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View Full Version : How To: Wetsanding paint touchups.


picus
April 21st, 2006, 09:25 AM
Hey folks - I've posted this on a couple detailing forums but I think it might be worthwhile here too. Cheers. (edit: PC = Porter Cable DA polisher http://store.bettercarcare.com/pc-7424.html)

Remember, everything in this post is my opinion only. There ARE other ways to do this and lots of different products you can use. Also, remember that trying this is at your own risk. Damaging a paint via PC is hard, but with sandpaper it's very easy. So let's start:

What you'll need:

1) Matched paint. A jar is best, a pen is ok. You can get it at a dealer or local automotive store.

2) A fine paint brush (medium bristles, fine tip), and/or a plastic toothpick.

3) Rubbing alcohol, some automotive wash soap, access to water.

4) Some sandpaper. I like Meg's unigrit 2000 and 3000. Non-unigrit and less than 2k at your own risk.

5) A sanding block. Both soft and hard work. I prefer soft as it is easier to manipulate and can go around curves.

http://gtaindetail.com/fp/blackg35sedan/megsuni3000.jpg

http://gtaindetail.com/fp/blackg35sedan/sandingblock.jpg

6) Polishes. What kind of polishes will depend on if you're using a PC or not. I will be using a PC, but will include by-hand instructions.

Onward.

First make sure the car has been washed, what wash you use is up to you. How you wash it is also up to you but remember, two buckets and a quality mitt (or 3).

Second, make sure the area you're repairing is clean. By clean I mean no sealants, waxes, nothing. To do this you'll need to a) use a cleaner polish or b) (my choice), wipe with ISA:water. What's that? It's rubbing alcohol (the regular 70% kind) mixed 50:50 in a spray bottle with water. Spray the area thoroughly and wipe. Do this twice. You want *no* dirt, wax, anything in the chip.

Alright, so filling in the chip/scratch. Two ways to do this, first I will go with my choice for chips and that's using a plastic toothpick. Before I go on, there are good instructions on how to do this here: http://autopia-carcare.com/inf-paint-polish-clinic.html. I basically follow the same process. Dip the toothpick into the paint about half way up, then touch the tip of the pick to the center of the chip and capillary action will pull the paint into the chip. It will take a couple passes to level it out so let the paint dry at least 4 hours in between and be patient.

The other way is good too, but less accurate. It's good for scratches that are larger than chips and would take too long to fill in via the toothpick method. Put a little paint on to your brush (very little, immerse maybe 1/4 of the brushes tip), and touch the tip to the center of the scratch. You'll see the paint pull into the scratch. Depending on the size begin to move the brush in one direction through the scratch. Repeat this every 4 hours until you're level.

Whether or not you add a layer of clear is up to you. I normally do as I find it makes the paint match better after sanding/polishing.

Alright, so now you have a blob, sort of like this:

http://gtaindetail.com/fp/blackg35sedan/blobb2.jpg

Or in the case of a scratch, like this:

http://gtaindetail.com/fp/blackg35sedan/readfendb2.jpg

No go have a beer and wait until tomorrow (or better yet, two days from now, then come back). This is important - let the paint dry or odds are you'll pop the chip right out when sanding.

The night before you said put the sandpaper in some water and let is soak overnight.

Alright so sanding time. This is the tricky part so go slow and be patient. Make sure the paper is right on the block (you'll probably have to cut it) and then spray the blob with a mixture of water and some soap (just mix some in a spray bottle), spray liberally and then start sanding. I like to sand against the blob, so the figure out which way the blob is longer and sand the opposite way. Sand very light, apply almost no pressure and try to keep the block flat. Also, sand in one direction, not back and forth. It's counter-intuitive but it helps. So swipe one way, lift, then repeat. Check your work often by wiping away with a mf towel. Before you do spray the area liberally again with the soapy water to lift up any particulates. You're done when the blob is level with the paint (as in, you can not feel it by running your finger over it gently). You'll have something that looks like this:

http://gtaindetail.com/fp/blackg35sedan/rearfendb1.jpg

And you'll probably be pretty nervous, but you're ok. As long as you were patient and sanded lightly you will not have removed more than a fraction of your clear. Just be careful!

Now clean the area with your ISA:water and get ready to polish.

If you're polishing by hand I hope you used uni-grit and 2500+ paper, because otherwise you're going to be really sweaty when this is over. Assuming you did grab your polish of choice. Products I like by hand are:

Sonus SFX-2
Poorboys SSR2.5
Menzerna Intensive Polish
Meg's ScratchX

I'd start with something like Sonus SFX-2 or PB's 2.5 on a cotton applicator. Apply a dab about the size of a quarter then start to rub. You *will* need to apply pressure and move quickly. You're trying to generate heat. Repeat until the marring is gone, or 90% gone then use ScratchX to clean it up. You should have nice smooth paint, and the chip should be 100% gone. Remember, by hand is tough work and the results are often difficult to achieve - I always recommend investing in a PC, but that's just me.

