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Rattle can adhesion promoter wrinkled spi 2k sealer

#1
After cleaning and prepping a tpo plastic bumper cover, I sprayed two thin coats of rattle can Ad pro followed by two thin coats of spi 2k sealer. The following day I wet sanded some orange peel and exposed some small areas back to raw pto. I attempted to spot spray these areas with some Ad pro and the surrounding sealer wrinkled. Two different brands neither of them spi had same result. This is not a feather edge issue. I suspect the sealer was not fully cured. 24 hrs at around 60 degrees.

I have since let the bumper sit for three days before I try again. My observation is that there is a lot of solvent in these rattle can ad pros. Yet most people discourage using solvent based cleaners on raw pto. This seems to be somewhat of a contradiction. Can someone please clarify why solvent cleaners should or should not be used prior to recoating a raw pto bumper cover?
 
#2
I stay away from using solvent wax and grease removers on plastic covers because I've seen adhesion failure in the past doing production work. Some people feel some of the plastics may absorb some of the solvent. Mostly the problems I've seen were on urethanes and some thermoplastics but I suspect the speed of production work may have contributed to the issues or the grade of solvents in the cleaners leaving a residue, you may not have problems if work time is extended or if you follow up with a waterbased cleaner. The issue you are having right now is that adhesion promoter is a 1K product that is forever soluable and solvent from the sealer is rewetting the promoter under the thin feather edge of your cut throughs allowing the edge to wrinkle. Your 2K sealer is not soluable but it will absorb solvent and expand causing the wrinkles. More flash time is needed to correct this and thinner coats of sealer until fully covered again and a barrier is achieved.
 
#3
Bob has far more experience than me on this or most any other topic for that matter,lol.

That being said - I was told to not use solvent based cleaners on plastics due to the static build up - discharge - fire risk, and that the use of it causes static electricity to attract dust onto the surface.
 
#4
bob is spot on. the adpro is soaking up the solvent from the wet sealer wrinkling up the cured sealer. just to add to this as well, try to keep your coats of adpro to one thin coat. the more adpro is on it the worse the adhesion and the more trouble you will have. i dont even like adpro in a spray can because of this. one extremely thin coat out of a spray gun is all thats needed.
 

Barry

Paint Fanatic
Staff member
#6
Everyone is exactly right on here and let me add more.

Another thing that can happen with too much adpro or not setting long enough is the adpro can get into the sealer and sealer will never cure right, usually the first coat of base will go on fine, in this case and the second coat of base will wrinkle the first. OR worse! the base goes on fine and first coat of clear wrinkles all of it.

Keep adpro to a minimum.
Watch dry times, to long can be worse then too soon.
Never use a solvent cleaner on a TPO, TEO, PP or PE type bumper.

With my adpro, I say one medium coat at 70 degrees and wait exactly 15 minutes and spray the next coating. (all adpros are different)
We have a place in CA that does close to 100 bumpers a day and that was an education for me.
 
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