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Brad4321 09-21-2012 04:28 AM

Basecoat Did Not Adhere
 
I have gotten myself into another newbie screw up, but I don't know what I did wrong and could really use some guidance.

This is an 05 superduty. I had some major bodywork on the bed, but the cab was sound. Original paint was sanded flat with 180 (did not break through to metal) and I sprayed 3 coats of SPI 2k. That was sanded flat with 320 and then 600.

4 coats of TCPGlobal's Restoration Shop basecoat was applied (coverage was less than expected) with a half hour between coats. Outside temperature was 66 degrees with a humidity of 40%. I only had slow reducer in stock, so I have it a much longer recoat time to be safe (TS says 10 minutes at 70). The base flashed off in approx 10 minutes. The basecoat was activated with SPI clear coat activator.

I waited 1 hour and shot SPI Intercoat Clear with HOK Ice Pearl. 2 coats, 30 minutes between coats. Intercoat was activated as well. Temperature was 75 degrees at time of shooting intercoat and stayed above 65 degrees for about 6 hours. I do not know actual metal temperature.

Truck sat overnight and 5 coats of SPI Universal was applied with 45 minutes between coats, normal activator with a air temperature of 75 degrees.

The truck was untaped the next day and pulled into the sun. I have waited 1 week in the sun (as I normally do) and started color sanding. I then noticed the basecoat is peeling off of both front doors in sheets. I have attached pictures in this link: Paint Delamination pictures by Brad4321 - Photobucket . I also added one picture of the hood a day after being painted. The paint looked really good, layed down like normal, and I didn't expect this to happen.

In the peeled paint, I can see grey outlines of where I sanded. This is the first vehicle I sanded with 600 before basecoat, I have always stopped at 320. I sanded to 600 as I read on here that it gives a smoother finish to metallics, pearl, flake, and etc. I strongly suspect that this is the source of failure, but I am not certain. The temperature was also marginal, but I have never had problems before with this temp.

It is actively peeling from both doors, but not from the rest of the truck. It may very well peel from the entire truck, I haven't tried past the doors. I should also mention that I used SPI waterborne and tact rags as well.

Anyone know the cause of this and how I should fix? Can I sand it back down to spi primer or will I need to start all over?

deadbodyman 09-21-2012 05:19 AM

Why did you use an activator in the base and intercoat???? I suspect thats the problem...ALL the bases I use get reduced ,thats it, nothing else.On the brite side ,it shouldnt be too hard getting it all off ,an air blower should do it.
I've done worse...

swvalcon 09-21-2012 07:25 AM

I've used activator in my base and I dont think that is your problem. Berry says 1 oz per thinned qt will help your base become stronger. Done it many times. Seeing as how the base is peeling from the primer I would say either you didnt get it clean enough or you didn't get it sanded enough. I always sand my primer with 320 or 400 and thats it. no 600 or finer. Just did a black hood and no sand marks.

MARTINSR 09-21-2012 08:07 AM

I wish the whole "2k" description would leave the paint world, I have to assume "2K" means Urethane, but being every product that you put a hardener in including epoxy are a 2K I am not sure what was used here.

But anyway, was the primer sanded wet? How long did you wait after sanding before base coat was sprayed?

The lack of adhesion is between the primer and base is what we are talking about so something to do with how it was sanded and how the base was applied is the issue.

First off, 600 isn't too fine if everything is done properly, heck, you don't even use 600 on a blend panel, 1000 is often used, or even a gray scuff pad. I am thinking either the primer was wet sanded and it wasn't throughly dry that could be an issue. It is unlikely being it's such a big job, unless these panels that are peeling were the last ones sanded right before it was painted. Is it peeling everywhere? Or is it just these panels, and are these the last panels sanded?

Next possibility, were these the last panels sanded and the urethane primer "healed" before it was painted? Some urethane primers can do this more than others. One primer I use has something crazy like a 4 hour window after sanding to paint, it "heals" that fast. So if it was sanded and sat for a number of days this could be the problem.

That and of course the metal temp was too hot and the basecoat flashed the second it was hit and didn't bite the primer.

Brian

MARTINSR 09-21-2012 08:15 AM

It is human nature and takes practice not to apply more on the horizontal surfaces so the hood is a common place for too much material which can cause problems like you have.

If the doors are the only things peeling, and the hood is the only place that did that, you have to think what was different with THOSE parts primer and paint application? Let's say the whole truck is peeling but the tail gate, yet they were all sanded with 600, you can eliminate that as the reason, if the whole truck was painted at once, but the tail gate was done the next day after you sanded it the morning of, that can tell you that the wait after sanding on the truck is the problem. If the tailgate was sprayed in a different temp, that could be the reason it worked and the rest didn't.

