Opps, all I was interested in was some info on gluing blue foam...
But since this thread has been so popular no sense letting it die... I believe all the trouble people have with Thermarests, and inflatables in general, can be attributed to how the mattresses are used and looked after. (I do agree that the large volume mattresses are affected by temperature changes which is a design issue not a user issue.) I bought my Thermarest shortly after they first appeared on the market many years ago (yes, the first one had a 'metal valve' and it was replaced under warranty) and I have never had a problem with leakage. I just throw it down in the tent and put my sleeping bag on top of it to help keep it flat while it self inflates. Before climbing on to go to sleep I'll give it a couple puffs with my mouth to blow it up slightly until it is taunt and rigid, seal the valve tight, and it always remains fully inflated. I believe its performance and long life can be attributed to having never used it as a chair outside of the tent, taking extra care that there is nothing sharp it is placed on, always storing it inflated, on edge with the valve open and at the top. Maybe I just got a good one… but quality control has never been an issue with the Thermarest and if anything materials have gotten better over the years.
Sorry for stirring the pot again… [}