"How would you remove the clamp from the longeron without damaging either (but if one needs to be damaged, preferrably the clamp."
I am going to make the assumption we are talking about a little excess that ran down and around the head of the clamp. I did this several times myself. Epoxy's weakness is its peel strength. If you loosen the clamp and then "wiggle" the handle back and forth it should pop off. If you have done a really good job of it you may have to get out the dremmel tool with the cut-off wheel. Stephen Teate Paradise, Texas