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AeroCleanse
08-11-2009, 11:26 AM
Great, I have a Meg's question for you. How long does the wet/dry sandpaper last. I mean how much of a car / cars can you do before needing a fresh sheet. Specifically the 2500 and 3000 grits.

Mike Phillips
08-11-2009, 12:44 PM
First I'm going to assume you've read this article?

Hand Sanding Techniques (http://meguiarsonline.com/forums/showthread.php?t=27410)

As for how long a single sheet of paper will last there is no hard answer, different brands will vary in how long they will last due to their physical make-up of both backing material, adhesive and grit dispersion.

Most of my experience is of course with the Nikken Finishing papers because it just makes so much sense to use them when the goal is to leave as much paint on the car during the process.

Keep in mind, as shown in the pictures in the above thread, there are two common ways to wrap your paper around a backing pad for hand sanding, neither allow you to use 100% of the sheet of paper but instead you're folding the paper in such a way that the usable area matches the surface area of the actual face of the backing pad. (Click the link and look at the pictures and the last sentence will make perfect sense).


Wet-Sanding by Hand
So with all of the above said, and assuming you're asking specifically about wet-sanding by hand, then here's what I do, I rely on my sense of touch and vision to gauge when the paper has reached the end of it's working life. This requires a few things, one is a person has to do a lot of sanding so they can get experience. Sanding down something like a Suburban is a good start and that's the first vehicle I did a complete sand and buff job on back in about 1990, were talking about a lot of real-estate and luckily most of the panels are fairly flat and basic so that makes it a lot easier to work on.


Monitor paper drag as affected by cutting effectiveness
Then as you're sanding, and this is key, focus on the task at hand. I know that sounds so basic but it's vitally important especially if it's not your car you're sanding. By focusing on the task at hand this means you're using your sense of touch to gauge the drag of the sandpaper against the paint. When using a brand new sheet of sandpaper you will feel the most drag as the abrasive particles cut into the paint. The more you sand the more the particles will wear down and even come off the paper and the level of drag or cut will decrease. It's your job to sense the change as you sand.


Monitor paint residue coming off the panel.
As you sand, you need to look at the water/paint solution on the surface. You can see the paint particles you've removed suspended in water on the surface of the section you're sanding and when a paper is new you will see more paint suspended in the water than you will as the paper wears out.

If you're working on a clear coat the water will have an opaque, milky look to it. If you're working on a single stage paint you'll see the color of the paint in your water solution only it will be harder to see because it will match the panel you're working on.

Using both your sense of touch and your eyesight, that's how you gauge when you're paper is cutting good or when it's cutting ability starts to fall off. As it falls off you'll need to decide when it's cost effective to either re-fold your paper to expose a fresh section, or if you used up the paper to the best of your ability to wrap it around your backing pad then switch to a new sheet of paper.

Trying to use a piece of paper for too long will result in the sanding process to take longer as the paper will remove less paint with each stroke. Tracer problems tend to increase as the paper wears out also.

That's how I've always gauged my papers, (sense of touch and visually looking at the paint suspended in water). It's not a perfect system but when it comes to hand sanding there's not a lot of great methods to gauge the fall off of your paper's efficiently.

Keep in mind you're sense of touch and looking at the section your sanding is real-time monitoring assuming your focusing on the task at hand and for big jobs that requires you focus on the task at hand because it's easy to get distracted and sand with your hand while looking somewhere else or thinking about something else.

If you want you could try to count strokes but that's not a very good system on a large project.

Another thing you can do is test your paper as you move to a new section, again you have be focusing on the task at hand and take a little time to squeegee the water off the panel and then inspect your progress and/or results. Testing works well if what you're doing is removing orange peel because you can sand for a few strokes and then squeegee the water off the section and then inspect and it will be real easy to see where any orange peel remains in the section you've sanded.

By this I mean, start out sanding a section about a foot squared or so and squeegee off the water and inspect the paint and remember or lock into your brain how long you sanded that area or approximately how many strokes you used to sand that section along with your downward pressure before stopping to squeegee off the water.

