Auto body repair & detailing: Water bleeding out of primer., relative humidity levels, air compresser

Question
Hi Gary I have a problem that maybe you can help me with. My Dad and I are working on a 69 camaro as a restoration project and about 4 days ago we spray the car down with surfacer primer. After about 1 & 2 dasy later, you can see that there is water bubbles under the primer. Before I spray with my spray gun I always make sure that the air lines dont have any water in them. I have two water filters for the air compresser and one right on the spray gun so no water is coming out of the spray gun. And made sure that the prime had no water in the can also. What I think it may be is that the temp has bin to cool(30-39 degress). I have painted cars in the summer and have not had this problem, but it seems that no matter how hot I get my paint buth up to this water under the primer happens to me. So I would like to know if you have had any thing like this happen to you and what can i do to stop this from happening. Thank you

Answer
Hi Ray,

If I understand you correctly, you are spraying a warm product on cold bare metal. This could cause condensation between the product you're spraying and the warm surface. This would be amplified if the relative humidity levels were very high. No matter how well you filter your air for moisture this problem will still occur if you don't pick a warmer day with low humidity levels.