I picked my baby up from the body/paint shop today (VIPER BLUE)!!! THe painter told me he would like to wait 2-3 weeks before he COLOR SANDS it. He said this will allow the paint to harden properly. Is this true?

 

Yes, that will be fine.
I usually color sand sooner but some like to wait a little.

 

If he waits 2-3 weeks the paint will be very hard and will take much longer to buff. Today's urethanes will sand and buff very easy in less than 24 hrs. If he is used to doing it this way and is willing to spend the time to do it properly it can be done, but if it was me I would do it now!. Craig :cheers:

 

If he wants to color sand, he still has more painting to do. Normally you would color sand after the first few coats of color...then add a couple more coats of color to finish. If you are doing a 2 stage...you then do the clear and basically do the same thing. The trick is not to use too coarse of a sandpaper. Anything from 600 - 1200 should work fine depending on how good of a job the painter is doing.

 

Has a lot to do with his personnal experiences with whichever clear he used and how much hardener he put in. I have a lot of cut and rub hours under my belt, and most of it was done within 48 hrs. It's his baby. If he wants to wait, let him wait. If you happen to get any shrinkage, it might be better to give it a couple weeks to fully come out, then cut it. Everybody has thier own system.

 

We colorsand and rub out the day after the car comes out of the booth. This prevents the clear from getting too hard, and it sands and buffs a lot easier. We also bake our cars at 160 degrees, so the clear hardens really well in a very short time.

As a note to one of the comments made above... you never colorsand the basecoat prior to clearcoat - only the clearcoat is sanded out once the whole job is done. Also, you would never use 600 grit to colorsand a car - the scratches would never come out. Colorsanding is done to the clearcoat only, and you use 1500 grit wet. It can be done at any time after the clear has hardened, but the longer you wait, the more difficult it is to buff out the sanded finish.

 

A-Listen to Lars, he is the most all around knowledgeable C3/otherwise person I know of! Others will agree.

B-I sprayed my Monte' with PPG Global HS Clear with medium reducer and slow hardener, and didn't cut it until 6mo. later. Rubbed like butter! Stunk like PPG.

 

you never colorsand the basecoat prior to clearcoat - only the clearcoat is sanded out once the whole job is done.

Please pardon my ignorance, but why is it called "Color Sanding" if the clear coat is being sanded :confused:

 

It's leftover terminology from the days of lacquer. Back then, guys actually would sand the color coats - even sand between coats. This is no longer done with the new basecoat/clearcoat systems, but the term "colorsanding" is still used to describe the process of sanding the final coat of clear, and then rubbing it out. You can try to change the term to "clearsanding," but with all the old farts in this painting business, I doubt you'll get anyone to change the term... :D

 

Thanks :)

 

lars,
my paint was put on in 1999 for the 1999 power tour with lots of hardener. when we color sanded it we missed a spot or two. i want to know if i sand those spots today will a clay bar remove the sanding marks?
thanks,
mike

 

Depends if the car was sprayed laquer or bs/cc...laquer you wait 3-4 weeks so that the solvents evaporate. I finished painting my 68 durning the winter months, and when the hot, hot sun hit the car in July, the paint shrunk, had to color sand the whole car again.

 

Michael -
The urethane clears can be colorsanded and buffed out even after they have fully hardened - it just takes a little more time and effort. You can successfully wet sand your clearcoat using 1500 grit wet; some prefer 2000 to reduce the sanding scratches, but the 2000 won't pull out much of the orange peel ripples. Put a few drops of dish soap in the water you're using. Wrap the sandpaper around a short piece of paint stir stick (those thin wooden sticks they give you for free at the paint store) and sand out the area. For rubbing it out, you will need an electric buffer, a 3M white foam pad, and a 3M black foam pad, 3M Rubbing Compound (white) and the 3M Perfect-It II finishing compound (black). With your fully hardened urethane, it's going to take a little effort with the rubbing compound to get a "haze-free" finish. You can put a lot of pressure and effort into the rubbing with no fear of burning through as long as you stay away from the edges. Keep using the white rubbing compound until all "haze" is gone and there are no sanding scratches. only then should you switch over to the finishing glaze to get your mirror finish.

When the clear is younger and softer, you don't need to put by far as much time and pressure into the rub-out process. But it will still rub out after full cure.

 

Clears are not the only paints that can be color sanded.
Single stage catilized non metalic colors can be sanded and buffed to a mirror finish. In fact I think some colors look better without clearcoat. Black for example... :cheers:

 

why thank you mr. lars, you just caused me more work than it is worth. the spot was missed the first time because it is on the hood where the L82 emblem goes. i did not use the buffer there. i had a 14 year old kid helping me and he must have missed it too. HOW MANY OF YOU GUYS WOULD LET A 14 YEAR OLD KID THAT NEVER WET SANDED A CAR BEFORE NEAR YOUR FRESH PAINT WITH SAND PAPER? i have been wanting a L88 hood so i might just get one.
thanks,
mike

ps the kid is now 17 and does an awesome job on both paint &body and upholstery (sp) :smash:


[Modified by Michael Tucker, 2:00 PM 7/20/2002]

 

Yellow -
Good point - you're absolutely right. Catalyzed single-stage paints (non-metallics) wet sand and buff out to an absolute mirror finish. For the money, they're really a good value. The only drawback I've noticed is that at our high altutude out here, the clear-coated paints tend to hold up a little better to the excessive UV.

Michael -
I've been told I'm really good at making work for people.... But it sounds like all you need to do is a little buffing since the areas have already been sanded. You should be able to pop the emblems off and buff the areas out nicely. But a new hood sounds like a great idea...! :yesnod:

 

I'm a firm believer in color sanding the color coat of a two stage polyurethane paint job. I'll use up half a gallon on the first color coats and then wait about four or five hours for the paint to dry. Next comes the wetsanding of the color with 1200 or 1500 grit paper. This gives me an opportunity to see if there are imperfections and if there are....to fix them. I'll sand out all orange peel and if the car was properly prepared (by me), there won't be any spots that get sanded through to show primer. Once the car is color sanded...I finish the color coat and then almost immediately begin the clear coat process. I do the same thing......use half the clear coat and then wait and sand again. Then....finish the clear coat and wait about a month to rub and polish. If I had an oven....the process would not be the same.....but I don't. This process works for me but it's a lot of work and takes some extra time. Allowing the paint to fully dry for a month helps minimize any shrinkage...but you still get some.