Re: Can G10 sheet be laminated?

["Finn Hammer" <f-hammer-at-post5.tele.dk> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Gavin!

G10 can be laminated with ease, I would suggest a couple of points to
look out for:

The surface of the G10 can be covered with a layer of wax. This has to
be ground off, and this has to be done with some care, so that you
actually remove material.

A good adhesive is epoxy, and preferably a thin flowing type. This is
used extensively at boatbuilding yards, so if you live at the coast, go
to talk to some boatbuilders, then you can probably get a couple of jars
of it at a reasonable charge.

When you start the laminating process, you need 2 plates of some
reasonable flat material, I have found that MDF board works well. Cover
the first board with a layer of Polyethylene then lay the first disc of
G!0 on it. Now apply a pool of the epoxy in the middle of the G10, add
G10/pools of epoxy till you have the desired thickness, and finish with
a G10 disk, sheet of polyethylene and the other MDF board.

Now you need 5-7 carpenters clamps, one of which needs to be able to
reach into the midle of the discs. Tighten this one down slowly, to
allow the epoxy to flow out of the gaps, and take care that the stack
remains aligned. It is a good idea to drill a couple of dowels trough
the MDF plates near the corners, to keep them aligned, and not
interfering with the round G10 discs. When you feel that there is
contact in the midle, tighten the other clamps down some way inside the
perimeter of the discs, to expell as much as the epoxy as possible.
Leave  to cure for 24 hours, and the polyethylene peels right off!

I have made many pieces of structure this way, using 1,5 mm FR4 from
printed circuit board, and it works really well.

Hope this helps.

Cheers, Finn Hammer

Tesla List wrote:
> 
> Original Poster: ghub005-at-xtra.co.nz
> 
> Hello list members
> 
> I am building a RSG for my 5-10kVA coil. I had intended to build the disc
> from 10 or 12 mm Tufnol 10G-40 phenolic laminate. Unfortunately, the NZ
> distributor only has 3.2mm sheet in stock.
> 
> Can this sheet be safely laminated to form a thicker disc? The disc will be
> 250 mm diameter and will carry 12 flying electrodes made of 6.5 mm
> tungsten/copper rod - each electrode will be 50 mm in length. I intend to
> run the gap at 1500/3000 rpm (sync) but would like to occasionally use a
> higher speed for expermimentation (assync).
> 
> If it can be laminated, what adhesive/pressure/technique should be used etc.
> 
> Safe coiling,
> 
> Gavin Hubbard
> 
> P.S. The electrodes are made from a 75% tungsten/25% copper alloy that is
> designed for spark erosion machines. It has fantastic erosion resistance +
> good conductivity and it isn't thoriated.