Toss out all your preconceved thoughts blaming something and study it to see WHAT WAS DIFFERENT about the panels that are failing? Why is the hood different than other panels? THESE are the questions you need to ask yourself.

Brian

tech69 09-21-2012 08:20 AM

good response. Could also be he wet sanded, didn't clean the sludge off, then tried to rinse it off after it turned to concrete.:D Or it could have been sanded, left to collect dirt in the scratches, then painted. Are we talking Urethane 2k? As Brian mentioned, technically anything with two parts is a 2k but most companies will call a Urethane Primer a 2k, but just want to be sure cause if it's an etch 2k the acids in it might be giving you trouble.

MARTINSR 09-21-2012 09:13 AM

Quote:

Originally Posted by MARTINSR (Post 1592556)
Next possibility, were these the FIRST panels sanded and the urethane primer "healed" before it was painted? Some urethane primers can do this more than others. One primer I use has something crazy like a 4 hour window after sanding to paint, it "heals" that fast. So if it was sanded and sat for a number of days this could be the problem.
Brian

I'm sorry, I meant to say they were the FIRST panels sanded thus they sat longer before the paint was applied. And yes as Henry stated wet sanding helps the ISO's kick even more and often the urethane primer will have a different recoat time if it is wet sanded than dry sanded. Being sorter if it's wet sanded allowing less time to get the top coat on.

Brian

Brad4321 09-21-2012 09:43 AM

As swvalcon said, Barry recommends adding activator to the base and intercoat. I have done this before without issue, so I do not think that is it.

The primer I used is "regular 2k" from SPI. That is what it is named. Yes, it is urethane primer.

I did not wet sand. I always dry sand primer. The primer was shot and sanded the day before. It was approx 12 hours inbetween applying the primer and the base. The last coats of primer were block sanded first with 320 and then 600. I was wondering myself if I missed a spot sanding when I first seen it flake off, but I didn't miss the entire door.

After sanding, I clean with waterborne wax and grease remover and a white, lint free cloth until no more dirt shows up. The towel comes out clean. I give the waterborne about 30 minutes to dry with the booth fans on.

I didn't measure metal temp sadly enough, but I did monitor air temp. If anything, the metal was too cold not too hot.

The hood doesn't have any issues that I am aware of, just the doors currently (I have not tried to peel the paint on the rest of the truck, the doors started peeling on their own while color sanding). I added a picture of the hood basically to show what it looked like before sanding and doesn't have any real relevance to the discussion.

It is quite possible that I sanded the doors first. I don't remember, but it is likely. I waited about 1 hour after applying the primer to sand (SPI says 20 minutes). I wouldn't think that SPI primer has this "healing" property if it says to sand in 20 with no recoat window. Anyone know for sure?

I don't know of anything I did different between panels or for any other vehicle I have done. I thought that the bit of grey and sand scratches on the peeled paint might be a clue to someone in the field as to what went wrong. I am fishing for ideas on the cause so I don't make the same mistake twice.

MARTINSR 09-21-2012 10:09 AM

Quote:

Originally Posted by Brad4321 (Post 1592581)
As swvalcon said, Barry recommends adding activator to the base and intercoat. I have done this before without issue, so I do not think that is it.

The primer I used is "regular 2k" from SPI. That is what it is named. Yes, it is urethane primer.

I did not wet sand. I always dry sand primer. The primer was shot and sanded the day before. It was approx 12 hours inbetween applying the primer and the base. The last coats of primer were block sanded first with 320 and then 600. I was wondering myself if I missed a spot sanding when I first seen it flake off, but I didn't miss the entire door.

After sanding, I clean with waterborne wax and grease remover and a white, lint free cloth until no more dirt shows up. The towel comes out clean. I give the waterborne about 30 minutes to dry with the booth fans on.

I didn't measure metal temp sadly enough, but I did monitor air temp. If anything, the metal was too cold not too hot.

The hood doesn't have any issues that I am aware of, just the doors currently (I have not tried to peel the paint on the rest of the truck, the doors started peeling on their own while color sanding). I added a picture of the hood basically to show what it looked like before sanding and doesn't have any real relevance to the discussion.

It is quite possible that I sanded the doors first. I don't remember, but it is likely. I waited about 1 hour after applying the primer to sand (SPI says 20 minutes). I wouldn't think that SPI primer has this "healing" property if it says to sand in 20 with no recoat window. Anyone know for sure?

