Hobie Cat Forums

It is currently Wed Apr 16, 2014 5:42 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 10 posts ] 
Author Message
 Post subject: Gelcoat Removal
PostPosted: Mon Nov 19, 2012 12:38 pm 
Offline
Site Rank - Captain

Joined: Mon Sep 17, 2012 6:56 pm
Posts: 57
Location: Durham NC
It's winter time and the boat is completely apart. I want to paint my hulls Carolina Blue (they are white now) but I'm going to go the gelcoat route instead of paint. Any recommendations for finding that color gelcoat? Hulls are in excellent condition so no need for fiberglass repairs.

I have the time, space, and tools. What I don't have is experience. So from doing some searching here is what I've come up with.

1. Clean the hulls thoroughly of any dirt, debris, grease. Thinking just good old dish soap and water.

2. Break out the orbital sander and start with 80-100 grit. After a good sanding all around wipe it down with some acetone.

2. Do another round of sanding around 300-400.

3. Right before I gelcoat wipe it down with acetone once again.

I remember reading somewhere that I need to make sure I remove the wax out of the gelcoat before I start spraying the new gelcoat. Is that accomplished with the acetone or should I use something else? Any recommendations?

Am I missing any important steps or is this fine? Considering I am going from white to blue should I remove the anti skid on top and then redo it according to some previous posts? Or can I just spray the new gelcoat on top of the antiskid to turn it blue?

Just want to be sure I get the specifics right and collected all in one place. Hulls are hanging from my rafters in my garage in suspended anticipation. I know some of you are going to try to convince me to just paint it but I'd appreciate responses to doing this with gelcoat, not paint.

I'm sure I'll have more questions about spraying the new gelcoat in a couple of months when I'm done sanding and prepping.

Thanks in advance.

_________________
1984 Hobie 16


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Mon Nov 19, 2012 1:47 pm 
Offline
Site Rank - Captain

Joined: Sat Apr 14, 2012 1:38 am
Posts: 54
I just did mine so I have a couple of suggestions:
1) I would skip the 300 grit step. The gel will cover up the 100 grit marks and I think the rougher surface will actually let it get better purchase.
2) Where I am I can go to a local company (fiberglass Hawaii, in my case) and get gelcoat precolored in about a dozen stock colors. If you have something like that where you are you might want to think about going with a stock color. The thing is that in the future you are going to want to patch it and with a stock color getting a color match will be easy (plus or minus fading).
3) I did mine using foam brushes instead of spraying. I think the spraying will give a much better result, but will obviously be a pain. If you were to end up doing it with a brush, I would recommend using dixie cups for mixing the resin. I premixed a whole gallon of the gelcoat with the surfacer, but obviously did much smaller batches with the catilist. I started out with about 1/2 cup but found I could not get the whole thing on before it started to setup. A 5oz dixie cup filled about 1/2-3/4 full was perfect as far as what I could get on before it started to setup.
4) On one batch I did not get the catilist mixed well enough and I ended up with spots that never setup. What a pain to clean it back off with acetone. Make sure each batch is super well mixed all the way down to the bottom corners of the mixing container.


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Mon Nov 19, 2012 7:17 pm 
Offline
Site Rank - Captain

Joined: Mon Sep 17, 2012 6:56 pm
Posts: 57
Location: Durham NC
Thanks for the tips. I'll definitely be spraying. I'm definitely looking for a "stock" blue if possible. I don't have any good boat stores that would stock gel coat close by. There is a west marine about an hour from me.

Did you just wipe down with acetone to remove the wax out of the old coat?

I still got about 3-4 hours of prepping the hulls before I can sand. Just took off the pinstripes off the right side. Pretty straightforward with a heat gun. Except for the ones on top that had tears all over the place. Not looking forward to removing the adhesive that stayed behind. Hoping a good wipe with some rubbing alcohol will be sufficient.

Btw I found about a handful of fiberglass flakes/strips floating around inside the hulls and coming out the drain holes. Something to be worried about?

_________________
1984 Hobie 16


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Mon Nov 19, 2012 8:11 pm 
Offline
Site Rank - Captain

Joined: Sat Apr 14, 2012 1:38 am
Posts: 54
I'm not sure about all the colors, but Fiberglass Hawaii's 'international orange' looked quite a lot like the Hobie stock orange for my Hulls. I have another set of Hulls I will redo some day, and I am thinking of blue. I am looking at their 'neon blue', and thinking it looks pretty similar to what I have seen on stock blue Hobies.
Of course Fiberglass Hawaii is on the way to the office for me, but I think you can also get their stuff on the mainland as they have a shop in California.

I sanded and then wiped my hulls well with Acetone. I have not had any adhesion problems except at the very bottom of the hulls where I did not sand well enough and then dragged the hulls around on the sand before the coat was 100% hard.

http://fiberglasshawaii.com/resins/resi ... lcoat.html

If I was not going to buy the pre-colored gel coat, I would think hard about using regular polyester finishing resin and coloring it instead. I'm not quite sure about the surfacing agent thing required for the gel-coat and not quite comfortable that I ended up with as hard and as non-sticky a surface as I would normally expect from regular resin.


