Wet-sanding fresh paint - need tips

[jarred767]

So, I’ve got a customer that I will be working for in a couple weeks doing a complete wet-sand, compound and polish on his freshly painted truck (will actually be close to three months by the time I get my hands on it). I am very new to wet-sanding (customer knows this and said he was fine if I used his truck as a "guinea pig") as I have just done some defect removal on minor areas and some headlight restoration via damp sanding. I’ve done a couple little test spots via true wet-sanding by hand, but nothing major.

The Truck: 1987 Silver Toyota Pickup The owner completely stripped the old paint, put two layers of primer, a layer of base coat, and a pretty thick (his words) layer of clear on the truck. After talking with me about a month ago, he decided he was going to do the wet-sanding and polishing himself so he did the hood and passenger front fender with 1000 grit, then 2000 grit, then polished it up. He also started doing some other rough sanding on the tailgate and passenger side with 1000 grit, but then threw in the towel and decided to hire me.

My Plan: I want to be as ready as possible for this job in a couple weeks and thought I’d see if anyone had any thoughts, advice, or tips that they could share. This will be a huge learning experience for me (and the amount I’m charging him is evidence of this, but I’m just chalking it up as R&D) and I want to try and learn as much as possible through the entire process leading up to it, and the two or three days of sanding, compounding, and polishing that it will take.

My first and biggest question is to make sure that I have everything I need and that there isn’t anything that I’m forgetting or overlooking. Also, since I’ve never done this much wet-sanding before, it’s tough for me to gauge how many sanding discs and everything that I will need/go through.

What I’ve got so far:
3” backing plates S3BP and the W63 which I have an adapter to use with the DA
3” foam interface pad
3” 1000, 1500, and 3000 grit Meguiars sanding discs
6” backing plate S6BP
6” foam interface pad
6” 1500 and 3000 grit Meguiars sanding discs.

I've also got all the compounding and polishing stuff that I'll need.

I know I’ll probably need a sanding block maybe the 3” circular hand pad and some actual Unigrit sandpaper, but I wasn’t sure if I really needed anything coarser than 1000 grit, and how many levels I should plan on doing (like 1000 to 1500 to 3000?)

Thanks for taking some time read this and share any thoughts or suggestions that you might have.

Here are some pictures of the truck, lighting was horrible and I'm used to capturing swirls not roughness in the clear, but these are the best I got:
Hood after his sanding and polishing (the paint looked decently flat, but there are a ton of swirls that will need some M105 for sure and possibly some more wetsanding)


He started doing some sanding on this passenger side panel:




And this is what the majority of the truck looks like, (and what everything else was like when he finished spraying the clear)




Tried some different lighting on these last two to help show the texture of the clear on the front drivers side fender




Thanks in advance for any help or tips that anyone has.

[scapegoat]

Re: Wet-sanding fresh paint - need tips

Start out with 1500 and work your way to 2500 . Watch your edges . You can sand or buff through them . Then you will need to repaint . The real problem here is you don't know how many coats of clear where applied . Usually 2 to 4 coats are sprayed . it depends on the paint system and the painter . Less coats of clear , will give you a better chance of going through it . Thus needing a re spray . Try to find out how many coats of clear before you start . It will help guide you . Good luck !

[Stephan]

Re: Wet-sanding fresh paint - need tips

Hard to tell but paint looks like top left corner in photo below. (Wrinkling according to Sherwin Williams Trbl Shoot Guide):

WRINKLING

(Crinkling, Puckering, Shriveling)The surface of the paint contains irregular grooves or ridges resembling the skin of a prune.____________________________________________________________________________

CAUSE_____________________________________________________

(A) Excessive film thickness or "piling on" of heavy wet coats.(B) Placing a newly painted finish in hot sun too soon after spraying.(C) Using lacquer thinner to reduce synthetic enamel.(D) Spraying in extreme hot, humid weather conditions.(E) Under reduced and/or too fast evaporating thinner/reducer for spray conditions.(F) Air pressure too low during spray application.(G) Force drying of air-dry enamels without the recommended additives.

REPAIR______________________________________________

(1) If defects are minor; Sand the top surface smooth, allow to cure and refinish.(2) If defects are severe; Remove the affected area and refinish.

PREVENTION______________________________________________

(A) Avoid excessive film thickness and heavy coats.

Always allow for sufficient flash times.

(B) Keep newly painted finish away from direct sunlight until finish has dried/cured.(C) Use reducer that is specifically recommended for the topcoat.(D) Use the recommended reducer, additive, and/or retarder when spraying in hot humidweather.(E) Select recommend thinner/reducer based on temperature, humidity, air movement, and sizeof repair.(F) Use the proper reduction ratio and spray at recommended air pressure.(G) Select the recommended additives to suit drying conditions.

Follow force dry temperatures

and time recommendations.

[jarred767]

The real problem here is you don't know how many coats of clear where applied . Usually 2 to 4 coats are sprayed . it depends on the paint system and the painter . Less coats of clear , will give you a better chance of going through it . Thus needing a re spray . Try to find out how many coats of clear before you start . It will help guide you . Good luck !

Thanks for the tips, I'll be sure to tape off sharp edges and be extra careful around them. As for the paint, I forgot to add that in the original post, it was two heavier coats of Summit Racing acrylic urethane clear coat

[Evan.J]

Re: Wet-sanding fresh paint - need tips

Taping off all edges and body line is a great idea.

[Detailing by M]

Re: Wet-sanding fresh paint - need tips

Just be carefully and keep thinking every step of the way.
One panel will be different from the next or even the same panel can act differently.
As you go up in grit make sure you've sanded out the last sanding marks.
A good way to do this is to sand in one direction and another with the preceding grit. Kinda hard when using a DA but take your time one your first panel and you should understand how the paint reacts.
it's going to take about 20 hrs to do a truck so prepare for a few days on it or longer so you can learn.

[scapegoat]

Re: Wet-sanding fresh paint - need tips

You don't have wrinkling , you have a really ( dry ) paint job . Cause of this , spray gun held to far away from surface , used wrong reducer for temp , or didn't get the fumes out of the area fast enough . In one of your photos after someone sanded it you can see the problem is gone . Just needs to buffed then . If you would have wrinkling you would need a repaint . Sometimes a scuff and shoot , sometimes strip it , then spray . Just take your time and watch those edges !

[Detailing by M]

Re: Wet-sanding fresh paint - need tips

You don't have wrinkling , you have a really ( dry ) paint job . Cause of this , spray gun held to far away from surface , used wrong reducer for temp , or didn't get the fumes out of the area fast enough . In one of your photos after someone sanded it you can see the problem is gone . Just needs to buffed then . If you would have wrinkling you would need a repaint . Sometimes a scuff and shoot , sometimes strip it , then spray . Just take your time and watch those edges !

Good point.

Over at Autogeek.net
Mike Phillips just knocked down ORANGE PEAL with a pad and a DA!
The pads are Denim and Velvet! $4 each!
I'm getting some!

With this new pad you don't have to sand, buff or polish!!!!!!!!
Just polish and your done!
Sounds to good to be true but he used it and I'm waiting with baited breath for mine.

[jarred767]

Thanks again for all the added advice guys, it has been helpful. For anyone reading this in the future, there is also an amazing article over at Autogeek that Mike Phillips wrote on wet sanding and damp sanding http://www.autogeekonline.net/forum/wet-sanding-cutting-buffing/25915-dampsanding-tools-tips-techniques-mike-phillips.html
Regarding the "wrinkling" up close it doesn't look like that pic, more just like extreme orange peel, so it should be able to just be sanded down.

So, a couple of quick follow up questions. I know all paint is different and will react differently, but is it realistic to think I can knock down all the orange peel with 1500 and my DA (I also have the little 3" 1000 grit discs if I need a little extra in some areas). Should this be adequate, or should I have sheets as well that I've soaked before starting. I'd like to do it all by DA, but just curious on what others think.

Also, how long should I expect each 6" disc to last? How many will I realistically "go through" on a little pickup truck? Thanks again guys.

[scapegoat]

Re: Wet-sanding fresh paint - need tips

Yes you may use a DA and 1500 for your first cut . Word of caution , edges , I said this a hundred times . Also with a DA watch out for dirt or the clear balling up under the sand paper . It will really leave some nasty scratches in your clear . I would then hand / wet sand with 2000 , followed by 2500 . Remember you have only 2 coats of clear on it . Don't go crazy , less is more .

[jarred767]

Anyone have any thoughts on durability of the 6" discs??? I don't need specific exacts, just approximations so I can be sure to have enough.

I'll probably be using a combination of the 1500 grit sanding and finishing along with the 3000 grit sanding. Thanks in advance

[Michael Stoops]

Re: Wet-sanding fresh paint - need tips

The finer the grit, the longer a disc will last. You may go through 4x as many 1500 grit finishing discs as you will 3000 grit finishing discs, and you can usually finish off a full sized car with 3 or 4 3000 grit finishing discs.

[jarred767]

The finer the grit, the longer a disc will last. You may go through 4x as many 1500 grit finishing discs as you will 3000 grit finishing discs, and you can usually finish off a full sized car with 3 or 4 3000 grit finishing discs.

Thanks for replying Mike, I really appreciate it, so for a car (and this is a small truck so similar surface area) I should have about 5 3000 grit finishing discs and probably 15-20 1500 grit finishing discs just to be safe? Plus some 3" discs and paper and a sanding block for tighter areas.

[Michael Stoops]

Re: Wet-sanding fresh paint - need tips

That should take care of it, yes.

[jarred767]

Thank you so much to everyone for the help so far. It is really appreciated and this project will go smoother because of this help.

One last quick question before I order all my stuff. If I'm using the 6" foam interface pad with my DA, will I essentially be getting the same results from the 1500 grit sanding discs vs the 1500 grit finishing discs since the interface pad will be giving some cushion to both? It seems much more economical to go with the sanding discs over the finishing discs ($1.89 each vs $4.49 each on ADS), and of course follow it up with the 3000 grit finishing discs, but am I missing something? Any clarification or reasoning why the 1500 finishing discs would be advantageous when using the interface pad would be greatly appreciated. Thanks!!