AA7BG Matt Trott wrote:
>I put a
>smear of it on a non-metallic flat surface yesterday so I could see how
>conductive it was. I was surprised to see no deflection at all in my VOM
>when I stuck the two probes into it. It looks like it's impregnated with
>zinc or some metal so what gives? The joints I've used it on show good
>electrical connections so I'm relieved to see that it's not the perfect
>insulator that it appears to be when not in contact with metal.
There's a film of grease around each metal particle, but the grease
itself is non-conducting. It needs the clamping force between two pieces
of metal to force away the grease and make the particles bridge the gap
What is the practical difference between the zinc-loaded and copper-
loaded types? Both are sold as being suitable for aluminum. I have
always preferred the zinc type for antenna elements because zinc is
closer to aluminum in the electrolytic corrosion series, but does this
effect matter inside the clamped joint?
BTW, the ARRL BBS file GREASE.TXT contains a lot of information on
various brands, the probable formulations and where to buy them.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
IFW Technical Services Clear technical English - world-wide.