Thanks so much for this demo bud. I have a thermarest that leaked at the seam after 15 years of reliable service and my first stab at resealing was a fail. The clamp should do it, and I think opening the hole up a little more to get at the weak tapered part of the seam with glue will also help. Just about every other video for resealing a thermarest deals with punctures and patches, not the seams. Thanks!
Good info. Use masking tape on the area where you don't want to get glue and I would use wax paper on top of the seam because wax paper doesn't stick to glue usually.
I normally use two wooden plates and a little sand bag to distribute pressure evenly. This makes at sandwich for the clamp to hold. I use this method for patches as well.
Since you've repaired this one seam, what makes you believe that the integrity of the rest of the boat is sound ? have you had any other problem since this was posted 4 years ago ?