How do I gel coat my hull?

Snouch

Seaman Apprentice
Joined
Apr 12, 2013
Messages
31
Hi everyone, I'm new this this forum, I just purchased my first boat 14 foot fiberglass ( cottager boats) , my hull has lots of deep scratches all over the hull, I wanted to gel coat it using a roller and brush method, but don't know the steps involed,
I have been reading and watching YouTube videos for the past 2 weeks, if any one has done this before please help.
I would like to put a couple of coats on, my boats hull colour is white, and will be staying that colour. Any help would be awesome.
Just want some info on sanding, cleaning hull with what solvent after sanding, then next step and so on.
Thanks
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Re: How do I gel coat my hull?

First of all welcome to iboats. :welcome: Good to hve you aboard...

Personally I have never used any Gel Coat for anything. I'm sure others will chime in here and explain the process. But I'm sure you will have to fill all those scratches first before applying anything over them. So be prepared for doing some sanding for starters. And remember that preparation to any finish is the key to how well it comes out. Anything you even think is not correct will certainly show through in the final finish... With that stated, you can make your new (to you) boat loook amazing I'm sure. And post some pictures to show everybody what you are dealing with for starters as well. Pictures convey a lot of info and are most of the time more informative then words...
 

tpenfield

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Staff member
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Jul 18, 2011
Messages
17,620
Re: How do I gel coat my hull?

You might be able to get decent results from 'rolling & tipping' of gelcoat . . .

your challenges will be:

filling in the scratches gouges on the hull and getting it all smooth and sanded.

Thinning the gelcoat properly so that it will flow out before hardening

working in small batches and going fast enough so the gelcoat does not set up on you.

Spraying is a better way to go, as the application can be faster than roller & brush.

If your boat only has a few scratches, it may be worth doing individual repairs rather than a prep and coat. If the scratches are numerous and/or the existing gelcoat is in poor condition, then a re-coat would be the way to go.

Post some pics as you go.
 

Snouch

Seaman Apprentice
Joined
Apr 12, 2013
Messages
31
Re: How do I gel coat my hull?

Thanks for the info, i prepared for sanding, i will be starting this project hopefully tomorrow, i just waiting for some friends to come by and help me flip my boat.i will post pics once i flip the boat. what do i use to thin out the gelcoat. the gel coat that im using is finish gelcoat. i just want to hopefully lay 2 coats down. After i sand is down what do i clean the hull with? just water and wipe it down,???
 

DeepBlue2010

Lieutenant
Joined
Aug 19, 2010
Messages
1,304
Re: How do I gel coat my hull?

My advice would be to slow down a little and don’t take on this project until you are ready for it. No offense, but despite what you said about spending 2 weeks reading and watching how to videos, you still don’t know how to thin GC. As our gel coat experts stated in this forum multiple times, GC is not paint and it will not level as paint. Roll and tip results will be very questionable for GC. The one and only time Ondarvr (iBoats GC expert) OK(ed) it for someone, he was from England and the consensus were that GC in England is specially formulated for rolling. Other than that, I never came across an expert recommendation to roll GC. Read this thread, I do believe you will find it useful in your situation. Best of luck to you.



http://forums.iboats.com/boat-restoration-building-hull-repair/gelcoat-stage-help-needed-465692.html
 

zool

Captain
Joined
Aug 19, 2012
Messages
3,432
Re: How do I gel coat my hull?

You know, there is no rule that you have to gel over gel...most ppl choose a paint system...its usually more cost effective and the results can be VERY acceptable. Gelcoat makes a nice base to prep over so no need to remove it all. Look into Interlux Brightside or the like. Which ever you choose, try to stick with one product line for primer/paint/hardeners and thinners as they are chemically formulated to work together, the spec sheets provided by the manufacturer will advise which products work best with each other....Keep in mind the air temperature plays a roll in which accompanying products to choose, again, its all in the spec sheets.
 

greenbush future

Lieutenant Commander
Joined
Aug 28, 2009
Messages
1,814
Re: How do I gel coat my hull?

Pictures of your project will really help the experts here, I'm not one of them, but I do agree that most of the projects that are finish related here are paint not Gel coat. I bet you will have better luck.
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
Re: How do I gel coat my hull?

If you've never gelcoated you really need to research and study up on the application of it. It's totally different than paint. As others have said, for the DIY'er it's usually much easier to paint but, having said that, we have several DIY'er members who have done great jobs on gelcoating their hulls so it can be done by the diy'er too!!! You just need to know what you're getting in to before you attack it.
 

Yacht Dr.

Vice Admiral
Joined
Feb 26, 2005
Messages
5,581
Re: How do I gel coat my hull?

Hi everyone, I'm new this this forum, I just purchased my first boat 14 foot fiberglass ( cottager boats) , my hull has lots of deep scratches all over the hull, I wanted to gel coat it using a roller and brush method, but don't know the steps involed,
I have been reading and watching YouTube videos for the past 2 weeks, if any one has done this before please help.
I would like to put a couple of coats on, my boats hull colour is white, and will be staying that colour. Any help would be awesome.
Just want some info on sanding, cleaning hull with what solvent after sanding, then next step and so on.
Thanks

Hello mate and welcome to Iboats :) ..

80 grit profile then acetone wipe . Mask off.. then spray your gel for 4 coats of a Medium to heavy spray.

Wetsand and buff out the orange peel that comes with gelcoat. ( sometimes its starting with 320 or 400 .. depends on how well it sprayed on :) ) .. surely sand with 800-100- grit before you buff it out.

