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Thread: Thinking of changing my process of prep and finish paint work?

  1. #1
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    Default Thinking of changing my process of prep and finish paint work?

    I'm sanding out this 68 Mustang convertible before I paint it, and I am doing it by hand. Here is my question?

    I have thought about buying a DA for finish sanding, but it's expensive for the sander and then to buy the paper. I like to do the best job I can, but I'm not sure if using a DA is better quality than hand sanding? On the cars I do, I charge by the hour and not the job usually, so my time is what they are paying for regardless. They also pay for materials, so the paper is not an issue either, but bottom line is, does the DA do as good of a job as wet sanding by hand?

    Do you guys DA your final sanding before paint, with 400,500, or 600 and do you trust the DA to do a good job?

    How about cutting with a DA on finished paint? I know my buddy does this and he seems happy with it.

    Is there a combination of both DA and hand sanding that works well?

    Thanks

  2. #2
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    Quote Originally Posted by kcode View Post
    I'm sanding out this 68 Mustang convertible before I paint it, and I am doing it by hand. Here is my question?

    I have thought about buying a DA for finish sanding, but it's expensive for the sander and then to buy the paper. I like to do the best job I can, but I'm not sure if using a DA is better quality than hand sanding? On the cars I do, I charge by the hour and not the job usually, so my time is what they are paying for regardless. They also pay for materials, so the paper is not an issue either, but bottom line is, does the DA do as good of a job as wet sanding by hand?

    Do you guys DA your final sanding before paint, with 400,500, or 600 and do you trust the DA to do a good job?

    How about cutting with a DA on finished paint? I know my buddy does this and he seems happy with it.

    Is there a combination of both DA and hand sanding that works well?

    Thanks
    Once you use a "good" DA to sand your paint before buffing you won't be hand sanding most of the vehicle any longer. You'll be able to sand about 80 to 90 percent of the vehicle with little effort and the rest is done by hand in areas where the DA can't be used. The paint job will come out as good as if you did all the finish sanding by hand.

    I know some people sand their primer with a DA but I find that it is better to use a block and wet sand using 400, 500 or 600 paper. When guide coating and sanding primer you are usually finishing the leveling process and you can't address this leveling very well with a DA it needs to be block sanded.

  3. #3
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    So Steve, you satisfied now??
    Pete's Ponies
    Mustang RUSToration & Performance

  4. #4
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    One tool for cutting and buffing you cant do without is the airvantage sander with some trizact. Best investment I made yet. Also use it for 400-600 and general scuff and shoot. You have to block bodywork and primer as repairs need to be leveled and straight , you just cant get that from a da.

  5. #5
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    Quote Originally Posted by Len View Post
    Once you use a "good" DA to sand your paint before buffing you won't be hand sanding most of the vehicle any longer. You'll be able to sand about 80 to 90 percent of the vehicle with little effort and the rest is done by hand in areas where the DA can't be used. The paint job will come out as good as if you did all the finish sanding by hand.

    I know some people sand their primer with a DA but I find that it is better to use a block and wet sand using 400, 500 or 600 paper. When guide coating and sanding primer you are usually finishing the leveling process and you can't address this leveling very well with a DA it needs to be block sanded.
    So which DA do you recommend for this type of sanding? I too am also thinking about buying a good DA to do final sanding before paint and also for color sanding. I always block my body work out by hand and guide coat but would like something for the rest of the vehicle so I don't have to spend all day playing in water.

  6. #6
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    Quote Originally Posted by xtremekustomz View Post
    So which DA do you recommend for this type of sanding? I too am also thinking about buying a good DA to do final sanding before paint and also for color sanding. I always block my body work out by hand and guide coat but would like something for the rest of the vehicle so I don't have to spend all day playing in water.
    I use several AirVantage sanders, they are the best I've found for this type of work because of their low profile, good balance and good price.

  7. #7
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    Quote Originally Posted by Len View Post
    I use several AirVantage sanders, they are the best I've found for this type of work because of their low profile, good balance and good price.
    Where will these products ship from? I live in the panhandle of Florida and wondering about shipping times.

  8. #8
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    Quote Originally Posted by xtremekustomz View Post
    Where will these products ship from? I live in the panhandle of Florida and wondering about shipping times.
    AirVantage ships out of S. Calif, it takes 4 business days to reach Florida.

  9. #9
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    Quote Originally Posted by xtremekustomz View Post
    So which DA do you recommend for this type of sanding? I too am also thinking about buying a good DA to do final sanding before paint and also for color sanding. I always block my body work out by hand and guide coat but would like something for the rest of the vehicle so I don't have to spend all day playing in water.

