I am thinking about starting to remove all the old paint off my car and wanted to know if it made any difference if I was to do a section of the car, repair body, and shoot epoxy at different times. I am working on it in my spare time and didn't know if I should wait until I can strip the entire car and shoot the epoxy over the entire car or what.

What is the difference in the epoxy that is laid on over the bare surface and the 2K primer that is used to block sand the car? Can anyone give me some brands to use and etc? Thanks.

 

I don't see a problem with doing a panel at a time.

I do admit to being confused why so many want to use an epoxy primer. On my '71 we shot PPG K36 (urethane high-build primer) directly over the fiberglass. What's the epoxy supposed to do?

 

I have no idea, I am new to this and that is why I am open to suggestions. I have read where people shoot a sealer over the bare panels and then shoot a 2k primer to block sand the car. Why do you use different coats and not block sand the coating you put over the bare panels?

 

One of the first things you should do is decide on the paint brand and line before you start using products that may not be compatible with each other. There are a lot of brands and different quality lines within each brand to choose from. You may find it advantageous to choose from a local business as opposed to mail order. Especially if you run short of product one day. I prefer PPG Deltron and Vibrance products.

Ask the paint manufacturer you choose what the expiration is on the hardeners that you will be using. Some hardeners are only good for 7 days after opening. Probably every painter has exceeded that at one time or another, but since there is an expiration time, obviously there is some risk involved in using old product. Wasted or unused material can get expensive.

The first coat of paint over a bare substrate is the most important coat of the whole paint job. I prefer epoxy since it more universal and can be used on fiberglass and SMC. A 2k primer such as K36 will work on fiberglass but epoxy is the better adhering of the 2 products, however there is no referrence on the K36 tech sheet for use over SMC. Epoxy will hold down loose strands of glass, K36 not as well. Body fillers can be applied directly to epoxy, but not to K36, K38 or other sanding primers. By doing major resin/glass repairs and coating the body sooner, you eliminate additional contamination risks on bare fiberglass or SMC. Epoxy will create a barrier that will prevent moisture from absorbing into bodywork and paint materials from behind increasing the longevity of the paint job.

Some epoxies don't sand well, a 2k primer is designed to be sanded.

 

ahoover: OK, I see what you're doing with the epoxy. Although we didn't have any problems skipping it. We did all the body work directly on the fiberglass and once it was all shaped and prepped, shot the urethane primer over it. My rear deck is SMC and the urethane primer stuck fine.

But I guess there's no problem is shooting epoxy over the raw glass as soon as you have it stripped.