primer

[mikec53]

i want to primer my 53 buick, and use ppg dp 90 primer on the steel then use k 36 for final sanding, but i was reading through ppg's book and it said when using dp 90 you can prime the stel then sray your k36 on top within the same working day without scuffing the surface. however if you leave the dp 90 for mor than a working day you have to spray a coat of dp 90 and then your k36. my buddy did this and is having a nightmare his paint is blistering, and now im nervous about using dp 90 on my car. did this happenn because the dp 90 was still giving of fumes and was not cured? can i use k36 on the bare properly cleaned metal, after all it is a urethane. im scared about the epoxey stuff now. my buddy says that the dp90 takes about 2 to 3 days to cure using dp 402 catalyst

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[MARTINSR]

I have to say that if the DP90 was used properly, you buddy wouldn't have had a problem. Something was done improperly, period. Your thoughts of the traping of solvent is probably right on.

I personally only use epoxy when it is going to be directly top coated with color. It is jsut too hard to work with.

So if I plan on useing a urethane primer for surfacing, I use an etch primer under the urethane. PPG's DPX-171 or even better DPX-1791 would be my choice.

If you plan on primeing over paint/plastic filler/primer that is on the car, the etch prime isn't necessary. And if you are going to spray over plastic filler, PPG doesn't recommend it, but if the plastic has cured at least 12 hours, I have never seen a problem.

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Life long Buick fan,
1965 Gran Sport Conv.
1965 Skylark H/T
1948 Chevy P.U. with 401 in it.