How do I avoid mixing air bubbles into the epoxy?

Match the mixing tool to the batch size, and mix slowly.

Any batch under 1 gallon combined must be mixed by hand with a stir stick. A drill mixer on a small batch whips in excess air that is much harder to pop with a heat gun or torch, so if you're getting micro bubbles, check the mixing tool first. Only when mixing a full gallon at a time (1/2 gallon resin plus 1/2 gallon hardener) can you use the mixing drill bit along with the stir sticks. Even then, don't mix fast or vigorously, and keep the paddle away from the surface, where it creates a vortex that pulls air into the batch.

Work at 75°F or warmer, and keep the room above 75°F for 72 hours after pouring. Warming the resin bottle in warm tap water for 10 to 15 minutes before mixing thins it so bubbles escape more easily. Tiny bubbles in resin straight from the bottle aren't a concern; they release once the epoxy is mixed, poured, and lightly heated.

Don't let the mixed batch sit. UltraClear Bar & Table Top Epoxy must be poured out completely within 5 minutes of mixing or it starts to overheat in the container. Pour no thicker than 1/8 inch; in a thicker layer, bubbles get trapped and can't be heated out. Then pop bubbles with a torch or heat gun within 20 minutes.