How to go about fixing a ding in fresh base?

MikeS

MikeS

Camaro Nut
I’m hoping someone can give me some guidance. I’m a hobbyist painter and for the most part I strip a panel and start from scratch to paint so I’ve been spraying whole cars. But, this problem may fall into the realm of a collision repair method.
Yesterday, while spraying PPG DBC base on the front end sheet metal, a very slight ripple was detected when the base was still wet. It is only 2” in length (vertical) but enough to cause an image of a straight line to wave ever-so-slightly when passed through it. I didn’t see that during the block sanding phase and I do use a dry guide coat so I suspect it was bumped into by someone else in the garage. Of course, now that I know it’s there, it bothers me. This is a show car so I want it to be as perfect as I can get it.
I’m not certain how to go about it being the base isn’t even 24 hours old so I halted working on that fender to fix it. I didn’t even spray clear on it yet.
How it was prepped: The panel was stripped down to bare metal, 80 grit DA, Epoxy with PPG DPLF, Rage Gold filler where needed (dings mainly), PPG DPS primer (sprayed as a primer surfacer) and blocked using dry guide coat. Any very minor spot work was fixed with U-Pol dolphin glaze, sealed with SPI epoxy mixed as a sealer (1:1:1) then DBC based applied.
My thinking is I can use Dolphin Glaze to fix the area then spray it with some DPS primer surfacer then SPI mixed as a sealer to that area then scuff sand the whole fender with a gray Scotch-bright pad and re-base the followup with SPI UC.
It’s the time frame I am unsure of with the base being so new. How would you go about repairing this?

Thank you very uch!
Mike
 
If you really want to fix it, you have to DA sand the base coat off of the area where you will put filler, then putty the spot over the cured primer. It's a bad idea to put filler on base coat, but you don't really need to go to metal. Just allow extra cure time for the putty and the primer, because your repairs can soak into the underlying areas a little and cause shrinkage or poor adhesion. This time of year, a half hour of sun to cure the putty would probably be ideal, and then more sun after priming, preferably the next day, after lightly blocking the surface to break it open. This will help the solvent get out and get your repair area "caught up" with the fully cured material on the rest of the vehicle.
 
Aside from what Crash said your first mistake was using PPG Epoxy, it is nothing like the way they use to make it. SPI's epoxies and their other primers give all the other Co.'s products a severe case of red ass. I think I have some of PPG Epoxy left from my comparison test I did, if I can find it I'll give it to ya if you want it, I know I will never use it for nothing.
 
Thank, Crashtech, that's how I'll repair it.
I've used DPLF for several years now and haven't had any problems at all. I read some people were able to wipe it off with a rag soaked with thinners and I've tried that on months cured DPLF and I've not be able to wipe it off. I've only used DPLF with with DP402 activator and shot right after it was mixed instead of using the DP401 ,that required an induction time, so maybe the 402 gives different results. But, I have since used up my PPG stock and switched to SPI. Aside from waiting for the induction time I don't see much difference in how it lays down, which isn't to say SPI isn't a better performer. This fender with the problem was primed 2 years ago with the DPLF and I'm only now getting around to completing the car's final painting.

Mike
 
It's all good I quit using it when they changed it from the original DP Epoxy which I used for years and when they changed it I quit using it they kept telling me it's the same just relabled I called BS. It was the best in the day just not now and it is over priced.
 
I thought LF stood for Lead Free. That's what the paint rep told me years ago. I've heard what you are saying from several painters though about the performance hit once LF. I've only known and used DPLF but I got fed up with the almost twice a year price increase on all the PPG line. Now I'm an SPI guy.
Now that I think of it...I wonder if Barry will ever add an activator like the PPG DP402 where you can mix epoxy and spray immediately instead of waiting for an induction time.
Barry, got your ears on? (And here I though CB radio talk was dead).

Mike
 
When you pull something out of a formula (it can be anything) that one thing can and will bring something else with it so when you take that item out you now have to replace it with something else. For instance take the new diesel fuel for trucks when they pulled the sulfur out to make the EPA happy it also pulled the lubricant out and older trucks should not use it without risking some sort of damage, ask me how I know. The same goes for the new gas an older motor such as my lawn equipment have had to have new carbs put on because the new gas ate the seals and they quit running.

So when Co.'s change something and tell me it's still the same as before I call BS. The only exception to that rule would be if Barry said it to me I'll believe it, he is the one owner of a Co. that has never lied to or mislead me.
 
Hi Crashtech,

The area was repaired. It took such little filler that is looks almost transparent. I'll be spraying a few coats of DPS3051 primer surfacer starting in the center of the repair area then gradually widening the area by the 3rd coat. It's sunny so the fender has been getting a nice dose of IR.I'll lightly sand the dried primer with P400 but my next question would be sealer. Should I seal the repaired area with a small overlap to the surrounding base, or, scuff the whole fender with P400 and reseal before spraying base. The base was catalyzed so I'm not worried about it wrinkling from the new base.

Thank You,
Mike
 
Use the SPI epoxy 1:1:1, but since it will be spotted in, you'll have to wait a while until the rough overspray ring can be lightly sanded smooth. You'd probably do best to lightly sand and wipe down the whole project at that point, imo.
 
I'll spot the sealer (mixed 1:1:1) and wait a few hours then lightly block the whole panel with P400 to even out the texture before base.

Thanks!
Mike
 
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