Guess my idea about adding micro-balloons is different from the purpose of mitigating galvanic corrosion between dissimilar metals. I think a great test would be to add the micro-balloons to some Hysol in one sample and none in another. Fasten identical plates together with rivets. Have identical arms hooked to a scale that would test the separation strength of the bond after the rivets are removed. I think the micro-balloons actually allow Hysol to remain in the bond area more so than squeezing out of the area with none.