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Refurbishing a pre-71 Sunfish Gelcoat

br549

New Member
To All,

We just acquired a pre-71 Sunfish that needs some gelcoat restoration. The glass fiber cloth is showing through the gelcoat on the bottom of the boat. What materials should I use? 3M Gelcoat? Epoxy? Automotive epoxy and urethanes? Brands? Methods? I am an experienced hobbyist and auto restorer. I figure that I would sand the existing gelcoat smooth and apply several new coats.

Is there any reason to preserve the tan color? It looks spoiled milk brown. Any concerns about updating it? Is it worth more as a vintage unit?

I have a new rudder to install, but see the bracket is narrower than the indent for the old draw pin in the transom. I will probably need to install an inspection cover. Where should I buy an inspection cover?

fortunately, the hull has been inside a garage for the past 25 years and is clean otherwise.

What are the two brass screws for on the top of the deck? ARe they drain plugs? Any thoughts or suggestions?

Thanks for your help,

BR549
 

minifish

New Member
To All,

We just acquired a pre-71 Sunfish that needs some gelcoat restoration. The glass fiber cloth is showing through the gelcoat on the bottom of the boat. What materials should I use? 3M Gelcoat? Epoxy? Automotive epoxy and urethanes? Brands? Methods? I am an experienced hobbyist and auto restorer. I figure that I would sand the existing gelcoat smooth and apply several new coats.

Is there any reason to preserve the tan color? It looks spoiled milk brown. Any concerns about updating it? Is it worth more as a vintage unit?

I have a new rudder to install, but see the bracket is narrower than the indent for the old draw pin in the transom. I will probably need to install an inspection cover. Where should I buy an inspection cover?

fortunately, the hull has been inside a garage for the past 25 years and is clean otherwise.

What are the two brass screws for on the top of the deck? ARe they drain plugs? Any thoughts or suggestions?

Thanks for your help,

BR549

As far as recoating the entire thing, if gelcoat is too thick it will crack. So you might want to see about adding gelcoat to the low spots and buffing/wetsanding the rest. Mine had terrible oxidation. It was like chalk and would turn your hands white. I got it back to enough of a shine that I slide off and into the water more easily than I'd like. I could spend more time on it and get it to look like glass, but I'd rather be sailing.

Gelcoat isn't too bad to work with and it can take a serious beating. If you've done body work before, that will help. One of the best things about it is with matching colors. Gelcoat is the same shade wet or cured. So as you match the color, just don't add hardener until you figure out your ratios of tint and you can just wipe it off.

I used west marine's gelcoat. It was fine.
There's two ways you can buy it, waxed and nonwaxed.

The waxed is made for one single application. I haven't used that version but the wax is supposed to rise to the top as it cures and block exposure to air so it will harden.
The nonwaxed will cure to a tacky finish so you can put another coat on without any prep. It will require something like PVA mold release to keep air off of it for it to fully cure.

The store will tell you to get that "make a sprayer" deal. You pour your substance of choice into the glass jar, screw on this valve full of compressed air, and voila, you have a spray can la-tee-da, and you ride your unicorn down the rainbow and out to your car with roses shooting out of your butt. :rolleyes:

It doesn't work that nicely. Both the gelcoat and PVA mold release are too thick. I ended up painting on the mold release because I wasn't sure how to thin a water based liquid (maybe more water, but I had done a bunch of work to my boat and didn't want to risk ruining it). Gel coat is easy-just thin with acetone.
If you can spray it, do. Much, much better results and less finishing work.
 

NightSailor

Captain
As far as recoating the entire thing, if gelcoat is too thick it will crack. So you might want to see about adding gelcoat to the low spots and buffing/wetsanding the rest. Mine had terrible oxidation. It was like chalk and would turn your hands white. I got it back to enough of a shine that I slide off and into the water more easily than I'd like. I could spend more time on it and get it to look like glass, but I'd rather be sailing.

Gelcoat isn't too bad to work with and it can take a serious beating. If you've done body work before, that will help. One of the best things about it is with matching colors. Gelcoat is the same shade wet or cured. So as you match the color, just don't add hardener until you figure out your ratios of tint and you can just wipe it off.

