you have to be careful with the heat setting too - because the epoxy does not let the heat dissapate - you will end up with a lot of shrinking in one area if you leave the iron on there too long - also - the heat weakens the bond of the epoxy - so less is more when it comes to applying it.
Proviously, I have coated the epoxy with balsaloc or PVA glue to give the "cote something to tack to at a lower heat setting......