Heres my tutorial on how to do a return edge on a TK. Same principle can be applied to most plastic armor. Hope this helps!
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I have a lot of people asking me how to do a return edge, or tips when they've bought a heat sealing iron and can't get it to work. So I figured a video tutorial would be helpful.
Here's online sources for heat sealing irons:
http://www.towerhobbies.com/products/towr3250.html
http://www.horizonhobby.com/Products/Default.aspx?ProdID=HAN101
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB361&P=0
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB363&P=0
http://www3.towerhobbies.com/cgi-bin/WTI0095P?FVPROFIL=++&FVSEARCH=sealing+iron&search=Go
With that out of the way, here's a 2 part video tutorial for how to create return edges using a heat sealing iron. I hope it's helpful for all the people asking for tips on how to get a better return edge!