What’s the best way to prevent bubbles in resin coasters?

[Hannah.H]

I’ve been trying to make a set of matching coasters using resin, but I keep getting tiny bubbles trapped right in the middle of the design no matter how carefully I mix. I’ve tried warming the resin and using a lighter, but it just seems to make the problem worse on these smaller pours.

[Ethan60]

I hear you. I had the same mid design bubbles when I did a batch for coasters. Warming the material helped with big pours but on small layers it just pulled air into the center. I tried a quick pass with a lighter and it seemed to push the bubbles somewhere else and they stuck in the middle anyway. Not sure if I did something wrong, but it felt like the heat did more harm than good after a certain thickness.

[Kyle.R]

Moisture or mold contamination seems possible. I once left the silicone mold out in a breezy room and a tiny bubble formed in the middle as it cured. The air cooled or dried and got trapped. I can't prove it, but it seemed to come from humidity more than how I mixed.

[MiaCT]

Could the design itself be the real problem? I swirled a bit and the bubbles lined up with the center, like the pigment was releasing gas. Not sure if that's what happened, but it crossed my mind.

[Dennis25]

I drifted into a different hobby for a spell, playing with beads and pigment in water, and forgot the bubble drama for a while. Then I came back and the same issue waited. On rainy days the room humidity climbs and that tiny water layer on the surface might be part of it. I keep trying different molds and pour depths, but I don’t feel close to a fix.