Actually, I'm just trying to solicit some advice on this subject from MARTINSR. I was wondering how to go about color sanding a painted surface in preparation for clear coating. Of particular interest is the sanding techniques themselves. Do you sand back and forth, in a circular motion, in one direction, etc?

MARTIN, good work so far. Keep them coming!!

I remember reading that you should only sand in one direction when wet sanding and you should never go in a circular motion, which I think causes more swirl marks in the process of wet sanding. Martinsr?

Since martinsr hasn't checked in yet, let me stick my nose in.

You said "...color sanding a painted surface in preparation for clearcoating..."

Generally speaking, you would not sand the color coat of a base/clear system prior to spraying the clear. This is especially true when the color is a metallic. It will cause streaks in the metallic. Even with non-metallic colors, any sanding should be restricted to "de-bugging" or "nibbing". If you sand through the top coat of color, it will frequently leave a blotch.

The correct sanding technique is to sand in one direction using a "cross-hatch" pattern. i.e., sand in one direction, then sand over the same area in one direction about 45 degrees from the original direction. As already mentioned, sanding with a circular motion can cause mega swirls.

What color are you painting and what type of paint?

Randy, Vetterella is right on the money with all his info. The big question is Jimmy's, what are you painting with?

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

I was under the impression that metallics were a No-No and solids were OK too block out.. I've seen it done BOTH ways, and now am confused as too the best process. Someone tell me if I am wrong here..

I will be painting a solid color (Black)

First two coats of black, block sand too remove peel, nibs, sags and runs (with 500 grit wet)

another two coats of black barring any major nibs, runs, or sags I'll clear with 2 coats and block out with 500 grit.

Two more coats of clear and final block and polish..

I know it's a bit overkill but I want it too be smooth.

I was under the impression that if you blocked one area too remove a nib or run you would create a distortion or wave in the paint? Am I crazy? http://www.chevelles.com/forum/biggrin.gif (you don't really have too answer that last part http://www.chevelles.com/forum/smile.gif )

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X-Ray View of my Chevelle :D (http://www.normieschevelle.com/sideview.jpg)
Getting Closer (http://www.normieschevelle.com/passfull.jpg)

Make sure you use Meguairs sandpaper only!!! Other sandpapers average 1000 grit with 2000 grit to make 1500 grit paper. I've seen then leave scratches that can't be buffed out. Meguairs uses a consistant grit. Cost a little bit more, but worth every penny!!

Normie, if you're painting a straight black, I strongly suggest a single stage urethane. Clear coat over black looks OK, but park it next to a single stage job and it will look dull! Believe it or not, it will look deeper than a BC/CC black if wet sanded and buffed correctly. As far as I know, there are NO Base coat colors that can be wet sanded. You can spray a single stage urethane on, wet sand it and clear over top of the color, as well as lacquer or a hardened enamel. I would only use clear on a mettalic or pearl essence paint.

Another trick for the super straight black (or any straight color) paint job:

*Put on two coats of single stage urethane.
*Let dry for a few days.
*Block (wet) sand with 600 with a 5 gallon paint stir stick, 6-8" long
*spray another 2 coats single stage urethane
*wet sand with 1,000 then 1,500
*3M Perfect-It steps (See 3M's new product info)

This will make your overall surface look much straighter, flatter and smoother. I promise.
Even though you can block sand the primer before painting, You'll never truley see what the finished surface will like until it's painted, sanded and buffed.
The urethane paint is much harder than the primer/surfacer. I think it's easier to get a truer 'flatter' surafce because you can more easily SEE what's going on than with the primer/surfacer.
Always remember to use an even, steady stroke and don't apply too much pressure when sanding. If you use too much downward force on the block, it will 'follow' the irregular surface instead of removing material from only the high spots. When sanding with 1,000 grit or higher, you can use a swirling motion on the surface when wet sanding, despite what the consensus (books, training videos) says. Make sense?



[This message has been edited by Jimmy P (edited 01-21-2002).]

