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View Full Version : How To: Wetsand & Polish



picus
04-19-2006, 07:21 PM
Hey guys - I posted this at a detailing forum and one of your members mentioned that I should post it here. If anyone has any questions/comments just let me know!

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Alright guys - so probably the #1 question I get here and at Autopia is \\\"how do I repair a rock chip or deep scratch\\\", well here is how I do it. 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 tight 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 figure out which way the blob is longer and sand the opposite way. Sand very lightly, 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 crap yourself, 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. For example, in the second pic above someone might say \\\"holy smokes, you\\\'re down to the metal!\\\", but I\\\'m not. As a matter of fact I took a paint reading before and after and I was down less than 0.02 microns. That\\\'s under 2% of my total clear thickness. 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 go ahead and 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.

By PC I like the same products (minus the ScratchX), or if you\\\'re in a hurry SFX-1, Menzerna PG, or PB\\\'s SSR3. I usually use SFX-2 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 like option 2 because it\\\'s quicker and works better, but if you\\\'re nervous about that try option 1 first.

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/dyi/rearfenda1.jpg
http://gtaindetail.com/dyi/rearfenda2.jpg

Questions, comments? You know where to find me. Some pics for your enjoyment!

http://gtaindetail.com/fp/blackg35sedan/after16.jpg
http://gtaindetail.com/fp/blackg35sedan/after9.jpg
http://gtaindetail.com/fp/blackg35sedan/after13.jpg

S.F.W.
04-19-2006, 07:57 PM
Solid write up. Thank you for the contribution.

Xenon
04-19-2006, 08:28 PM
WOW... that\'s a faboulous write up, and the final result: No one would have ever known about the scratches.

LOL, now I just need to gather the confidence to try this :sarc

Dave_Mazda3
04-19-2006, 08:50 PM
Where\'d you pick up the by-hand polish?

picus
04-19-2006, 08:59 PM
Originally posted by Dave_Mazda3


Where\'d you pick up the by-hand polish?

I\'ll just list where I got them all in case anyone is wondering.

All Sonus products come from autopia-carcare.com
Poorboys, Menzerna & Optimum stuff was purchased from www.pakshak.com
Meg\'s ScratchX (which is the only \"by-hand only\" polish listed), was purches locally. You can get them from autozone or pepboys.

Cheers.

bluntman
04-19-2006, 08:59 PM
- stuck -

Dave_Mazda3
04-19-2006, 09:15 PM
Thanks alot!

majic
04-19-2006, 10:43 PM
Originally posted by bluntman


- stuck -

since you\'ve been gone... we got a \'how to\' area now.. moving..

bRANDO
04-28-2006, 10:29 PM
PLEAS READ THIS AND ADVISE! (http://torontomazda3.com/forum/read.php?TID=5018)

It would be a great help, if you could read this thread, look at the pics of my poor car, and advise a course of action. I really dont want to paint my whole rear-end like body-shops want. BUt i also want it done right-ish. Feedback woudl eb apperciated.

picus
04-28-2006, 11:20 PM
Originally posted by bRANDO


PLEAS READ THIS AND ADVISE! (http://torontomazda3.com/forum/read.php?TID=5018)

It would be a great help, if you could read this thread, look at the pics of my poor car, and advise a course of action. I really dont want to paint my whole rear-end like body-shops want. BUt i also want it done right-ish. Feedback woudl eb apperciated.

Ouch - man that\'s going to be tough. The second picture doesn\'t phase me much - looks like it\'d just be a matter of taping it off really well, spraying with a duplicolor can, sanding and polishing to blend. I just wrote a really quick \"how-to\" on another boards involving spraying and would be happy to post it here. You could actually even touch that one up with touchup paint, but the chip on the curve will be very hard to sand.

It\'s the first picture that\'s the killer. Honestly I don\'t know that you\'ll be able to do that one without a repaint. You *could* sand the entire area down, spray carefully (tape off everything), sand, polish and pray, but with metallic paints that\'d be almost impossible to match correctly. It\'d be too big an area. On the car above it\'s non-metallic black, which is the easiest to match, more importantly it\'s a smaller area. The size and shape of the egg damage just leaves you with almost no options. I really hate to say \"you\'re screwed\", but I think on this one a re-paint is definitely the best option. Totally sucks and I feel terrible for you. :( I wish I could help more.

bRANDO
04-30-2006, 10:24 PM
thanks for the response! i had the feeling i was screwed form the minute i saw it. Looks like the tax return just found its use this year!

picus
04-30-2006, 11:02 PM
Originally posted by bRANDO


thanks for the response! i had the feeling i was screwed form the minute i saw it. Looks like the tax return just found its use this year!

Man, it really burns me up knowing you have to spend your tax return on that sort of thing. Hopefully the re-paint turns out nice and you\'ll look back on this and laugh some day...

Good luck.