Wet Sanding & buffing with a DA only.... product advice needed

[helgathe109]

Hi all,

I’m just finishing up a restoration on a 1968 Mercedes 300SEL. The car was painted on October 23^rd and the painter has done a terrible job (IMO). There’s a lot of dirt in the paint, heavy orange peel on the lower panels, and a run in the paint on the roof. I’m challenging this with the painter, but it doesn’t seem to be getting me anywhere.

I realise that this isn’t going to be a show car paint job, regardless of what I do to correct it… but I’d like to have a go at removing as many of the nibs as I can, the run on the roof, and also getting rid of some of the heavier peel. Any improvement would be better.

My intial thoughts were to wet sand (by hand) each nib, then use a 3 step process to get rid of the wet sand marks. I’ll be wet-sanding (by hand) the run in the roof using a block, and taking it slowly with 1000>1500>2000 grit.
Given there are so many nibs on the car, I’m now thinking that using my DA with the appropriate pads might be a better option. I only have a DA, so any recommendations on pads/compounds should keep this in mind.

I know this is a mequiars site, so don’t want to post up too much unrelated stuff, however I did get a pad/liquid kit via a local vendor containing Scholl products. Basically I’ve got;

Scholl Concepts S3 Gold Compound
Scholl Concepts S17+ Medium Compound
Scholl Concepts S30+ Nano Polish
Scholl Concepts S40 Finishing Polish
6” Backing Plate and Scholl Orange, Yellow, Blue and Black pads.

I was considering bypassing wet-sanding altogether and using the CarPro Denim pads on a 5” backing plate, as they seem to get good results on a DA at levelling peel… just not sure if you can attack nibs in the same “bulk” method, or if you have to treat them individually…

Would the 3000 sanding discs work in this situation? Given they are foam backed, does this mean they won’t be useful for the nibs? I know this won’t help much when it comes to the peel, as the foam backed discs will follow the texture of the current paint.

I’ve been researching the Unigrit system, 3m’s Trizact system, CarPro’s Denim Pads + various compounds (M101 seems to be the favourite)… just not sure which way to go. I guess the fewer steps the better, so any advice is welcome.

Cheers,
Pete.

[drumdan]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Of your're plan is to remove the sanding marks by a random orbital, go as to as fine a grade paper as you can.

I've never used any Scholl Concepts products, but I have been successful with Meguiar's M100/green hex logic, and a PC 7424 in removing 1500 grit. It was on a medium hardness single stage.

[helgathe109]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Thanks Drumdan..
I just finished sanding out the run, and it seems to be very soft single-stage paint. I got the run out within a minute by hand sanding (extremely gently) with just 2000 grit.

It's left me a nice dull spot now, but I guess it's a good opportunity to test the pads and compounds I already have and see how far they get. If I need to step it up, then I'll be looking for a tougher pad, maybe even the DAMF range.

[Nick Winn]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Hi Pete,

Welcome to MOL! We would suggest dialing in your complete process in a small test spot, essentially finding out what works in that small area, so it can be repeated on the entire car.

In regards to using a DA to remove the sanding marks, we would definitely recommended refining your sanding marks to 3000 grit or even finer. Unfortunately I am not familiar with the compounds & polishes you have, but if I were to make a recommendation for our products to remove sanding marks with a DA, it would be either our DMC5/DMC6 DA Microfiber Cutting Disc, combined with either our M105 Ultra Cut Compound, M100 Pro Speed Compound, or M101 Foam Cut Compound. We also have our DMX5 & DMX6 X-tra Cut Microfiber Cutting Disc which will increase your cut 35% over our standard DMC5/DMC6 Microfiber Cutting disc, mainly for use on flat panels. We would then following with our M205 Ultra Finishing Polish on our DFP5/DFP6 Soft Buff Yellow Foam Polishing Disc, and then follow with a wax or sealant if the paint is cured, or if the paint is not cured, our M305 Ultra Finishing Durable Glaze is a breathable paint protectant.

In regards to the dirt nibs, we would recommend addressing these individually, with one of our Professional Mirror Glaze Unigrit Sanding Blocks, or an appropriate grit automotive sand paper backed with the appropriately sized hard backing pad/block. The idea is to confine your repair area to only address the dirt nib. Our Professional Unigrit Sanding Blocks can also be used for runs.

Hope this helps!

