"the PRC Desoto sheet called for a 36 hour room temp cure to 35A
durometer in 48 hours,"
Woops! Make that "the PRC Desoto sheet called for a room temp cure to 35A
durometer in 48 hours,"
Kevin Glidden
Manufacturing Engineer
Luminescent Systems Inc.
-----Original Message-----
From: Kevin Glidden [mailto:[log in to unmask]]
Sent: Wednesday, February 11, 2009 9:56 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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