If you use the K-36 in the open coat time then no. I always ran a scotch brite pad over the DP-40 anyway. If this is the first time you've painted PPG then you might not find the system so great for durability on bare metal. I didn't. I found it didn't stand up to the salty conditions in the Canadian winters. If you're PPG certified they'll guarantee it otherwise it's your baby. It worked just fine on winter stored cars though.

PPG has a primer/sealer that is tintable (I don't remember the number) it's a little cheaper than K-36 and in my opinion is just as good as a sealer but not as a surfacer. I haven't shot PPG in years and I'm not up to date on their products.

 

I am currently stripping and epoxy priming a 71 Cutlass. I am doing one panel at a time, stripping to bare metal doing any body repair then priming. I am going to cover all this with K-36 and then block sand it. My question is do I have to scuff the epoxy primer before I shoot the primer surfacer ? I know that the Epoxy has a 7 day "open coat" is this just for re-coating with more epoxy or does this apply to the K-36. I've got the tech sheets for both but was a little confused. Thanks in advance. - Jim

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Like the first post said if the primer is applied in 7 days no sanding is needed.
After seven days some epoxies all you need to do is scuff and than shoot your 2K primer.
Other epoxies after 7 days you must scuff and re-coat with epoxy first. It depends on how the activator is formulated.
You need to call PPG tech on this in case recent changes have been made.
If you can't get an answer to be safe scuff the epoxy and spray a coat just to be safe, one person that may know is Randy Fergusion.

 

If this is the first time you've painted PPG then you might not find the system so great for durability on bare metal. I didn't. I found it didn't stand up to the salty conditions.
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This is a smart painter!
It sure is not what it use to be!
bk

 

Hi Guys,
Maybe I just like to sand, I dunno, but I usually don't wait much over 30 minutes between coats of DP primer and K-36. I like to spray "wet on wet" as much as possible, as I believe you get maximun merging of materials with this method. You don't want to spray the K-36 over the DP too soon, but after 30-60 minutes should be fine. Much beyond that and I would scuff the DP with a red scotch brite pad. Sanding isn't much of an option with the DP primers as they are gummy and do not sand well.

To be quite honest, from what limited use I have of this product, I am very pleased with it, and that is the 6600 series epoxy primer available from Southern Polyurethanes Inc.
www.southernpolyurethanes.com
It sprays great, sands super and sticks like mad.
They also have 2k primers available, as well as a range of clear coats. Check 'em out!!

I have more of their products to try, but haven't gotten the opportunity as of yet. If the rest of their products work as well as the epoxy though, I will be quite pleased!! Their prices are better than you will find for the "big name" products too.

What you must keep in mind is that many paints are based on the same raw materials, with a little different recipe here and there. Look at the product labels sometime. Each companies paint contains similar products. I'm by no means a chemist, but I have managed to learn over the years how to spray some of this stuff. Still learning everyday!!

Randy Ferguson
Metalshaping & Kustom Paint

 

J Cal

Over clean bare sanded metal I do the following.

1. spray 1 coat dx1791/1792 etch wash. Let dry 30-40 minutes

2. spray two coats of DPLF. Let dry 1hr

stop here if you need to do filler work and let the DPLF dry for 24 or preferably 48 hrs. Scuff with 80-120 grit and apply filler. Once you are done with filler work shoot with at least 1 coat DPLF(minimum of 2 coats over any bare metal) and let dry for 1hr.

3. spray 3-4 coats K36. After 24hrs block sand 120- 180 grit and repeat 3 coats K36. After 24hrs block sand 320-400 grit.

After doing this you should have straight well protected sheet metal ready for top coats.


To address BarryK's remark about PPG not holding up well in salty conditions. PPG products have always worked well for me ,but you sometimes have to read between the lines of the P- sheets to get all the info. When PPG went to DPLF from DP epoxy they took out the lead (to meet EPA regs I guess). Lead helps make the paint more durable. PPG revised the P-sheet recently to say that to obtain maximum corrosion resistance you should use the DX1791/1792 etch wash. I think that long term durability testing showed the DPLF was not holding up as well as they thought it would. You also must make sure you have the minimum film build of epoxy for it to protect properly. That usually means 2-3 coats of DPLF over ALL surfaces. Even those hard to get at spots need 2-3 full coats.

Keith

 

J Cal

Over clean bare sanded metal I do the following.

1. spray 1 coat dx1791/1792 etch wash. Let dry 30-40 minutes

2. spray two coats of DPLF. Let dry 1hr

stop here if you need to do filler work and let the DPLF dry for 24 or preferably 48 hrs. Scuff with 80-120 grit and apply filler. Once you are done with filler work shoot with at least 1 coat DPLF(minimum of 2 coats over any bare metal) and let dry for 1hr.

3. spray 3-4 coats K36. After 24hrs block sand 120- 180 grit and repeat 3 coats K36. After 24hrs block sand 320-400 grit.

After doing this you should have straight well protected sheet metal ready for top coats.


