QuestionHello, my question is 2 part: please explain what the differences are between a 2k, urethane, and epoxy primer and how do you determine when to use each of these. Also. I was recently trained using the PPG Envirobase line of paints. Having never used a water based automotive paint I have been leery. The company claims repairs can be achieved without priming, directly over the factory paint. I find this difficult to believe because I've been painting for years and oil over water is a no-no without using the proper primer. Also I have never been very successful at doing small spot repairs without doing the whole panel. Can you please answer these questions and offer any advise or tips on blending and minor scratches and spot repair??
AnswerHi Michael,
2K stands for 2 Component. The term originated for Urethane paints that require a Polyisocyanate to fully cure the product. Now, the automotive industry basically uses 2K to say that something must use a catalyst, hardener, or activator to fully cure.
Epoxy primers typically don't have good fill or sanding characteristics but have extremely good adhesion and corrosion resistance. So epoxies are used as a primer/sealer for coating bare metals or previously painted surfaces.
Urethane Primers have great sanding and filling characteristics as well as good adhesion. However, they don't typically have good corrosion resistance. Urethane primers work well for filling and blocking out rough surfaces but are not usually good for bare metals because of low corrosion resistance.
Envirobase, is a finish that PPG has high hopes for. Apparently, it is doing a fantastic job all over North America. California has mandated that all base-coat finishes must be water-based. I personally have not used it myself but from what I hear it sounds like the next big thing in the paint industry. I was talking with a PPG Rep the other day and I asked him if he personally thought that PPG has finally got a good handle on water-based finishes. He emphatically said he believed water-based finishes are here to stay and he firmly believes that PPG has the best product on the market in Envirobase.
I have not had official training in Envirobase as of yet. However, I have personally spotted in OEM cars using PPG's Deltron solvent based base-coats without priming or using a sealer. Sometimes, I will use Deltron color blender as a ground coat to avoid metallics standing up and causing a halo look around the repair. But on solid colors I go directly over the original paint (sanded of course). I have been using this method for several years now and have never had any issues. I suggest you either talk to your paint store's tech rep or PPG rep and they should be able to give you specific instructions as to how to use the Envirobase the same way.
Good Luck!
