How much sanding gelcoat

[6meter]

Gelcoat is very oxidized and grey. Should be Dark Cherry. I started with a light wet 400, then 600, 800, and then 1000. the grey was still there so I did it again, 600, 800, 1000. Washed it all off and still has some grey oxidized streaks and spots. One more time. It's cleaner but definitely still there. It still has a very different look than the good paint on the boat. It's no where near having a shine. How much can you sand it without going through the gelcoat? I read oops bilge liner restore and he mentioned a "soft pad" sanding block. I would say mine is pretty hard rubber. Were are these availible?

 

[sasto]

Re: How much sanding gelcoat

If she were mine..I would buff out a small area with some 2000 grit buffing compound and see if it's something I could live with.

 

[Yacht Dr.]

Re: How much sanding gelcoat

When you were wet sanding it..did you have red residue ? Or was It kinda clearish ?

YD.

 

[6meter]

Re: How much sanding gelcoat

It was mainly more on the grey side, the oxidation grey. I did get some red. At one spot though it looks like you can see through it and its black like. It has been machine buffed with compound several times. Clearish would indicate what?

 

[Yacht Dr.]

Re: How much sanding gelcoat

Clearish would indicate some build-up of some kind of waxy crap..

If you wet sand on a color..your arm/hand/face and anything else that gets a little spash of your sand/water residue should be the color(ish) of what your working on..

If your sanding red and your residue is clear/greyish..whatever other color then red ..then your not sanding the gel .. Its...something..erm..else.. (coughshouldnotbeonyourboatcough).

Heck..it might even be Vaseline ..

YD.

 

[6meter]

Re: How much sanding gelcoat

Actually when I first dry sanded a side the dust was grey, on the red gel coat. The bow has been red when I was washing it off but still grey left on the boat when dry. Started on the sides with dry 600, all grey on sandpaper, ozidation, but the fiberglass checkerboard pattern started showing. Haven't gone through the red gel coat but it looks to be very thin. Am I wrong here?

 

[oops!]

Re: How much sanding gelcoat

Heck..it might even be Vaseline ..

YD.

lol

carry on YD...too many cooks....

 

[oops!]

Re: How much sanding gelcoat

YD appears to be off line.

ok the sponge pad i use on my sander is avalable at any dedicated auto paint shop...

i use a company here called white and peters.

you will need a compound to remove the rest of the oxidization. i use farecla, but 3m makes a rubbing compound. the compound will also remove all the other stuff on the hull that YD is talking about....could be wax or another magic cure that someone tryed

the print from the glass is showing thru but will dissappear when compounded.

go dry sanding all the way to 1500.

then buff with a dry mop (on your buffer) then wax.

cheers
oops

 

[Yacht Dr.]

Re: How much sanding gelcoat

Actually when I first dry sanded a side the dust was grey, on the red gel coat. The bow has been red when I was washing it off but still grey left on the boat when dry. Started on the sides with dry 600, all grey on sandpaper, ozidation, but the fiberglass checkerboard pattern started showing. Haven't gone through the red gel coat but it looks to be very thin. Am I wrong here?

Hello m8..

Your checkerboard pattern is from " print " of the woving glass in the construction.

If you need to bump it down to 400 grit then you can.

What seems to be thin ? The Gel or the Coating ?

If it were mine I would take a 5-6 " D/A sander with some 400 grit to it till most of it was gone.. then 600 D/A .. then 1200 wet .. then buff it till done. ( But I have the tools and location to do this with ).

Aside the tools your going to have to do this old school and wetsand ( with a soft block NOT hard block ).

YD.

 

[oops!]

