> One of my friends just tried putting some LEDs in clear polyester resin.
> I saw the results, the epoxy is completely invisible, you just can't see
> it at all

Cool. The level of catalyst affects the final polymerised colour. As I
mentioned, the promoters / inhibitors in polyester can be quite strongly
coloured and getting the stoichiometry (reagent ratios) right can be a
little trial and error. Sounds like he/she was spot on, colour-wise

> What exactly is release wax?

In a pinch you can use waxy furniture/car polish, although it may
contain perfumes/solvents, but carnauba is the preferred one. Not
expensive and a little bit goes a long way

http://www.iasco-tesco.com/cat55/pg_0078.htm

The trick is to put it on and polish it off. Essential if you're using a
mold,
and especially if you want to use that mold again. For example a boat
shell

We'd do lunch-time encapsulations in 100ml Pyrex lab beakers and
although resin shrinkage separates it from the glass, without wax that
separation isn't always uniform and you get ridges. They can be
polished out with wet/dry paper, brass polish and silver polish but it's
a darn sight easier to wax the glass in the first place

> > smooth surface. Air inhibits polyester curing and any exposed surface
> > will be the last bit to cure and will not be smooth, and may be sticky
>
> Ahh, I'm definetely noticing that in the castings I've been doing, takes
> as much as a week for the air exposed bits to go hard.

When I make coasters I have circles of laminating plastic that I put
on the "bottoms" (they're in upside-down molds) to keep air out. A
sheet on the workbench too

Works a treat. I'm sure any copy shop that does laminating will
have scraps

My friend gets her film from  http://www.jenrite.co.nz/  I forget
the exact composition but I think it's a polyethylene/polyester mix.
Quite standard laminating film anyway

> Hmm... Can you speed of curing though application of heat?
> Basically, put less than the needed amount of catelyst in, mix
> thoughly, and then artifically bring the temperature up evenly

You can't be too stingey with catalyst as it's needed to initiate the
cross-linking. Some experimenting might be called for. It depends
on the volume : surface area ratio. It would be better to heat the
resin before adding catalyst. But don't go too crazy with the heat
if you want the bubbles out

I've got a block of polyester that was shot with a nail gun before it
cured, and it shattered inside. Looks brilliant when hit with a laser
pointer

> Hmm... Wonder how conductive the aluminum will end up? I'd be
> worried about trying to make a long-lasted connection to it with the
> wires, tough stuff to solder I'm sure

You'd wrap it around the wire and use a pen or something to rub
it smooth to make contact

> I've gotta build a mini-spot welder all the same though...

When trying the zapper technique (a big capacitor charged to about
20V IIRC) for revitalising NiCds the zapper wire often got welded to
the terminal

> Hmm... Any sort of easy to apply coatings that styrene can't attack?

Nitro-cellulose lacquer is good. I've used it for printed material like
photographs and newspaper. A quick first spray dries very quickly
and then you can build on that. Well-cured epoxy too for porous
materials, but not anything soluble like inks

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