I don't know of anything I did different between panels or for any other vehicle I have done. I thought that the bit of grey and sand scratches on the peeled paint might be a clue to someone in the field as to what went wrong. I am fishing for ideas on the cause so I don't make the same mistake twice.

Barry may recommend it, but does the manufacturer of the paint? THAT is who I would listen too about a product. He may very well be right, I am not saying he is wrong, but the manufacturer of the product is who you need to go to for something like that. It's like this peeling problem, now go to Barry, he may have some answers for you.

I am suspecting that the waterborne wax and grease remover may be at play here. It can be VERY slow evaporating, if you used it as liberally as it sounds you did that may be the crux of the problem here in that one of two things. The waterborne could have help to "kick" it healing it OR it soaked up the water and that came up between the base and primer eliminating the adhesion of the base.

With so little adhesion that the paint came off during color sanding!:pain: That is some SERIOUS loss of adhesion, one I have never seen before in my 35 years of doing this stuff.

I am thinking the primer had soaked up some water, it shouldn't as it's a quality 2k but that is what it looks like to me. Maybe the mixing ratio wasn't right on?

Brian

swvalcon 09-21-2012 10:35 AM

Brain I've been doing this for 40 yrs and I've never seen that big of a area peel like that. I dont think the water borne wax and grease would do it unless as you said he didnt get it dry. I've used it but just didnt care for it so went back to the solvent. With that long of a time span before the frist coat of paint I think a quick scuff with a scuff pad should have been done. Just cheap insurance. It's either the primer closed up or a flim between the primer and frist coat of paint and at this point its kind of hard to tell which.All that can be done is strip and redo.

MARTINSR 09-21-2012 10:38 AM

You may be very right, or I am right, or we both are and the "Planets were aligned" with a little of both!:mwink: I am thinking it's something like that.

The only thing that comes close to that type of failure that I have ever seen was my sanding the basecoat test, now THAT peeled off in sheets too.

Brian

tech69 09-21-2012 11:46 AM

I know it said sanding can happen in 20 minutes but I've never sanded primer within an hour. That right there raises an eyebrow but again, I've never sanded a primer within an hour so don't know for sure if it healed up your scratches or not, but do know those sand times are given with the thought that you are spraying in ideal conditions, which affect curing time.

Interested in hearing what Barry says, the guy is a mad genius with some of his posts. :D

Brad4321 09-21-2012 12:19 PM

Now that you mention it, this is the first time I have used Barry's waterborne, so that is a new factor in the puzzle too. I have always used solvent base from my local supplier. I like Barry's waterborne much better than the solvent base I was using (I can visibly tell the cleaning difference if nothing else). I turn on the booth fans, wipe the vehicle down until clean and wait 30 minutes with the fans on, tack it off and start spraying. This has been my standard procedure and didn't think twice about it with the waterborne. The truck never sat outside and didn't contact any moisture outside of the waterborne. This gives me two things different from my usual procedure: sanding with 600 and waterborne wax and grease. While it is true I haven't talked to TCP about activating their basecoat, I have used Restoration Shop a few times in the past activated with universal clear activator without issue, so that isn't my first thought.

I would need to scuff the primer for sitting overnight between sanding and base? I have never done that before, but if it is recommended I will start. I didn't realize that urethane primer has self healing properties, so that is really good knowledge.

Yeah, I am really interested in seeing what Barry says too. I posted this here instead of contacting him directly to get everyone's comment and hopefully help out a few other new painters too. I did a search and didn't see anyone discuss this problem before.

MARTINSR 09-21-2012 12:39 PM

Quote:

Originally Posted by tech69 (Post 1592616)
I know it said sanding can happen in 20 minutes but I've never sanded primer within an hour.

It wouldn't "heal" (from what I understand) from that as much as it would simply have solvents that didn't fully flash. But if this was left for a day it would certainly have flashed and sanding it open, though a little too soon would have helped it flash. After 12 hours of cure time before base this is pretty much a moot point I think, I think that is. :D

Brian

MARTINSR 09-21-2012 12:42 PM

Quote:

Originally Posted by Brad4321 (Post 1592628)

I would need to scuff the primer for sitting overnight between sanding and base? I have never done that before, but if it is recommended I will start. I didn't realize that urethane primer has self healing properties, so that is really good knowledge.

I DON'T know if this particular urethane has much of a "healing" property. I know that others that I have used have and some are VERY short as I mentioned. I did my Gran Sport in it and after sanding the car, right before it went in the booth yes, it got a scuff over the entire thing with a gray scuff pad just to be sure.

Brian


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