trimming aluminum

I am in a dilema. I bought .040 aluminum from a truck repair center, mainly for the width but mostly for the cost. I put the top on my teardrop the other day and tried to use a flush bit in my router to smooth up the edge. I smoked the bit and the aluminum just melted and balled up underneath. I know what someone is going to say, use a variable spaed router or a speed control device. It didn't work, wouldn't cut fast enough to work. I managed to file down the edge but now, I need to apply the side aluminum and am wondering how to trim it flush with the top. Any suggestions? Would a roto zip tool work? HELP!!!