Make Your Own Gear: Shortening a Therm-a-Rest UltraLite Self-Inflating Pad

I shortened a Thermarest Prolite 3 (the version preceding the current Prolite). I used Erin and Hig's method of using a hot iron to delaminate the fabric from the foam. The same cautions this article warns against apply.

1. I set an iron to the "linen" setting. Marked the desired cut point in pencil. The pad was lightly inflated and the wooden board was positioned 1/2" above the pencil line.

2. The board's weight/pressure protects the foam underneath from delaminating. Working carefully and using the point of the iron, I lightly heated up the pad and let the expanding air push the fabric from the foam and "bubble" up. I repeated on the other side.

3. I opened the pad valve and cut on the line.

4. This method cleanly separates the foam from the fabric. I then used the point of the iron and my fingers to carefully delaminate the fabric from the foam an even distance away from the cut. The foam can be "teased" away from the corners as well using this method.

5. I cut away the foam from the area I intended to heat seal closed and made sure the valve was open. Positioned and weighted the wooden board to make a straight edge and then heat sealed the end closed. I started from the middle and worked to the ends. I found that I had a bit of excess materials that got pushed to the ends.

I found, that with the sealing areas free of foam, that it was possible to heat an area, pick it open and reheat to seal it again. I used parchment paper to protect the ironing board and the iron.

Take your time and watch your fingers! Good luck!