Confounded by the plastic bag test !

tom p.

tom p.

Active member
I spent some time this weekend doing my spring cleanup on my car. My basic game plan is the same I’ve used for years: Clay (Meguiar’s Mild yellow) > KAIO (via machine) > 2X FK 1000p (via machine)</SPAN>



At the end of my session, everything looked and felt as expected, the surface was hugely gloss and certainly slick to the touch. Good! I’m done. </SPAN>



A bit later in the day I was chatting with a fellow Autopian via telephone and we discussed my new Griot’s RO polisher. I told him I liked it quite a bit and was hoping it would serve as well as my PC. He asked me if I did the plastic bag test and I said, “no”. After we hung up, I did the plastic bag test on a few surfaces, and much to my horror, it sounded like I was rubbing my hand across sand paper. Not good. Even worse, I had OptiCoated the hood, front fenders and bumper of the car a few weeks ago and I spent a good deal of time polishing and prepping the nose of the car. The OptiCoated sections are by far the worse in terms of bonded contamination. FWIW, none of this is visible (to me) and you can’t really feel it with your hand. I suspect it’s probably a blend of tree “sap” and environmental fallout. The horizontal panels are the worse, doors/vertical panels aren’t too bad.</SPAN>



I’m not sure how much effort one should have to expend on this. I attempted to remove some serious damage on the hood of a car we adopted a few weeks ago and polished the heck out of it with Meg’s Ultimate Compound followed by Meg’s #205. I then cleaned with IPA and coated the hood with OptiCoat. The surface looked great, but the scratches were not all removed, but I was not going and farther with it. Again, to my surprise, the hood could not pass the plastic bag test even after my efforts with these two Meg’s products. So, all of this has me scratching my head and wondering if I can actually remove whatever is on the surface so it will pass the plastic bag test.</SPAN>



  1. Do I scrape the paint with a razor blade like the Overspray Guy? (j/k)</SPAN>
  2. Do I ignore the plastic bag test?</SPAN>
  3. Is my tried ‘n’ true product selection all wrong?</SPAN>
  4. Do I need to break out my Presta wool and the Makita to get the surfaces clean?</SPAN>
  5. Does a stronger chemical (or mechanical) cleaner exist that can quickly remove these contaminants?</SPAN>
  6. Do I need to start spending hours on each panel of the car ‘til it can pass the plastic bag test?</SPAN>
  7. Would one of the paintwork cleansing lotions help out? Is one stronger than another?</SPAN>



While I can add more prep steps, there’s going to be a limit on how much time I’m willing to invest to correct this. I’m sure some of you will have experienced this problem. Have you found any direct solutions?</SPAN>



Thanks.</SPAN>
 
I'd try a nonabrasive method first, especially on the horizontals where there is no OCoat. A decon and/or a more aggressive clay should solve the above surface bonded contaminants. You can clay the OCoat as well.
 
How long are you claying? I ask because some people clay until it feels smooth, which it will pretty quickly, especially if you use a QD as lube vs something like slick like ONR. If you clayed until the clay was no longer getting dirty, I'd be surprised. I clay once a year usually (I know, I know), and it takes me about 2 hours to do a thorough job.
 
Guys, thanks for the comments.



Dan, I probably clay the entire car in about twenty minutes. The clay is moving very rapidly when I'm done with a panel. I' using ONR as my lube.



My clay may be too mild, too. I guess I should be doing the plastic bag test after claying, right? I just don't know if I can/should expect clay to fully remove whatever is on the cars.
 
Tom, 20 minutes sounds very quick, I think I spend longer than that on my hood (one of the worst areas). Try doing a panel until the clay no longer gets dirty and then try the bag test. You can spend less time on the side panels (but more on the lower panels like rockers). Roof is always pretty bad too.
 
Alright, I'l go back and focus on just the trunk to determine what I really need to do. Is it fair to expect that the clay should remove 100% of the stuff or is that unrealistic?



Yeah, the roof of the car is bad :(



Any decent clay to be found OTC (Pepboi, Wmart, AAP or AZ??)



thx.
 
I think it's unrealistic. It's just shearing off the contaminants at the surface level. The ABC ought to actually remove them.
 
Thanks, Bill. I was wondering if that might be a solution.



What worries me is that I can remove all this stuff, but will it just be back again in 4 weeks?
 