On my ss urethane I used 3M finishing film(1500) on an electric da dry and the results were great and it didn't take long to do it. You'll still have to do a few spots by hand but not many.

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Elcaminos are special!
I'd rather walk around with a Chevrolet hubcap in my hand than drive a Ford

Ole Paint (http://www.chevelles.com/showroom/olepaint1)

It'll be PPG two part urethane, bc/cc when the time comes, but the question mainly concerns smoothing out the finish if it ends up a little orange peeled. I should have mentioned that.
If I'm understanding you guys right, if the finish comes out glass smooth (in theory, if my paint skills haven't abandoned me), then there's no need to sand?

Thanks guys!

Randy, the theoretical "smooth as glass finish" is probably just that...theoretical. Enough clearcoat should be sprayed to allow for "color sanding" and buffing to remove the inevitable imperfections in the paint job. I like to think I can squirt paint with the best, but there ain't no such thing as a perfect paint job without color sanding and buffing to some extent.

I respectfully disagree with those who advocate single stage over base/clear systems. Single stage paints have their place, but in my opinion their place is not on my "proud to own" vehicle.

<BLOCKQUOTE>quote:</font><HR>Originally posted by vettefella:
Enough clearcoat should be sprayed to allow for "color sanding" and buffing to remove the inevitable imperfections in the paint job.<HR></BLOCKQUOTE>

Did you mean to say, "Enough basecoat..."?

By the way, the last time I painted a car, Dupont Centauri was all the rage! It's been a while.

Color sanding is a term for the 'final' sanding of a paint job.
You didn't answer the question of "what color is it going to be?", so I'll answer this question this way:

You don't sand base coat. Any color, anytime.

You wet sand the clear coat of a BC/CC system or a single stage urethane color.

When you desire a 'slick as glass' finish, you want to apply an extra coat of paint because you are going to remove some paint in the wet-sanding process, whether it's clear coat or single stage paint.

No matter how good of a painter you are, you're still going to have orange peel. I don't care if you're Tony Nancy, you'll still have to wet sand and buff to get a slick paint job. You'll have dirt, you'll have orange peel. Good ole' elbow grease and the right products will bring a good finish.

<BLOCKQUOTE>quote:</font><HR>Originally posted by vettefella:
I respectfully disagree with those who advocate single stage over base/clear systems. Single stage paints have their place, but in my opinion their place is not on my "proud to own" vehicle.<HR></BLOCKQUOTE>

Thats strange, everybody that sees my ss urethane paint(colorsanded of course)asks me how many coats of clear are on it!!

Somebody must like it, I got trophies at 3 of 4 local shows I entered last season!!



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Elcaminos are special!
I'd rather walk around with a Chevrolet hubcap in my hand than drive a Ford

Ole Paint (http://www.chevelles.com/showroom/olepaint1)

Big James, don't go getting all sensitive and defensive now. I respect your opinion even though I disagree with it. I have sprayed many gallons of single stage paint, most of it before base/clear systems came on the market. If I were going to use single stage paint, it would be Imron or similar polyurethane. Even then, the urge to apply Imron clearcoat would be almost irresistible.

If single stage works for you, elicits compliments on your car and contributes to winning trophies, go for it. Who am I to argue with success? I'll stick with base/clear myself and continue to recommend it over single stage.

You dont sand basecoat. The only time you sand the basecoat is to remove a piece of dirt or sag, not to remove the orange peel.

Normally you just apply two coats of clear and some minor sanding and buffing will be ok. But if you are going to really go after it, you would be better off by appling three or four coats of clear. You do this so you wont cut through the clear coat and when you cut through it means that you will be repainting.

Blocking the clear out will remove the orange peel that you see in the base coat. You have to remember that the basecoat is very thin and by the time you get the basecoat applied there is no more then probably 1 mil of thickness. And any orange peel is very minor. As where clearcoat is much thicker and will have a film build of around three to four mils depending on number of coats. With that much film build, blocking the clear will fill any orange peel in the basecoat leaving behind that smooth finish

Oops, I thought I had mentioned the color Jimmy. It's going to be code 67, Castillian Bronze, according to the '71 color charts.

