[Elecraft] New KPA100 Rev.

[d.cutter at ntlworld.com]

I'm going to have to clarify what I said:  I would not use the vinegar variety for caulking, ie in large quantities where there are electrical parts "in an enclosed space."  I was talking about in free air.  I have used Dow Corning 3140 for that.

Sorry for misleading anyone, but, as always, glad to raise the issue for others to learn from the group experience.  

David
G3UNA  
> 
> From: "Don Brown" <DolfinDon at msn.com>
> Date: 2006/10/18 Wed PM 04:00:46 BST
> To: <w3fpr at arrl.net>,  <elecraft at mailman.qth.net>
> Subject: Re: Re: [Elecraft] New KPA100 Rev.
> 
> Hi
> 
> My company manufactures a small controller used on aerobic sewage treatment 
> plants. I have over 50,000 of them installed. One of the requirements is to 
> seal all of the electrical wiring where it enters the controller box using 
> silicone rubber. This is to keep chlorine, HS2 and water vapor out of the 
> box. We provide a 4 Oz tube of GE Silicone II so our installers will not use 
> the wrong type of silicone. The Silicone II is alcohol based rather than 
> Acetic acid based (vinegar). I have received several circuit boards returned 
> with green corrosion on the resistor leads and circuit traces due to the 
> wrong type of silicone used. We found this because the silicone we provide 
> is clear and the installer had used white bathroom calk bought at the local 
> hardware store. I guess he lost the tube we provided in the parts kit.
> 
> I would not recommend any adhesive be used on any Elecraft kit just as it 
> states in the manual. The wire leads are strong enough to hold the toroids. 
> If you must use something I would suggest a small strip of double stick foam 
> tape.
> 
> Don Brown
> KD5NDB
> 
> 
> ----- Original Message ----- 
> From: "Don Wilhelm" <w3fpr at earthlink.net>
> To: <elecraft at mailman.qth.net>
> Sent: Wednesday, October 18, 2006 9:35 AM
> Subject: RE: Re: [Elecraft] New KPA100 Rev.
> 
> 
> > David,
> >
> > I beg to disagree, some time ago I used some of the 'vinegar' stuff on a
> > splice with insulated copper wire (#14 THHN) - and I can say that the bad
> > stuff keeps creeping for a long way.  After a couple years, I had occasion
> > to examine it and found the stuff had crept up under the insulation and
> > caused corrosion as much as 6 inches from the point where it was applied -
> > It did make a good weather seal, but at the cost of electrical properties
> > loss.  Fortunately, this was not in any critical application.
> >
> > No longer will I use commonly available RTV direcly in electronics
> > applications - even the consumer grade 'non-corrosive' RTV commonly
> > available that I bought recently had a vinegar smell to it.
> >
> > 73,
> > Don W3FPR
> >
> >
> > > -----Original Message-----
> > >
> > > I think too much is made of so-called corrosive RTV (it's the
> > > vinegar).   The level of corrosion to bare metal is very small
> > > and in free air stops fairly quickly.  For other components
> > > bathroom sealant is perfectly adequate.  Enamelled copper wire
> > > and toroids should be immune anyway.
> > >
> > > David
> > > G3UNA
> > >
> > >
> >
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