Lacquer primer exposed to 2k primer warning

[Steve302]

Hello,
I have been stressing about an issue with a customers car that involved unusual blisters in the trunklid. Now that the tests have been run and the problem is answered now i can share what actually happened.
About a year and a half ago i restored a 69 Charger R/T that had been a former show car in orange paint with black stripes. the 20 year old professionally done paint job was still in great condition and when i began to sand on the car i saw that the workmanship was top quality. At that point i told the customer that stripping the car to metal was not needed(big mistake).
I took out a few dents and waves, moved some body lines around and shortly the car was ready for primer. I loaded the body heavily with sikkens 2k urethane primer. About a week later i began to block the body down to be arrow straight because the car was going to be painted black.
The car took home 3 first place awards during the show season last year.
Just 3 days before the last show it started showing blisters across the back of the trunklid but due to lack of time it couldnt be repaired before the show and was entered with the flaws. Somehow it managed to get its 3rd first place award of the season.
I finally had time to bring the car in and take a razor blade to the trunklid and see what the hell was going on, i had several professional people look at the samples and test the materials to see what came about.
The verdict was that the 2k primer loaded over the 20 year old Lacquer primer had caused it to soften due to the 2k solvents, the lacquer primer did not lift or anything like that, it actually hardened back to a solid state but had delaminated from the metal it had been sitting on for so long.
I am very fortunate that i have cool customers, and of course i warrantied the repair 100% but this is a lesson that the old arcylic and laquer primers are no longer part of the new painting systems, everything now has a cure type of chemichal (hardener catylist etc...) and the old solvent based air dry products are a thing of the past.

[hardtailjohn]

Good post Steve! I've spent years trying to convince people that some really bad things can happen when you mix systems. Yours is a perfect example. I was a manufacturer of aircraft polyurethane paint for a couple years and did alot of the tech stuff...it was amazing what people tried to put it over, and then had problems and blamed it on the topcoat. You did a great job of figuring out what happened!
Oh, by the way...we want pictures of the car!
John

[My427stang]

How heavy did you apply it? Not questioning your knowledge, you clearly sound sharp with what you do, but are you sure it wasnt a solvent penetration issue due to a heavy of a 2k coat?

I have seen some guys lay material real wet and things start crawling

I havent personally have not had any issues at all if the base was solid.

However, your advice is good, people seem to think that 2k primer is a plastic bubble around anything.

Its certainly made bodywork inifintely more forgiving, but like you show, if the base is bad, all it does is waste some expensive materials

[1971ford]

my favorite old car is a 69 charger!
im going to need some pics

[69twotone]

Thanks Steve I am always learning from you.

[fordman]

yea you cant mix laquer and the new stuff.

[averagef250]

Hmmm. OK, so what do you do if you have a car painted in laqcuer and need to repaint it?

My 23 bucket was painted in the early 60's. It's 20 some odd coats of beatiful lacquer that's got enough chips and dings now that it needs a repaint. It's a tiny tub, but the thing to understand is the bodywork is imaculate and I do not want to strip it down.

Is there anyway I can seal the old stuff and shoot on the base clear PPG I've already bought?

[foghorn]

It has always been my belief that ya dont mix products also. But i have never had this problem before. But i always lay my first coat kinda dry to start with kinda like spraying a enamel job. It has to have a tack coat to hold. But doing the first coat kinda dry can save ya a lot of headaches later down the line. Ya never know when whats underneath is gonna cook when you lay a med heavy to heavy first coat. Cook = lift or wrinkle. But if your using sikkens base you cant use ppg or dupont clear is a example of what i was refering to. The chemical make up is just to different.




Foggy

[Steve302]