I used west marine's gelcoat. It was fine.
There's two ways you can buy it, waxed and nonwaxed.

The waxed is made for one single application. I haven't used that version but the wax is supposed to rise to the top as it cures and block exposure to air so it will harden.
The nonwaxed will cure to a tacky finish so you can put another coat on without any prep. It will require something like PVA mold release to keep air off of it for it to fully cure.

The store will tell you to get that "make a sprayer" deal. You pour your substance of choice into the glass jar, screw on this valve full of compressed air, and voila, you have a spray can la-tee-da, and you ride your unicorn down the rainbow and out to your car with roses shooting out of your butt. :rolleyes:

It doesn't work that nicely. Both the gelcoat and PVA mold release are too thick. I ended up painting on the mold release because I wasn't sure how to thin a water based liquid (maybe more water, but I had done a bunch of work to my boat and didn't want to risk ruining it). Gel coat is easy-just thin with acetone.
If you can spray it, do. Much, much better results and less finishing work.

Very Nice blog on the Minifish. I wish we could see more of the steps involved. You do beautiful work. It looks just gorgeous--like new. Thanks for sharing your experiences with us. Valuable stuff! How many hours did you put in on that project?

Regarding Gelcoat tinting. I haven't done that yet. I've been told the color match is the hardest part, and that there is a change in tint when it dries. It is reassuring to hear some first-hander's experience I can trust. One fellow told me he used the paint department at home depot for tinting.

I've had one problem uisng gelcoat with surfacing wax. At times there was not enough wax for a cure. I've found that it is important to have thicker coats of gelcoat, when it is too thin, not enough wax comes to the surface and cure rates are very slow or it simply won't cure. Also, thicker gelcoat adds heat and helps it kick off and save time waiting for it to cure.

I've used wax paper to block the air--which leaves lines and wrinkles, but works. I've tried using spray on wax like Pledge with poor results. I've also tried spraying mold release and it caused little pits in the gelcoat.

The built in wax seems to work the best for repair--if the gel coat is thick enough, and the weather is dry. High Humidity, or worse--rain, will ruin your work too.

Also Cab-o-Sil, SiO2, is a high surface area product that makes a nice thickening agent. It is white. In small amounts it works great as a thickening agent for gelcoat. $100 buys a bag as big as a man, and it is so light it wants to float away.

On larger boats, I use equal volumes of gelcoat and Cab-O-Sil for non-skid--rolled on and left rough--or sanded slightly--leaves a nice non-skid surface.
 

minifish

New Member
Very Nice blog on the Minifish. I wish we could see more of the steps involved. You do beautiful work. It looks just gorgeous--like new. Thanks for sharing your experiences with us. Valuable stuff! How many hours did you put in on that project?

Hey thanks :D

About the hours, I'm not sure I even want to count.
Had I kept track, I might have shucked it off a cliff. :p
I'm having difficulty even estimating. Weather played an important role since it gets over 100* here. Many days I had to stop around noon when the shade ran out.

When I finally took her out, all those long hours were easily forgotten. I'll just say that. Though I do remember being able to move around that boat a lot easier when I was a kid. :eek:
 

NightSailor

Captain
Hey thanks :D

About the hours, I'm not sure I even want to count.
Had I kept track, I might have shucked it off a cliff. :p
I'm having difficulty even estimating. Weather played an important role since it gets over 100* here. Many days I had to stop around noon when the shade ran out.

When I finally took her out, all those long hours were easily forgotten. I'll just say that. Though I do remember being able to move around that boat a lot easier when I was a kid. :eek:

It is hard work. And it is worth it when the project is done. This is one way in which anyone can buy a cheap boat, fix it up and have fun, without it costing a ton of money.

I really admire your gel coat work. I wish my skills were as good in that area. You must have more patience than I do. I'll work on that. To make it look so perfect is certainly a daily tribute to you.

