I recently made a rocket launcher that had a rather large LED in it. Unfortunately, during final assembly, the leads for the LED snapped off and I had to remove it. The problem was that the LED I used to replace the broken LED was smaller than the original. The hole I had drilled was too large and the LED would not stay in place. What to do?
Sugru to the rescue!
As you can see from the picture above, the sugru was inserted around the LED. I had to hold the LED in place for awhile until the sugru held. Then, I left it alone for a few days to dry. The sugru is still a bit malleable but it is solid enough to plug the hole.