Sealing waterproofing material on wetbags?

butterflygrooves

I am thinking of making my own wet bags and see that Planet Wise and Monkey Foot Designs somehow seal their waterproofing material after sewing... 

Does anyone know how to do that?  If you've made your own wetbags and haven't sealed them, have you had any wicking issues?

pixy_stix

You just run an iron along the outside seam of PUL when you're done.  The plastic sticks to itself.  The trick is to *only* do it along the outside edge, and not have your iron too hot or too cold.

butterflygrooves

Do you know what temp?  I would need to iron over the seam, right?  Also, do you know if sealing would work with a different water proofing material?