|01-08-2013 03:59 AM|
Your right about the DP40 and the lead content...it was deadly...but, ever since they took the lead out, it wasn't quite the same product...just like Centauri from Dupont...when they took the lead out of that Acrylic Enamel it never seemed to cover as well (if I remember correctly yellows where a real bear to get coverage on after they took the lead out) or shine as much and the durability seemed to drop of as well.
But that's old school paint and water under the bridge.
|01-07-2013 11:10 PM|
As to the OP Question: If he did everything according to Hoyle, then it could be, like Deadbodyman suggested a couple drops of sweat or wrong primer.
For the our situation with the deck lid and dozens of small bumps: I think the only answer is to put it in the Archives under "Unsolved Mystery's" & "Lesson Learned". Having said this, I seemed to remember the reason we continued to use one light coat of DP40 thinned down, under the paint. If not for insurance against chemical burn-in,....then because we noticed that the polyurethane seemed to lay down flatter and smoother. It might not behave the same now that the lead is gone. This was our hobby - turned restoration pro and made our living for twenty-some years.
Glad DP40 no longer has lead in it,...this is one hazard of the trade, that needed to be gone.
|01-06-2013 08:08 AM|
Mabee the OP used lacquer primer..and was too embarresed to come back...
|01-05-2013 09:27 PM|
|ReflectImage||Bare metal, DA, DP40, bodywork, primer, DP40 thinned down, scuff for mechanical adhesion, then paint. We always strived for concourse restorations through out the years. One of our cars was judged 99.99. This has been a interesting discussion - time for my night cap - have to get up early. Goodnight.|
|01-05-2013 09:09 PM|
|ReflectImage||Forgot to answer the sink question: No, this was a perfect deck lid needing very little bodywork or fillers.|
|01-05-2013 09:02 PM|
Wow, your right...this is an assignment. I still say that the Rep was wrong...sorry, I'll try and explain why. If the paint was so hot and the paint flashed over before the thinner could evaporate it wouldn't blister, it would solvent pop...and the fact that it almost went away when the sun went down tells me it's not thinner, it's expanded air...one way to get air to expand is by oxidization or off gassing and it doesn't take much oxidization to create a gas between metal and paint. Even if you trapped thinner, how would putting DP40 over top seal it and stop the bubbles? Because it was so hot, could it be tiny bits of water vapor from the compressor?
This may need to go on "Unsolved Mystery's"...LOL...but I can't see it being trapped thinner...that would cause a pop, not a blister...I could see it being moisture from an over heated compressor...not droplets...atomized moisture going through the paint gun.
One more stupid question... did you go, bare metal, body work, DP40, paint or bare metal, DP40, body work, primer, DP40, paint...Or how did you guys do it back then?
|01-05-2013 08:43 PM|
|ReflectImage||Wow - This is like a assignment, but for austerity I will try to answer your questions. Because we had success we continued to follow the process as I outlined. We only scuff for mechanical adhesion adhering to the 72 hour window. I still have a few bodies that like you say sealing isn't necessary. When we used chemical strippers we always use a DA after to remove any bit and pieces left behind. The rep opinion at that time was - that we may have trapped thinners into the substrates, because the paint at that time was so hot that it burt into the substart and then flash off before the thinners could evaporate. That's why he recommended sealing with a epoxy. The car actually when into storage for quite a long time before taking it to Arizona where it set in the hot sun and broke out covered with bumps. Funny thing when the sun went down the bumps almost disappeared. When we got back to Montana and took down to the metal bit by bit to see what happened and there wasn't any signs of rust. Montana is a fairly dry state and this particular car had very little rust anywhere. After shipping we always DA for mechanical adhesion. It was a complete tear it down take it appart restoration. Prior to using this poly we always used enamel so this was quite the shock. Luckly, we never had this kind of problem again and we continued to poly paint. Thanks for you input hope this answers your questions.|
|01-05-2013 07:48 PM|
Not sure what happened to the thread starter, but thanks for not getting offended.
I don't know about this Ditzler Rep. DP40 is an epoxy and even when it was called DP40 (now it's DP40LF...the LF stands for lead free) should not have needed to be sanded. It should have a 72 hour window before you need to scuff it or open it for mechanical adhesion, anytime in that window and at about 70 degrees you can top coat it without scuffing. I firmly believe that if a vehicle is prepped properly, sealer isn't required.
You mentioned that you chemically stripped the deck lid and dried it...did you rough up the metal with the DA before you put the DP40 on? If you didn't, you could have had some residue left from the chemical stripper that could cause oxidization (same type of reaction as rust) and cause lifting.
Do you remember how long after painting it took for the bubbles to show up? If it was traces of chemical stripper on the panel the reaction would be fairly quick...if it took a while like the thread starter (his took a year and that's why I say it's moisture causing rust) then it wouldn't be the stripper.
