On Mon, 13 Mar 2006 23:14:29 -0800, Roy Lewallen
wrote:

The advice to avoid acetic-acid smelling RTV because of corrosion is
passed along from person to person like an urban legend, but like an
urban legend it's just about impossible to find anyone who's actually
seen any corrosion result from its use. (A number of queries I've made
over the years has produced just one, using a very early version of RTV.)

OK, here is number 2. Hmmm wait... couldn't we use a different
ranking...

I retired from the industry and I worked for the original developer of
"Silastic RTV (TM)". My address if Midland MI if any one needs another
hint.

Yes there is an weak acid released from the regular RTVs and it
depends on the moisture in the air to aid in curing.

Is it, or will it be a problem? That is a Yes and no, or it all
depends answer.
I use plain old fashion "bathtub calk" on my antenna connections and
connectors *outside or outdoors*

The acid is not normally a problem *except* where the item is either
potted, or enclosed in a container. I would not use it on PC boards
where the foil is thin.

Outdoors I just "gob it on".

As to real corrosion:
Some years back we purchased a bunch of remote sensors that were
potted in metal boxes for use in harsh environments. They worked very
well... for about a year. One failed and who ever removed it brought
it into the shop. I decided to perform an autopsy on it. I cut the
seal, pried off the cover, and dug out the circuit board, or rather
what was left of it. The copper traces were mainly a green powder
with bigger chunks of powder around the solder joints where the wires
hung loosely.

The manufacturer of the sensors had used the wrong potting compound.
Had they used the neutral stuff (really stinks) they would have been
fine. They replace them all, they were expensive, and we had a bunch.


I've used the acetic-acid smelling stuff for decades on a variety of
metals including tinned and untinned wire, aluminum, nickel, and copper
circuit boards, and never seen a hint of corrosion. But formulations
vary widely, and my experience certainly isn't exhaustive. I'm not

There are two main producers of RTVs and the formulations are pretty
much standard. If you analyzed a tube of the stuff I doubt you could
tell which manufacturer produced it. However they have slightly
different formulations aimed at the specific use. What every you
purchase under what ever brand name most likely comes from one of
these two producers unless it says Made in China.


entirely convinced, though, that among the many formulations there
aren't others, which don't have that smell, which might be corrosive to
some materials.


People who worry about this should buy an industrial product and stay
with it, since there's a much better chance the formulation won't change
in the future without notice.

The last I knew the only difference was in the packaging.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Roy Lewallen, W7EL