Dave Tracy

Finally put some paint on the doors and hood with reasonable results a couple weeks ago. I am using PPG DCC acrylic urethane as a single stage in ermine white. Today, I smoothed the paint out with 2000 grit paper very easily on a door. Just minor orange peel. I then used 3000 grit followed by polishing using 3M polish with a 3 1/2 inch foam pad as recommended by Porchdog. The pads were rinsed often with water. This was followed with McGuire's swirl removal polish. When I examined the finish, I found linear, not circular or swirls, scratches in the finish. I marked them with a Sharpie and could remove them using 5000 grit paper. These scratches could not be felt with my fingernail. After multiple attempts at sanding and polishing, I quit because I obviously am missing something. Also, I would be less likely to pound holes in the body with a hammer, drain the oil and run the engine until it seized, douse it in gasoline and torch it. I was almost ready to do that due to my frustration after so much work on this project. Any suggestions as to the scratches? Thank you in advance.

13611

Are the scratches going in a direction that was typical of the direction you sanded it? When wet sanding I do a "X" type pattern. Sand one way for a bit and then another way, 90 degrees to the first direction. That way (for me anyways) if I see any scratches after polishing, I can usually tell if they are from my recent wet sand or if I have prep issues showing up from under my paint. Did you get all the "peel" out? Because if you did, it may be in the prep work under the paint. There's a few variables/maybe type things like... contaminants getting on the sand paper or a sharp edge on the paper from not soaking it for a bit before using it, etc. If the scratches show up in photographs, some pics might help get some additional info from members here. That's a bummer!!! Been there. Don't burn it... you did the right thing by walking away and airing your frustration here

porchdog

go here and order this sample kit .
the 31/2 pads are for tight places. i use the 6 in pads either hexlogic or lake country .


http://www.chemicalguys.com/V_Line_P...ap_vkit_04.htm


this kit will do the car .

Dave Tracy

Thank you Porchdog and 13611. I ordered the kit and pads, Porchdog. Regarding sanding, I have seen written and demonstrated that wet sanding with the very fine grits to not use a circular motion but to sand in one direction. What techniques do you all use? Could the smaller pads be causing the scratches?

porchdog

i do as much as i can with a da sander. method of sanding is not important imo . people just think they can tell witch scratches they are seeing. i polish until there are no scratches . you will see gloss well before you have gotten rid of any scratches. keep it clean so you can see what your doing and use a light to inspect the panel .

DUB

FOR WHAT IT IS WORTH:

I personally sand in one direction. That way...when I buff...I have my pad going across these sand scratches and thus aid in taking them out.

AND YES...I get the same lines also from time to time....and I know that I need to buff a bit more.

I DO agree with 'porchdog' ... I keep buffing until I see the scratches GONE....then I go in with finer polishes, etc.

I can say...that it is highly possibly that you did not buff it long enough in the initial stage of buffing. I do not want to get into a conflict...but I do not use a foam pad when I begin my buffing initially. I HAVE used a foam pad when I began my buffing and I feel it takes me longer to get it where I want it before I go to the next stage. We all have our own techniques..and I can bet....that a perfectly slick, texture free, swirl free CRYSTAL CLEAR paint job CAN be achieved using different methods.

DUB

porchdog

giving up my wool pads was tough . the foam pads in the beginning were pretty much junk imo . at most i used them for finish. it wasn't until i discovered the compounds were the culprit that i switched back to CG and foam. i was a little ticked off when they changed their compounds. to the point i even called and complained . after trying the sample pack i had to call and chew on that crow. i'm sure they got a kick out of that.
the new pads now are graded like sandpaper and work really well. on a black car i will use 4 pads and all 4 compounds . not really sure on the hybrid but i use it any way.
i like the way the vseries works. long lasting and not a lot of dry build up.
i have found a little goes a long way and cleaning the pad every third application keeps things clean .

it is worth the money to try the sample pack . you may be surprised.

remember ! foam pads generate more heat than wool . be careful. speed is not your friend .