By PC I like the same products (minus the ScratchX and add Optimum Compound), or if you're in a hurry SFX-1, Menzerna PG, or PB's SSR3. I like to take my time and don't normally advocate using products that are over-kill in the name of speed - as such I usually use SFX-2 or Optimum Compound via an orange LC pad (medium abrasive), and just polish as normal. Apply a couple dabs to the pad, work in at speed 3 for 20-30 seconds and apply enough pressure than the PC almost bogs down, then kick it to 6 and apply the same pressure until the polish flashes. One or two passes will take out 2500-3000 grit marks easily.

Now, if you have some marring that isn't coming out you can do one of two things. One, use a stronger combo of pad+polish, or two, sand again with a higher grit then polish. I normally do option two but Iam getting pretty decent at sanding. If you're nervous about it I'd stick with option 1.

When you're done clean again with isa:water then apply the wax/sealant on your choice and call it a day. Here are the afters of the chips/scratches I posted above.

The blob was in the circle.
http://gtaindetail.com/fp/blackg35sedan/after11.jpg

Scratch was in the circle.
http://gtaindetail.com/fp/blackg35sedan/rearfenda1.jpg
http://gtaindetail.com/fp/blackg35sedan/rearfenda2.jpg

Now if this is too scary, you can use products like Langka (www.langka.com (http://www.langka.com)) or top of the lines touch up magic - they work too, although in my experience not quite as well.

Cheers.

http://gtaindetail.com/pics/03g35041606/photo5.jpghttp://gtaindetail.com/pics/03g35041606/photo9.jpg

Aitch
April 21st, 2006, 10:42 AM
When you say PC you mean a Porter-Cable right?

Nice write-up; not sure if all the pictures are showing up though.

picus
April 21st, 2006, 12:02 PM
When you say PC you mean a Porter-Cable right?

Nice write-up; not sure if all the pictures are showing up though.

Yep - sorry, should have been more specific. I mean a Porter Cable random orbit/dual action polisher.

Which pics aren't showing up? The host site may have had a hiccup but it looks ok now.

Johnny5
April 21st, 2006, 12:22 PM
WARNING WARNING WARNING WARNING WARNING WARNING

Guys, I have done this to my hood and rear bumper. I was taught by a guy that does it for Ontario Ferrari after they have come from repairs and charges over 4000/car.

THIS IS NOT SOMETHING TO TRY AS A NOVICE ALONE! THE CHANCE FOR RUINING YOUR PAINT IS VERY HIGH! ANY PREVIOUS BODY WORK SHOULD NOT BE ATTEMPTED UNLESS YOU CAN VERIFY SUFFICIENT CLEAR COAT TO TAKE THE SANDING.

I thought about posting this too however, wetsanding is a very skilled job. I would only reccomend someone do this under supervision of a trained expert. It also will take a few days to do.

The supplies bought from CT are not of the quality you should use. Source from a professional body shop supplier the proper stages of glazes. Approx 200 in polishes. Also I high speed buffer and water for sure or you could burn through your paint.


I would Higliy reccomend getting a proper high speed buff and polish to remove small circles before attempting this. Great write up, just big warnings for the guys.

Side note: I will be hosting a detailing meet soon.

picus
April 21st, 2006, 12:32 PM
I agree, this is a job that takes practice, skill, and experience with automotive paint - I posted it because I'm under the impression that a lot of the folks here do have experience with detailing and of course I'm happy to answer any questions anyone has about this.

For anyone interested in wetsanding entire panels to remove orange peel or large defects, definitely contact a professional.

Cheers.

dead_cactus
April 21st, 2006, 01:23 PM
Side note: I will be hosting a detailing meet soon.

Awesome, I'm hoping to pick up a PC but want to know how to use it properly first (I dont want to ***k up my paint).

A bit off topic but does anyone know of any schools (college's, etc.) that offer some sort of automotive detailing classes? I know the Meguiars offers classes but they arent availalbe in Canada :( :(

I know the basics but there is still alot of room for improvement.

SodiumSulfate
April 24th, 2006, 07:59 AM
Awesome HOW-TO! Thanks!

