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Wet Sanding...What is it...How to???


Boater59's Avatar
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04-04-09, 08:49 AM   #1  
Wet Sanding...What is it...How to???

On my boat I have a recently painted spot after a repair. It is a gel coated surface. I want to get it as smooth and shiny as possible to lessen it's noticability.

I keep getting told to "wet-sand" it. Is that literally wetting high grit sand paper and sanding it smooth? Or is there some sort of oil or other liquid that needs to be used? I don't have a clue and I'm afraid to experiment for fear of making a mess of the surrounding area making things worse.

Could someone give me the basic-101 on wet-sanding and what I should be looking to do as far as materials, steps, etc.?

 
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04-04-09, 09:03 AM   #2  
Wet sanding is using water to lubricate the wet/dry sandpaper. Some will use a spray bottle to keep the paper wet, I like to use a water hose [at a trickle] to keep the area flooded with water.

You can't use just any sandpaper - it must be the black wet/dry sandpaper, sold at most any automotive parts store or anywhere automotive type paints are sold.


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04-04-09, 09:34 AM   #3  
You will need 1500-2000 grit paper. And then have to buff it with rubbing compound to get the shine. Is the side painted or did they blend in the paint over the repair? If it is blended,you will have to be careful not to sand too much of the edge or tou will see the repair.

 
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04-04-09, 10:38 PM   #4  
I don't know if rubbing compound is the best thing for the paint on a hull repair. Polishing compound, maybe?

If you use a power buffer, take it easy where the repair meets the original gel coat.

Rubbing compound with a power buffer will also permanently discolor stainless steel and aluminum, so be careful around cleats and railings.

 
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04-05-09, 04:01 AM   #5  
Polishing compound and finer would be the best to use but what kind of paint did you use?
Enamel paints have a gloss sheen from solvents rising to the surface as the paint dries.
You will not really get much of a gloss from buffing.
Lacquer is a paint type that will shine when buffed.

Perhaps a clear spray will do what you want


GregH.........HVAC/R Tech

 
Boater59's Avatar
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04-07-09, 09:15 PM   #6  
Geez, I'm not sure of the paint type. All I know is a gouge in the hull was made and repaired. It was painted and you can only tell via looking at it from an angle and see the rough sheen. I want o buff/polish/wet-sand the area to get a more smooth look and make it less noticeable. So in a generic sense, my best bet for as smooth a surface as possible without stripping the repaired paint suface off, is what? 2000 grit black/wet sand paper using water from a spray bottle, then soft rubbing compound using a buffer?

 
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04-08-09, 02:50 PM   #7  
If they used an automotive paint the person who mixes the paint can use an additive to give him whatever sheen he wants.
If he used an automotive base/clear type of paint he would have used a clear top coat in a pre-made sheen.

Like I said, if it is an enamel the shine or lack of one is in the top surface and what you get when you buff it will be anyone's guess...................You could possibly make it worse.
Your best bet is to talk to the folks that painted it for a recommendation.

I am not sure who might have painted the repair but I have seen a highly experienced automotive painter make a patch like yours invisible.


GregH.........HVAC/R Tech

 
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