Dave Tracy

Porchdog-From your description, it sounds like the CG polishing compounds are initially very abrasive to very fine if a 4 oz/bottle kit will do a complete car. Is that assumption valid? Regarding speed on a polisher, I have a Makita with variable speed. Should all polishing be done at low speed with the foam pads? Thank you all for taking the time to answer these seemingly mundane questions.

porchdog

there are some good tutorials on cg site. the compounds are rated much like paper. you use 32 with a cutting pad , the 38 is used with a polishing pad. it sounds like a lot of work but so is painting.
i use all the grits of paper and do not skip grits. i use all 3 pads and all 4 compounds. you can get by with 32 and 38 but it is like going from 1000 grit to 2000 grit. lot more work than 1000,1200,1500,2000 .
many guys will overheat the paint trying to buff out 1500 grit scratches or burn through .

randy ransome

What brand of sand paper are you using? I've had problems in the past with cheaper paper not being consistent. I use Meguiars 2500 paper only.

Just my .02 worth.

Good luck.

13611

Good info Porchdig! Back to that speed question. About how many RPMs are you buffing at?

porchdog

i use a flex buffer and use the lowest speed. i just dont get in a hurry and do not like heating the paint. the highest i go is to #2 on the speed dial and do that when final polishing .
many will disagree but that's fine . when you overheat paint it will loose clarity. it will be smooth and shiny but have a very fine texture which will not buff out. good luck with it .

i use eagle brand paper.

DUB

I use EAGLE paper also.

This is NOT directed at anyone.
AND I AGREE...the common misconception is that some people may think that if the buffer is set a high RPM...like that is MACHO and that is it going to do a better job....well....GO RIGHT ON AHEAD AND DO JUST THAT!!! Let me know how that works for you. I have shown the guys I have trained that even at the slowest setting on my Makita variable speed buffer....it is still faster than by hand. There is a fine line on how hot/warm you can get the paint.

When a person has had a buffer in their hand for decades...it is almost second nature to know how much compound/polish to apply to an area..and how much area that that amount of compound will buff/polish. For those who do not have that experience.,...the one thing I can write is to take your time and do not expect to duplicate the actions of a person who has done it for years and years. The most important thing is NOT TO DAMAGE what is painted due to getting frustrated and wanting it to gloss back up QUICKER. This CAN BE...the 'kiss of death'....that many of us who have experience have experienced. NOTHING...and I mean NOTHING is worse than burning through an edge or burning the paint when you are so close to the 'finish line' and then having to back track and repaint it...wet sand it and do it all over again. WHEN that happens.....YOU will wish you could turn back time and do it again and be patient.

It has SO MUCH to being able to 'read' the paint and see that you are done buffing and getting the scratches out....so you are not sitting there ....buffing the same spot time and time again and then 'wonder why' you are now seeing primer or sealer show up.

DUB

porchdog

i will buff a part more than once . reason being heat . if you overheat the paint on say the top of the fender you expand the solvents in it which can and usually will end up loosing adhesion . like dub said polishing the finish is the last place to get in a rush. slow down and enjoy the results. i spend a lot of time on finish. i will buff , clean and inspect several times before i'm satisfied .

Dave Tracy

Thank you all for your advice. After the material arrives, I'll give it another try.

DUB

1000%

BUT...'porchdog'...we have done this more times than we both can count. And WE both know how important this final step actually is ( not writing that others do not know this).....and one thing that I do know....is that when a customer sees their car and part of it is buffed....they get so 'jacked-up' and excited...they want it done in a day or two....and that is when I laugh. And I tell them..." I have spent so many hours of my live getting it to THIS POINT...I am NOT in any hurry to get it done ....because if I screw something up...then that sets the timeline of delivery back even further".

To all of those who plan on doing this....one thing I will add to 'porchdog's comment. Wet sanding and buffing/polishing your car at this stage of its repair/restoration is so important. Especially if the standard is going to be very high on getting the paint finish flawless. SO....to quote 'porchdog' "SLOW DOWN and ENJOY the results".

Wet sanding/buffing/polishing a car is like driving your Corvette in the mountains.... AT NIGHT...with NO headlights and NO FULL MOON in down pour rain. It can be done...but VERY SLOWLY...and PAYING ATTENTION.

DUB