Wet Sanding Gelcoat

J

JustMrWill

Master Chief Petty Officer
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Aug 12, 2003
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Quick question. I sprayed gelcoat. I now have some orange peel effect. What is the "recommended" wet sanding procedure...what grit should I start with and how fine should I go? At what point do I switch to polishing compound? Thanks.

-JMW
 
ondarvr

ondarvr

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Re: Wet Sanding Gelcoat

It can depend on the type of gel coat and how smooth (or rough) the orange peel is. If you are doing a small repair then start with 400 then go to 600 and on up, many times you don't need to go past 600 though. At anytime you can try to buff it to see how good it looks, and if doesn't look as good as you want it to, then continue sanding. Many people go to 1000, 1,500 and even higher, sometimes it's needed but not often, once you get past 1,000 grit you need to use the correct buffing pads and compound to get better results and you also need to use a good gel coat.

If you want, try 600 to start with, it makes it that much easier to get the scratches out.
 
J

JustMrWill

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Re: Wet Sanding Gelcoat

Thanks. That is what I wanted to hear. I was planning on 600 then 1000 then polishing compund.

This is the bottom of the boat so perfection is not necessary. I shoot the gelcoat before winter...and we getting a few mild days so want to get it done so I can flip the hull back over and get the transom and floor in.

-JMW
 
A

andy6374

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Re: Wet Sanding Gelcoat

Like mentioned above, it really depends on the "deepness" of the peel effect. You can try 600 to start but my guess is that you'll throw your shoulder out before you get any results. I'd start with 320 or 400. I'd go through 1000 grit. A schedule like 400, 600 1000. After you've hit down the peel with the 400, it shouldn't take long at all with the 600 and 1000. I'd say you should spend 10% of time sanding with the 600 and 1000 grit, as you did with the 400.

Since it's a curved area (hull bottom) you kinda have to hand sand. But for other parts like the transom and hull sides, forget the block, slap some sandpaper on the DA a go to town.
 
Yacht Dr.

Yacht Dr.

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Re: Wet Sanding Gelcoat

hey andy.. did you notice on his page that he sprayed only 1.5 PINTS ??? ( including transom ? )

Will... you dont have enough gel to sand out if you sprayed it ( you had to thin the gel out to spray )

was that a total after thinning ( 1.5 pts ) ????

unless you want to burn through all over and want a semi finish.. rub a marker or pencil all over your gel and sand with 400g and buff lightly

assuming you have a surfacing agent in your gel ( like wax or patch aid or duratec addative ) your gonna wipe off the last half coat of gel before you can sand

I suggest you sand/scuff 220 and re-gel with another 2qts overall transom and keel ( 50 bucks and sand away )
 
ondarvr

ondarvr

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Re: Wet Sanding Gelcoat

On larger areas I normally go with a DA, but it needs to be held flat or you may get an uneven surface. 220 or 320 on a DA is a good place to start. I'm not sure how thick you sprayed the gel coat, and like YD said, if it's thin you may sand right through it, you just need to try sanding and see what happens.
 
J

JustMrWill

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Aug 12, 2003
Messages
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Re: Wet Sanding Gelcoat

opppss...that is a typo....it should be 1.5 quarts


I hit is with 600 by hand...and I can still see VERY MINUTE crevices. I am going to hit is again with 600 once this snow storm passes.

I just wanted to re-seal it...if it looks good..thats a plus. I actually rolled on a coat on the center section first. I sprayed the entire bottom with waxed.

-JMW
 
M

ManOfwar690

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Jan 6, 2007
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Re: Wet Sanding Gelcoat

a d.a is a directional orbiter sander do not use this as u cant use wet paper i like to find a hard rubber sponge mat and about the size of my palm it helps keep the surface of the paper even unlike your palm which is concaved with fingers and creates grooves
 
Yacht Dr.

Yacht Dr.

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Re: Wet Sanding Gelcoat

ManOfwar690 said:
a d.a is a directional orbiter sander do not use this as u cant use wet paper i like to find a hard rubber sponge mat and about the size of my palm it helps keep the surface of the paper even unlike your palm which is concaved with fingers and creates grooves
Click to expand...

Actually..I recomend using a DA whenever I can..its easyer to buff out and faster..much faster

and yes you can use water with an Air DA depending on what paper you buy .. but you dont need water
 
A

andy6374

Lieutenant Commander
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1,617
Re: Wet Sanding Gelcoat

Also, I find with the rubber hand blocks and wet sandpaper that you tend to sand through the gelcoat. Don't understand it, but I've played enough with it to tell that wetsanding with a handblock on gelcoat removes tons of material.

A steady hand and keeping the DA flat with constant movement will produce perfect results.


Wet sanding isn't a priority if dust control isn't.
 
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