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Mon Nov 19, 2012 11:47 pm 
Offline
Site Rank - Old Salt

Joined: Thu Apr 24, 2008 3:58 am
Posts: 560
Location: Knoxville, TN
I've sprayed gel a couple of times so I'll pass on some relevant advise. You mentioned separating the wax from the gel - just buy wax that doesn't have gel mixed in it in the first place, like this stuff: http://www.fiberglasssupply.com/Product ... coats.html, scroll down to part number F57-2940. Mix up your first coat with the catalyst per the instructions. It will set up, however, the micro thin layer in contact with the air will remain tacky - that's a good thing because subsequent coats will adhere to it. I typically wait 30-45 minutes between coats. If you try to put on coats that are too thick, the gel will run. Don't be greedy, multiple thin coats work best. When you put your final coat on, go with a mixture of 50% Duratec High Gloss Additive, also available at Fiberglass Supply, part number F60-0175. The Duratec will make the finish coat very glossy, and it'll harden without a bunch of orange peel effect. It also causes the top coat to dry hard. Be careful not to spray with too much pressure or hold the spray nozzle too close to your work or it will cause dimples. I learned this the hard way. The good thing is that even if your finish doesn't come off nice and smooth, it can be sanded smooth, polished, and look great. Gel coat is forgiving, just have a good power sander. If you sand too hard, you may have to spray some touch up gel in places, this is pretty common.

Decks are tough to deal with. Gel coat will gum up the non-skid pattern in the decks. If you aren't concerned with class racing rules, you might consider sanding the decks smooth. Once there, you can either leave them smooth or try to replicate the pattern with a mold, as per previous posts. Here's another idea - you may consider leaving the decks white and just gel-coating the hulls below the decks. Two-tone hulls were standard from the factory in the 70's, and white on blue (actually a shade close to Tarheel blue) was one of the legacy combinations. If you leave the deck white, coat it with Poliglow and it'll yield a high gloss shine while preserving the pattern on the deck. I used this on my decks and the results were fantastic. Here's the Poliglow link: http://www.poliglow-int.com/.

You can find some pre-mixed colored gel coats here: http://www.fibreglast.com/category/Resins. They claim to be able to match 900 colors.

Let us know how your project turns out.

_________________
Mark Van Doren
Division 9 Chairman
H16 #112205 (Richard Petty Signature Edition)
H14 #47787
H20 #647 (sold)


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Tue Nov 20, 2012 6:33 pm 
Offline
Site Rank - Admiral

Joined: Tue Feb 03, 2009 6:53 am
Posts: 225
Location: Storm Lake, IA
MVD wrote:
If you aren't concerned with class racing rules,

This is from the rule book...
9.6 Non-skid surfaces on decks may be changed
provided the non-skid surface is at least equal in
size and location to the originally designed area.


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Tue Nov 20, 2012 6:43 pm 
Offline
Site Rank - Captain

Joined: Wed Aug 08, 2012 9:43 am
Posts: 51
Location: NJ
I have been restoring my hulls on my h18 and used a soda blaster on the non slip decking. It worked pretty good i would say its the equivilant to 300 grit . So it would probably leave a good base to spray gel over without losing the original non slip


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Tue Nov 20, 2012 7:24 pm 
Offline
Site Rank - Captain

Joined: Thu Jun 21, 2012 10:24 pm
Posts: 32
passingwind wrote:
I have been restoring my hulls on my h18 and used a soda blaster on the non slip decking. It worked pretty good i would say its the equivilant to 300 grit . So it would probably leave a good base to spray gel over without losing the original non slip


What type of soda blaster setup do you have? I was thinking about trying that as well.


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Tue Nov 20, 2012 7:33 pm 
Offline
Site Rank - Admiral

Joined: Tue Feb 03, 2009 6:53 am
Posts: 225
Location: Storm Lake, IA
You want to ruff the surface before spraying the Gel. Like 80 grit sand paper 300 grit is too smooth. If your sanding the old gel down then don't waste time cleaning the hulls before sanding. sand with a orbital sander 80 grit then clean very well with acetone and spray.
Temperature is very important! should have 80 degrees Surface(of what your spraying), air, and Gel temp for the best results.
New Gel is also important! Gel has a shelf life. Make sure your buying fresh Gel... ask them. If they don't know how long its been sitting on their shelf don't buy it.
I have had good results with..
http://www.uscomposites.com/polyesters.html
You can call them with questions and they seem more then happy to give you the info you need and then some.
BTW they show 3 different blue pigments
http://www.uscomposites.com/pigments.html


Top
 Profile  
 
 Post subject: Re: Gelcoat Removal
PostPosted: Tue Nov 20, 2012 7:37 pm 
Offline
Site Rank - Captain

Joined: Wed Aug 08, 2012 9:43 am
Posts: 51
Location: NJ
DonP wrote:
passingwind wrote:
I have been restoring my hulls on my h18 and used a soda blaster on the non slip decking. It worked pretty good i would say its the equivilant to 300 grit . So it would probably leave a good base to spray gel over without losing the original non slip


What type of soda blaster setup do you have? I was thinking about trying that as well.


Its one from eastwoods. Not that much. I taped off all but the non skid and it came out pretty well. My hulls were badly oxidized so it left a little haze in spots but a thoisand times better ghan it was.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group