Resin vs. UV Resin: Which One Should You Use?
Two bottles, two completely different workflows, one confusingly similar name. New makers grab “UV resin” thinking it’s just a faster version of the epoxy everyone talks about — then wonder why their thick pendant came out gooey in the middle. They’re not interchangeable, and picking the wrong one for your project is a quiet, common waste of money.
So here’s the real difference, and a straight answer on which to reach for depending on what you’re making.
The core difference is how they cure
Epoxy resin is the two-bottle kind. You mix a resin and a hardener, and a chemical reaction slowly sets it over hours. Time and temperature do the work.
UV resin comes in a single bottle, pre-mixed, and it stays liquid until you hit it with ultraviolet light — a UV lamp or strong sunlight. Then it cures in minutes. No mixing, no ratio to measure, no overnight wait. Sounds like the obvious winner until you hit its limits.
That one distinction — chemical cure over hours versus light cure in minutes — drives every other trade-off between them.
Where UV resin shines
Speed and convenience, mostly. And for the right project that’s a big deal.
If you’re making small, thin, flat pieces — stud earrings, small charms, flat pendants, nail art, little embellishments — UV resin is a joy. You pour or brush a thin layer, cure it under the lamp for a few minutes, and you’re done. No waiting a day to see if you nailed it. You can build up a piece layer by layer in one sitting, curing as you go, which is great for embedding things at specific depths. And with no mixing, there’s no ratio to get wrong and no leftover cup going to waste.
For high-volume small work — say you’re making a batch of simple earrings for a market — that fast turnaround genuinely adds up.
Where UV resin falls apart
The light has to reach the resin. That’s the whole catch, and it’s a hard limit.
UV light only cures what it can penetrate, so anything thick, deep, or opaque is a problem. Pour UV resin more than a few millimeters deep and the top cures while the bottom stays liquid. Add an opaque pigment or a solid embedded object that blocks the light, and the shadowed resin underneath never sets. So deep molds, chunky pieces, heavily pigmented casts, and anything bigger than small are off the table — or at least a fight.
It’s also pricier per gram, the cured result can be a touch more brittle, and it tends to yellow faster over time than a good UV-stabilized epoxy. Fine for small fashion pieces; less ideal for heirloom work.
Where epoxy is still the workhorse
Anything with size or depth to it. Coasters, paperweights, deep cube pendants, river-style pieces, anything you pour 5mm or thicker, anything boldly pigmented, anything with chunky inclusions — that’s epoxy territory. It cures all the way through regardless of light, color, or what’s embedded in it.
Epoxy also tends to give a thicker, more “liquid glass” doming and a slightly more durable finished piece, and per gram it’s usually cheaper, which matters when you’re filling a coaster mold. The cost is patience: you mix carefully, you pour, and you wait a day or more. Most of my own work is epoxy for exactly these reasons — I make a lot of pendants and small decor with real depth, and I want them cured through and built to last.
So which should you buy?
If you’re doing small, thin, flat pieces and you value speed — earrings, charms, nail art, quick layered embeds — start with UV resin and a decent lamp. If you’re making pendants with depth, coasters, decor, anything thick or richly colored, or anything you want to keep for years — go epoxy.
And here’s what I’d actually tell a friend: a lot of makers end up owning both, because they do different jobs. UV for the fast little stuff, epoxy for the pieces with presence. You don’t have to choose forever. You just have to match the resin to the piece in front of you — and now you can.
Both, by the way, pour into the same flexible silicone molds, so your mold collection works either way.
Browse my handmade silicone molds — they work for both.
Not sure which fits what you’re trying to make? Tell me the piece — size, depth, whether it’s colored — and I’ll tell you which resin I’d reach for.
— Nikolai