Building a resin studio in a Mumbai monsoon
Ninety percent humidity, no climate control and a deadline. What we learned the hard way about amine blush.
Every resin tutorial on the internet is written in a temperate climate. We opened in July, in Fort, in a building with no air conditioning and a monsoon outside. The first three weeks were an education.
Amine blush is real
Above roughly seventy percent relative humidity, the amine hardener reacts with atmospheric moisture and CO₂ and forms a greasy carbamate film on the surface. It looks like a smear you can't wipe off, and any resin poured on top of it will not bond.
It is not a defect in the resin. It is the room.
What we actually changed
- A dehumidifier in the pour room, held under 60% RH — non-negotiable
- Pour in the morning, before the afternoon humidity peak
- Curing cabinet with a 40W bulb, holds 28°C overnight
- Stopped storing resin on the floor — cold concrete thickens it
The unexpected upside
Warm ambient temperature means resin flows and self-levels beautifully. Once the humidity was solved, our Mumbai cures were better than anything we'd managed in a cooler workshop. The problem was never the heat.
Put it into practice
Everything in this article, on one bench.
Our starter benches ship with enough material for two attempts and a printed pour card — so the technique above has somewhere to land.