    Some segments of doing body work and paint work need to be done by hand if you want the car to look right when you're done. A DA/orbital palm sander is fine for cutting old paint and feather edging old paint around repair areas. DA/palm sanders are NOT good for block sanding primer and for final sanding primer just prior to paint. Because of the way sanders operate they don't cut primer even/level while sanding, which causes the primer to have an uneven surface that will not be flat. When you paint over that uneven surface it will be visible when you're done. To get a quality custom paint job some things are non negotiable and hand sanding final primer is one of those non negotiable parts of a quality paint job. DA's/palm sanders are NOT good for guidecoat block sanding primer either for the same reason that they don't sand the material flat. Hutchins makes an orbital air file that works good for the initial guidecoat block sanding of primer but the final guidecoat block sanding of primer still needs to be done by hand with a longboard hand sander.

    A palm sander like the Dynabrade/air vantage DO work fine for cutting new clearcoat for buffing (best way to do the job). So then you ask " well, if an orbital palm sander won't sand primer flat then logically it won't sand the clear coat flat either." Which logically it would appear that way but because the sand paper grit for sanding clearcoat is so much finer than sandpaper used for primer that the clearcoat sanding doesn't eat into the clear like coarser paper does into primer. I should say an orbital palm sander will work fine for MOST clear coat sanding for buffing and polishing, not all. If the clear was sprayed on a little heavy or the temperature in the spray area was a little cool then you can end up with "urethane wave" which causes the surface of the clear to be uneven. Sanding urethane wave with a palm sander will NOT make urethane wave flat. That sanding needs to be done by hand with a flat sanding block (and not over 1000 grit sand paper for the initial urethane wave block sanding).


    Kcode - you're working on a '68 Mustang convertible. What engine configuration does your car have ? The K code was the 289 cu.in. 271 hp HiPo used only from '65 through '67 and only in a modified version for the '68 Shelby GT350). In 1968 Ford went to the 302 cu.in. engine with the 'J"code 4 barrel carb. The HiPo engines for '68 were all big blocks (with the exception of the Shelby GT350). Doing a quality restoration on a '68 Mustang convertible the $120 for an air vantage palm sander is chump change. I have owned close to a dozen '64 1/2 to '73 Mustangs and currently own a newer Shelby Mustang.
    Last edited by James M; 04-22-2012 at 11:16 AM.

  10. #10
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    Quote Originally Posted by James M View Post
    Some segments of doing body work and paint work need to be done by hand if you want the car to look right when you're done. A DA/orbital palm sander is fine for cutting old paint and feather edging old paint around repair areas. DA/palm sanders are NOT good for block sanding primer and for final sanding primer just prior to paint. Because of the way sanders operate they don't cut primer even/level while sanding, which causes the primer to have an uneven surface that will not be flat. When you paint over that uneven surface it will be visible when you're done. To get a quality custom paint job some things are non negotiable and hand sanding final primer is one of those non negotiable parts of a quality paint job. DA's/palm sanders are NOT good for guidecoat block sanding primer either for the same reason that they don't sand the material flat. Hutchins makes an orbital air file that works good for the initial guidecoat block sanding of primer but the final guidecoat block sanding of primer still needs to be done by hand with a longboard hand sander.

    A palm sander like the Dynabrade/air vantage DO work fine for cutting new clearcoat for buffing (best way to do the job). So then you ask " well, if an orbital palm sander won't sand primer flat then logically it won't sand the clear coat flat either." Which logically it would appear that way but because the sand paper grit for sanding clearcoat is so much finer than sandpaper used for primer that the clearcoat sanding doesn't eat into the clear like coarser paper does into primer. I should say an orbital palm sander will work fine for MOST clear coat sanding for buffing and polishing, not all. If the clear was sprayed on a little heavy or the temperature in the spray area was a little cool then you can end up with "urethane wave" which causes the surface of the clear to be uneven. Sanding urethane wave with a palm sander will NOT make urethane wave flat. That sanding needs to be done by hand with a flat sanding block (and not over 1000 grit sand paper for the initial urethane wave block sanding).


    Kcode - you're working on a '68 Mustang convertible. What engine configuration does your car have ? The K code was the 289 cu.in. 271 hp HiPo used only from '65 through '67 and only in a modified version or the '68 Shelby GT350). And also doing a quality restoration on a '68 Mustang convertible the $120 for an air vantage palm sander is chump change. I have owned close to a dozen '64 1/2 to '73 Mustangs and currently own a newer Shelby Mustang.
    I thought when I posted "So which DA do you recommend for this type of sanding? I too am also thinking about buying a good DA to do final sanding before paint and also for color sanding. I always block my body work out by hand and guide coat but would like something for the rest of the vehicle so I don't have to spend all day playing in water." I thought I made it clear that I wasn't going to be using this for sanding primer? Sorry for the confusion. Len I ordered the kit you had put together on your website. AVSPEC. Ended up doing the 2 day shipping. Only $7 more so hopefully I will have it soon!

  11. #11
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    Xtremecustomz, My previous post was not directed specifically towards you. It was mainly in answer to Kcodes questions and for those less experienced in the use and applications of air sanders. Where they work well and where they don't work well. My point was that most of us are looking for easier less labor intensive ways of prepping a car for paint and for cut and buffing a new paint job. Air tools work great for some applications but have serious negative side effects for other operations that are better left done by hand sanding.

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