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Re: Better bottle caps



What I was thinking of doing was knocking up the caps with foil outer for
toughness and a sprayed inner to get in all the cracks. They should be
quite a bit lighter than the salt solution ones and easier to move around,
you don't have to worry about spillages :) Also the idea of etching the
inside with hot conc. NaOH sounds fun to get a good surface. I might
experiment and see how they measure up agains the straight salt
soulution/foil types.

Bye the way rick, did you compare the capacitance for your solid, iron
fillings against, salt caps? Were they any better?


Cheers 

mike






At 17:34 24/05/00 -0600, you wrote:
>Original Poster: "Richard Barton" <richardbarton-at-caving5.freeserve.co.uk> 
>
>Hi Michael.
>                    I take it you mean the Nickel aerosol spray cans (pretty
>expensive).
>I've tried it. The conductivity is "so so".
>I sprayed a beer bottle/salt water cap and it came out at .53 nf.
>Using aluminium foil instead, I got .65 nf. There are a couple of other
>downsides
>to the stuff too.
>a. The coating doesn't stick too well to glass. It tends to fall off in
>large flakes.
>b. It's quite delicate and if you are intending to place the bottle in a
>foil-lined box,
>the coating quickly rubs away around the edge of the bottom of the bottle.
>c. The nozzles on the cans are VERY prone to clogging up (You get a spare
>nozzle
>with the can, so they know about this problem), and even shaking the can for
>the
>full specified two minutes, they STILL clog up very quickly and have to be
>cleared
>with a needle.
>I've gone back to foil myself.
>							Richard Barton
>Original Poster: "Michael Cox" <95moc-at-kings-school.co.uk>
>
>I came across a metallic spray in a catalogue ( I don't have the catalogue
>here, so no specs at the moment) and thought it might be the perfect thing
>to replace salt water in bottle caps. Just spray it into the bottles stick
>you electrode into the top and away you go. Has anyone else come across
>this stuff before, how good a conductor is it? I'm guessing its better than
>salt solution. Has anyone got any comments on this,
>
>
>cheers,
>
>Mike
>
>
>
>