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1996Z15
05-07-2003, 11:11 AM
Does anyone have any experience in wet sanding gelcoat? I am contemplating attempting this myself but I am quite nervous about the prospect of ruining my boat. Can anybody provide some tips or things to look out for? I am pretty sure that the boat has the original gelcoat if that makes a difference.

DUCATIF1
05-07-2003, 11:21 AM
I am not boat guy but I would assume gel coat is gel coat. Why don't you try an agressive compund first before you break out the paper. You will have to compound after anyway so it will be a worthwhile investment and experience. You will be surprised what a coarse compound can bring back and take out. There are a lot of good systems so that will be up to you or the system your local auto paint supply house sells.

Rootsy
05-07-2003, 11:31 AM
FWIW,

my red stripe (top and side) get very oxidized and develop a white haze and turn almost pinkish if left in the sun for a matter of maybe a week...

i find that 3M super duty compound on a 2000 or so rpm buffer with a 3M foam compounding pad does the trick. takes about 3 go arounds before it removes it and makes it "RED" again... you'll know when it begins cutting, generally on the second round after it strips the wax, etc...

Jamie - "red again :) "

smokediver
05-07-2003, 12:20 PM
Making the finish come back to near new isn't really as hard as it is time consuming..You didn't say if it was a dark or light color.What you want to do is remove the oxidation with the least amount of abraisive.. So you want to start out backwards and once you find the right one go from there.super duty 3m is about the most aggressive on the market.I would use a white wool pad for that product.Now then you need to reduce the size of the scratch or swirl left by the compound.switch over to a white foam cutting pad and use 3m perfect it 3 compound. it is white and will reduce the swirl marks. from there use machine glaze with a black foam pad. this will make it look like a mirror.. and they have machine glaze for dark colors. after that apply a wax in the shade and really let it dry well..and then remove the haze and wax again.you will go through these steps if you wet sand just after the sanding is done. I have been doing this for years as a side job.. here is a 36 hinckley picnic , yes it is painted but it is the same theory, make the swirls as light as posible.
http://www.donzi.net/photos/jtay1.jpg

Fish boy
05-07-2003, 12:27 PM
Smokediver, that sure is a purty boat. Love the lines, and the finish looks great.

Digger
05-07-2003, 01:29 PM
good info there guys, thx.

that Hinckley is beautiful. But I still can't believe the arrogance of Hinckley to sue a handful of boatbuilders for "infringement of trade dress". Like they invented the most beautiful sheerline. puh-leeze.

oldLenny
05-07-2003, 04:53 PM
On a side note, gel-coat is a porous polyester resin. It cuts well, shines like new again, but the surface is changed and no longer has the chemical properties (polymer cross-linking)and porosity levels it had before it was "cut". A cut/sanded gelled hull will fade faster than a new untouched one of equal shine.

Porosity and lack of, and reasons for the advent of Vinylester and Isothalic resins(gel-coats)are due to "blistering and osmosis issues" as well as mechanical flexibility. Our boats don't sit at marinas in the water for extended times so this is not an issue, but one to be considered.

Gel-coats and resins rank for water resistance in this order.
Best-Vinylester
2nd- Isothalic
3rd- everything else (general purpose)

Most new hulls today, when cost is not as much of an issue employ Vinylester gel-coats, skin outs and lay-ups, or Vinylester for gel-coat and skin out and then an ISO for the lay-ups.

Donzi and others today use Hydropel vinylester resins and gels. An AOC product.

Jamesbon
05-07-2003, 07:20 PM
Here are the FACTS as I experienced them.
1) Shot new gel
2) Wet sanded with 400 on a flat block
3) Wet sanded with 600 on the same block
4) Wet sanded with 800 on a block
5) Wet sanded with 1000 on a block
6) Buffed with 3m buffing compound using a non orbital pneumatic buffing wheel.

Results: Looks and feels like new :D

1996Z15
05-07-2003, 07:47 PM
Wow guys; thanks for the great information. I am hoping to start polishing the boat this weekend. I'm sure it will take a few wekends and I will try to post pictures hwne I'm done. I think I'll try the different compunds before I resort to the wetsanding. Wish me luck.

1996Z15
05-07-2003, 07:47 PM
Wow guys; thanks for the great information. I am hoping to start polishing the boat this weekend. I'm sure it will take a few wekends and I will try to post pictures when I'm done. I think I'll try the different compunds before I resort to the wetsanding. Wish me luck.

Moody Blu'
05-07-2003, 10:23 PM
I cant wait to buff my boat out Finally! :cool:

DOND
05-08-2003, 11:22 AM
I just had the cockpit and deck on my 69' 16 regelled. I did all the prep work and had a pro shoot it. I am now doing the finishing part of it.
My fiberglass guy suggested the following:
Wet sand 400
wet sand 1000
wet sand 1500
buff with Malco cutting creme.
I had started to use 3m super duty but he suggested the Malco.The Malco is great, it buffs to a much higher gloss than the 3m,when going over the buffed area with a glaze you can hardly notice a difference between the two.
Don

blue-z
05-08-2003, 11:38 AM
I went to the next step of 2000 paper. I did not use and aggressive compound as I found it counter productive. I went 800 in spots where needed followed by 1000. Next I used 1500 over whole hull followed by 2000. I then used finesse-it-2. The boat looks nice. I would rather be cool water sanding on a hot day with a cold beer in my hand then powdery compounding with dust in my beer. I also polished my prop with 1500, 2000 with water mixed with dishwashing soap and it is awesome.

1996Z15
05-10-2003, 10:12 AM
Before I start sanding or polishing the boat can anyone tell me if there is a way to tell if the boat has it's original gelcoat or if it's been painted.
I'm scared to death that I'll ruin the paint.

knee deep
05-11-2003, 05:26 AM
For what its worth I just did the 18. I had 582 opinions and finally listened to the guy at Joe's Auto Marine, here, in Fort Lauderdale. I rolled three coats of gel, then:

1) wetsand with 320 using an orbital
2) wetsand with 320 using a file index
3) wetsamd with 600 using a block
4) wetsand with 1000 using a block
4) buff with Aquabuff Blue Compound

I agonized over the paint vs. gelcoat issue for months. I finally got a sample of the original color from Minikote and had a 5 gallon pail of the stuff mixed at my local paint supplier. Boy, it was a pain in the neck but the hull looks great and better than factory new.

I'm really glad I did it, what I feel is the right way.......................