I am encapsulating LED circuitry in a PVC tube using a two-part, optically clear urethane adhesive. I am having a problem with the urethane outgassing during curing and bubbles permanently forming. This gives an unfinished look and has negative effects on the light output. The urethane is being cured at room temperature, but the problem also occured when I tried curing at a raised temperature. Are there any other methods or tricks I might try to get rid of the bubbles, or any other optically clear materials I could use for this application?
20 years ago