Once you've removed the orange peel and the section is flat to your expectations, move to a new section. Repeat the process and inspect the results by squeegeeing off the water. As your paper wears down, you'll notice that it's taking longer to remove the peel to get a flat looking uniform appearance. Again you'll have to make the decision to either keep sanding with the same sheet of paper or fold to a new side or replace the paper.


Doing a GREAT job of sanding a paint job flat is a lot of work and some would consider it an art form, I know I do.

Don't know if that helps you at all but that's about all I can share with how to gauge when your paper's cutting ability is falling off.

Nikken Finishing papers are a tad on the spendy side as compared to any basic wet/dry paper as they are a fairly high-tech paper. But keep in mind that whenever you're sanding paint you only have so much film-build you can safely remove and if you make a mistake because of lesser quality papers the cost of repainting a panel more than justifies the higher quality Nikken papers, not to mention the time involved in fixing a mistake and the fun of telling the owner of the car what happened. :)

Nikken Finishing papers were introduced to North America by Bill Stuart, the guy that owns and sells the Absorber. Bill was an Meguiar's RDC owner until Meguiar's bought all the RDC's and then he went his own way. At some point in the 1980's Bill sold his rights to sell the paper in North America to Meguiar's, that's how Meguiar's obtained distribution rights. Bill told me that the Nikken paper is actually an electronics grade paper and the quality control as such was much higher than an automotive grade paper. The Nikken papers used a latex impregnated paper for a backing so they won't and don't break down like lesser quality papers and instead of having grit particles dropped onto the paper during the manufacturing process, somehow an electrostatic charge is used to draw the particles up to the paper so the paper travels down the manufacturing process upside down.

Nikken Finishing papers offer Unigrit Particle Size and just as important, Uniform Particle Placement over the entire sheet of the paper whereas a traditional wet/dry paper is about a 60/40 fill with much less control over particle size of the grit.

Because of this, Nikken finishing papers offer sanding marks with a uniform depth and uniform sanding mark pattern over the paint being sanded. Note I didn't use the word scratches, as in a uniform depth and uniform sanding scratches because the quality of the paper tends to leave the paint just looking dull, not filled with sanding scratches.

The goal is enabling a person to remove the least amount of paint to get the job done, (that means more paint on the car for the customer over the service like of the car), while leaving a sanding mark pattern that will buff out faster and with more control on the side of the technician. If you use papers that have little or no control over the particle size or placement of particles on the face of the paper you lose control over the sanding marks and thus the technician looses control over the process.

Of course, given the chance I prefer to machine sand with an air powered DA Sander first and save hand sanding for areas that don't lend themselves well to machine sanding.


What's really cool is Autogeek offers people the ability to get a collection of different grits instead of having to purchase entire sleeves of a single grit.

Meguiars Unigrit Sand Papers 8 Sheets - Your Choice! (http://www.autogeek.net/meguiars-sandpapers.html)


For those of you on the East Coast that want to learn how to hand sand and wet-sand this will be one of the classes we will be offering.

Hope that helps a little...


:)

Hope that helps a little...

AeroCleanse
08-11-2009, 01:21 PM
Not really, I'm trying to get an idea of how much work a single sheet of Megs 2500 paper can do. While I understand that each case is different, I would like to know many sheets you need on a typical sized car. I don't want to buy more paper than needed, yet I want to buy enough.

Mike Phillips
08-11-2009, 01:44 PM
Not really, I'm trying to get an idea of how much work a single sheet of Megs 2500 paper can do. While I understand that each case is different, I would like to know many sheets you need on a typical sized car. I don't want to buy more paper than needed, yet I want to buy enough.

What are you working on?

Fresh paint job?
Factory baked-on paint?
Small touch-up paint blobs?
Removing Orange-Peel?

#2500 is pretty fine for chopping down orange peel, I would start with #1500 and then either sand again with #2000 or #2500 before cutting out your sanding marks with a wool pad, compound and a rotary buffer.

If you're going to be doing a lot of this then purchase a sleeve of #1500 and #2000 and you can tackle just about anything that comes your way. I'm not much of a counter, when I sand on a car I put my papers in a bucket of water with a Grit Guard in the bottom at least the night before and then I have plenty of papers to use until the job is done. Any papers left over can be used in the future.

