[Prev][Next][Index][Thread]
Electroplating
----------
From: Ralph [SMTP:rjdown-at-fan-dot-net.au]
Sent: Sunday, August 23, 1998 8:28 AM
To: Tesla List
Subject: Re: Electroplating
Sorry to come in late on this thread.
I made a copper plated toroid quite some time ago. Its not as hard as
some other writers suggest!
My toroid blank was an old life-buoy obtained from a junk shop and
filled & cleaned up with car body filler. I then sprayed it with a
graphite compound called Aquadag (some older TVs used to have the
cabinet sprayed with this on the inside for shielding. Two aluminium
foil pie dishes were fitted bottom to bottom to sandwich the toroid.
Body filler was again used to fill any gaps or blemishes and a second
coat of Aquadag applied. A wire was attached to the centre of the pie
dishes with a brass nut and bolt. I used copper sulphate disolved in
water and I found that a small fish tank heater with the thermostat
shorted helped the process by warming the solution.
This whole thing was placed edgewise in a suitable sized fish tank. I
had to use a couple of wire coat hangers to force the assembly below the
level of the solution (life buoys tend to float!). A large piece of
copper pipe was used as the other electrode and a car battery used for
power. It was a while ago - can't remember which polarity.
It didn't take long before the graphite coating was covered with a
pinkish brown material (copper I hope!). In my excitement, I stopped
the process to see what the coating was like, and was at first
diappointed because it rubbed off easily. Anyway, I decided to leave it
overnight and check again next morning. This time the coating was a lot
better, but I needed to rotate the assembly and have about 4 more
sessions before it was covered evenly. When I removed the finished
assembly I dried it carefully and used a metal polish called Brasso to
bring it to a reasonable sheen. (It didn't come up like polished copper
- I think because the coating is slightly powdery to look at! Maybe
different grades of cutting compound would do the trick).
I didn't bother sealing it with varnish because it didn't look shiny
enough - so I just left it. It looks a bit like an old toilet cistern
now, very tarnished, but it could be plated with another metal to make
it "chrome-like". I recall seeing some stuff from a local electronics
supplier (Dick Smith) for tinning copper clad circuit board. A bag of
white crystals which when disolved in water, will coat bare copper with
a tin (or tin-like) metal layer. - no electroplating - . It could then
be brought to a high polish.
I only used the toroid briefly - it was the wrong size! I now have a
selection of plastic spheres (light fittings) with aluminium foil
triangles stuck all over the outside surface. (triangles are easier to
form around a sphere) ranging in size from 5" to 20". I am currently
using a 12" sphere on my 10" x 24" coil.
Regards
Ralph Down