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Date: | Mon, 22 Jul 2013 13:53:53 -0500 |
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Steve,
I have not used that specific material before, but have worked with 2-part
systems. A few questions and observations:
1. What did you mix the material with? Metal spatula (good) or popscicle
stick (bad)?
2. How well did you scrape the sides of the container? Was it a clean
plastic mixing cup (good) or wax-coated Dixie cup (bad)?
3. Did you bake out the potted assemblies first?
4. Was there a primer involved?
5. What kinds of "schmutz" may be on the assembly that may poison the
cure reaction? Urethanes don't like water.
6. Does the manufacturer recommend a rest time before potting? Degassing
before potting?
You might want to pick up IPC-HDBK-850, The Potting and Encapsulation
Handbook for lots of good information.
Doug Pauls
From: stephen gregory <[log in to unmask]>
To: <[log in to unmask]>
Date: 07/22/2013 01:46 PM
Subject: [TN] Epic Resins S7144A 2-part polyurethane potting
material
Sent by: TechNet <[log in to unmask]>
Hi All,
Have any of you used Epic Resins S7144A 2-part polyurethane potting
material?
I tried to last week, and pretty much made a mess. Followed the datasheet
and mixed it in the volume ratio of 3-parts part-A (300-cc) to 1-part
part-B (100-cc). I mixed more material than I actually needed. I'm mixing
it by hand because we don't have a MMD system.
I thought I had mixed everything thoroughly (4-5 minutes). I determined
ahead of time how much material would be needed for each unit (35-cc's).
After mixing, I drew the material into a 60-cc syringe and
dispensed 35-cc into each case. I let it room cure (24-30 hours).
I did 4-units and each one of them had a different result, from swelling
and bubbling of the material completely out of the case, to little or no
cure. I'm at a loss as to why that happened.
Just wondering if any of you have ever used the material and can give me
some pointers.
Thanks guys,
Steve
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