Soak/ring up issues

I wish ya luck and hope it works out for you.
I've been painting cars for 30yrs and can only and will only tell you of my experiance. You can scuff the base down but will atleast have to wipe down with a watered down rag a tac-rag by itself will not be enough and it will stick there is no hardner in the reducer like PPG had or Sherwin Williams. I know first hand. You can de-nib and be alright. As for pushing the window before clearing I really don't know I have never wanted to push my luck once you loose your ass on a job because of de-laming you learn real quick, and I done that twice and swore to never do that again. My de-lam issues were corrected before they left the shop if that makes a differance to it sticking. I just never pushed the recommendations of the manuf..

Dave
 
Thanks for the input. Gonna double check on how much base I have left and weigh whether or not to lighlty scuff and recoat, or just clear it. In the 8 years I've been using chromabase I've never had a problem with knocking down an entire panel of base because of a problem occuring from my gun, or contamination in the lines etc etc. I've scuffed back down after a few hours, cleaned the panel, corrected whatever external problem then cleared with no delam problems as of yet that I am aware of. I have not done that with chromapremier though. I think from now on I will make sure I can get clear on within the 24 hour reccommendation. But I've also waited multiple days before clearing something when doing pinstripes, custom designed tanks and such and haven't had any issues so far. But I've only been doing this for almost a decade and youve been doing it for a crap load longer so I will certainly heed your advice sir. Thanks to all the input you guys have provided.
 
I re-read the Tech-sheet and when you read it they "recomend" that you mix with Base, Basemaker (reducer)and Premier activator (hardner) for best performance. I have never used the activator (hardner) in my mix, I just add Basemaker. Then they continue to explain about the time window and only de-nibbing. I believe they are refering to that perticular 3 part mix ratio. The hardner would, IMO, make the raw base turn harder with time and not allow clear to bite-in causing it to de-lam.
So in that I believe we are all correct in that if you followed the 3 part mix in Duponts Tech-sheet then if they (Dupont, Bob) said no you must sand off all base and start over then I would say I learned something I did not know or heard of before.

In my case I only use 2 part mix (Base, Basemaker). So mabey the max 24hr window doesn't apply (Jim comment) so again I might have just I learned something.

I have sanded and just tacked the Base (due to forgetting to tack off the panels) and then reBased only to have it de-lam the next day. I found that when I did sand and tack off the base it had a slick feel almost like it had a waxy feel. Then when it happened again (sometimes you do forget the tack rag) I again sanded the base down and tried the tack rag until clean (or I thought) and then took a damp (water) rag and wiped it down and the rag had base dust on it. So now when I have to nib or do an entire panel, I 1st use a damp (water) rag then follow with a tack rag, that works for me and is the way I do it when needed.

Either way you end up doing it I hope everything works out good for you. You will find that everyone does things differantly even if just a little bit, but in the end if the job turns out good that is all that really counts.

I look forward to hearing what you ended up doing and how it came out. Which mix did you use?

Dave
 
If you sand DuPont's Chromabase and Chroma Premier regardless of what grit is used... regardless if you use 222S, and regardless of the recoat window... you will have poor adhesion at that sanded level. I've tested this with solid colors and metalics. I was warned about this and thought the ex-paint rep that told me this was out of his mind. Then I tested it for myself and found he was absolutely correct. I used two hoods with sections taped off, the base coats were sanded with different grits and I also had a section that was unsanded, I also tried DuPont's 222S as one rep told me that was the save all for sanding between coats and also if past the recoat window. I let the hoods set in the sun for 30 days and did a scratch test-all sections failed with delamination at the sanded level, the unsanded section was perfect. Set youself up a test for yourself. I emailed DuPont to pick there brain and I have a response email saved somewhere that says do not sand our basecoats. I've seen failures to the point the clear with some based attached comes off in sheets at the sanded level with compressed air or a pressure washer to milder cases where stone chips end up being 10X larger than what they should be and grow because of poor adhesion at the sanded level. I seen failures as an everyday collision tech years ago and it was always on the high end work where I had sanded the base between coats-the reps didn't have a clue what the problem was back then and all I can think of is DuPont hadn't tested that scenerio back then, and back then I never thought sanding the base would be an issue. If you use the product like the tech sheet says there won't be any problems but don't treat it like any other basecoat-it should not be sanded.
 
Bob were you using their 3part mix ratio or just base and basemaker. I would never put 222 over basecoat for any reason I would use that mainly over the blend panels before spraying base then clear. I have never had a problem with it using the base/basemaker mix I even put tape to it and ripped it off the day after to make sure it wasn't going to get silly and never had one show a problem. That is odd and new to me cause our Reps have said you must scuff the base if the window is missed.
 
Datec, the tests were done with base+basemaker without hardener. Next day tape tests on only the base won't confirm the adhesion-it all changes again once clear is applied and the solvent in the clear goes into the base. One rep always recomended a coat of 222S on base that had gone past the 24hr clearcoat window. You may be right about the clearcoat activator correcting the issue but I would test it myself. Denib only for me, I will not sand anything larger with this paint.
 
I ended up just clearing it. Datec, I just used the base/reducer. Unfortunately it doesn't even matter cause Im gonna have to sand it down and start over. After my first coat of clear, I came back half an hour later to find a huge fly stuck in the clear at the front of the hood. I went to pick him out and he basically exploded leaving all his gunk behind. This is a light metallic silver so anything that's not silver shows up like an eye sore. So ill go back in today to sand it all down and start over. Lots of good info here.
 
Bob Hollinshead;37874 said:
Datec, the tests were done with base+basemaker without hardener. Next day tape tests on only the base won't confirm the adhesion-it all changes again once clear is applied and the solvent in the clear goes into the base. One rep always recomended a coat of 222S on base that had gone past the 24hr clearcoat window. You may be right about the clearcoat activator correcting the issue but I would test it myself. Denib only for me, I will not sand anything larger with this paint.
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Me being a new member I surely don't wish to come off as argumentative but things seem to be getting lost in translation. I just got off the phone with my Jobber and the Dupont Rep. to check myself and the best I wish for you is a great end result.

Dave
 
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