hello,
Im not sure how many have noticed but my posts are done at some of the stragest hours, reason being is that the shop is running 24 hours right now to catch up on jobs and im here usually from 10pm to 11am or so, and late at night even though there is alot getting done i have alot of dead time waiting for materials to set up and such (its not like i can go run to town to buy materials or call customers this time of night).
-My427stang, yes it was a matter of heavy 2k build that softened the lacquer, and as a result when it re-dried it no longer was holding on to the metal, if i had known that the lacquer was over bare metal i would have sanded it all off.
Some professionals stress the point that you should never mix different paint products, this is true in some cases. I myself would never throw paint reducer from DuPont into PPG paint or any material mixing like that.
If i use a primer, paint, clear or anything like that i use the hardener and reducers that are required to go with that product. Of course some say go a step further and never even use different companies, for example if you like PPG paints then use PPG products from start to finish. This in todays paint world is untrue in many cases. The refinishing comapny U-Pol is european and is just now coming into the american market heavily. they make some of the best products from bodyfiller, polyester fillers, primers, clears etc..... But what about their paint? well they dont make any! The products are designed to be used with paint from other companies, and no issues are known, they even have a warranty that will stand along with this.
What i have found is that product failure is 95% user error, in this case with the car i mentioned i sprayed over a 20 year old product that was never designed to tolerate the solvents of todays materials. Im very glad it happened to this car because now i know what needs to be done from now on, if i never saw the car again, or if i got lucky and it never did blister, then i may have done 100 more cars that could have all failed. Over the next few weeks im tracking down all the restorations i have done over the last 2 years (ones that were not stripped to bare metal) to see if any need repairs as result of lacquer remaining on the vehicle. I have looked at 7 so far and see no problems, but im not treating this one car as a freak incedent, it could happen to the others.
I posted a pic of the car from its first outdoor show, sorry the pic is not all that great and does no justice for the car at all. It now has Magnum 500 wheels custom made to fill those huge fenderwells and keep a more stock look.

[My427stang]

What i have found is that product failure is 95% user error, in this case with the car i mentioned i sprayed over a 20 year old product that was never designed to tolerate the solvents of todays materials. Im very glad it happened to this car because now i know what needs to be done from now on, if i never saw the car again, or if i got lucky and it never did blister, then i may have done 100 more cars that could have all failed.

I agree completely. I have cheated over the years, and in the days of Acrylic Enamel (or I can even date my self with Synthol Enamel) things were pretty forgiving. Reducers were pretty universal, and I even used to buy the off brand hardeners to save some dough

Now I personally dont mind using one brand of primer with another brand of paint, however, like most you usually end up with one supplier that treats you the best, so I generally end up doing that.

I dont do it daily anymore, but did a ton of spot repairs for the quick insurance money, and I have found straying from their instructions, mixing, and application makes a blend much more difficult as well

You are certainly all over it, but as you pointed out, we all need to watch laying it on wet. Even the new stuff can lift if you lay it on too heavy, and it doesnt need to flow in like the old lacquer primer/fillers anyway, so its not just an old substrate issue. Not to mention, if the prior repair/paint was marginal of course a chain is only as strong as its weakest link rgardless of what you put on top.

My car I did with an Evercoat primer over mostly new panels, with Dupont Chroma-one over it, however, the roof had original paint that I just knocked down with a DA and 220. Been 7 years and so far so good

[Steve302]

Thats a beautiful Stang there!
I have lots-o-respect for any painter who has the talent to lay down a good Chroma-One paint job. I tried the stuff a few times and im sure i broke the record for most runs and sags on a car. I always wondered if using far less reducer than DuPont calls for would solve that issue, but i gave up. Chroma-one holds up great from what i have seen (seen other painters do, not mine) My cousins Blazer was done in Chroma-one back in 1996 or so and has been outside ever since and still looks great.
The craziest mixing of products i have ever done was on a Nissan 720 lowrider, we based it in Chroma-base platinum pearl , did all the graphic layout in Fine aluminum lacquer, candied it with Diamont singlestage blue toner using no binders and reducing it about 200% with ppg DT870? and using PPG DCX61 catylist, we then cleared it with Omni synthetic urethane clear, somehow it still looke like new and we are going on 3 years, go figure.
Steve

[foghorn]

Wow that is a crazy mixture. Im surprised it didnt give ya problems during the spraying of it.




Foggy

[Steve302]

I was worried, but we tested it by doing the door jambs first. I would never try anything like that again, and it was done under a "no warranty" agreement

[My427stang]

I am not a Chroma-one fan after this car. Chroma-base/clear flows so nice and is so easy, but Chroma-one, like you said, wont flow, then it hangs if you try to make it lay out.

It wasnt horrible when it was done, but you are seeing post-block and buff.

Best thing I have found is to spray Chromaone so that it looks the way you want it.

It wont melt or level into the pervious coat at all, so just lay it on watching the shine and it should stay put.

Thats real hard to get used to spraying that way after a lot of acrylic enamel or base/clear experience!

[Steve302]

I will take your word for it! But i still dont have the guts to try it again.
I like Chroma-base and have been using it for years, but I use U-pol clears over it. Seems to be a really good combonation. Though this is my last year doing this as a profession I am going to try Lessonal polyester basecoats as a replacement for the Chroma-base, from what i have seen lessonal basecoat lays down much better and metallics can actually be tacked between coats and not disturb the metallic layout, this could never be done with Chroma-base and not risk streaks.