QuestionHi, I've been trying to get a better understanding of black surface/epoxy primer and there difference. It seems (in general) the epoxy primer is used for bare metal, and the surface primer is meant for covering body work is this correct?. Since my ride is in a preliminary stage, I would like to cruise with this look indefinately while I play the idea of doing it permanentatelty. I would just like the finish to be somewhat smooth. I notice alot black primered cars look very rough, and that's probally the only thing I want to avoid...
Oh, and is spray can primer a waste of time?
AnswerHi Gene,
Many people are confused between epoxy primer and primer surfacer. To see the difference you have to look at the main benefits and draw-backs of the two products.
For example, epoxy primer is designed to be applied over bare metal. It provides excellent adhesion to bare metal and excellent corrosion resistance. The draw back with epoxy primer is the fact that it does not have good sanding characteristics. Depending on how quickly you sand it, epoxy will either be gummy and ball up or it will be like sanding a rock.
Alternatively, primer surfacer sands really well after cured the proper time but don't work well when sprayed direct to metal. The main reason is, primer surfacer don't typically have corrosion resistance and rust will tend to grow invisible underneath the surface.
Primer surfacers are also called primer filler and can come in several qualities. For instance, acyrlic lacquer based and urethane based are the types found in automotive industry. I generally will always recommend urethane based products, However there are hybrid primer surfacers that work very well also. Here is a link to a product that is hybrid that can be used as both epoxy and primer surfacer: http://www.repaintsupply.com/sem-ml010-metalock-dtm-primer-kit-p1062.html
Something else that should be noted: There aren't any primers on the market to my knowledge that have u.v. stability built in. In other words, as soon as you start driving the vehicle outside with primer exposed it will begin to break down and won't protect the bare metal from the elements for long. If your looking for the flat black finish that primer leaves but you don't want to take a chance of the metal rusting check out this product: http://www.repaintsupply.com/sem-hr010-hot-rod-black-paint-kit-p3658.html
As for spraycan primers there are some very good ones on the market if you use them correctly. The best aerosol products on the market are made by SprayMax. The have actually designed an aerosol can that has a separate chamber inside that holds a activator. When you are ready to use the product simply press the button on bottom and it releases the activator into the product. Shake it up and you have a high quality product similar to what a body shop would spray. These work great for small jobs. Here is a link for SprayMax: http://www.repaintsupply.com/spraymax-3680061-2k-urethane-clear-coat-aerosol-p36
