Here's my latest attempt at a better lid for my wonderful SnowPeak 600 mug.
The old foil lid is on the table for comparison, the new one on the mug. I cut it from a flexible plastic cutting board, slotted and super glued a kevlar webbing handle into place and used a bead of silicone glue to hold it down.
The trick was to liberally coat the mug's rim with liquid ski wax (the release compound), let it dry, then hold the plastic circle in place while I applied a nice fat bead of silicone glue around the lip. After the glue had cured, I stuck the bottom half of the mug in a pot of boiling water to melt the wax and the lid came right off.
The first time I did this, I tried to put a bead of glue down on the plastic then pressed the mug down onto the glue. This didn't work very well. The glue dried so fast it was already too firm to make a nice indentation around the lip and there's really no point in having glue anywhere but outside the rim either. Fortunately the glue scraped off easily with a hobby knife.
For the second try I put so much glue on that I had to cut it back with diagonal cutters, but the grip is marvelous (when cold).
So how well does the lid work? The plastic warps a little when heated by boiling water so the lid tends to stay cupped after it cools. It's still flexible enough and the silicone grippy enough that it's no big deal. Thing is, the silicone gets really flexible near boiling and the lid lifts up on one side, but it's not in any danger of actually falling off.
Definitely MYOG, but I'm happy with it compared to the flimsy foil lid I had before.
The glue I used is fancy hobby shop stuff called Zap-a-dap-a-goo. I know there are silicone formulations out there which aren't so heat sensitive, but I have no idea what or if I can buy them in glue form. Any ideas?
Finally, since this is BPL, what does it weigh? It's 6g (1/4oz), which suits me just fine: