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-   -   minor ? - wet sanding vs color sanding (http://www.hotrodders.com/forum/minor-wet-sanding-vs-color-sanding-128583.html)

cboy 11-20-2007 04:08 PM

minor ? - wet sanding vs color sanding
 
After spending the day reading tons of posts and articles on painting and paint prep I'm a bit confused on one issue. I read references to "color sanding" the clear coat and "wet sanding" the clear coat as if they were two different things. Are they different...and why?

kenseth17 11-20-2007 05:02 PM

No. The term colorsanding is probably left over from the old days of lacquer and single stage finishes. Base clear is what is often used today, so you aren't really sanding color (at least you don't want to be, that means you went through, and have some repainting to do). Today some people sand the clear dry with a orbital palm sander and special pad as well, years ago pretty much everyone sanded wet by hand (the way I still do it). They also have water bug sanders to sand by machine wet. A shop I worked at got one and saved my arms, but my shoes ended up even wetter then normal doing it that way. :D

Arrowhead 11-20-2007 05:40 PM

One word of caution, the solvents in the base coat will lift the clear. Probably makes no sense, right?

Lets say you've layed down your base coat and then you clear it. You go to town wetsanding the clear to remove the orange peel and accidently go though the clear and base coat into the primer. No problem, touch up with some base coat and re clear, right? Well, the base coat will act like paint remover on the fairly fresh clear coat and wrinkle it up.

302 Z28 11-20-2007 05:58 PM

Quote:

Originally Posted by Arrowhead
Well, the base coat will act like paint remover on the fairly fresh clear coat and wrinkle it up.

I can attest to that, happened to me. Only way I got away with it was to apply several dust coats of base.

Vince

stitcher_guy 11-20-2007 09:08 PM

What about sanding on a single stage paint, like acrylic urethane? I repainted a mirror on a Buick a couple weeks ago. It had some orange peel, but I didn't do any color sanding because of the metallic in the paint. I didn't want to flatten the metallic.

Could I have color sanded? What if I use a straight color with no metallic? I'm getting ready to paint my VW Beetle, and don't know if I want to use base clear or AU. Any input??

Russell

Centerline 11-20-2007 09:59 PM

I've done both SS and BC/CC and prefer the BC/CC by far. I'm also one of those guys who color sands with an air orbital sander and 2000 grit paper (that stuff feels just like regular paper by the way). The biggest reason is that I can color sand a complete car in about two hours instead of taking a day or more by hand. Investing in an AirVantage sander was one of the best things I ever did.

The biggest thing to remember about a BC/CC paint job is to make sure you get enough clear on the car so that you DON'T sand through to the base when removing orange peel. Like has been said already, fixing a sand through is a big job and usually results in re-basing and clearing the entire panel rather than just touching up a small spot. The same thing holds true for SS. You need to have enough paint on the car that you don't sand through to the primer when removing peel, although in most cases a sand through with SS can be spot repaired.

cboy 11-21-2007 06:53 AM

Quote:

Originally Posted by Centerline
... I'm also one of those guys who color sands with an air orbital sander and 2000 grit paper...

Just so I'm clear (so to speak). When painting BC/CC your reference to "color sand" would be sanding the clear coat NOT the base coat?

Arrowhead 11-21-2007 07:52 AM

Correct, you just need to "colorsand" the clear. The only sanding you would need to do to the base coat is if there are problems, or you let it dry past the manufacturers reccomended recoating window.

Centerline 11-21-2007 02:27 PM

Quote:

Originally Posted by cboy
Just so I'm clear (so to speak). When painting BC/CC your reference to "color sand" would be sanding the clear coat NOT the base coat?

Correct. I try never to touch the base at all. Unless I have some sort of a problem, then I'll fix it and respray the panel with base before continuing.

CDJr 11-21-2007 03:14 PM

To add to whats been said, you definitely dont wanna sand on any that have metallics, pearls, etc, and if you MUST, then you also need to lay another coat. If you use an activator with basecoat, in certain circumstances it can be a lifesaver in case of any accidental sand-thrus, as it may be able to keep you from having to redo an entire panel.

Russell, you are correct, sanding on a solid color with no metallic would be fine. However, Id still prefer BC/CC over SS. This is just my 1 cents worth...

cboy 11-21-2007 05:14 PM

Thanks to all for comments. I'm feeling a bit more at ease about tackling this (first time for BC/CC AND pearl).

t66turbocobra 11-22-2007 07:15 PM

I dont know if this was mentioned yet. But I almost never wetsand. I sand with a finishing D/A that has a interface pad on it. I start off with 3M Hook-it finishing film the slowly work up to 3000 grit 3M Trizact Hook-it II Foam pads. After any imperfection are removed; I follow up with bringing the finishing back to a mirror shine. I start off with a extra cut fine rubbing compound with a foam pad. Then I set up to a swirl mark remover/polish on a soft black foam pad. After the paint is swirl free with a nice shine. I finish off using a high quality non silicon hand glaze. To me wet sand leaves scratches and takes to long. The process of using a DA is much faster and leaves a smoother finish.

cboy 11-22-2007 09:03 PM

Quote:

Originally Posted by t66turbocobra
I sand with a finishing D/A that has a interface pad on it.

What is an interface pad? I have a number of different pads for my D/A (rated by color for the different "grits" of compound or polish one would use) and also pads made of different materials (foam and wool) but I don't recall any being referred to as an interface pad.

Also, do you use, or would you recommend, this same procedure even in the event of fairly substantial orange peel in the clear coat? I would assume you take some sort of special care around any edges or sharp curves to prevent the D/A from burning through. Could you talk about that as well?

t66turbocobra 11-22-2007 09:20 PM

Quote:

Originally Posted by cboy
What is an interface pad? I have a number of different pads for my D/A (rated by color for the different "grits" of compound or polish one would use) and also pads made of different materials (foam and wool) but I don't recall any being referred to as an interface pad.

Also, do you use, or would you recommend, this same procedure even in the event of fairly substantial orange peel in the clear coat? I would assume you take some sort of special care around any edges or sharp curves to prevent the D/A from burning through. Could you talk about that as well?

A interface pad is about a 1/2 inch thick pad that is placed between the sand paper and D/A. This pad is for sanding not buffing. The pad is there to reduce the possibility of burning through the paint. I personaly stay about a 1/4 inch from any edges when using the 6 inch D/A. I follow up with a smaller 3 inch D/A using the same method that i used with the 6 inch. 3M and Norton make all materials I mentioned before in 3 and 6 inch.

When it comes to sanding out orange peel, it depends on how bad the orange peel is. If its a small spot or if I know i can knock it out quick I'll go ahead and sand it out using the process Im writing about. If the orange peel is to bad. I would just go back over the the clear with 600 grit to scuff it back up and shot another layer of clear. I know it sounds crazy, but from personal experince it so much quicker and more then likely you will sand into the base trying to get the orange peel out. I hope this helps some. If not. ask

t66turbocobra 11-22-2007 09:21 PM

Here is the link to 3m for the interface pad. http://solutions.3m.com/wps/portal/3...beQTM5DLXZ75gl


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