Randy, Your color will have metallics within it, DO NOT sand or buff it at all!! You WILL disorient the metallics with the paper which will cause streaks, blotches, and or different reflections from the "Non-Sanded" areas. Just go heavy on the clear and work the imperfections out from there. If by chance you run or sag the basecoat, sand them out and redo the entire panel with base then clear, otherwise you will run into the aforementioned issues...


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X-Ray View of my Chevelle :D (http://www.normieschevelle.com/sideview.jpg)
Getting Closer (http://www.normieschevelle.com/passfull.jpg)

What we used to do for all the cars to get the wet glass finish.
1.Sand last coat of primer 1000 grit.
2.Seal with dp epoxy primer (WHITE)
3.Spray first two coats stright color
4.Mix clear into stright colors
5.Clear coat car two coats.
6.Wet sand with squeege sponge.
7.Buff and use swirlmark remover
8.wait for first ding and cry http://www.chevelles.com/forum/frown.gif

DAVE, you cut to the chase there. http://www.chevelles.com/forum/smile.gif

But I have to jump in and point out that not all basecoats can have clear integrated in at your discretion. So look at the tech sheets and do what they say. On the sanding primer with 1000, again, that is not recommended in any tech sheet I have seen. And the epoxy sealer, may not be needed, if you used a 2K primer on the complete panel.

Now, please, understand that you have gotten good results from your system, I am just pointing out other ways.

I feel (there is that word again "I") that the epoxy just adds texture that you have to cut and buff out of the clear. If the primer (2K, I prefer urethane) is sanded with 400 to 600 (I use 500, on nonmetallic and 600 on metallic) and basecoated, it will leave you with the minimum of texture.

We are just standing around a shop BSing here http://www.chevelles.com/forum/smile.gif

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

<BLOCKQUOTE>quote:</font><HR>Originally posted by MARTINSR:
We are just standing around a shop BSing here http://www.chevelles.com/forum/smile.gif
<HR></BLOCKQUOTE>

Yes, isn't it cool? http://www.chevelles.com/forum/biggrin.gif

One thing that I've done to reduce the very tedious wet sanding of a (BC/CC) clear coat is to apply two wet coats of clear, let dry over night. Next day, wet sand entire car with 1000 and put one more wet coat of clear on. That last coat of clear goes on SOOO Much smoother than the first final coat, and it really levels out nice. After a couple of days of drying, take th 1000 to it again, then 1500. Thre's much less orange peel to remove.

Randy, that's a nice color. Too bad it's not more popular. I'm sure you'll do it justice!

I'm just a teen here, but my dad is a paint/body man, and I'm speaking from my own experience painting my truck. The only things I recommend sanding prior to clearcoat are model cars http://www.chevelles.com/forum/smile.gif Yeah you can also sand to "debug", but I usually don't cuz of fear of causing a bigger problem. My advice on minimizing bug problems? DON'T PAINT IN THE SUMMER!!! We spray & clear entire car, let dry overnight, then sand with 2000 until there are NO shiny spots whatsoever(be extra careful not to sand thru to metal, I did that alot http://www.chevelles.com/forum/frown.gif). Afterwards, we buff(I hate buffing, the pink buffing compound always gets under cracks/chrome/weatherstripping & if it doesn't get wiped off right away, it will probably never come off) Unfortunely, there will always be some swirls since no one is a perfect wetsander and the buffing pad SPINS, but hey, that's what carwax is for.

Hope this continues, as it's one of the subjects we all need to understand.

Team Members,

Richard, Judy, MAXX2


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'69 Elke (Frame Off); GM HO 350/330-Mildly Ported Vortec Heads-Manley Severe Duty SS 2.02/1.60 Valves, Comp Cams Full Roller Package (Magnum)-Custom Grind CS 3315/3316 HR112-.510/.520 Lift, Edelbrock Air-Gap W/750 Performer Manual Choke-Performer 100 HP NOS, March Pulleys, 4L60 (Non Computer) W/Lokar Shifter, 12 Bolt Posi.