I need a Pro's opinion on primer. My 69 is getting a quick winter makeover to it's 7 yr old chipped , scratched, abused single stage paint job. Here's my dilema - the body work is finished and I primered the body with a gallon of PPG DZL32 that I had left over in the garage and used Finish Pro 5100 Lacquer thinner to reduce. I purchased a gallon of Matrix MP4-2K 2 part gray primer with activator from the local paint supplier. The Big Question: Can I use the new MP4-2K over top the old PPG DZL32 even if I'm going to seal it with a white Matrix sealer as the base for the base coat\clear coat? Or or should I plan on sanding it all back off with a 180 grit and re-primer with the Matrix MP4-2K? I'm concerned about the compatability of the two... Thanks

That DZL is a lacquer primer, it will not "lift" or anything else when a urethane is applied over it (I assume the Matix is a urethane). It is however a VERY poor base for all your hard work. Lacquer over the baremetal is a weak link that is for sure.

I suggest if you want to go the extra mile, block the lacquer primer with 120 or 180 until it is gone or near gone, then epoxy prime the car and THEN apply your surfacing primer in the form of Urethane.

Hey Brian - Thanks for the response - The MP4-2K is a urethane and that's what I'm was worried about. Looks like I've a bunch of work ahead of me!!!!

The urethane primer will not lift a laquer product. Laquer products simply do not lift, they will however become liquid again if penetrated by a solvent. Catalyzed products may lift if used over a soluable product that becomes saturated. If your laquer primer becomes saturated with solvents again it will hold them and cause the catalyzed urethane primer above to wrinkle and lift. Only catalyzed products are suseptable to lifting. If you are very carefull with your basecoat application it will be fine, if you dump the basecoat on really wet and don't give it enough flash time it will wick solvents into the laquer primer and may lift your urethane primer. Hope this makes sense. Bob

Hey Bob - thanks for the post and actually it does make sense - tonight I beat feet into the garage and started removing the lacquer primer with 180 grit paper - My game plan is to get it back down where it was before the PPG DZL32. Reprime it with the Matrix MP4-2K Urethane, block it and prep it for Matrix sealer. Given that I give everything ample time to set - can I assume the sealer will be insurance against any incompatible products underneath (assuming I got rid of all the lacquer primer) as well as a good base for the base coat? Thanks for the post!

The sealer should offer some degree of protection as a solvent barrier, I think it will be fine. Matrix must offer some descent products, I've seen it in quite a few shops that I visit. Bob

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