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Old 03-02-2007, 10:04 PM
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Interesting test on sanding base coat paint (against the data sheets recommendation)

Ahhhhhhh, very interesting test results......

Soooooooo, back a while ago we had very heated discussion on going against the manufacturers recommendation and sanding a base coat. (click here for the discussion). So, in this discussion I repeated information that has been told to me over the years from paint reps, and my own research and development dept when I myself was a paint rep for Sherwin Williams.

I am not a chemist, never claimed to be one. But I can read a tech sheet and comprehend what sounded like good information given to my by these fellows I refer to.

To say that people disagreed with me is putting it mildly.

So, after this discussion I found myself at a forum I had never been on because someone told me I may find something there interesting. On that forum I found a guy calling me a dumb m-fer and that I give bad advice and on and on. He had read my posts on the discussion about sanding basecoats and made some lame joke (very, VERY lame) about something I said that these base coats have a wax in them (at least the S-W it is right there in the MSDS). Anyway, as I read this lame joke I thought he was going to tell me how to do an adhesion test and I kinda ran ahead of the joke thinking that he was going to say I should spray out the base, sand it, then spray more then clear and then do a cross hatch "X" scratch thru the clear. Then lay duct tape over the area and pull it off to see if any clear or anything comes off.

Well his LAME joke was something about putting tape over the paint and "collect" the wax that dripped off the car from the base coat so I didn't have to buy wax.

Soooo, anywhooooo, I found myself with some time last weekend to do my test. I went and bought a pint of silver DuPont Chromabase and some basemaker.

I brought home a fender from work with some good OEM paint on it and scuffed it with a gray scuff pad and water just as normal for a blend.

I painted two coats of this Chromabase over it. Then, I sanded one area with 1000 grit paper. I then applied another two coats over the whole thing.

I then thought I would do another test, I sanded another portion of the fender with the 1000 and cleared over the whole thing.

The fender was painted right to the tech sheet with proper metal temp, temp basemaker, flash time, right to the letter. All of course except I ignored the "Do not sand base that is found on the recommendations of DuPont.

I let this set for one week outside in the California sun (and a little rain too) and pulled it inside after work for my test.

I did a cross hatch "X" scratch with my pocket knife on three areas. The sanded base and re-base, the sanded base and cleared and the one done to manufacturers recommendations.

I then layed a liberal amount of duct tape over each area pushing it down real nice............. And then yanked it off.


The following is the results.

The base sanded and recoated completely delamed at that point, JUST AS the all the reps and chemists had told me. The tape was COVERED with the two coats of base and clear. We are talking EVERY SINGLE SQUARE MM OF TAPE!.

The spot where the base was sanded and then cleared, yep, the tape pulled up the clear right off the base, leaving NOTHING. Again, we are talking EVERY SINGLE SQUARE MM OF TAPE!.


The spot where I followed the manufacturers recommendations????? You probably have guessed, it held on perfectly, I could barely get the tape off!!! I pulled and pulled to get the tape off leaving the paint PERFECT with only a couple of specks coming off that were broken loose by the knife.

Hmmmm I wonder if that guy will read this and give me the appology that I think I deserve.

Again, following the manufacturers recommendations, the recommendations that the people who make the darn stuff say to do. The people who have spent MILLIONS of dollars on their product. The people who have BILLIONS of dollars at stake if their products were to fail. Yep, they are not that stupid after all.

Now, I am sure, I am darn sure that someone will beat up my test. "Well you did this or did that or the paper was too fine or too coarse, I never said this or that." That is all fine. I am not refering to what ANYONE said in the text of the original thread. I didn't read it before I posted this (though I found it interesting that it resurfaced after all this time just today as I came in here post this) and I am NOT saying anything personal about anyone. UNLIKE the guy who ripped me calling me a Dumb M-FER all I am showing is what I found to support what I was told by MANY representatives from a couple of different MULTI BILLION dollar a year paint manufacturers who have been around for a HUNDRED YEARS making paint and paint products.


Brian

Edit, actually the photos got mixed up. The first is sanding between coats of color, the second is per data sheet and the last is sanding base before clear. If you hold your curser over the photo you can see those are the names of the photos off my hard drive.
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Last edited by MARTINSR; 03-02-2007 at 11:43 PM.
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Old 03-02-2007, 11:50 PM
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Thanks for sharing this information Brian.

Thats a good test and I believe proves your point to the fools who think they
know better.

X711.
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Old 03-03-2007, 12:47 AM
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This is very interesting.. how do u fix a goof up in the base then?
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Old 03-03-2007, 12:51 AM
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As I was told and said in the original thread, "lightly scuff in one direction". Keep it as small as possible. Epoxy seal it? Maybe, I don't have all the answers.

Brian
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Old 03-03-2007, 01:57 AM
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Martinsr..... That wasn't the first time you got called names and was ridiculed for your posts, and won't be the last. Part of your problem is that you post long drawn out posts that say one thing, then when pointed out that you are wrong, either edit them, or say that wasn't what was meant.

