Questions on wet sanding/polishing

What is "the appropriate compound"? What was the last grit of sandpaper that was used in the wetsanding process?

There are a LOT of variables in wet sanding and orbital buffing. The more information you can provide, the better.

--Matt

 

You *can* buff out scratches by hand, but it depends on what grit you wet-sanded with. If you have wet-sanded with 1000-grit followed by 2000-grit (better yet follow it by 3000-grit) you can do it. If you stopped at 1000-grit, it would take you forever to do it by hand.

Yes, a random-orbital is better than a plain orbital for just about ANY polishing task you'd want to do on a car.

 

I have never seen 3000 grit wet-dry paper....I thought 2000 grit was all you needed to get rid of fine scatches after 1500 W-D paper...Then compound should do the rest.

Maybe some "pros" can outline the benefits of using finer grit than 2000 paper.

VK

 

I would wrt sand it with 3000 grit by hand, then use a clay bar and appropriate lubricant . Most body shops use the clay to remove overspray and I've had good luck removing some white dots I picked up on a black car driving past some guys painting a crosswalk.

Girots Garage has a sponge clay holder that fits on a Porter-Cable random orbit polisher. Prices are high there, but if you look around you can find them cheaper.

 

I seem to be the one disenter here about the random orbital. I fell for Richards claims of the R/O and absolutely find it useless. I have used his rubbing compounds and 3M with no difference. I have used it on my Dodge truck, my F car, and other assorted Italian stars and it just doesn't get the job done. Plus he is about $100 more than anyplace else I have seen the Porter Cable unit. But, use the 3M with a good variable speed orbital, I use a Makita, and with practice you will be amazed at the difference. Go with the others advice about wet sanding, then switch to the tan colored 3M compound, finish with the white polishing compound. You must also use different buff's for the 2. Go to the TIP sandblasting site for good offers for the polisher and different heads.
David

 

For metal or wood needs - Makita makes excellent, reliable sanders - way, way, way more reliable than Porter Cable. In a 60-man Cabinet shop, an on-site Full-time repairman was chit out of things to do after we dumped Porter Cable...

 

I've been using a Craftsman DA air sander with a commercial velcro surface pad similar to the Porter Cable one Griot sells.

Results are beautiful.

I use 3M foam backed sanding pads:

1200->1500->2000 grit.

Important to soak the pads for a couple of hours before you start to ensure they're nice & soft. (Same for sandpaper.) Otherwise, you can get a fold or sharp corner that'll put a scratch that 600 grit won't take out!

Keep a squirt bottle of water with a few drops of dish detergent in it at hand to ensure the surface stays wet while sanding. I clean off each panel with a damp terry towel before moving to the next one. Change towels each time I move to a finer grit as some grit always comes off & gets embedded into the towel.

I then move to polishing compounds with 3M PerfectIt foam polishing pads (Like the towels, I always use a different pad for each level of compound as compound particles get embedded in the pads. Lable the pads with Sharpie pens & keep each one in a different plastic bag so they don't swap grits)

I then use 3M polishing compounds & glazes:

PerfectIt II -> FinesseIt II -> PerfectIt Glaze -> Imperial Hand Glaze

The above is the full course treatment. I often find that for very fine orange peel I only need to start with 1500 or 2000 grit, then can move to the polishing compounds.

Again, while polishing I keep a squirt bottle handy to mist the surface as it starts to dry. (Do NOT mist once you're working with glaze, it's supposed to get polished dry.)

For normal detailing, I just use the FinesseIt II & upwards.
Using the polishing compounds with a DA polisher takes a very long time, but you will get there. I usually switch from the DA to a rotary air polisher when I go to the FinesseIt II.

Can't find my notes, but I'm pretty sure I once went directly from 1500 grit wet DA sanding to rotary polishing with PerfectIt II & finer with great success. This is consistent with 3Ms claim that it'll take out 1200, 1500, & 2000 grit scratches. Took a very light hand on the polisher while doing it.

3M may have replaced some of these with 'III' varients. I bought my supplies in pints & quarts a couple of years ago. I've got at least a 10 year supply of most of them!

Now I see the 3M finishing compounds being sold in smaller containers.

 

I have the exact same problem. My rocker panels were repainted (rock chips) and need color sanding and polishing. The body shop guy told me that you can't get the scratches out with an orbital, you need a circular buffer. The orbital will simply fill in the scratches. Trouble is, you can't get a circular buffer into the right, concave surfaces.
Now what?

 

You can do it by hand, it will just take longer.

 

Thanks!

 

Take down the scratches in steps using ever finer paper untill you can buff it with compound.

There are many colorsanding videos on the internet, watch a few and you'll be an expert.

 

But I'm so scared!!

I wish you lived close by, I would pay you to do it.
)

 

The biggest risk is sanding through an "edge". Put blue tape over all the risky spots and just proceed carefully. Using ultra-fine paper (1200 - 2000 grit) by hand takes a while to get in trouble. Rinse it and look at your progress frequently, assuming the clearcoat was thick enough to start with you'll be okay.

I always put the car on my lift for this. If you can get the rocker up to a good working level and put good light on it you'll do fine.

 

3000! , you could wipe your ass with 3000. Overkill and a waste of time.
Claybar after sanding with anything is also redundant.
OP's 2000 and any buffer should be fine.
OP; Don't use a wool bonnet unless you are experienced, a foam bonnet and good compound is all you need. Enjoy.

 

much more important than the question 2000 or 3000 grit is, that you change the water before switching to any finer grit.
Of course this only applies, if you use water from a bucket. But even sometimes fresh water from a hose contains dirt and rust particles.
If you don't do this, you will still have residue of the coarser grit in the water.
Say; if you don't renew the water after switching from 1000 to 2000, you will produce 1000-grit scratches.

Best Regards from Germany

Martin

 

Okay, I watched a few videos and it looks straightforward, except...
Everyone says to not try this without a sanding block. However, the surfaces that I need to wet sand are very tight and concave (the scoops in front of the rear wheels, the air intakes on the top of the rear fenders, 2000 360). So, what do I do?

 

It's okay to use your fingers on concave surfaces, just be careful and check your progress frequently. Use a small piece of paper, folded in half or in thirds. Don't press too hard.