the truth about wetsanding/colorsanding

**k20z3kid** · 07-30-2007, 11:15 AM

first off... what is the difference between wetsanding and colorsanding? are they the same?

ive also heard that wetsanding can lead to clearcoat failure over time. i really want to get my car professionally wetsanded but i dont want to deal with clearcoat failure down the road. is there any truth to this??

ive seen a few cars that were wetsanded and their finish is amazing.

D · 07-30-2007, 11:22 AM

Wet sanding and color sanding are the same. Wet sanding CAN lead to clearcoat failure if done wrong.

**Grimm** · 07-30-2007, 11:50 AM

One reason it is risky is because of the UV protection in the clear. People always talk about how thick the clear is, but don't often mention the fact (or so I've read) that the first third of the clear contains UV protection, so if you go past that you have compromised that protection and the paint will fade.

I've also read that factory paint is much thinner than a custom repaint since a good repaint for a show car will have multiple layers of color and clear. So if your car has a repaint, you may have less to worry about.

**Totoland Mach** · 07-30-2007, 12:33 PM

Typically, wet sanding is used to remove surface defects such as acid rain (which I just completed a job on), deeper scratches than a normal compound could not remove, etc. In reality, you could almost accomplish the same results with compounding as you can with wet sanding...but it would take a long time.

Here's a trunk lid that had acid rain etching. I used 3000 grit, but should have used 2000 or 2500 grit (which I did use on the hood). I always use a paint guage before I start to insure the thickness can support a wet sand operation.

After 3000 grit

After compounding

I didn't take any pics of the hood after 2000 grit, but it was very dull in appearance and required a bunch more work in compounding. Even when I thought I finished, I wasn't even close (under the halogens). I ended up using Optimum Hyper Compound for the last step and the finish is virtually flawless.

If you are contemplating having this done, be sure to check references of the shop doing the work.

Toto

**Malu59RT** · 08-01-2007, 08:03 AM

Toto,

I'm doing a Black 98 Toyota Camry that was neglected since the day it was bought basically. There is faded paint, horrible swirls, etc. I was testing one of the panels w/ compounding (3M) and PO106FF (used w/ Hitachi Rotary), and then a section w/just PO106FF, and another section w/1500 Grit Sand Paper (wet) followed by Compound and PO106FF. I couldn't tell the difference w/any of the different methods used. Is 2000 grit a good idea for that old of a finish, and would it be a bad idea to wet sand the panels before compounding the entire care? Also, after buffing, it looked like there were pin sized bumps in the paint. Is that a characteristic of old paint or possibly a result of the rotary generating more heat? The bumps are what have me contemplating wetsanding the entire car. I have always felt comfortable using the rotary on new cars/finishes, but don't know how far I can "push it" with something this old. Don't worry, this car is going in for a respray, but I'm just trying to save the $2,000 and get the current finish looking good (which all except for the hood, seems possible). Thanks for the advice!

Jason

**Totoland Mach** · 08-01-2007, 08:58 AM

Originally Posted by Malu59RT

Toto,

I'm doing a Black 98 Toyota Camry that was neglected since the day it was bought basically. There is faded paint, horrible swirls, etc. I was testing one of the panels w/ compounding (3M) and PO106FF (used w/ Hitachi Rotary), and then a section w/just PO106FF, and another section w/1500 Grit Sand Paper (wet) followed by Compound and PO106FF. I couldn't tell the difference w/any of the different methods used. Is 2000 grit a good idea for that old of a finish, and would it be a bad idea to wet sand the panels before compounding the entire care? Also, after buffing, it looked like there were pin sized bumps in the paint. Is that a characteristic of old paint or possibly a result of the rotary generating more heat? The bumps are what have me contemplating wetsanding the entire car. I have always felt comfortable using the rotary on new cars/finishes, but don't know how far I can "push it" with something this old. Don't worry, this car is going in for a respray, but I'm just trying to save the $2,000 and get the current finish looking good (which all except for the hood, seems possible). Thanks for the advice!

