Has anybody done a foam surround repair kit? I have an old GK 250ML guitar amp that my brother-in-law gave to me with the parting words: "If you can fix it, then you can keep it." I repaired the electronics, then forgot about it. Today I was showing it to my daughter, and we noticed that the surround was gone on one of the speakers. Anyway, I'd like to take a crack at fixing this, but am wondering if the repair kit is as easy to use as claimed.