Jim, a couple of things came to mind. I have sometimes found in the past that the culprit is air trapped in the pores of the wood. When you spray the lid heavy it traps the air and especially if heat is involved the air expands but cannot escape hence the bubbles. I learned this accidentally when setting a sprayed piece in the shade only to come to the realization that the sun moves! Other sources of heat can exacerbate this problem such as Hvlp spraying systems or heated paint systems. I have also found that filler application and drying time are important. Several people have suggested spraying dry first coats and more drying time between, I agree. This may not solve your problem but I had to put my two cents worth in. David Koelzer DFW
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