So, what are you working on?

I'm heading out to the Training Garage for product testing the rest of the day but I'll check back here later for your reply.


:)

AeroCleanse
08-11-2009, 02:12 PM
Probably factory paint removing orange peel and RIDS.

I want to start offering color sanding to my customers, but want to start out slowly.

Superdutytd
08-11-2009, 07:14 PM
Probably factory paint removing orange peel and RIDS.

I want to start offering color sanding to my customers, but want to start out slowly.

Color sanding factory paintjobs is a tricky subject as the clears are so thin! I would def only offer that if I had a PTG.

Mike Phillips
08-12-2009, 11:12 AM
I'm trying to get an idea of how much work a single sheet of Megs 2500 paper can do.




Probably factory paint removing orange peel and RIDS.


#2500 and #3000 are very fine papers and also very safe which is the right paper for what you want to do, which is working on factory thin, baked-on paint. I've never counted how many papers it takes to sand down a panel, or at least kept track. If I were sanding down the hood of a Corvette and trying to be stingy my best guess would be 2 to 4 half sheets to do a good job of leveling the orange peel flat. Leveling orange peel with #2500 by hand is going to take a lot of time because it's too fine of a paper for what you're trying to do, it's the safe approach because it's not going to remove a lot of material very quickly but that's why it's going to be the slow approach.

Using #1500 grit would be the fast way but the problem you're going to run into is factory paint is very thin.

I've typed about this for years on MOL and maybe you've read some of those posts over there? If not I can probably dig some of them up.



Color sanding factory paint jobs is a tricky subject as the clears are so thin! I would def only offer that if I had a PTG.

I wouldn't take the job personally, especially if the customer didn't want to pay top dollar.



I don't want to buy more paper than needed, yet I want to buy enough.


If you're serious about this then start out with a sleeve each of, #1500, #2000 and #2500, I mean if you're going to start wet-sanding cars for a part of you're business then these are the staples for this kind of work.

It would be faster and safer to use an air-powered DA Sander and something like the Abralon system by Mirka or the Trizact system by 3M to at least knock-down all the flat panels. Abralon goes all the way up to #4000 grit and with a foam interface pad between the backing plate and the paper you can even reduce the cut a little more, this will make buffing out your sanding marks a breeze.

If you have someone offering to pay you to sand down the factory paint on a new car, more than likely it's going to be a higher-end car, like a Corvette or something similar. If their expectations are a show car finish, that is a totally flat, orange-peel free finish then you have more guts than I have as I wouldn't take the job. All you have to do is make one mistake, that is burn through the clear layer of paint and expose the color coat and you'll lose all your profit as you're going to have to show the owner the mistake and then pay to repaint the car.

Remember, sanding removes paint, compounding removes paint, second-step polishing is going to remove a little paint too and you're tackling the hardest job their is in the detailing world and that's sanding and buffing case-hardened, THIN paint.

I've made this mistake, I had to pay to have a customer's hood repainted and it left such a bad taste in my mouth that I won't do it any more. I tell guys that don't like the orange peel in their brand new cars that while it's brand new and doesn't need any body work that if having a show car finish is a top priority to them then to take it to a custom painter and have the car re-painted and then sanded and buffed. Tell the painter your expectations, (an orange-peel free finish with NO swirls when they're done and then the painter will spray extra paint onto the car and whoever does the sanding and buffing will do it while the paint is still soft enough that getting the sanding marks out of the paint will be easy.

The majority of all wet-sanding and cutting and polishing to entire cars is done to cars that are painted at body shops where more paint is sprayed and there's a window of time that the painter's helper can remove the sanding marks easily.

We use rental cars for our wet-sanding classes and stick with the higher grit papers for training purposes and I don't remember any students ever sanding through the clear layer to expose the color coat but it's still very risky.

How much are you going to charge for this service?

:)

AeroCleanse
08-12-2009, 12:50 PM
How much are you going to charge for this service?

:)

Plenty! :props: