Hey everyone,

The reformulated PPG DP-90 just isn't the same. Not sure how it was reformulated (I think the lead content was removed) but I'm having a hell of a time getting the new DP-90 to look like the old stuff did. The new formulation looks really flat after it's sprayed, whereas the old stuff was a good match for semi-gloss black. Any ideas, or do I just need to topcoat the stuff?
Thanks!

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Tony Nausieda
1970 SS 396-4??hp
1977 Caprice, no dingle balls or hydraulics
1966 Buick GS 4-sp vert FOR SALE
1965 Le Mans EFI'd 468, 4-sp
1639 total cubic inches :)

70,

you are right since it was reformulated its not the same. the semi-gloss finish is gone. i was never really satisfied with the adhesion of the dp line. but the new stuff is really substandard are far as adhesion goes in my opinion. for my money trans-star makes a much better product.

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My 68 (http://www.chevelles.com/showroom/68racer1.jpg)
My Engine (http://www.chevelles.com/showroom/68racer2.jpg)

Yea its just not the same, but if you are looking to semi gloss something i wouldnt count on a primer to do so. Try to topcoat it with some base and clear with flattner in it, or some single stage black with some flattner in it. there are mixtures for both and a paint store should be able to mix it for you. Spray a few coats of the dp let flash and spray on with the color, no need for sanding. The mixture on the can is 2 to 1, try adding 1 of reducer, that is for sealer before topcoating.

good luck

http://budruski.myplace.com/

As someone who works for PPG, this is the first time I have ever heard anyone say they didn't like the DP epoxy primers. Granted they did lose something to make them more environmentaly friendly, but doesn't everything. Only gripe I ever hear from people is they wish the pot life was a little longer with the 402 and if the paint is left in guns overnight they will clog up.

analyte,

the company i work for used to do some small parts for the heavy truck industry. we used to use dp-90 on those parts as a top coat. when we informed them that is was reformulated they did adhesions tests on it and found it to be inferior to the old product. keep in mind this was right after it was changed so it may be different now as i have no experience with it lately.

if you don't believe me do you own adhesion test against trans-star's epoxy primer i think you will be surprised at the results. and it costs about half as much.

i personally liked the dupont prime-n-seal best myself but it to was redone and in my opinion is not as good as it was. the trans-star is the best primer i've found lately.

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My 68 (http://www.chevelles.com/showroom/68racer1.jpg)
My Engine (http://www.chevelles.com/showroom/68racer2.jpg)

68Racer, sorry to give the impression I didn't believe you, its just I have only been told positive things about our DP line. I was with PPG only a short time before we changed to Lead Free so I really don't have any experience with anything but the LF. It is nice to hear different opinions on our products. But as I have said, once products are changed to make them more environmentally friendly they are never the same.

I have worked for BASF before and was courted by Dupont before I went with PPG and the only reason I chose them was I felt and still believe PPG has the best product line. Though Trans-star may have some good products out there at half the cost, I have to wonder what they are losing in durability and coating strength to get have a cheaper price. I am just old fashioned and still believe you get what you pay for and PPG is used by lots of people because they believe it is the best system. Some others may have one or two products that are good, but all will say you should stay within one brands coatings systems whether it is Dupont, PPG, or whoever.

Kerry
66 Chevelle

I never undestood the restorer's facination with PPG DP epoxy. I went to the PPG school and they stressed that DP primers are definately NOT to be used as a stand alone product. Also, they no longer recommend Epoxies as a base, but now want you to use their etch primer. Actually, I have found a far better product,much higher in quality. I use Spies/Hecker products.In this application, first apply either 3255 or 3688 etch primer .Then apply 8590 urethane primer either as fill or as a sealer. Then apply Spies's Rallye Matte Black single stage urethane which also can be "glossed up" using single stage gloss black. This gives a much better and durable finish and provides superior adhesion to epoxies.
Gordon VM
Restoration Motorsports

LS6

i only use an epoxy as a sealer under a top coat. i use a self-etching primer as well. i just always thought that the dp line from ppg was overrated. i mean you can scratch it off with your fingernail.

i usually use dupont centari 99A mixed with about 30 percent flattener. it makes a very nice looking semi-gloss black. sometimes you have to experiement a little to get the desired gloss. you can also use a single stage urethane as you mentioned. i have used both and they both work well.

