Technical Epoxy Primer

Now that I have put my project into epoxy . What is next ? Its my understanding you cant sand this stuff ! Can you just pick up in a few months , do bodywork and prime right over it without sanding? I am worried about primer and or topcoat adhesion without sanding first . Is it true that all the epoxy will do is gum up the sandpaper? Educate me guys , I need help ! Thanks, Andy..

 

After 72 hrs ya gotta sand it b4 going any farther

 

Epoxy is real good stuff. You can do bodywork right over it if you sand it with 80 grit first. You can paint or prime over it only if it has been sanded. You can also use it as a wet on wet sealer but you would need to follow the manufactures instructions before doing so cuz all companies are different. You should be able to pull up a "P" sheet online if you type in the product to give you more info you might need.


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Also it will in some cases ball up your paper. It does need a good 65-70 deg for 24 hrs to cure fully. It's not the fastest curing product under the sun but if you aren't in a rush it's a really good all around product. Much better then an acid etch primer, those are very temperamental


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Epoxy primer is great stuff, but they are not all created equally.
I have tried DP90Lf. It won't sand worth a crap. And cost about $125 per half gallon. It was then suggested that I try Southern Polyurethane, Inc.
black Epoxy primer. Sands amazingly well, wet or dry, and costs $175 for 2 gallons, free shipping. You can apply body filler over it without sanding for 7 days.

 

All epoxies are NOT the same, as others have said. Please check your tech sheets to see how to work with it!
Personally I use House of Kolor KP-2. Sands easy, fills scratches, adheres great and can be used as a sealer. Others do not have all these qualities, they are made for specific purposes, not 'all around' work.

 

Thanks guys I was having shit fits thinking this was going to be a bear to get on later because of my preconceived notion that it was going to clog my paper . It will be a couple of months before I get back to this project anyways so it should have set up by then . One other question . I primed over all my work on the Buick , and the primer soaked in just like any other primer. This I am assuming is the qualities of the epoxy as well! Thanks Andy..

 

Here's what I am talking about . I suppose it's been compounded by the fact that it is black !!

 

Somebody ease my mind on this, as this is the first time I have used epoxy primer on anything and this looks like shit to me . Maybe once it cures I will sand it to blend everything together . What say you ?

 

What does the bulletin/tech sheet for THIS product tell you? We shot DP-90 over a bare frame, ft suspension, rear end. Dried 1 day, Scotch Brite it and shot AG Enamel over it and looks killer.

 

I only have one word of wisdom about epoxy primer - never ever leave a mixed up batch in your spray gun for any longer than it takes you to spray it. Clean that shit out immediately.

Ask me about how I know this.

 

Thanks guys , but is this normal for epoxy to soak in like the pictures ? And yes Mechanic talk about screwing up a gun in a hurry. Dont clean it and see what you get !

 

yes, if you applied sealer on body work(fillers), feathered paint,and primer spots it will "soak" or show up like in your pictures.

 

My advice is leave it as it is for the two months or so, then when you're ready to do the body work, hit it with 80 grit, do the body work, then two good coats of a high fill primer, block it with 320, primer again, block it with 400, one more primer coat, guide coat it and block it with 400 one final time until the guide is gone. If you took your time and blocked it the right way it should be nice and flat and ready for the top coat. That's how I did my roadster and it turned out nice, and I am not a painter but I listened to a guy who is. It's a lot of work but that's why they get the money they do for a good paint job.

 

Hey Andy,

Who's epoxy did you use, and what did you reduce it to? As chopolds suggested, get a tech sheet for your product, and read up on what will work.

The days of $25.00 a gallon primer are well behind us, and guessin' at what will work for you could get very expensive! My WAG says you shot your epoxy alittle thin, and don't have enought product on the job to seal the work underneith it.

 

72 hrs in Oklahoma where it's pretty warm.

In New Brunswick, you could leave it an extra day or two just to be safe.

Where I live, it's common to cure in 48 or less because it's rather hot.

And who said you can't sand epoxy? One of the joys of epoxy is that you can carve it into any shape you need.

 

Thanks guys my mind is at ease . Dry time wont be a problem as I probably wont touch this again for at least a month or longer . Our summers are pretty hot up here so I will roll it outside when it arrives !!! If ever at this cold rate LOL!

 

What was the purpose of using epoxy at this stage?

 

@ AW1950

It looks to me like you have thin paint in spots and this may partly be an issue of technique with the paint gun. Is this your first car paint job?

Some paints are harder to see when you're painting. It's important to have a lot of light when you paint. I've never painted in a booth I thought had enough lights & I have even set up extras. I never had a real shop & I always borrowed or rented booths from others.

Isn't life strange?

I had no problems sanding the epoxy on my boat, but when I did my boat in polyurethane it was a PITA to sand & do the touch-up.

For this reason I was going to avoid polyurethane on my car.

But I think the issue was the paint was kicked fast (I rushed like mad to shoot it & clean the gun!) but cured too slowly.

I'm thinking that in both our cases there was a curing issue.

 

The epoxy, I will admit is an industrial based product that a lot of guys up here use . They have no issues that I know of . They probably have the same issues . I reduced 4:1 as the directions say . I know it was shooting quite thick as I had hardly any atomized primer floating in my shop needing to be vented . Andy...

 

How cold was the air when you shot it?

 

I'm posting this from experience. I ran my own custom and restoration business for 20 years until retiring and came to realize how expensive those epoxy and high build primers are. The one I used exclusively and still do if I have a new project of my own is PPG primer NCP270 or NCP271. One is a red oxide the other is gray. This is a "right over properly prepared bare metal, corrosion resistant, extremely high build, easy sanding primer."
This is a no bullshit product. It's almost like spray on bondo... You do not need to use an etch primer first- (nice money and time savings there). I have used it under single stage urethane, single stage acrylic enamel (Centari), and under base clear custom show paint jobs. In all the years that I used it not one paint failure. No die backs, no peeling, no lifting, absolutely no problems. So here you have a single primer that needs no special etch base, sands easy, and works great. Just thought I'd pass this along. Go to PPG and punch up the data sheet. PPG NCP 271

 

It's not really a sealer though. It must be put on bare metal, right?

 

I had the shop up to 76 - 80 degrees . So this should not be an issue . Andy..

 

Thanks for the post and info . My local supply house does not carry the PPG line and it's to cost prohibitive to get on line up here . There are a few other suppliers but honestly I never use them . I have a good relationship with the guys at my current supplier. They have never steered me wrong on product yet . Just the same I am going to go to PPG website and check out their products . Andy..

 

The PPG NCP 2710 or 271 can be used over sanded original finishes or properly prepared, clean bare metal. it also may be used as a non-sanding primer....

 

Dumb question, but was the gun cup vented, did you have a full wet spray pattern? A plugged fluid tip or cap, or supply tube will not deliver fluid at the rate to produce proper build, this could produce dry spots in your finish.

 

X2!!! Another major fan of So. Poly's epoxy primer here. I also use it (thinned) as a sealer under my base coats. For the price, quality, and tech support from the SP folks, you can't beat this product IMO.

 

I use the PLC high build BUFF colored primer. My first coat over fresh body work I shoot without thinning just turn my air up and go for it. I found the black and grey are a bit thinner for some reason so I use buff for first coat throw a pass over just bondo and when I get all the spots done feather it out a little further let it cure than depending on final color sand it with 220 and do final Knicks in the bdy work and go light or dark thinned out just a bit. I do it this way so my base coat doesn't get sucked into body work.

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Lower quality fillers and insufficient filler curing will cause bleed through.