVA to determine HOW
the material is becoming "contaminated" after a few days of usage.  Please
note, once we get in a new batch of compound the cycle begins again.  (The
first few days are perfect and then around the 3rd day or so...more bubbles)
The potting mfg has discussed that this compound is susceptible to moisture
contamination but we are struggling for answers because the dispensing
system appears to be a closed loop system without any outside air
introduction.



Any thoughts or insight would be helpful.



TIA...



Rich Lasko

Quality Assurance Manager

Badger Electronics









---------------------------------------------------
Technet Mail List provided as a free 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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700
ext.5315
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a free 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/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------