Re: How much sanding gelcoat

lol....as you can see there are many ways to sand a boat.

im not a big fan of wet sanding necause you cant get any scratches out if the paper "digs" into the gell. with dry sanding you can.

i did 2 spots on the bottom of my hull, one dry and one wet....(this was on a fresh a sprayed gellcoat surface) the dry sanding i thought actually finished out better than the wet. don't kid your self.....both were nice, but the dry was less work and achieved a better sheen than the wet.

i attended a gellcoating workshop at svfara boats here in kelowna with some 30 other gellcoat finishers, and that was also the general consensus.

however i have also found that different areas (geographically speaking) use different methods... allmost nothing is right and wrong just different ways to to it to achieve the same goal.

what works best for you?

cheers
oops

 

[boat1010]

Re: How much sanding gelcoat

Maybe I have missed something. You never mention buffing it out after you sand. Are you doing that or not? I wet sanded mine and ended it all with 1000 then buff it out with Maguires diamond cut rubbing compound. Looks great.

 

[lowvlot]

Re: How much sanding gelcoat

I too wet sanded mine with 1000 grit and buffed with a turtle wax buffing compound on a power buffer then hand polished with turtle wax. Night and day difference.

 

[6meter]

Re: How much sanding gelcoat

Hello m8..

Your checkerboard pattern is from " print " of the woving glass in the construction.

If you need to bump it down to 400 grit then you can.

What seems to be thin ? The Gel or the Coating ?

If it were mine I would take a 5-6 " D/A sander with some 400 grit to it till most of it was gone.. then 600 D/A .. then 1200 wet .. then buff it till done. ( But I have the tools and location to do this with ).

Aside the tools your going to have to do this old school and wetsand ( with a soft block NOT hard block ).

YD.

I knew it was the woven glass, just conserned that there wasn't much gel coat left on the side of the boat to sand it past the oxidation. I looked like a few more strokes and I'd be sanding just the fiberglass. Trying not to paint.
I do have a 6" D/A and a machine buffer and a garage to work in. Sounds like I need to find a soft block too. The one I've been using is hard rubber.
Oops, I am suprised the consenceces is to dry sand. I would have thought that wet would give you a smoother surface without the scratches. An education for me. I learned about wet sanding back in my old car days painting with lacquer. Paint. Wet sand 600. Buff.
I do plan on machine buffing afterwards, it was just the grey streaks still in the paint and the "woven" pattern on the side that concerned me. Ask first to save work later attitude I guess.
I'll give it another shot the weekend. Thanks for all your help!
I'd take pics of before and after but no digital camera and phone is old school.

 

[Yacht Dr.]

Re: How much sanding gelcoat

Hello 6meter..

I still hold firm that if your not getting red sand .. then your only sanding some crap on there..

Even though you might think your thin..you may be thick.

Gel is thick..and if your sanding " print " at that age..then you should feel ok to sand all the print out and leave a Sweet finish.

Ive Penciled/markerd many boats..600 D/A then sand till marks are gone..buff.. and come to a brand new boat without burning through.

Test a spot m8..where its "gray" .. sand a bit on one spot and buff..

Look at your buff pad as well.. is it "red" .. you can determine alot from your pad.

IF your gel is in fact that thin then you have no other choice then to re-gel or prime and paint to keep your baby looking good. ( unless you want to put years and years of wax/bs clear/Vasaline..etc therfore making you or someone work that much harder to just replace as needed ) .. If you understand..

YD.

 

[6meter]

Re: How much sanding gelcoat

I'm gonna give it another shot this weekend. Got a soft sponge sander pad and will bring the compressor, D/A and buffer. I ain't EVER gonna put vaseline, WD40 or any other stuff like that. I screwed up when I bought the boat new in '86 and only got a toneau cover for it, instead of a full cover. It sat in the water all summer. The 2nd summer it started. What that cover, covered, kept the gel coat in great condition. Its what wasn't covered, is bad.

 

[oops!]

Re: How much sanding gelcoat

yd is correct,

if you are not getting red on the sandpaper. you are not sanding the gellcoat.

keep going till you are at the gellcoat

 

[6meter]

Re: How much sanding gelcoat

Thanks guys! Was back at it this weekend for a bit. Sanded it one more time with a little more effort on the oxidized parts. After the sanding and washing, I broke out the buffer withe some meguires stuff. Had to go out and buy the swirl remover after. I think my buffer pad has seen better days but couldn't find a new one. Still, the boat look about 90% perfect. We won't be painting. Still need to wax.