To address BarryK's remark about PPG not holding up well in salty conditions. PPG products have always worked well for me ,but you sometimes have to read between the lines of the P- sheets to get all the info. When PPG went to DPLF from DP epoxy they took out the lead (to meet EPA regs I guess). Lead helps make the paint more durable. PPG revised the P-sheet recently to say that to obtain maximum corrosion resistance you should use the DX1791/1792 etch wash. I think that long term durability testing showed the DPLF was not holding up as well as they thought it would. You also must make sure you have the minimum film build of epoxy for it to protect properly. That usually means 2-3 coats of DPLF over ALL surfaces. Even those hard to get at spots need 2-3 full coats.

Keith

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Is that not something.!!
Dp was once the best epoxy in this marked over last ten years it has been degraded so bad that now the WHITE cannot be used over bare metal! Its true a company that hated etch now has no choice but use it the product has changed so much.
Did they lower the price?????

No, its gone up every year and now the painter must buy an extra product to make it work. And now the base is not the weakest part of system any longer.

 

The holding up issue: I painted my Jimmy and the following winter (about four months after painting it) it started to peel on any area that was new metal (replacement skins from different manufacturers so don't think it's the steel). I took off the transport paint, washed it, etch primed it followed by NCP-250 in some places and tinted K-36 all over followed by base and clear. My friend who was helping me was a counter person for PPG and attended all the tech seminars. We had all the P-sheets (some tech sheets that the average joe can't get) and installed the products to the letter. This was still when the etch was DP and not DPLF. Oh yeah, we did have and use a mil gauge.

I painted a cutlass and the same problem happened with a different batch of everything. I painted a Blazer with the DPLF and guess what? it happened again. Only on the bare metal once again.

I had the tech guys over to the shop and they couldn't give me any reason why it was happening (good thing I had one of their own helping me with it). We worked something out to resolve the problem, but I won't use DP again.

I love the Deltron base/clear. I think the Omni clear is excellent but order enough Omni base to do about a dozen coats 'cause it won't cover (especially red). I've never had any problems with the NCP-250 or the K-36. The DP should be deported in my opinion.

 

PPG knows they have a definite problem. I was told by several sources with PPG, not to use the DP primers NOR their wash (etch) primer. The times I've used their etch primers, they didn't stick. fortunately, I found that out BEFORE getting to the topcoats. A PPG rep, and mny jobber both told me my best bet was to use DuPont Vari-Prime, followed by K-36 on an aluminum dragster body I painted. You know it's bad when the guys from PPG have to lower themselves to suggest using DuPont.
I honestly think the Southern Polyurethanes Inc. epoxy is the way to go. Do some research and find out what the salt spray tests prove across the board. I think you find that it's a superior product by far.

Randy Ferguson

 

Wow!

I can see I have not made any friends here!

Seriously I have not had any adhesion problems with PPG except when I used a metal prep on a door skin and did not properly sand and clean the metal and that was with the old DP epoxy.

Flyfisher,

I am curious about the failures you have had. On your bare metal what grit did you sand it with? You say you washed it then etch primed it. What did you wash with?

I also noticed you said "This was still when the etch was DP...". DP or DPLF is not an etch primer. It is just a straight epoxy primer with no etch built in like VariPrime.

Just trying to make sure I understand what is going on with your bad experience with PPG so I do not duplicate it. I have to agree with you about the OMNI colors. I will not use them.

Keith

 

Wow!

I can see I have not made any friends here!
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I think you did good! I have known what was was going on for last year.
but without some one else bringing up there was no way I was going to point it out with all the DP users here at risk of castration!
There is another very popular product on here the same thing was done 9 months ago to make more profit and it is showing up in shops but may take 6 months for problem to surface here,
until than I'm not bring up.
What I love is shops that have used it for ten years, have the problem and they just say your doing something wrong.
How else can your sales be down 24% and net profit be a record?
Is that economic's micro or macro??

Its the user that gets screwed everytime.

 

I am just a hobbyist that ends up doing my own paint work. If something screws up, I am the only one to blame so I tend to download the latest P-sheet for the product I am using and read it start to finish. I rely on boards such as this to get others experience with procedures and products since I have only my own experience to judge a products performance. When someone has a problem with a product that I also use I want to know what went wrong and why so I do not go there. Nothing I hate more than having to redo a project that I thought I did right. So far that has not happened.

Paint prices I agree have gotten a bit ridiculous. I am on pretty good terms with the local PPG jobber so I get some discounts, but it still hurts when I load in a batch of paint products to do a project.

Keith

 

The "etch" comment was a misnomer. etch wash and DP bare metal prime. It's been a few years since I've used PPG, but I usually pass 240 grit, then 400 before sealer with a wash of DX 330 or DX440 before sanding, between sanding, and after sanding.
I don't shoot PPG any more mainly because my friend now works for a DuPont supplier. The last car I shot with PPG was excellent and is still in excellent condition. I used a bare metal primer that was given to me from another friend from a heavy equipment manufacturer. (I don't know the name of it, but it seems to have worked well).
I probably would still use PPG with the exception of the bare metal primer. Their products are pretty good if you know their idiosyncrasy's.