Heating the spar to loosen hysol ??

Deleted, sorry

1100 will melt the aluminum. The lower setting will soften the epoxy.

Be careful not to overheat the aluminum spar tube. Keep the temperature as low as possible and for as short a time as possible. The 6061-T6 tubes can lose considerable strength, permanently, at temperatures well below the melting point. I think to be safe I wouldn't go over about 400 deg. F for any extended period of time.

Thanks for the replies...........I was able to remove the fuel tank without using any heat. Frankly I didn't want to take a chance of using heat on the spar, so careful chiseled it away, what a job.

For future reference here's a great paper which documents a study of whether aluminum can degrade in high-heat paint ovens. It gives good time / temp / strength plots for 6061-T6 and others:

http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1132&context=matesp

And of course, John nailed it. Keeping below 400F for any reasonable period of time should retain all your strength.