Quite frankly, I have doubts that most anyone that has worked in the business for any length of time really values your information at all. A test conducted by you, to prove your point, is not a reliable test, as far as I am concerned.

Quote:
This is very interesting.. how do u fix a goof up in the base then?

Quote:
As I was told and said in the original thread, "lightly scuff in one direction". Keep it as small as possible. Epoxy seal it? Maybe, I don't have all the answers.

Your last comment is the one that you need to remember and understand!

Ideally, every paint job will have absolutely no defects. If there are defects, there are ways to fix them, without completely stripping all of the product off and starting over. It has been done many many times. You sand out the problem and spray over it.

Aaron
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Old 03-03-2007, 08:33 AM
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Boy oh boy, I'm never using Dupont anymore. Never tried SW and I guess I don't want to now. Along with everyone else I come here to learn and today I learned I don't want nothing to do with Dupont anymore if that test is valid.

The only time I ever had a delamination problem with Dupont products is when I sprayed base directly over Variprime (this is a big no no), this was many years ago now. I haven't sprayed Variprime for at least 10 years. I've denibbed and sanded Chromabase and Chroma Premiere many times-especially when doing graphics-removing overspray, etc.... and never seen any problems.
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Old 03-03-2007, 09:40 AM
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Brian Martin,Freelance adviser
 
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Aaron, I don't edit my posts as others do. On that discussion you can see that I left stuff there that I could have edited out. I edit for spelling and grammer because I don't want to look like I have a third grade education, sometimes before editing it gives that impression.

On the "Book" thread by Barry you rant and rave about the people who post yet just say "adjust your gun" instead of telling the guy HOW to adjust the gun. I tell them how to adjust the gun, that takes longer than "You sand out the problem and spray over it." I respond with (click here) in a long drawn out post.


Names, people with poor vocabularies call names, I give facts and live with them.

Now, explain to me guys how I "didn't not follow the tech sheets wrong" Did I "Mistakenly not follow the tech sheets in the right incorret way?" What I did is EXACTLY what was discussed on the other thread. I sanded the base, PERIOD. How exactly is someone who reads either of these threads to interpret this? I SANDED the base. And yes Aaron, there is a certain amount of "slant" being I wanted it to fail. HOWEVER, I FOLLOWED THE TECH SHEETS in every regard EXCEPT the little part about sanding it. I sanded it FLAT much more than "nibbing" as the tech sheet recommends. It was mentioned in the original thread this was fine, sanding the base was fine. This was said over and over. How is a newbe who comes here looking for advice supposed to take that?

You want honestly? Prior to grabbing that fender and doing the scratch test yesterday I had no idea what would happen. I had a "hunch" but nothing to the level of failure that I got. I had thought about, "what if this test proves nothing, will I post the results?" Now, THAT still wouldn't have proven that it "couldn't" fail because of this sanding of the base. Because it may still have needed to have the "Planets" aligned with a perfect cercomstance of flash times, solvent choice, etc.

But this test, it was pretty definitive, follow the tech sheets to the tee except sand the base flat and you WILL have the makings for a failure.

Now, I do plan on doing the test again, this time I will have a few test points with different degrees of sanding or "nibbing" to see just how far can you go and be safe.

Brian

p.s. By the way, the reason I havn't done this test in the weeks and weeks following the idea is that it has been very cold here (for sunny California)and I WANTED honest results.

Last edited by MARTINSR; 03-03-2007 at 09:48 AM. Reason: Spelling, grammer and adding the "Post Script".
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Old 03-03-2007, 09:42 AM
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Quote:
Originally Posted by baddbob
Boy oh boy, I'm never using Dupont anymore. Never tried SW and I guess I don't want to now. Along with everyone else I come here to learn and today I learned I don't want nothing to do with Dupont anymore if that test is valid.
Bob, just as if I would have sprayed the base outside in the snow, just don't do that and the product is fine. The area where the tech sheet was followed passed the test.

Brian
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Old 03-03-2007, 03:38 PM
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WOW!

You just made thousands of chemistry books with regards to "solid mass"
totally useless and invalid.
I have no doubt you will take an international award for this finding.
Hey remember all us little guys when you get the award.

OR
You just did a demonstration as to why no body shop should ever use S&W or Dupont, or whatever one you tested.

Brian, don't PM me again to see this crap as I don't have time or really care about the tests as they mean nothing.
I have a life.
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Old 03-03-2007, 03:46 PM
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Brian Martin,Freelance adviser
 
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Barry, YOU said you could sand DuPont base coat. You said DuPont had "other" reasons why it couldn't be sanded. Why in the world can't you explain now why this test is invalid?

I am just a normal guy who can't understand what you just said about "solid mass" can you please explain it?

Anyone???? I did EXACTLY as was told by a number of people to be fine, that I was nuts to believe the paint reps.

Please, Barry, you took the time to come here and beat me up but you can't take the time to explain to everyone why this test is invalid?