ClayMagic blue is the best stuff out there as far as OTC goes. If you keep folding the clay and it comes up clean on the last pass, it should be smooth with the bag test.
 
Hey Tom, as we've been discussing privately I used a two stage claying process starting with the Wolfgang and finishing with the Pinnacle clay bars and that still didn't pass the bag test. IME, you have to use something like P21S Paint Cleanser, Wolfgang Paintworks Polish Enhancer (which is what I used) or equivalent to get the surface truly containment free. I would be surprised if any clay bar would pass the bag test on it's on merit, though I would love to be proven wrong!!! Also just got a second opinion and apparently all the clay bars work more efficiently when using a designated clay lube. In my case, I used ONR mixed to 8 oz/gallon for my clay lube which is the dilution for QD Spray - which is apparently to slick to achieve maximum clay effectiveness. So my plan is to buy a dedicated clay lube and see if the results improve.
 
Thanks, Addy! I'll let you know the result with clay only. It would be great if I could get away with a simple solution :)
 
WARNING: Autopian Heresy follows!



tom p. said:
At the end of my session, everything looked and felt as expected, the surface was hugely gloss and certainly slick to the touch. Good! I’m done.
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OK, you're done. Enjoy the car.



A bit later in the day I was chatting with a fellow Autopian via telephone and we discussed my new Griot’s RO polisher. I told him I liked it quite a bit and was hoping it would serve as well as my PC
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Good, glad to hear that!



He asked me if I did the plastic bag test and I said, “no”.
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I haven't done a plastic bag test since forever and I don't plan to any time soon.



After we hung up, I did the plastic bag test on a few surfaces, and much to my horror...[horrific description :eek: ]... none of this is visible (to me) and you can’t really feel it with your hand. ..
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Hold it, I thought everything seemed fine before :think: Heh heh, now it sounds like things might be not-good after all but you didn't notice.



IF it were somebody else's vehicle (as in, "hand off!") sitting in the real world (or even at a show), what would you think of it?



I'm trying to choose between "I didn't notice before, but the car is in need of some special attention" and "the car is perfectly OK except for not passing the baggie test". If the former, OK...gotta redo; if the latter, I'd quit thinking about it here and now.





I’m not sure how much effort one should have to expend on this.
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Heh heh, I'm pretty sure my answer is "less than any of us do spend on it!" ;)





Do I ignore the plastic bag test?
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That's probably what I'd recommend. Yeah, yeah, I can hear it now...."your terribly contaminated paint is gonna be ruined! Your LSP won't last a week!" Seriously dire gloom and doom!!



Do I need to break out my Presta wool and the Makita to get the surfaces clean?
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Heh heh, that sounds as crazy to me as the razor blade joke!



[*]Does a stronger chemical (or mechanical) cleaner exist that can quickly remove these contaminants?
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Well, you do know how I feel about "ABC" ;)



Do I need to start spending hours on each panel of the car ‘til it can pass the plastic bag test?
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Not IMO. I mean...seriously, I could have a perfectly happy life without ever rubbing my paint with a baggie.



Would one of the paintwork cleansing lotions help out? Is one stronger than another?
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Eh, some are probably better than KAIO, but the application/etc. method probably factors in a whole lot too.



While I can add more prep steps, there’s going to be a limit on how much time I’m willing to invest to correct this.
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Good, glad to hear that last bit :xyxthumbs
 
I like clay magic, but is there really that much of a difference? I never clayed a car and not have perfectly smooth finish after it.



Although I do use an aggressive version.
 
Accumulator said:
IF it were somebody else's vehicle (as in, "hand off!") sitting in the real world (or even at a show), what would you think of it?



I'm trying to choose between "I didn't notice before, but the car is in need of some special attention" and "the car is perfectly OK except for not passing the baggie test". If the former, OK...gotta redo; if the latter, I'd quit thinking about it here and now.
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The car(s) look great, there's nothing lacking, just a lingering concern that the surface really isn't Autopian clean. I guess I have to determine how much additional work I have ahead of me to gain that last 3% I'm missing. I think I'm going to attack the trunk lid to determine how much additional effort I have to take to pass the plastic baggie test. I'll find the Clay Magic and look at adding M205 before I apply my KAIO followed by the LSP.



I kinda wish I never heard of the baggie test :think:
 
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