Hi Kevin!
Just wanted to let you know that the material we have is exactly the
same material. I said Bergdahl earlier, but that was the distributor.
The stuff that we have IS from PRC-Desoto...
I really appreciate the tips you gave me. I think we can live with a
couple of days to cure instead of a week or more.
I mixed a little up to play around and see for myself how it behaves.
One thing about this stuff is that you can make a real mess if you're
not careful! It "strings" quite a bit when you are applying it.
Thanks again,
Steve
-----Original Message-----
From: Kevin Glidden [mailto:[log in to unmask]]
Sent: Wednesday, February 11, 2009 8:56 AM
To: 'TechNet E-Mail Forum'; Steve Gregory
Subject: RE: [TN] Staking Question/Help...
Hi Steve,
Glad to hear you made it through the storms OK.
I used to use this material extensively, and as luck would have it I was
able to locate some old notes...
The specific material I used was PRC Desoto 1440B. I am not sure if the
PRC material is different, or if there was some sort of acquisition or
merger, BUT the PRC Desoto sheet called for a 36 hour room temp cure to
35A durometer in 48 hours, but all the performance data was performed on
cured
14 days.
Anyway, I like you, could not tolerate that, so I called the PRC Desoto
technical assistance, and wrote down there response:
------------
Heat Cure can be used. Must room cure at 1 hr minimum before oven
curing to allow chemical evaporation. Then place in a 140F to 150F oven
for 24 hours.
Failure to observe the one hour at room temperature prior to oven cure
will result in blistering of material.
------------
I never had any issues with this method. We too used it for bonding of
components, on military backplanes. In my experience, all 3 major
primary defense contractors use it, and it is prefferred as it has high
chemical resistance, maintains elasticity, and decent dielectric values
as well.
One last note is that there is also a B 1/2 formulation available per
the same MIL-spec with a shorter 30 hour RT cure time, but also a
shorter pot life.
Good Luck.
Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.
-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Wednesday, February 11, 2009 9:34 AM
To: [log in to unmask]
Subject: [TN] Staking Question/Help...
Morning All!
Well, survived all the storms we had last night. Actually, it wasn't bad
in Tulsa as it was to the south and to the west of us.
They think there was a tornado that touched down in a city called Pawnee
to the west, one in Edmond to the south, and there were eight lives lost
in Lone Grove last night. Really early for tornado season here...
Anyways, we're building a board that has a requirement to stake some PTH
radial parts and they reference MIL-S-8802, Class B2 as the material to
be used for the staking. Our buyers purchased a 2-part material from
Bergdahl called PR-1440 Class B. So I got the datasheet and started
looking at how to use it, and discovered that the fastest that I can
cure it is 7-days at 250 F., or 14-days at room temperature. That really
puts a kink in our schedule...
I'm not very familiar with that spec, but what I can find is that most
everything I find that is listed and complies with it, is actually
aircraft fuel tank sealant. Why they want to use that is beyond me, but
that's what is on the drawing so that what we'll use.
I'm wondering if any of you know of anything that will cure quicker than
that and complies with the above spec? Any help is appreciated.
Steve
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