The way I would have done the job would be to strip the panel, do my body work, 2 medium wet coats of DP40, let the DP40 flash, 2 to 3 coats of primer, (I would only use 2K primer up until recently), let the primer cure, block sand and paint. I would not have gone bare metal, body work, light coat of DP40, scuff and paint. Did the body work areas ever sink?
|01-05-2013 07:36 PM|
|ReflectImage||Hello Old Fool, I like the idea of fake bullet hole stickers. It's too bad the photo look pretty straight. Fix it the right way - dig into it - as you say find out and then fix it. But without knowing what was used - we all just shooting in the dark.|
|01-05-2013 07:12 PM|
|ReflectImage||Hello 69 Widetrack. No worry, I am too old to be offended and I am always ready to learn. Anyway you are most lightly right about this particular situation of small paint bubbles/blisters. With my situation, the deck lid brook out in little raised bubbles after sitting in the sun for a few hours. The Deck lid was chemically stripped down & dried before applying DP40 metal sealer, followed with body fillers and primers. I am sure we were using Ditzlers Polyurethane Black Paint, being black may have something to do with it. The mistake we made according to the rep (I want make a correction it was a Ditzler rep) he said we were supposed seal with DP40 before laying down the paint, to keep the paint from burning into the substrates. We took the deck lid down to metal & redid the body work, got it all in the same substrate and followed the rep suggestions, spayed on a light reduced coat of DP40, scuffed lightly with scotchbrite before laying down the paint. Wrong or right - it turned out great. To make a long story short - we continued to do other cars with the same process. This was a long time ago - have been retired for over ten years - I guess things have changed. Anyway, what happened to this thread starter?|
|01-05-2013 06:52 PM|
|01-05-2013 06:34 PM|
Doesn't look like he even returned to the post?
He could shave the surface off and see what is under there, a careful shave cut and one of those fake bullet hole stickers and he would be set <jk>
My hunch is acid wash primer or similar as the original cause. But I am not a gambling man, so I wouldn't put any money on my hunch,LOL.
|01-05-2013 06:03 PM|
It could even be a lacquer primer if that was used... we need to know if it was stripped to the metal and what was done after that metal preps ,primers did you wax & grease it...theres a ton of stuff but moisture\oil in the air line and lacquer primers or improper metal prep are the most common.but explain the proceedure and materials used from start to finish. but be prepared ,when you see bubbles even small ones theres only two ways to deal with it ,,,,live with it or sand down untill the bubbles are gone,most times it has to go all the way to the metal before they're gone..but you might get lucky and only the paint has to come off...never know but you cant just buff them out ,you need to fix the problem or just deal with it..
.It looks pretty good from here though
|01-05-2013 05:14 AM|
[QUOTE=ReflectImage;1630742]That's a terrible feeling when something like this happens; I've been there! Like the other replies if your going to get help you need to tell what products & what procedure you used. From experience and advise from PPG that we received - you need to 'seal' before laying down the the color. This could be what happened if didn't you seal the primer surfacer before painting. It could be that the color was so hot (chemically) that it burned right into your surfacers and body filler and then trapped moisture under the surface. If you haven't solved the problem yet, as I see it the only way is to find out. Would be to first lay down a strip of masking tape on all four side of the bubble and shave it off with a razor blade. Then let the viewers know 1)what you see, 2) what products you use maybe then someone can give you hand in where to go next. Just so you know I am not current on todays 2 stage products, only experience is with one stage and sealing with with DP-40 before paint.[/QUOT
I wasn't going to reply but after thinking it over I decided I better and the only reason is that if someone else reads this they are not getting the right information.
ReflectImage....I don't mean to offend you but in this case you are wrong...If this is the information that a PPG rep gave you...The PPG rep was wrong. Sealer has absolutely nothing to do with what happened here, sealer is a product designed to even out poor substrates, for example, if you have a vehicle with several different substrates, say lacquer primer and or whatever Acrylic Enamel, or a vehicle that is not sanded with the fine grit required so sand scratches won't show when painted. If a vehicle is prepped properly and the substrate (either existing paint or a quality primer) is consistent, sealer is not required and has no bearing on what happened here.
The problem is either trapped moisture under the paint causing rust or existing rust that was not removed completely before painting.
So again ReflectImage, I'm not trying to offend, I'm just trying to correct...And yes, I was a Rep for PPG.
|01-04-2013 08:50 PM|
|ReflectImage||That's a terrible feeling when something like this happens; I've been there! Like the other replies if your going to get help you need to tell what products & what procedure you used. From experience and advise from PPG that we received - you need to 'seal' before laying down the the color. This could be what happened if didn't you seal the primer surfacer before painting. It could be that the color was so hot (chemically) that it burned right into your surfacers and body filler and then trapped moisture under the surface. If you haven't solved the problem yet, as I see it the only way is to find out. Would be to first lay down a strip of masking tape on all four side of the bubble and shave it off with a razor blade. Then let the viewers know 1)what you see, 2) what products you use maybe then someone can give you hand in where to go next. Just so you know I am not current on todays 2 stage products, only experience is with one stage and sealing with with DP-40 before paint.|
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