I was wondering, how long did it take you to finish off that small spot? I've got a few paint chips I want to try to get rid of.

picus
April 24th, 2006, 08:27 AM
Well I let the paint dry overnight, but if you just include working time I'd say about 30 minutes. Just clean the chip, touch it up, let dry (the long part), wetsand and polish. The actual time it takes to touchup, wetsand, and polish a small spot like that is pretty low. Just remember if you're doing multiples you can touch them all up at the same time (obviously :) ), but wetsand them one at a time then polish them out. It takes a bit longer but it's a lot safer.

SodiumSulfate
April 24th, 2006, 09:39 AM
Nice!

I'm looking at buying a used 2002 Mazda Protege 5...it's seen some rough days so it's got a bunch of paint chips and a couple of places which look like it has some surface rust (the yellow colour seems to be reddish, but not bubbled). I was hoping to scrape off some of the rust and fix up the paint chips...and this tutorial is just what I needed!

Is there a similar tutorial on how to use Bondo? I think my potential new ride might need a little bit of bondo work underneath the rear running board. I was hoping to grind off the surface rust and touch it up.

picus
April 24th, 2006, 12:55 PM
I'm not sure if there is a bondo tutorial anywhere. I haven't used bondo in quite awhile so unfortauntely I can't help you there. I do use 3M's super red putty and it works really well, but it's for pretty small jobs. It's incredibly easy to use - just spread and level with a plastic flexible trowel, sand away excess after an hour, and you're good to paint. Oh, make sure to use some rust converter on that rust even after you've sanded it away. I made that mistake once :/ It's a gross product, but it works.

SodiumSulfate
April 24th, 2006, 02:19 PM
3M super red putty...that sounds like what I should be using. Is that the actual name? I'm looking at a stone chip that outgrew itself, now i've got to do some amputating :(

picus
April 24th, 2006, 03:34 PM
Yep, that's the actual name. :)

http://products3.3m.com/catalog/us/en001/auto_marine_aero/automotive_aftermarket/node_GSWR4PGCY5gs/root_GST1T4S9TCgv/vroot_GSLPLPKL4Xge/bgel_F77FRHLBRQbl/gvel_VBF19DZVHXgl/theme_us_aad_3_0/command_AbcPageHandler/output_html

Like I said, it's for small areas only - but for those it's great. Very easy to manipulate, nice long working time, dries in about an hour, sands down really easily and won't shrink.

.miKEy.
May 5th, 2006, 12:12 AM
3m super red putty? never seen that... can you pick it up at crappy tire or if not where?

picus
May 5th, 2006, 12:11 PM
I ordered it online from 3M. I have not seen it at CT. I think you *might* be able to get it at Autozone, but don't quote me on that. Cheers.

Yellow666
May 9th, 2006, 10:23 PM
Picus, just have a few questions:


Whether or not you add a layer of clear is up to you. I normally do as I find it makes the paint match better after sanding/polishing.

What kind of clear coat are you using here, and any idea where we can get them locally/online?

And can you also share where you get the Megular's unigrit 2000 and 3000 sand paper?

Thanks for the great write-up

picus
May 10th, 2006, 07:49 AM
I use two kinds of clear. Either the stuff on the back of the paint pens you get from dealerships, or a jar of duplicolor from Canadian Tire - either works.

The only place I know of to get unigirt is Meg's Online Canada (http://meguiarscanada.com/products.asp?type=default&sub2catid=69), it's pricey but you get 25 sheets and, imo, it's worth it to do it safely. They also have 3000 grit blocks if you plan to do a lot of sanding.

Cheers.

kornstar369
December 2nd, 2006, 12:23 AM
i think im gonna have to give this a shot...thanks for the info

Spyder01
December 2nd, 2006, 12:27 AM
i think im gonna have to give this a shot...thanks for the info

I don't think this is something you want to 'try' yourself. Maybe you should contact picus instead and have him do it cause this job really really require a professional

picus
December 2nd, 2006, 07:14 PM
If you're familar with a PC odds are you can safely wetsand. I would not recommend this as a "first time detailing" activity. :)

Johnny5
December 6th, 2006, 11:25 AM
I just reiterate my warning on the first page. Seriously, this takes a long time to learn right.


There is a reason why my used Jags get charged 1200 per car to get this done. As far as places that can do this work if you want that wet show car look I can make recomendations.

picus
December 18th, 2006, 07:13 PM
As I mentioned, if you intend to color-sand an entire car that is something I absolutely recommend you look for a professional to attempt. I assume you're not charging $1200 to wetsand a single touchup; you're color-sanding entire panels, right?

This how-to was posted because this board has a number of users who are familar with at least the basics of detailing (so using a porter cable correctly). If you can use a PC correctly, use a quality block (3k unigrit), and are patient, this is not more difficult than most of the "how to" mods on this board.

Cheers.