Actually guys, PPG's DP epoxy is a very poor sealer. PPG recommends that it NOT be used for this purpose. It causes "die back". They prove that by spraying out a panel, half using DP as a sealer and half using one of their other sealers. Both sides are base coated and cleared. Then they wait. A few weeks later,the DP side is much duller and died back. You can prove this for yourself and you will see a difference.

GOrdon VM
Restoration Motorsports

if you can't use it on bare metal and not as a sealer what the hell is it for. seems like it has no real purpose. but like i said i never much cared for it.

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My 68 (http://www.chevelles.com/showroom/68racer1.jpg)
My Engine (http://www.chevelles.com/showroom/68racer2.jpg)

The DP primers were a masterful work of the PPG "marketing machine". They did a fine job of cutting a niche in the market with the "need" of epoxy primers/sealers. No disrespect analyte, I am sure you would agree, MARKETING runs the show.

As I have said, I really don't understand why anyone would use any sealer in restoration. If you are totally priming a panel with a "quality" 2K primer for your blocking, you just don't need a sealer, period.

But if you are going to use a sealer, for goodness sakes use a urethane.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Well, everyone else has managed to take this subject all around the world for the past week without tackling the original question (flat-black vs. semi-gloss black), so now I'm gonna jump in.

I personally have not noticed a difference in the gloss level of the lead / no-lead DPs. I still use the DP90LF on firewalls and frames as a topcoat....but then again, nerve-wracking, stomach-cramping, 100-point concours restos. aint my thing; so if it looks good and works good I go with it.
One option would be to clearcoat the DP with a semi-gloss clearcoat. Yes it can be done, its in the P-sheets. The Omni 161 clear would be a good option for this as its CHEAP and available in qts. and the jobber SHOULD have the info to make it semi'gloss. Another option would be to topcoat the DP with a couple of coats of Krylon semi-gloss black. That would not be as durable as using a catalyzed urethane semi'glossed, but would be every bit as durable as what was on there from the factory. Then again, I use Krylon semi'gloss to do touch-ups with on frames and firewalls over DP90LF because it is a perfect match......things that make you go "Hmmmm".

Now to address other comments. If your having problems with DP OR DPLF adhering to practically anything then your doing something wrong. Let's throw out the possibility of bad product....not that it can't happen, but it's so unusual and when bad product does get out PPG is on the ball with "Stop-Sales" that bad product aint gonna stay out there for very long. Adhesion is the biggest thing going for DP primers, or any epoxy primers for that matter. No, it isnt the best for bare metal, and DEFINIETLY dont but it straight to galvanized metal. For bare cold steel a self etching primer is best. However, fresh sandblasted steel is as clean and etched as that steel is ever going to get....and you should put DPLF directly to it without a etch....PPG stands behind that for lifetime (certified repair shops / painters).
Also, using the 401 catalyst, DP and DPLF can go directly to electrodeposition primer on OEM parts WITHOUT SANDING....must not be any concerns with adhesion.
As for Dpand DPLF directly to galvanized,adhesion is not the issue, it will stick and you will not even scrape it off with a razor blade. The problem with galvanized is corrosion. Galvanized MUST be coated with a acid containing self-etching primer.

Sealers....as mentioned, full paint jobs or repairs that are primed with urethane primers there is not need for a sealer...UNLESS the topcoat is known to be transparent then I suggest a sealer. For example, I always seal with white when I'm gonna spray yellow.