Brian

Edit: And Barry, don't go knocking DuPont or S-W. I used DuPont and I ABUSED it, of course it did not perform as it should. DuPont is used in tens of thousands of shops around the world and they sell billions of dollars in product all backed by a lifetime warrantee. That is IF you follow the tech sheets.

THERE IS NOTHING WRONG WITH THE PRODUCTS USED IN THIS TEST. IT WAS APPLICATION ERROR.

Last edited by MARTINSR; 03-03-2007 at 03:58 PM.
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Old 03-03-2007, 04:04 PM
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Bob..... I garee with you completely. If that test were valid, ther would be no way I would use that product again. I am not Brian Martin, so I do not spray perfect paint. That means that there will be nibs and such that would need to be removed. Obviously, according to the "paint god", that means that you could not repair the base, you would have to keep striping it off until you got it perfect, so you could spray clear. It would have to be sprayed exactly as the tech sheet says also. Otherwise, you will be really busy making sure no one comes near it with duct tape, as the paint will come off onto the tape.

I am really surprised with SW though. They weren't smart enough to ask Mr Martin before they posted the Tech Sheets online. They say that you can sand to remove nibs, as long as you shoot more base over it. How can they be so foolish!!!!! All they had to do was ask him, and he would have set them straight.

Brian.... I tried to understand your posted response to me. Maybe you should go back to taking care of those Happy California Cows I see on TV. They would be used to someone that shovels so much BS.

Aaron
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Old 03-03-2007, 04:22 PM
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You guys are so sad, soo sad.

Are you accusing me of lying? Are you accusing me of spraying WD-40 on it to make it loose adhesion? Are you saying that you shouldn't be able to stick duct tape on a car? What is it you are saying??

I did a valid test, not "scientific" but a valid "general" test that YOU could chose to do. Just paint a fender with three coats of base allowing the recommended flash time then sand the base with 1000 grit sand paper and spray another couple of coats on it. Clear the panel and wait a week and do the scratch and tape test. It is that simple.

Are you saying I didn't do that? What are you saying?

Both S-W and DuPont (and others by the way) say a light "nibbing" of dirt is ok. I have said that over and over.


What I did is EXACTLY what I we were told by a number of people was just fine.

This is exactly what I figured would happen. You guys can't admit anything, it is mind blowing actually. Argue something, but you have nothing to say but tired old crap making up things I said or Dupont or something.

FOLLOW THE TECH SHEETS AND YOU WILL BE FINE I have been saying that for almost ten years on forums. Once in a while I get some guy or guys who insist that I am wrong some how for suggesting such a stupid thing as follow the tech sheets. My God men, how in the world can you keep going without stopping and saying hmmmmmmmm.

Brian
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Old 03-03-2007, 04:34 PM
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Brian... I never accused you of lying. To do that, I would have to feel that you were intelligent enough to know what you were doing, and provided false information. To me, that is obviously not the case!
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Old 03-03-2007, 04:39 PM
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Interesting stuff. I post results of a test. There is no discussion, only attacks at the messenger. Very interesting stuff indeed.

Yeah I posted it with a little glee, do you blame me? I was beat up for this before, now I am being beat up again. All for saying FOLLOW THE TECH SHEETS. Funny stuff this auto paint.

I wonder if there is a forum for doctors where some guy is saying "But you have to sterilize your surgical tools" and there are some other doctors saying "Hey, nothing has ever happen that I know of and I never sterilize them".

Brian
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Old 03-03-2007, 04:59 PM
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Crawling out of my hole momentarily...

I was a painter for nearly 20 years. Before starting my sheetmetal shaping business, I spent 6 years as the painter in a collision shop.

EVERY new part that was installed on a vehicle was sanded with 320 grit, rubbed down with red scotchbrite, sealed and painted with three coats of base prior to hanging on the car. When the body man was finished with repairs, my job was to prep for paint and in doing so, the raw basecoat was sanded with 600 grit wet. Basecoat was then applied as usual with no special attention to the raw base. This shop had been doing business like this for at least 5 years before I started, and probably longer than that, truth be told. In 6 years, guess how many vehicles came back with delamination problems.......ZERO. We had the reputation of being the top shop in the area. Our reputation insured us repeat business and many times we would see the same car back in the shop time after time for collision repair. Now, if paint was going to delaminate, shouldn't it do so when a fender, hood or whatever has been severely damaged in a collision???? It never happened, not once!!!!! Most of the time, my paint would adhere better than the OEM stuff.

We were using PPG Deltron, by the way.

Brian's test may have worked as it did because of a poor product. These multi billion dollar companies aren't necessarily putting out the best product, in fact, they try to cut cost every chance they get.

The very few times I ever had a product failure, they would never admit to a problem. The blame was always placed on the painter. I rarely changed my technique, so if 1 in 1000 paint jobs would fail, How is that painter error???

Use good products, you'll get good results. Common sense should tell you if a basecoat will not adhere to itself after sanding, something is seriously wrong, as you have neither a chemical nor mechanical bond. The red flags should be flying!!!!!

crawling back into my hole now.

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