Now that I'm older, I can't move around very easily--one reason I like keelboats. I'm 6'4" 250 lbs and not as limber as I once was. When I gybe a Sunfish I can seem to hold on to either the tiller or the mainsheet! <grin>

I've done my time on boat repairs. Here is a horror story for you--over 1000 man hours. Cheap boat, but tons of work. In this phase: Two months, with two people, my brother and I, and this was not all the work we did (see pictures). We worked about 12 man-hours total per day, excluding rain days on this project.

It gets hot up here too. I try to do most of my dirty work in the spring. This year I'm planning on a air conditioning system for my big boat's interior work since it will be hot and the wind dies when it does. Otherwise, in an oven, I won't get anything done.

http://sports.webshots.com/album/152458492GHeWXX

Last season a November storm broke one of my dock lines when I was out of the country, and banged up the sides. So I have a bit of repair work to do and some repainting when I haul out on June 12th.

My next big job is installing a new interior on this boat. I have some ideas to create a very durable interior that will last the life of the boat. I also want my new motor to be very quiet so I've designed a new enclosure which will be lined with a lead blanket, special paint, and encapsulated foam. It means lots of grinding fiberglass, tabbing in fiberglass panels, grinding up the excess, and more of the same.

Despite all this work, at some point, I'd like to find a still bigger US built boat that needs a new interior and refit it to USCG inspected standards for charter work. I plan to buy a pressurized suit and graphite lubricated compressor for my next big project to give myself clean air to breath, and to keep the fiber dust off my skin.

Here is another project, that I'm still working on. Hope to have in done soon. I'm installing deck hardware right now. I still have some gelcoat work to do, but I can finish that up later one. I want to get it sailing. I did most of the work, with some help from two friends Chris and Patty, and my Uncle Tom. No idea on the hours on this one. Nasty dirty work grinding fiberglass and more sanding than I care to think about. The boat is very strong now, and designed so that water can't get into the core. The deck is stiff enough that it can take major abuse. The flange around the tub is now reinforced so that it won't crack--as is common on these boats.

http://good-times.webshots.com/album/560166062GlPvzp
 

Stevefirsthome

New Member
One of the best things about it is with matching colors. Gelcoat is the same shade wet or cured. So as you match the color, just don't add hardener until you figure out your ratios of tint and you can just wipe it off.


One of those lightbulb moments, this. I've struggled to get the colour right, it didn't occur to me to mix it before adding hardener. What a dope! Thanks
 

mixmkr

Well-Known Member
old thread...
but, matching colors precisely is about 98% of the expertise in gelcoat. Although you may think it matches, realize your newly applied surface texture is totally different than what you may be trying to match. It "may" LOOK smooth...but believe me, once it's sanded and final buffed, you may be surprised. There are probably as many shades of white as there are colors too. Not to shy people away, but doing good gelcoat work isn't rocket science but experience goes a loooong way. Kinda like painting a car, maybe??
>>>>when you add that first TINY DROP of black to your white, to make it "off white".... you then realize it is waaaaaay to dark and no way to turn back except to start over. One drop of black can be "deadly"!!
 

L&VW

Well-Known Member
The glass fiber cloth is showing through the gelcoat on the bottom of the boat. Any thoughts or suggestions?
My guess is that the glass fiber cloth "that's showing" is probably on the keel—on opposite side to the bailer's position. That's a circumstance from just moving the Sunfish around—not a real hazard—and will likely occur again after the repair.

"Situation normal". Go sailing instead. :)
 

andyatos

Well-Known Member
One of the best 2 part videos I've seen on how to get a perfect color match for existing gelcoat, whether the gelcoat is new or old. It's just as mixmkr says. There's a real art to it... but way easier when you have this kind of step by step video instruction.

Here's the video. Starting with Part 1.

- Andy
 

mixmkr

Well-Known Member
One thing I've also experienced with patching/repairing older gelcoat is that "todays" repair may look great. Two years+ down the road, it becomes readily apparent that the different aged gelcoats don't look the same color anymore. That isnt typically a major problem but it isnt uncommon either.
 
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