Why use DPLF or DP as a sealer...I find it to be a favorite sealer in production shops where the painter can mix up a batch of sealer in the morning and use it the rest of the day on all his jobs without having to mix sealer for every job. It has a long potlife and that is what hurts it as far as the aforementioned "dieback". Most all of the urethane sealers have a quick potlife, usually less that an hour. Why do shops use sealers....as mentioned earlier, all new parts should have a sealer or primer coat applied before topcoating. Also, in production shops where bodywork only gets one priming, it is handy to seal over that bodywork if the painter had to really get on it when sanding and broke thru the primer, again this is where the DPLF comes in handy for the production painter who may already have some DPLF sealer already mixxed up.
Granted, DP and DPLF sealers are not the highest build, fastest, or slickest sealer out there.....but I have never seen the Dieback be to the point that it hurt the job. Sure, you cant put DPLF as a sealer over 320 scratches as you could one of the better urethane sealers, but then I dont recommend final prepping with 320 using sealer or no sealer. My point.....over properly prepped surfaces (500 wet) dieback using DPLF sealer as opposed to one of the urethane sealers is negligible.

Shannon,

i assure i was doing nothing "wrong" and a multi-million dollar company did their own adhesion tests and found it to be inferior. if you don't believe me by a quart of any other quality epoxy and do your own test. you will see for yourself.

as far as a semi-gloss back as i mentioned before i like to centari 99-a with about 30 percent flattener. it makes a nice durable finish. but i'm sure there are a lot of other ways too.

martinsr,

your right with a good urethane primer you don't need a sealer and i don't use any. but if its a quicky paint job not a restoration where you have a lot of bare metal areas showing with several different undercoats. i will use an expoxy sealer. but not on a restoration.

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My 68 (http://www.chevelles.com/showroom/68racer1.jpg)
My Engine (http://www.chevelles.com/showroom/68racer2.jpg)

Maybe I need to put my 5 cents in again too. I just dont understand the debate about the DP epoxy. Opinions are just like (well you know) everyone has one. I love the stuff and when there is a chance to use it I use the hell out of it. I am a certified PPG painter and have been to many classes, just like shannon said " PPG stands by it/lifetime". But my problem to this question being asked is why would you expect an epoxy primer to give you a gloss or semi-gloss like paint. If you primed your car grey would you expect it to have a semi-gloss shine, no. Have the paint store mix you up some semi gloss black, spray the DP as a sealer, let flash and spray a few coats of the black.


To MARTINSR I fully agree with what you said about sealers. I have restored tons of cars and I think I sprayed sealer on 1 car. If you restore a car and prime/block/prime/block etc.... and then sand to paint and see bare metal showing through, to me the car is not ready for paint. There is still some body work left to do. Especially if you have stripped the car etched, dp, prime whatever you do, what are you sealing when you use the sealer??? As long as you are using urethane primer and not lacquer you will have no problem. Anyway I dont want to ramble too much but primers are primers and not topcoats.

http://budruski.myplace.com/

I agree with Martinsr on the subject of not applying sealer before base coat,but, without a few precautions, serious adhesion problems can result, especially with some brands of primer. When you sand urethane primer, it should be top coated within the same day.(check specific munufaturer's recommendations). If you let the sanded primer stand longer than that, you should at least scuff the entire finish with a gray scuff pad before painting just to make sure. The reason for this is urethane primer, if not allowed to cure for several days, can tend to smooth itself out after sanding, causing adhesion problems. The trick is to make sure the primer is dull and not slick and shiny before you apply base or top coat.
Gordon VM
restoration Motorsports

Gordon, you are very right. In fact, Sherwin Williams tintable urethane primer had a window of only about 2 hours if wet sanded! The isos being moisture and heat driven would link up more after the wet sanding and then the surface would be to slick and hard for good adhesion.

Now, I don't believe that warning is on the tech sheets anymore with that product because of reformulation. But as always READ THE TECH SHEETS on the particular product you are using.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"