Re: [IRCA] IRCA Digest, Vol 41, Issue 5

["Guy Atkins" <dx@xxxxxxxxxxxxx>]

Craig,

Just a caution on this. Years ago, when I wanted to add some weight to a
NRD-525 tuning knob, I poured this sort of 2-part resin into the hollow
space on the back of the knob. The heat of the chemical reaction (curing)
warped the plastic knob severely. I ended up having a machinist friend make
a completely new knob from a solid block of "black Delrin" material, which
worked great. However, the resin experience taught me to experiment first
before using it on anything important or valuable. 

You'll have no problem if you are pouring the stuff into a cast metal box,
but be careful if it's plastic.

Guy Atkins
Puyallup, WA


------------------------------

Message: 7
Date: Sun, 2 Sep 2007 00:04:43 -0400
From: "Craig Healy" <bubba@xxxxxxxxxxxxxxxxxxxx>
Subject: [IRCA] Sealing boxes
To: "AM-DX List" <am@xxxxxxxxx>,	"Mailing list for the International
	Radio Club of America"	<irca@xxxxxxxxxxxxxxxx>
Message-ID: <00b301c7ed16$65ffe100$3c32a8c0@ng1u>
Content-Type: text/plain;	charset="iso-8859-1"

A little while back there was a bit of a thread on filling antenna matching
transformer boxes with something to waterproof them.  I think I suggested
automotive silicone seal.  Found something today that I think will be
better..

While waiting for my wife to find something at a local hobby store
(Michael's), I found a product called casting resin.  This is a two part
epoxy used to envelop items in a liquid plastic that cures to a plexiglas
type material.  I think we've all seen dollar bills in plastic, among other
things.  This is the stuff.

I bought a 16oz can of the resin and the accompanying catalyst.  Twenty
bucks.  Looks easy to mix and use.  Sometime this weekend I'll mix up a
paper cup full of the stuff and pour it into one of the splitters I've made.
This should completely waterproof the thing as well as making it physically
much stronger.  The epoxy should be non-corrosive as well.

I'll take some photos and write up an article, if I get some time.

Craig Healy



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