Wet Sanding Basics.


Ron Harris

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This is just a basic example of wet sanding procedures.If you have never attempted this before

I recomend you find a scrape panel to practice with.

 

What you need

A large sponge

A 5 gal bucket

Foam sanding block.

2000 grit sanding paper.

A squeegee.

 

 

Our victim Porsche Carrera.

The right rear quarter was repainted as was the door and right front fender. Picture_003.jpg

 

Ok. What you want to do first is fill a 5 gal bucket with water and start soaking your paper. I don't add soap.Why?

I think that the lubricity masks the sound that dirt makes when between the paper and paint. I think it makes the paper cut deeper. Soak for 30min while you wash the car.

I use 2000 grit 3M Imperial paper. I feel that you can remove most imperfections with this paper.

Some like to start with 1200 but based on my experience you will just be adding a step that is not necessary.

When you start compounding you will have some stray deep scratches that will be hard to remove if you didn't sand enough with a finer grit. Seeing the stray scratches are impossible when there is no gloss. So you could end up removing to much clear

or burning the clear trying to compound them out.

 

Is your car clean? If not give it a good washing paying special attention to the nooks and crevices around the area

you will be sanding. Dirt trapped in these areas can be flushed out while sanding with the water and come between the paper and paint causing some deep scratches. You can here this happening and you should stop and flush your panel and paper with fresh water to remove the dirt.

Lets start sanding. You want to work in a cool well lit area out of the sun.

You may be able to see some of the imperfections like dirt or fish eye in the finish of the car but some may be hard to detect

but will show up during the compound and polishing step. Orange peel will be obvious and you only should remove enough to match the rest of the car. This takes practice to do. Your first time out don't go for a completely flat finish if your car dose not

have one. I start by lightly sanding the panel with my paper wrapped around a foam sanding block. I Call this giving you a guide to the finish. This will high lite all the dirt and orange peel. Squeegee off the water and examen. see example pictures.

Picture_002.jpg Picture_006.jpg The circles are showing you dirt in the finish.

 

So now we can see just how much dirt and orange peel in in the finish. Lets start sanding more. Keep the panel wet with water using your sponge. Remember if you here a gritty squeak stop and flush. Work an area stop squeegee and examine.

Looking at the next pic we can see that most of the orange peel gone but a big piece of dirt remains. We will need to sand this a little more. Picture_001.jpg

When working on curved surfaces you want to remove the block from the paper and use your hand.

You never want to sand with your finger tips.try to keep your hand as flat as possible and sand as if you were waving.

Sanding with the tips of your fingers will create valleys in theb finish that will look like waves when polished.

Picture_005.jpg Picture_004.jpg

 

 

 

 

So now the car is completely sanded Picture_010.jpg

 

 

Next Compounding

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For the compounding I like to use a wool pad. They cut a little cooler then foam. There is no need for twisted wool or any thing heavy duty. Just a good cut and polish type of wool pad.

Picture_011.jpg Picture_012.jpg

 

 

 

 

I will use Optimum Hyper compound Old Formula. You can use the New Compound which has the same cut as the old Hyper.

I place a couple of strips on the panel and pick up the product as I work across the panel. I'm running the buffer at 1500 rpm

Picture_013.jpg

 

 

 

When you come to an edge you want the pad to spin off of it. If you have the pad spinning on to an edge you can burn an edge very fastPicture_014.jpg

 

 

 

Make sure you don't get a buildup of compound on the pad it will become very gripy and can burn the paint fast. This holds true with foam as well. Use a wheel spur of compressed air to clean and fluff your pad.

 

Were done compounding and we can start to see some results. The finish has gloss and a lot of swirls.

We will polish with Optimum Polish and a White Lake country pad next.Then do a final polish with OP and a finishing pad both at 1500 rpm.Picture_015.jpg

 

The finished product. You can expect to spend a couple of hours of longer on a job this size.

Picture_021.jpg

 

This topic is open for discussion. No question is a dumb one. It,s only dumb of you not to ask.

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For the compounding I like to use a wool pad. They cut a little cooler then foam. There is no need for twisted wool or any thing heavy duty. Just a good cut and polish type of wool pad.

post-2-1182100649_thumb.jpg post-2-1182100680_thumb.jpg

I will use Optimum Hyper compound Old Formula. You can use the New Compound which has the same cut as the old Hyper.

I place a couple of strips on the panel and pick up the product as I work across the panel. I'm running the buffer at 1500 rpm

post-2-1182100885_thumb.jpg

When you come to an edge you want the pad to spin off of it. If you have the pad spinning on to an edge you can burn an edge very fastpost-2-1182101177_thumb.jpg

Make sure you don't get a buildup of compound on the pad it will become very gripy and can burn the paint fast. This holds true with foam as well. Use a wheel spur of compressed air to clean and fluff your pad.

 

Were done compounding and we can start to see some results. The finish has gloss and a lot of swirls.

We will polish with Optimum Polish and a White Lake country pad next.Then do a final polish with OP and a finishing pad both at 1500 rpm.post-2-1182101599_thumb.jpg

 

The finished product. You can expect to spend a couple of hours of longer on a job this size.

post-2-1182101720_thumb.jpg

 

This topic is open for discussion. No question is a dumb one. It,s only dumb of you not to ask.

 

 

One comment - please get a new handle??? Looks terrible! :)

 

Nice write up. However I like your dvd better.

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One comment - please get a new handle??? Looks terrible! :)

 

Nice write up. However I like your dvd better.

 

My polishers a work horse not a show dog. I have three different rotarys.

It would be bad luck to change it.

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What is still not completely clear for me (after a pretty good rotary history), is the "spinning off" the edge... Because one side of the pad spins off of it, that's true, but the opposite side spins "on" and attacks it. I'm using low speeds when doing these parts and lift the attacking side of the pad a bit just to feather pressure. A sensitive approach is essential.

 

Similarly I pick up product strips not only at the usual 10 o'clock but on the opposite 4 o'clock position.

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What is still not completely clear for me (after a pretty good rotary history), is the "spinning off" the edge... Because one side of the pad spins off of it, that's true, but the opposite side spins "on" and attacks it. I'm using low speeds when doing these parts and lift the attacking side of the pad a bit just to feather pressure. A sensitive approach is essential.

 

Similarly I pick up product strips not only at the usual 10 o'clock but on the opposite 4 o'clock position.

 

 

Bence,

 

With the more aggressive pads I will tilt the pad a few degres so the only the 1/2 spinning off is making contact with the paint.

I don't apply any pressure to the panel as well.

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