[TowerTalk] silicon sealant
Jim Lux
jimlux at earthlink.net
Sun Oct 22 12:57:47 EDT 2006
At 07:55 AM 10/22/2006, K7LXC at aol.com wrote:
>
>In a message dated 10/21/2006 4:32:53 A.M. Pacific Daylight Time,
>towertalk-request at contesting.com writes:
>
> > I have used various forms of silicon sealants for years and it seems
>they all have the same problem. They seem to be made for single uses.
>By that I mean they harden in the tube. I'm sure the manufactures love
>this. I'm not talking about cartridges but tubes for small uses. Is
>there a specific product that I can use , recap and use again and again
>in small amounts?
>
>
>I'll assume you're using silicon sealants for antenna and feedline
>connections. RTV (room temperature vulcanizing) materials are
>mostly the wrong things
>to use. The problem is that they outgas acetic acid while they cure.
Not all RTV outgasses acetic acid. Depends on which kind and what
chemistry is being used for the cure process.
The acetoxy chemistries outgass the acetic acid. I believe the
methoxy chemistries are non-corrosive.
RTV as a product name is trademarked. Other companies make the same
kind of products and they're not called RTV, so sometimes searching
on more generic terms is useful: Silicone potting compound or
silicone sealant. You'll also see RTV used as a descriptive term.
Most of the "good" electrical potting silicones are a two part, with
very long shelf life for the two parts. They use a different variety
of curing methods. Some are sold in those nifty dual syringes like
they use for epoxy adhesives, but I don't have my catalog handy to
look them up.
There's also Urethane potting compounds, as well as Silicone.
I used to buy stuff from Silpak (http://www.silpak.com/) they have a
wide variety of stuff that they sell in various quantities and
dispensing methods. They could probably tell you what's practical
and what's not.
I'd check DigiKey or Mouser catalogs as a start. Or go to the GE website
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