There are two more solutions, and in my opinion more reliable options, for curing gelcoat on an exterior surface.

1) Duratec gelcoat additive thins the gelcoat slightly so it will spray a little better and it also acts to promote curing of the gelcoat in open air - you don't need any additional additives to spray and cure. Reportedly the duratec cures the gelcoat harder than it would on it's own.

2) top coat with PVA (poly-vinyl alcohol). After you spray the gelcoat, you can spray a layer of PVA ontop of it to seal it from the air and allow it to cure. The PVA forms a "saran-wrap" esque coating that will peel or wash off easily once everything is cured. It is very water soluable and I use it all the time when I'm molding things to prevent resin from sticking to my molds.

Good Ideas Jake !!!

... those products just were not availible when I did most of my boat repair work. I started to become "Hyper-Sensitive" to the solvents and haven't done any major work for a number of years. I was stupid about taking baths in solvents ... dust masks .... etc

I've heard of such products , I just don't have personal experience w/ them ... but I've heard positive whisperings ..... I do have some small repairs to do (bows)....

The problem that took me the longest to reconize/understand/solve was the compressor oil contamination .... it was random.

Harry Murphey

I use a filter at my spray gun that screws inline before the quick disconnect fitting. I've not had any trouble with oil or water....knock on something.

Everything Jake says and... Spraying gel is pretty easy, and gel is very forgiving if you mess up. Definitely use Duratec, and you may need to thin it a bit more to make it flow. Use laquer thinner to thin it instead of styrene. I find that 3%+or- LT makes gel flow much better. Styrene yellows after a few years of UV exposure. You just have to take it a little slower with the coats.

Also, it doesn't take an expensive rig to get a good gel coat finish. Go up to your local Kragen, ect. and pick up one of their cheap gravity guns (no suction feed) on sale for $13.99. I swear you can't tell the difference between my $400 pro auto gun and the cheapo. I'll tell you the difference if I ever have a pot go off in my good gun.



Surface prep down to 320 is fine. (for most repairs I'll spray over 180 no problem and have sprayed over 80 for a quick and dirty) Once you're done, take it down to 1000 G and buff with this:


It works magic.

Hope that helps. I'm working od a video right now, but it's going to take some time.

J

The other way to get rid of epoxy blush is to use peel ply on your epoxy repairs (at the time of the repair.) Once you peel off the ply, you peel off the top layer of epoxy and the blush. And it leaves a nice level and rough surface for your next layer.

Wow I love all this new info. Is there any tips specific to asymmetrical hulls like my Prindle 18. All my wear covers a fairly narrow section on the point of the keels.

Bondo type products sand fast but they are not the best repair. It will collect water and swell and if water gets to the core of your board it is not good. The best repair is to use West System with a bonding filler to make a paste. The key to the repair is to have the surface clean and sanded to make a good contact. Be neet with your work. Read any body repair manual and apply the West System "paste" like bondo. Let it dry for a day or two the sand it out with sandpaper using a sanding block. You can use 120 - 180 - 220 - 400 progressive in grit.

Once you have it faired in you can buy gel coat and roll it on if you are not handy with air painting equipment. Make sure you add wax to the gel coat so it will dry tack free. From there you can wet sand the dry gel coat 400 – 600 – 800 – xxx.

The other option is to paint it with awlgrip paint it can also be rolled and it flows pretty well. Awlgrip is nasty paint if you do not know what you are doing gel coat is cheap and not as poisonous.

I’ll be repairing a dagger board on a Supercat 20 and document it. I need to get the picture part of my website up then you can see the steps. I've also done other repair work on boats and fabricated parts.

www.themanshed.net

A friend of mine, more familiar with fiberglass work, came over to check out my hulls today. He said they seem strong and it looks like the previous owner did just epoxy over the gel to beef the bottom up for beaching. So, I may just fill in the chips and sand that smooth. Would that be fine for every day use? I know it won't look pretty but as long as it can all stand up to the water I am fine with it for now. (since it sounds like gel coat won't go on over the epoxy very well?)

I'll definitely look more into the products you guys recommend such as the PVA. I just have to wait until it gets warmer here since I don't have a garage to do all of this in.

As for the dagger boards, I think the picture is misleading. It looks like the bottom of the board is worn but there is really about a 1/4" of some kind of clear resin on the bottom.

yeah, that's simply the very square cut on those type of nacra daggers

i was thinking of something with a nicer curve but realised that as there is no gasket in the lower slot they need to be that shape to fill the hole fully and so have the lease drag when fully up

MD,
I suggest filling in the bottom of the hulls with West and filler to make a paste it is hard. Bondo is a waste of time if you want to keep the boat. If prep is done gelcoat will work. You can use PVA but gelcoat wax additive to the last coat is cheaper and works just as well. Ask your supplier or look at Glue Products or same type of website. Gelcoat can also be brushed and rolled on the bottom it is out of site and can be sanded smooth. The key is to seal the glass.

Painting is great the best. If you have the equipment and knowledge or want to learn the ropes paint. It is hard but rewarding. I just finished painted this boat last weekend. The project included bottom work, fabrication, and fairing work. http://www.themanshed.net/supercat-20.html look at last picture. I need to get the picture part of website working I have a lot of repair type of pics that may help. I hope my webmaster gets that going soon, I just finished his boat....

If a slacker did the work, original epoxy, some people use epoxy when they should add glass. If your friend knows glass and says it is ok - you should be ok. I've seen slacker work, and I've had some of my old glass work popped when I suffered internal damage in the hull and the boat flexed after a nasty capsize. It is not nice to start sinking at sea, been there. Also I do not do any repair work with poly resin anymore.

If you "sail up" when you beach the boat and to just want to get by easy and cheap - tape off the bottom and go to Walmart and buy a spray can. The bottom will not show and it will sand off with each beaching.

Living and sailing on the beach for 30 plus years I've done my share of bottom jobs on cats. It is still thrilling to sail right up on the beach, baby the boat – I’d rather leave it on the trailer.

All of the posts are great, everybody is right it is up to you to decide. Me I'm a bit anal.

I've built boats, worked for several boat builders, built show cars, enjoy doing this type of "hobby", and I have 30 plus year of tinkering. It all started with a NACA 5.2 when they first came out and waxing then the hot cat a hobbie 16 in the mid 1970's. All of a sudden my 5.2 had a hole in it the 3rd race. Next weekend I learned repair work and it is all history after that.

My suggetion is set a few goals. How much money, time, and what level of effort you want to spend on the project. From those decisions you can go from Awl Grip, Gelcoat, Spray, Brush, Paint can from Walmart. I spent over 6 months of my free time on the SuperCat.

Enjoy!