Alt-BEAM Archive
Message #03022
To: "George Rix" rix.g@bmts.com
From: Jacob Booth J.Booth@mackillop.acu.edu.au
Date: Wed, 5 May 1999 21:48:10 -0700 (PDT)
Subject: [alt-beam] Re: Multiple Inputs for Nv neurons
At 06:50 6/05/99 +1000, you wrote:
>
>
>The container is about the size of your fist, but it's flattened. So, it
>has
>the diameter of your fist, but not the height. It's going to be good. I
>have
>plenty of silicone sealant, though, so I can use that. I also have the
>motor
>outside the case, so there are wires running from it to the motor's cases.
>I
>think I'll use silicone sealant on them, as well.
>Thanks!
>Signing off,
>Rob Rix
>
Just be sure to use 'neutral cure' sealant... A lot of silicone sealants
give off acetic acid whilst they cure. Whilst this isn't a stong acid, with
many different types of metal in a typical circuit (lead, tin, copper, iron
etc) it is only a matter of time before they corrode, and then the problem
is nicely sealed inside where it is hard to fix. Also be careful that some
neutral cure products sold cure into a 'nuetral product' but still may give
off the acetic acid WHILST they cure... meaning they won't help at all!
Another sealing solution (but permanent) is epoxy resin. You can thin it out
with methylated spirits and use it like a thick waterproof paint, or mix
with microballoons to make a light and strong filler. Microballoons can be
purchased at a model hobby shop...
Another thought.. if you still want to use silicone, and can't find any
neutral products cheap enough (now you know why dow corning neutral potting
RTV kits are so expensive) maybe you can use some PCB laquer spray on the
entire circuit before sealing it up... it should provide some corrosion
resistance. I think I will try this one for my next project.
Good luck,
Jacob
-----------------------------
j.booth@mackillop.acu.edu.au
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