Jason

Jason: Since the car is going for a re-spray, I'd try 2000 grit (wet) on a test area, then compound with a wool pad to remove sanding marks. The wool generates a lot less heat than a foam pad.

I don't know where you got the pin sized "bumps" from! I doubt it's from heat generated by the rotary (but could be if you used a ton of pressure or worked the area too long). Typically, I wet sand only the areas that need this type of process. For instance, I will spot sand deep scratches, but leave the rest of the body panel alone. The compound will level everything and the results will be what you are seeking.

Are you using a sanding block? If so, try a small area on those "bumps" and see if they level out.

Holler back with a pm or post it here...pics are always helpful.

Toto

**Malu59RT** · 08-01-2007, 10:18 AM

Originally Posted by Totoland Mach

Jason: Since the car is going for a re-spray, I'd try 2000 grit (wet) on a test area, then compound with a wool pad to remove sanding marks. The wool generates a lot less heat than a foam pad.

I don't know where you got the pin sized "bumps" from! I doubt it's from heat generated by the rotary (but could be if you used a ton of pressure or worked the area too long). Typically, I wet sand only the areas that need this type of process. For instance, I will spot sand deep scratches, but leave the rest of the body panel alone. The compound will level everything and the results will be what you are seeking.

Are you using a sanding block? If so, try a small area on those "bumps" and see if they level out.

Holler back with a pm or post it here...pics are always helpful.

Toto

Toto, thanks for the advice!
I was thinking the bumps may be because I was operating at high speeds (2000+ RPM on a Orange Edge pad) or for a long time. I know that is a no-no, but I wanted to see what would happen (I have nothing to lose on this car

). I bought a Fiber blend wool pad from our Ellis Color supply and will try the Menzerna Power Gloss on a side panel and see what the results are (at recommended operating speeds

). Unfortunately, the edge wool pads will have to wait until my next paycheck. I will have some photos to show later on, and if it's not raining when I get home, I'll snap a few and post up. Thanks again!

Jason

**Totoland Mach** · 08-01-2007, 10:48 AM

WOW!....that's some serious RPM with a serious pad. When I use compound, I typically keep my speed around 1,200 rpm on the DeWalt. I might bump it a little for wool, but the objective is to work the compound and not let the speed of the rotary dry out the product.

One good thing is: having a "test" car available, you can try all sorts of combo's. You might want to jot down some notes of product, pad, speed, results. I'm old, so I need to keep notes LOL.

Richard

**FloridaNative** · 08-01-2007, 12:31 PM

nice work as always Toto!

**StephenK** · 08-01-2007, 09:34 PM

Originally Posted by Malu59RT

Toto,

I'm doing a Black 98 Toyota Camry that was neglected since the day it was bought basically. There is faded paint, horrible swirls, etc. I was testing one of the panels w/ compounding (3M) and PO106FF (used w/ Hitachi Rotary), and then a section w/just PO106FF, and another section w/1500 Grit Sand Paper (wet) followed by Compound and PO106FF. I couldn't tell the difference w/any of the different methods used. Is 2000 grit a good idea for that old of a finish, and would it be a bad idea to wet sand the panels before compounding the entire care? Also, after buffing, it looked like there were pin sized bumps in the paint. Is that a characteristic of old paint or possibly a result of the rotary generating more heat? The bumps are what have me contemplating wetsanding the entire car. I have always felt comfortable using the rotary on new cars/finishes, but don't know how far I can "push it" with something this old. Don't worry, this car is going in for a respray, but I'm just trying to save the $2,000 and get the current finish looking good (which all except for the hood, seems possible). Thanks for the advice!

Jason

just curious did you look it over real good sfter sanding and before buffing? those bumps may have been there after the sanding. that would be dirt specks that got trapped in CC during painting. it happens all the time. when sanding make sure the color is uniformed. if there are darker spots thats dirt or low spots. i know i have said this in other post but the painter at the body shop i work at has been teaching me alot. when i started i just buffed out the finish. now i am trusted enough that they let me loose with a DA sander.( thats scary)