[GMW]

Last weekend I shot some PPG DP50LF, sanded, shot some more, sanded, etc. on a fiberglass spoiler for a Camaro. After the last sand I shot some PPG Omni MAE acrylic enamel, maybe three coats about 10 minutes apart.

I let all this dry all week. Today I color sanded the black and decided to put on some more. In a few areas I got what my PPG man says is re-coat lift. He says I can't re-coat acrylic enamel after more than a few hours. He also says there is no primer/sealer that can now be applied, that all I can do is sand it all off and start over.

Do you guys agree with all this? Is sanding it all off and starting over my only alternative?

The only other thing I think it could be is after last weekend I cleaned my gun with laqcuer thinner and I may have still had a small amount in the gun when I shot the acrylic enamel today.

The lifting only occured in some areas not all over the whole piece.

Thanks

[Randy Ferguson]

It shouldn't have caused a problem, UNLESS, you broke through the color, to the sealer. If you sprayed it too wet, it's possible, but it shouldn't happen otherwise. Try sanding the lifted area out and lightly spray on two coats of primer. The DP50LF will work, just thin it with some DT885 and spray light coats with plenty of flash time between coats. If it doesn't lift when you spray the DP primer, it should be OK to re-coat after the recommended 30 minute wait after applying the DPLF. Just don't rush it and you should be fine.

Randy Ferguson
Metalshaping & Kustom Paint
Robinson, IL
www.metalmeet.com

[BarryK]

First of all I AssUme you used a hardener in in the color!!??
If you did, did you mix it to the right ratio and second did you make sure it was mixed in real good with the paint?

Yes to all counts?

Here are your options:
Sand as needed and than do one of the two.
See if the jobber has a quart of "Bar coat" made by Upol most ppg jobbers will have this hidden in the back as the lifting is pretty common with this and some of there bases.
If he does spray ONLY one coat over the whole part let dry 30 minutes and do whatever you want as far as paint.
If he does not have this product he can have it the next day from his "PBE Warehouse". It would be worth the wait.

If you can't wait, than spay a light- medium coat of your DP and let dry until you can rest your hand on it and spray one more medium coat. Let set over night and paint. (skip this step if you did not use hardener)

Caution on the Bar coat- Spray one medium wet coat only! If you spray two it will peel in 6-9 months.
This is an alcohol base product and nothing will go through it or attack it and it won't even attack activated synthetic enamel. This would be your first choice.

[Centerline]

According to the "P" sheet for PPG DP50LF it is not compatible with the Omni line. That is most likely why you have a problem.


DP50LF is compatible with the following top coats:

DCP21 DELTRON 2 IN 1; Urethane Primer
DF Body Fillers
DX54 ROADGUARD Chip Resistant Coating
DZ KONDAR Acrylic Primer Surfacers
K36 PRIMA; Acrylic Urethane Primer Surfacer
K38 High Build Primer Surfacer
K93 Tintable Primer Surfacer Sealer
K200 Primer Surfacer
NCP250 NCT Primer Surfacer
NCP270/271 Corrosion Resistant Primer+
NCP272 Tintable Corrosion Resistant Primer+
NCS2000 Series Primer Sealers
CONCEPT (CLV) Acrylic Urethane
CONCEPT (DCC) Acrylic Urethane
DELSTAR/DELTHANE (DAR/DXR 80) Acrylic Enamel
DELTRON (DBU) Basecoat
DELTRON 2000 (DBC) Basecoat
DURACRYL (DDL) Acrylic Lacquer

+ Under these primers use DPLF catalyzed with DP402LF only.
Avoid excessive film builds.

It's always best to follow the "P" sheet precisely to ensure you don't induce a compatibility problem. Without this information it is impossible to determine if the paints will work together. Modern paints are marvels of modern chemistry and really bare no relation to the old enamels and lacquers everyone used to use. If you don't follow the the factory recommendations, its nothing better than a crap shoot.

Centerline

[BarryK]

Hi Centerline,
The P sheet I would GUESS! is written that way for warranty purposes.
None of the omni line is covered by warranty.
However epoxy is kinda my specialty and what you may not know is there are 123 manufacturers (in USA) of automotive type epoxies used for different industries. But bottom line is there is a big difference
between the quality and how they hold up under the "cross hatch salt spray test" (industry standard for corrosion control) Some may be 100 hours the highest ones are in the 1440 hour range.
But bottom line is epoxy is most friendly with all paints.
Yes I do know what the hour ratings are on the most popular in this business and no I will not rate them.
Will the omni epoxy work under concept? sure will if its getting proper dry time before painting.
Most epoxies also have a 7 day "open coat" but big difference is drying times before painting when you start fooling with industrial types and lead vs non lead. (Lead is not suppose to be used today) and a lot of little differences like some you can dry sand same day some you cannot and some don't sand good at all ever and some are just OK to sand anytime.
Of all our great chemical strides in this business the last 10 years the old basic dinosaur the epoxy remains the greatest problem preventer of all.

[GMW]

Thanks for the help so far.

I know the DP50LF and the Omni line are not specifically called out to work together, but my PPG rep told me there would be no problem. And, the first time I sprayed the black there wasn't. The lifting only occured after I let the first three coats of black dry for a week, color sanded it, and sprayed more.

I always refer to the P sheets. I always print them from the net and keep them handy.

Well, I sprayed the two light coats of DP50LF and only had a minimum amount of lifting in a few small spots. (Not the same spots, but different areas?) I'm pretty confidant I can sand them down without going through and then put one more light coat of DP down. If it goes without lifting I think I'm good to go.

I don't think I'll use the acrylic enamel anymore. I don't paint enough to get it right the first time so I need something that can be color sanded and recoated.

Thanks again!

[troy-curt]

When trying to touch up acrylic enamel after color sanding, this happens quit often. I sand out the lift and apply a few coats of urethane sealer-primer ,really dry and light to build the mill thickness up to paint level, then shoot a coat of clear re coat sealer from napa. This works for me most of the time.

On a item as small as a spoiler, you will probably be ahead to remove all of it and start over.

Troy

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