Question about priming
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Heel & Toe
Joined: Jun 2005
Posts: 19
Likes: 0
Question about priming
I have an 87 vette that needs paint badly. I have started sanding and have a few pieces ready to prime, and want to make sure I am on the right track. I plan on using PPG DPLF epoxy primer, followed by a high-build 2k primer-filler. Once I block sand that out, I figure some of the epoxy primer may show through in spots. Do I need to spray another uniform coat of primer so it is all one color or is it ready for paint? If I need more primer, do I use the epoxy primer or something else?
Also, I have heard of spraying a guide-coat for the final block-sanding. What is a good primer to use for that?
Thanks
Also, I have heard of spraying a guide-coat for the final block-sanding. What is a good primer to use for that?
Thanks
Burning Brakes
Joined: Sep 2005
Posts: 993
Likes: 3
From: Iowa
To answer your first question; we always come back in and prime our cars to make them an even color. This is really important to assure that you get an even result when you put down your base coat. I would get the panel where I wanted it to be and then I would come back in with some of the 2K (this is where it is important to be able to put it down smooth) just to even it up. In the House of Kolor line of products we have a primer that we use as an adhesion coat before we put on our base that integrates this step into the final painting process. You would have to check with the manufacturer to find out if anything like that is available through them. As for the guide coat; we don't use this step so I can't offer any help. I hope this helps out.
Intermediate
Joined: Apr 2007
Posts: 37
Likes: 0
"guide-coat for the final block-sanding"
3M Dry Coat part# 05860
This is a powder and comes with a sponge type applicator.
It is compatible with most all auto paints so if you leave a
little on the surface somewhere no need to worry.
*Highly Recommended*
If the 2K primer your planning on using is also PPG, like their
K36 or K38 you don't need any adhesion promoter. Just
apply it to the "DP" epoxy once it has had a chance to dry.
You will only need to scuff the epoxy primer if you let it set
24 hours or more before applying the 2K.
If your epoxy and 2K primers are the same color it would not
be necessary to re prime. But that will be personal preference.
If you need to apply any body filler you can put right on top of
the "DP" epoxy this what it intended for.
3M Dry Coat part# 05860
This is a powder and comes with a sponge type applicator.
It is compatible with most all auto paints so if you leave a
little on the surface somewhere no need to worry.
*Highly Recommended*
If the 2K primer your planning on using is also PPG, like their
K36 or K38 you don't need any adhesion promoter. Just
apply it to the "DP" epoxy once it has had a chance to dry.
You will only need to scuff the epoxy primer if you let it set
24 hours or more before applying the 2K.
If your epoxy and 2K primers are the same color it would not
be necessary to re prime. But that will be personal preference.
If you need to apply any body filler you can put right on top of
the "DP" epoxy this what it intended for.
Pro
Joined: Apr 2006
Posts: 650
Likes: 14
From: Highland Mi
Dan, Deakins is correct that it is wise to put down a uniform primer under your base so you do not get any weird effects. Some of the PPG reps say sealers are unnecessary and that you can put down a final coat of your 2k and then finish sand with a fine sandpaper, maybe like a 500 and then shoot your finish coats. I often use the DP mixed with DT870 and 401 hardener and use as a sealer on top of the final 2k. With the different DP colors you can often get close to the final primer/sealer color you want under the finish coat. The DP has pretty decent adhesion and flows out pretty well with the 870.
As for a guide coat they sell guide coat in rattle cans and since you are sanding it all off anyway there is nothing too disastrous about using rattle cans. I don't use a guide coat as often as maybe I should, but when I do, I use black lacquer in a rattle can-just a habit-dries pretty much on contact. Good luck with your project.-Jim
As for a guide coat they sell guide coat in rattle cans and since you are sanding it all off anyway there is nothing too disastrous about using rattle cans. I don't use a guide coat as often as maybe I should, but when I do, I use black lacquer in a rattle can-just a habit-dries pretty much on contact. Good luck with your project.-Jim
Le Mans Master
Joined: Nov 2000
Posts: 5,210
Likes: 104
From: Fort Worth TX
St. Jude Donor '06
Father & Son St. Jude Donor '09
I used DPLF as my initial coat of primer followed up with K36 and since it was too easy to inadvertently block through the K36 and hence the DP too, I tried a new system on my last project.
I sprayed multiple coats of K36 over the prepped body parts, blocked 'em flat and when I was ready for paint, I mixed up some K36 as a wet-on-wet sealer and sprayed one medium to thick coat.
Since I was using ppg's DBU base, I had to let it dry for 2 hours before spraying the base coat. After 3 hours passed, I decided to block the K36 sealer with 600 grit wet paper to eliminate a few dry areas. It blocked very nice and I was spraying base in 60 minutes. The base went down perfect and the clear was about as good a clear coat as I've ever sprayed.
Or you can apply DPLF over the top of the K36 like Jim does and use the epoxy primer as a sealer just before spraying the base.
Bottom-line, I won't be using DP as the initial coat again.
I sprayed multiple coats of K36 over the prepped body parts, blocked 'em flat and when I was ready for paint, I mixed up some K36 as a wet-on-wet sealer and sprayed one medium to thick coat.
Since I was using ppg's DBU base, I had to let it dry for 2 hours before spraying the base coat. After 3 hours passed, I decided to block the K36 sealer with 600 grit wet paper to eliminate a few dry areas. It blocked very nice and I was spraying base in 60 minutes. The base went down perfect and the clear was about as good a clear coat as I've ever sprayed.
Or you can apply DPLF over the top of the K36 like Jim does and use the epoxy primer as a sealer just before spraying the base.
Bottom-line, I won't be using DP as the initial coat again.
