Paint Prep revisited

[MoparGirl]

Hey All,
I've been prepping smaller body parts for paint and have run into a couple of different opinions on what I should be doing so I wanted to run them by you experienced folks.

We're down to bare metal on all body parts, so assume we are beginning there.

I've been using AutoBody Master Epoxy Primer as the first step over the bare metal. Reducing it 4:1 and catalyst 4:1. It's spraying great with no drips, runs etc., although that will be sanded over anyway.

Now depending on what paint I want to buy, PPG/Dupont/Nason there are different products from that point to choose.

If I go with PPG paint the "paint store guru" says I need to use PPG Epoxy Primer, PPG hardener, PPG Basecoat & PPG Reducer, & PPG Clear, etc. Basically I need to stay in the PPG Products for everything. That's okay, but I'm confused on the Primer/Surfacer portion of the program. The product number he gave for the Epoxy is the same as the number for the Primer/Surfacer. So am I not just using the same stuff, but maybe a different mix ratio for a seal coat? And if that's the case, why can't I continue to use the AutoBody Master Epoxy with a different mix ratio? I know you generally want to stay in the same product line in case of paint failure...you know who/what to blame for the mess. However, PPG is expensive stuff.

I thought all I had to do was use the Epoxy Primer (reduced & mixed of course,) sand, then do the body filler & putty where needed, sand, Primer/sealer coat, sand, then base coat, sand, then clear coat, sand, sand, sand.

Is that about right??

What about using different Epoxy with different paint manufacturers? Is this a no-no or no big deal?

Seems like everyone you talk to has a different opinion on what I should or should not be using and that's okay except I've already been told incorrect stuff by one of these "paint shop gurus." Also, they are in the end trying to make a sale. A sale of $500 bucks for everything under the sun looks better to them than say a sale of $300 bucks for things I just need to complete the job. I don't know how much of what they are telling me is for the sole purpose of making extra cash.

As always, you're insight is immensely appreciated.

Pam

 

[Rob]

You don't have to stay within the same line for everything, your supplier just wants you to buy it all from him. What you do have to do is use the same line for that stage, the reducers, activators, etc. have to match the paint or primer, don't use Dupont to activate PPG for instance, so yes you have to use PPG hardner for your PPG epoxy. I use Dupont epoxy, Omni (PPG's cheap stuff) high build and Dupont base and clear most of the time.

 

[ted_sweet]

if you mix and match and have issues nobody will stand behind any of the products

 

[Rob]

If you're not a pro they won't stand behind the products anyway, they're not even supposed to sell it to you, read the label. You may miss your top coat window, sanded your primer to fine, didn't de-grease, etc. There's a million things that can go wrong, shooting one brand over another is done all the time in collision shops and restoration shops. Nothing wrong with sticking to one brand but I prefer to spend $100 a gallon on high build not $300 and then put the extra money into high end base and clear. I've never used Autobody Master anything so I can't comment on that specifically, you should check the tech sheet on it, but PPG and Dupont are high end products that are compatible with each other, (Dupont makes Nason by the way)

 

[OldVart]

Pam, I would say you're on the right track. I always spray any bare metal with epoxy primer because it affords about the best protection around once it's on the metal. You can then do any required bodywork over that if you wish. Once all your bodywork is done, scuff your epoxy primer and respray a coat of epoxy if you have any bare metal areas. Then, within the epoxy's recoat window, squirt the whole thing with a hi-build primer and get out the long board with some 180 grit for block sanding. Use either a spray or dry powder contrasting colour to show any high or low spots during the block sanding stage. This stage of the game is where you can make or break a paint job. The more time spent getting the body perfect here, the better your final paint will look. As Rob said, it's good to stick with one product line for your paint supplies, but when it comes to the epoxy and high-build primers, I use different brands in keeping with years of previous experience with these products. Just prior to paint, I always shoot a complete epoxy coat as a sealer, so you don't have to worry about any reaction between the paint coat and any previous materials used for priming, and it also provides a uniform colour for your topcoats. Good Luck.