PVA your sprayed on Gel .. when its just about Dry ;) ...

YD.
 

Snouch

Seaman Apprentice
Joined
Apr 12, 2013
Messages
31
Re: How do I gel coat my hull?

5.jpg1.jpg2.jpg3.jpg4.jpgHi
So I flipped my boat so I can start my project and notice lots of cracks also in the hull. So now I'm in need of some advice on how to repair the cracks. These shots are from my cell phone. You can't see the cracks, but theirs lots. I have circled in orange all the scratches and cracks area. So I think gel coating my boat would be a good idea.
I have 120 grit sand paper, I don't want to sand it all down but just enough to make the gel coat stick to the hull. I will sand all scratches and cracks I little deeper. Then wipe down with acetone, then apply my first coat of gel coat, then sand again, and apply another coat and so on until I apply about 4 coats, does that sound right . Also I with be applying with a roller and brush? I own a automotive sprayer would that work, I know how to use it properly, just don't know if it would work with gel coat and how do I mix it so I can spray. Also Yacht Dr said it PVA after spray. What's PVA, lol remember I'm a newbie.
 

zool

Captain
Joined
Aug 19, 2012
Messages
3,432
Re: How do I gel coat my hull?

Your right, I cant really see the cracks, but they may be just blisters. You may have to grind those down slightly to glass, then build them back up to flush, then fair them out smooth, or they may return.

I would spray the gel since you have the boat flipped with good access. You will most likely need to thin the gel some depening on the tip your gun accepts. If you thin it with like Duratec, its a glossing additive that will thin it and give you a nice clear coat shine.

Thats just my two cents, but the gel guys here will help you thru it all im sure. I like single stage 2 part paint, but thats just me...

I sure with I didnt need to use bottom paint, I like the shiny bottoms with no cut line along the hull, but im in salt.
 

Decker83

Commander
Joined
Apr 5, 2011
Messages
2,592
Re: How do I gel coat my hull?

Hello mate and welcome to Iboats :) ..

80 grit profile then acetone wipe . Mask off.. then spray your gel for 4 coats of a Medium to heavy spray.

Wetsand and buff out the orange peel that comes with gelcoat. ( sometimes its starting with 320 or 400 .. depends on how well it sprayed on :) ) .. surely sand with 800-100- grit before you buff it out.

PVA your sprayed on Gel .. when its just about Dry ;) ...

YD.

You really need to listen to YD.. He knows what he is talking about..
You can forget anything you know about painting because they don't apply to gel coat..
The PVA is a chemical (in your case) that should be sprayed on after the gel coat is applied as YD has stated..Gel coat will not cure properly when exposed to the air.. PVA can be found at US Composite web site..

When the gel coat is properly catalyzed it can be used for about 15 minutes making it hard to roll and tip.. Gel coat will not flow out level on its own making it hard to roll and tip.. Mixing to much at a time can shorten the time it takes to setup or kick..

Gel coat is very expensive to use..

I don't think you should roll on a coat and sand between them..
Just my 2 cents..

Good luck with your adventure..
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
17,620
Re: How do I gel coat my hull?

Awlgrip may be a better approach than gelcoat . . . once you have prepped the surface and filled cracks, scratches, etc.
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
Re: How do I gel coat my hull?

You can't use an automotive sprayer for gelcoat. As previously stated, You really need to Read and Study up on the proper methods of applying Gelcoat. It's NOT like applying paint. You DON'T sand between coats. It's a polyester based product that sets up fairly quickly and goes on fairly thick. It requires a significant amount of sanding After it has been applied. Read and Study. That's my advice.
 
Joined
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Re: How do I gel coat my hull?

Cute boat. I would paint it. Probably cheaper, faster, and less hassle. More time on the water. FWIW
 

zool

Captain
Joined
Aug 19, 2012
Messages
3,432
Re: How do I gel coat my hull?

"You can't use an automotive sprayer for gelcoat"

Well, he can per say...but only if his hvlp gun accepts a big tip,like 2.0+...2.5 would be best, and if hes fast enough to clean it between each fill before the thinned gel kicks......A cheap resin/gel spray gun would work better...
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
Re: How do I gel coat my hull?

I stand corrected. This ^^^ is correct IF all the conditions as stated are met. But NOT as setup to spray a car, and that is what I was alluding to.
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
Re: How do I gel coat my hull?

"You can't use an automotive sprayer for gelcoat"

Well, he can per say...but only if his hvlp gun accepts a big tip,like 2.0+...2.5 would be best, and if hes fast enough to clean it between each fill before the thinned gel kicks......A cheap resin/gel spray gun would work better...

Yes it would have to be at the very very least a 2.0mm tipped HVLP gravity spray gun or a better gun would even be a 3.0mm tipped. But even with that, I'm sure the pressure would have to be increased as well. Usually an automotive HVLP spray gun is 1.3mm and needs around 35 PSI going into the gun so you have the 10 PSI on the tip (OSHA demanded in pro shops). But with such a high viscosity medium like Gel Coat, it would probably splatter out of the gun instead of atomizing like normal automotive paints are sprayed. And if you want to keep that spray gun, it would have to be immediately disassembled and cleaned promptly too...or it will be a throw-a-way... Since the do make such quality epoxy and catalyst paints of every shade imaginable, I would seriously consider going that route. But it is your boat and it can be done and will yield a nice finish if done correctly... just my 2 cents worth... :)
 
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