Gel Coat - sanding and polishing - need expert advice

So I'm in the middle of resealing my boat bottom with Interlux InterProtect barrier coat before i paint it with bottom paint for the season.

I had the boat soda blasted and now i am sanding the bottom to prepare it for paint. I noticed that when I'm sanding the gel coat gets it's original white color back. The sanded surface is of course not as shiny and smooth as the unsanded gel coat but the color is awesome. Sanding really brings out the original "like new" white.

My question is, can i just sand the entire boat and then polish it somehow back to its original gel coat polish?

How are boats made? do they polish the gel coat to achieve the shiny, smooth gel coat? Is it buffed? or is it clear coated over?

If I sand can i buff it our later to restore the color and achieve the factory-like smooth finish at the end?

thanks,

Luke

Re: Gel Coat - sanding and polishing - need expert advice

Moved this over to the Restore section. You'll get the most focused help with this over here.

Gel Coat - sanding and polishing - need expert advice

HighLineCBR said:

How are boats made? do they polish the gel coat to achieve the shiny, smooth gel coat? Is it buffed? or is it clear coated over?

If I sand can i buff it our later to restore the color and achieve the factory-like smooth finish at the end?

thanks,

Luke

Click to expand...

I'm not the expert you may want but I've worked with fiberglass since I was in my teens. Started at a boat building business when I was sixteen years old.....

When the boat was made it was done in a mold. The mold is just a heavy duty hull with the inside smooth and the glass added on the outside. These molds are waxed and polished to a high luster, then the gel coat is sprayed onto the inside of the mold. After this hardens overnight the fiberglass is added on top of the gel coat. The shinny surface you see on new boats comes from the waxed mold. You can sand which is removing the oxidation from the surface and keep using a finer grit then polish with successive grits of rubbing compounds until you get the shine you want IF you can do it before you run out of gel coat! This gel coat layer is often very thin and difficult to work with without going too deep. With the quality of paints now days I would just sand lightly and add several coats of paint. Then you can smooth and polish the paint.

Re: Gel Coat - sanding and polishing - need expert advice

Wet sanding is labor intensive and you can not be that aggressive. You have to start with a fine grade and end up with some of the finest grade paper available......and do it all wet all the time.

When the finest grade is reached THEN use a polisher and the entire finish should pop out....... finish with a coat of good wax.

Re: Gel Coat - sanding and polishing - need expert advice

What kind of waxes do you guys use? And I assume you use a high speed buffer?

Re: Gel Coat - sanding and polishing - need expert advice

Thanks for the info guys. A while back I watched a video on youtube about how boats are made. I thought i remembered that the final smooth finish was achieved by polishing.

How about Color hulls? I My hull is white with the exception of a 10" red section around the boat. Is the red part of the gel coat red all the way through? it is red gel coat or just red paing on top of the gel coat? Its all original and never been repainted. Im just wondering if i start wet sanding will it be red all the way through.

thanks again,

Luke

Re: Gel Coat - sanding and polishing - need expert advice

I don't think there's any way to tell without looking closely at the stripe. Take a close-up pic of that area of the boat and post it here.. by close-up I mean set the camera to macro and take a pic.

It may have been molded with the red stripe in the gelcoat.. however that's much more labor intensive (and harder to change) than just painting it on afterward. So it could be either way.

Erik

Re: Gel Coat - sanding and polishing - need expert advice

I'm not an expert by any means, but I've been successful in wet sanding and buffing my hull. I've outlined what I did in these posts:

http://forums.iboats.com/showthread.php?t=381567

http://forums.iboats.com/showthread.php?t=374293

Its a lot of work, but if you have more time than money I may pay off.

Re: Gel Coat - sanding and polishing - need expert advice

Dzrtcj7 said:

I'm not an expert by any means, but I've been successful in wet sanding and buffing my hull. I've outlined what I did in these posts:

http://forums.iboats.com/showthread.php?t=381567

http://forums.iboats.com/showthread.php?t=374293

Its a lot of work, but if you have more time than money I may pay off.

Click to expand...

Thanks for sharing. You did a really good job! I think i will try your method