so I was wondering what might be good to cover it with to use in
rankly, I’d not cover it at all. Opal itself is harder than any of
the resins you mentioned. If it’s too thin a layer to polish down,
it should still have the glassy look of a broken glass surface,
unless it’s already been sanded or something. If it is reasonably
shiny from it’s own natural gloss, it needs no additional sealant,
just as a properly cut and polished opan doesn’t need sealant.
The choices you mentioned are, I’d say, poor ones in any case.
Opticon isn’t designed as a surface seal. It’s an epoxy based resin,
used to soak into a stone’s fractures to make them less visible (not
stronger), after which the surface is then sealed with a bit more of
the resin to which hardener has been added. The last step is
actually optional, but prevents “wet” resin from weeping from cracks.
The the cured resin isn’t especially hard, nor a good surface gloss
agent either. In fact, epoxies in general are poor choices, as
they’re a bit yellowish in color, not especially hard, and not
always all that durable over time, though opticon is reasonably
Nail polish is usually an acrylic. It’s actually not all that bad,
as far as hardness goes, and is as good as other choices you’ve got.
Some of them are actually quite hard for a resin surface. But it may
not be the most attractive, as it tends to go on in a thick layer.
I’d guess your best bet, if you must coat it at all, would be one of
the spray on acrylic plastic coatings, such as Krylon. It’s
colorless, pretty durable, and has a high enough refractive index to
look reasonably bright for a coating.
but none of these are as hard as the opal itself, so Again, I’d
suggest just not coating it at all. If it needs a bit of
brightening, use some cerium oxide powder mixed with water to a
paste, on a small felt wheel, running at low speed (flex shaft or
variable speed dremel on low), and use that to bring up a higher
gloss on the opal layer. Cerium oxide is only a polish, and won’t
remove any thickness to the thin opal layer. it also won’t remove any
but the finest scratches, but if the layer is as thin as you say,
then you might not want to remove such in any case. you can still
get a glossier look right over any small scratches, though they’ll
still show if you look for them…
Hope that helps.