SEM Plastic Repair

[Sephiroth]

I used SEMS plastic repair and filler to make a bumper. When I fianlly finished it looked great, but recently (week or so) the lines have shown up and even in one spot it looks like a run because it has expanded so much. So my question is why is it doing this? Is the epoxy still expanding is it because the heat and the bumper and epoxy are expanding at diffrent rates?

This is what I did http://3sforum.com/albums/Sephiroth3si/100_0836.sized.jpg http://3sforum.com/albums/Sephiroth3si/100_0840.sized.jpg http://3sforum.com/albums/Sephiroth3si/100_0849.sized.jpg http://3sforum.com/albums/Sephiroth3si/100_1036.sized.jpg

Now take in mind in the last pictures its not bolted down. Now where the lines are forming are where I molded to two sides and you can now see the lines around the Mitsubishi star. Thanks for any help.

[Len]

I'm not familiar with the working characteristics of SEM plastic repair materials but my guess would be that the initial bonding of the plastic pieces was NOT done correctly OR the adhesive products you used were not a good choice.