[Amps] coating conductors with sealers

[2]

>Hi Rich, 
>-
>I'm always afraid to coat conductors in RF applications I 
>spent a lot of time building a 6 meter antenna, of 
>which I coated with clear polyurethane after completion 
>and testing. 
>The coating had some poor electrical properties 
>which made the antenna unusable until I removed 
>most of it with solvent (not an easy task).  A lot of 
>wasted time. 

Urethane can be removed with paint stripper paste.
>-
>Would we call said properties, the coatings D factor..?

Urethane has an ok D-factor up to 14kW. 
>- 
>I guess the only way I'd seal anything would be to 
>first do the homework and find coatings which are 
>known to be "passive" to RF, at least through the 
>VHF Low region in the example amplifier. 
>- 
>One might ask some of the PCB mfgrs what 
>sealer they use as I often see coated boards in 
>high end equipment.  Thanks for your idea, it 
>might be worth tossing out a list of known good 
>coatings by brand/type/name from amps members. 
>-
Varathane® works ok.

Rich, AG6K, 805-386-3734, www.vcnet.com/measures