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How Much Pigment to Add to Resin (Without Ruining the Cure)
Too much pigment makes resin bendy and tacky. Safe doses for liquid pigment, mica, and alcohol ink — plus how to rescue an overloaded piece.
Here’s a resin truth nobody puts on the pigment bottle: the most common reason a colored piece stays soft and bendy isn’t bad resin, cold room, or wrong ratio. It’s too much colorant.
Resin cures through a precise chemical handshake between resin and hardener. Pigment is a guest at that party. Invite a few guests, everything’s fine. Fill the room with them, and the two people who actually need to find each other — resin and hardener molecules — can’t.
The number to remember: 6%
Keep all colorants combined under about 6% of the total weight of your mixed resin. Most brands print something between 5% and 10% in the fine print; 6% is a safe ceiling across everything I’ve used.
In practice, for a typical small jewelry batch of 2 oz (60 g) of mixed resin, 6% is about 3.6 grams of colorant. That is a lot of pigment — you’d almost never want that much for color reasons alone. Which is the point: if your cure failed from overloading, you weren’t tinting, you were pouring paint.
The realistic working amounts sit way below the ceiling. Liquid pigment: 2–3 drops per 1 oz (30 ml). Alcohol ink: same, 2–3 drops, and be stricter here because the alcohol itself slows the cure. Mica: up to 1/2 teaspoon per ounce, and it’s mineral, so it plays by different rules — it thickens before it ever threatens the cure.
The batch that taught me the math
Two Decembers ago I was rushing coaster sets for a Christmas market in Toronto. I wanted a dense, solid white — properly opaque, no translucency — and kept adding white opaque pigment until the liquid looked right in the cup. No measuring, just vibes and a deadline.
Forty-eight hours later the coasters flexed like thick leather. Not sticky, just… rubbery. Dented under a thumbnail. I’d blown well past any reasonable pigment load chasing opacity that a proper white pigment would have delivered at a third of the dose. Eight coasters, two days before the market. The replacement batch — same resin, same mold, pigment weighed on the kitchen scale this time — cured rock hard.
Since then I weigh colorant for any batch that matters. Sounds obsessive. Takes ten seconds. A $15 kitchen scale from Canadian Tire already does the resin and hardener weighing anyway.
How overload actually shows up
Bendy or rubbery texture after the full cure time — 48–72 hours for most brands (cure time guide). A surface that stays faintly tacky no matter how long you wait. Sometimes oily streaks on top, where separated carrier fluid floated up.
Don’t confuse it with the other soft-resin causes: wrong ratio and undermixing look almost identical in the cured piece. The difference is history — if you measured right and stirred honestly, but the batch was heavily colored, the pigment did it. Full sticky-resin diagnosis here.
If you already overdid it
Warmth is your best shot. Move the piece somewhere around 75–80°F (24–27°C) — near a heat vent, in a curing box — and give it up to a week. Mildly over-pigmented resin often finishes curing eventually; it’s slow, not stopped.
Genuinely rubbery after a warm week means it’s done all it’s going to do. Some pieces have a second life anyway — a slightly flexible coaster still functions. A bendy pendant doesn’t, but it can be cut down and cast inside a fresh clear layer as a “fossil.” I’ve sold two of those. Nobody knew they were rescues.
Opacity without the overdose
The trap in my coaster story is wanting opacity and using quantity to get it. Wrong tool. Opacity comes from pigment type, not pigment volume — a purpose-made opaque white (Castin’ Craft, for example) at 2% does what a translucent tint can’t do at 8%.
If you’re mixing a pastel: opaque white plus a drop of color, not lots of translucent color. If you want deep solid black: one proper black pigment, not half a bottle of dark blue ink. There’s a whole article on this: opaque vs. transparent resin colors.
And color to 90% of the shade you’re chasing. Cured resin reads slightly deeper than liquid, every time.
Deep molds are more forgiving of pigment experiments than thin ones — more mass, more exotherm, more complete cure. Most of my molds run 1/4 to 1/2 inch (6–12 mm) deep, which is a comfortable zone for colored pours.
Ever had a batch fail and you never figured out why? Describe it to me — colored or clear, what pigment, how much. Overload has a signature, and I can usually spot it from the story.
— Nikolai