-Nick

[helgathe109]

Re: Wet Sanding & buffing with a DA only.... product advice needed

excuse the notes on the pics.. they were saved from my Instagram

To say I'm impressed would be an understatement. This was the first time I've ever wet-sanded or used a buffer.. was quite impressed that the marks came out so easily

Before:







Hand Sanded with P2000 grit:







After hitting with a cheap DA and;
Step 1: Scholl S3 compound + Scholl Yellow pad
Step 2: Scholl S30 + Scholl Orange pad





now I'm super keen to do the whole car (it's full of nibs), but think I might use a DA sanding product, as it seems difficult to keep very even pressure when hand sanding so as not to cause some tracer marks. I was so happy with the run removal on the roof, I tried to get rid of a bunch of nibs from the bonnet. I think because the bonnet is so low, I inadvertently applied more downward pressure and left two tracer marks that are hard for me to buff out in the same way.. they're not visible unless in direct sunlight with your face pressed against the bonnet, but if doing the whole car I'd rather the consistency of DA sanding pads... I think they'll be easier to get out

[helgathe109]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Thanks Nick! Although after hand sanding, I'm thinking machine sanding will be my preference to ensure a consistent finish. In the pics below, the roof came out great, but I think partially because it's around shoulder height, so there was no downward pressure on the paper. It buffed out easily. I then got excited and tried my luck with a few nibs on the bonnet/hood. They sanded out just fine, but I've left a couple of very light tracer marks that look like I may have applied too much force for 1 or 2 strokes. I'm not going to waste my time trying to compound them over and over, as I plan on wet sanding the whole car now anyway. But I'm thinking a P1500 disc followed by a P3000 disc will be much more uniform and easier to buff out.

Also I've looked at lots of de-nibbing tools and spot sanding tools, but there are literally 20-50 nibs on each panel, even more on the larger panels... I don't think spot treating will be efficient given the shear volume... hence my preference for a machine sand

Before:







Hand Sanded with P2000 grit:







After hitting with a cheap DA and;
Step 1: Scholl S3 compound + Scholl Yellow pad
Step 2: Scholl S30 + Scholl Orange pad

[drumdan]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Thanks Drumdan..
I just finished sanding out the run, and it seems to be very soft single-stage paint. I got the run out within a minute by hand sanding (extremely gently) with just 2000 grit.

It's left me a nice dull spot now, but I guess it's a good opportunity to test the pads and compounds I already have and see how far they get. If I need to step it up, then I'll be looking for a tougher pad, maybe even the DAMF range.

The DAMF is an awesome line. If I had those pads on hand that day I had to remove sanding marks, that's what I would have used.

I also forgot to mention that Mike Phillips did orange peel removal with denim pads, and M100 on a Porter Cable. It's on YouTube somewhere.

[drumdan]

Re: Wet Sanding & buffing with a DA only.... product advice needed

Hi Pete,

Welcome to MOL! We would suggest dialing in your complete process in a small test spot, essentially finding out what works in that small area, so it can be repeated on the entire car.

In regards to using a DA to remove the sanding marks, we would definitely recommended refining your sanding marks to 3000 grit or even finer. Unfortunately I am not familiar with the compounds & polishes you have, but if I were to make a recommendation for our products to remove sanding marks with a DA, it would be either our DMC5/DMC6 DA Microfiber Cutting Disc, combined with either our M105 Ultra Cut Compound, M100 Pro Speed Compound, or M101 Foam Cut Compound. We also have our DMX5 & DMX6 X-tra Cut Microfiber Cutting Disc which will increase your cut 35% over our standard DMC5/DMC6 Microfiber Cutting disc, mainly for use on flat panels. We would then following with our M205 Ultra Finishing Polish on our DFP5/DFP6 Soft Buff Yellow Foam Polishing Disc, and then follow with a wax or sealant if the paint is cured, or if the paint is not cured, our M305 Ultra Finishing Durable Glaze is a breathable paint protectant.

In regards to the dirt nibs, we would recommend addressing these individually, with one of our Professional Mirror Glaze Unigrit Sanding Blocks, or an appropriate grit automotive sand paper backed with the appropriately sized hard backing pad/block. The idea is to confine your repair area to only address the dirt nib. Our Professional Unigrit Sanding Blocks can also be used for runs.

Hope this helps!

-Nick

This is some great information!

I'm glad I bought the M305. I've been using it more than I would have imagined. Also, it smells like strawberry cheesecake!