Not sure if you have any ability to change the spec of the material you're using but a different mil standard, MIL-STD-8516 covers polysulphide rubber specifically for electrical applications. I think the material is very similar, it's just has properties idealized for electrical applications. The standard is titled
SEALING COMPOUND, SYNTHETIC RUBBER, ELECTRIC CONNECTORS
AND ELECTRIC SYSTEMS, CHEMICALLY CURED
The material employ a room temperature cure, and if my memory serves me correctly they can be accelerated with heat. We used this material for many years and although it's a pain to mix and has the lengthy cure, it's quite durable.
Gregg
-----Original Message-----
From: Ian Hanna [mailto:[log in to unmask]]
Sent: Wednesday, February 11, 2009 7:17 AM
To: [log in to unmask]
Subject: Re: [TN] Staking Question/Help...
Once you factor in the set-up time, bathroom breaks, and paperwork, a
36hour cure takes about 48 hours of line-time...
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden
Sent: Wednesday, February 11, 2009 9:59 AM
To: [log in to unmask]
Subject: Re: [TN] Staking Question/Help...
"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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