Silly Question about gelcoat repairs

[Sal]

" Each year I try to touch up

" Each year I try to touch up small chips, gouges and scratches wit a gelcoaat repair kit. Besides being a pain-it's very hard to match the boats color (blue) Tried to mix a large batch but it dried out in a span of 3 months (put it in an air tight jar- less hardener of course) Then I got the brainstorm idea (maybe I'm crazy)of using acrylic water based paint (the stuff they use for crafts,etc) I can mix/ match this stuff to the EXACT co;or of the boat. I would either fill the chip with a mix of acrylic paint and clear gelcoat resin (the stuff that already has hardener in it) or I would build up the acrylic paint in the chip and then apply the clear gelcoat over it to seal.In theory this sounds good but in reality, can it be done. Looking forward to hearing from all you gelcoat experts. Thanks in advance "

 

[jon]

"Sal,

As far as why the bat

"Sal,

As far as why the batch hardened on you; if it was a two part epoxy - it hardens as long as the amount of hardener/resin is within tolerance. Temperature/air/water have no effect on that stuff, it only might effect the amount of time it takes to dry. If you were using a polyester/vinylester - with even a small amount of air, it can actually dry without hardener, it is like paint in that respect. The hardener simply helps speed up the drying process; I've had it dry out on me without the hardener present.

Water based paint doesn't stick well and really has no place, if any, in a marine enviorment. With gelcoat repair, my #1 objective would be to seal the water out, my #2 objecive would be to get the cosmetic details right. That would mean if there was any quick fix, for me, it would be sealing up the scratch with clear resin and then painting over it ounce dry.

I'm not sure if you are using a 2 part epoxy resin or a polyester/vinylester resin. Polyester/vinlyester is inferior to 2 part epoxies as far as adhesion goes - the same thing can be done with either, but I'm recomending a 2 part epoxy for this reason.

Pick up a pint (or quart if you do lots of repair) of general purpose 2 part epoxy resin and hardner from your local marine store. They make a thinner, clearer, more UV resistant hardener, but if it's not available, the standard hardener will do. Pick up a coloring kit of some nature (example):
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&productId=13840&catalogId=10001&classNum=165&subdeptNum=11160&storeNum=4

Use a teaspoon for the coloring agent and a set amount of epoxy resin (measure out an ounce or so - 1 ounce == shotglass), and the required amount of hardner to make a test batch. It might take a few rounds, but in the end you will be able to figure out exactly how much of each color per ounce of resin. When you know the color ratio, make yourself a big batch of color-matched resin. Then simply take small amounts out and mix them with hardener, when it's time for repair. That batch will then get you by for years. Be sure to mix epoxy hardener/resin exactly as the directions say - more or less hardener with epoxy has not effect other than possibly the mix won't dry at all.

Jon"

 

[sal]

" Thanks Jon. The stuff I used

" Thanks Jon. The stuff I used to make the large batch was white and lt looked like nothing like the patch kits I bought previously that contained a thick gel like resin, several tubes of coloring agent plus a small tube of hardener. Guess the stuff I used in the "failure batch" was that of polyester/vinlyester and thatthe jar wasn't as air tight as I thought.Bought a large separate tube of coloring agent and closely matched the color of the boat.The gelcoat repairs I do are very, very minor-small chips, scratches,etc Sometimes if the repairs are very shallow I simply wet sand the area down wit extremely fine sandpaper an get excellent results.I just happen to be fanatical about the appearance of the boat (1977 Formula with a hull thats in incredible shape). So I figured that since my attempt to mix a batch that would seemingly last for years failed- then buying the tube of clear resin that requires no hardener would do the trick by just adding a coloring agent. Purchased this stuff at west Marine for $10,00. Is this still ideal to use- or would you nix it.
Thanks again,
Sal "

 

[jon]

" Sal,

Clear resin tha

" Sal,

Clear resin that requires no hardener? You've got me on what it is. There are "modified" epoxies out there that air dry, but I thought that was mostly for paint. It could also be polyurathane or something of that nature. Since you bought it, may as well give it a shot - worst senario, it falls off or you end up sanding it out. A good quick easy fix for cheap money would be those tubes of two part epoxy glue they sell at WalMart or anywhere. You could tint it, but you wouldn't be able to make a batch and save it for later.

Jon "

 

[tonyob]

" Jon and Sal,

I have seen

" Jon and Sal,

I have seen and used polyester products that do not use hardener. They cure on UV light. I don't know if the resin you are talking about is one of these, but it may be. These products were being produced in Europe since about 1995 as far as I know.

Actually they were very handy. They had fiberglass cloth that was impregnated with resin. It had a layer of plastic on each side. You peeled off one side and set the cloth in place. Then when you were ready to let it cure you peeled off the plastic on the exposed side and allowed UV light (from the sun or a lamp) to cure the resin.

They also had a fiberglass putty that you just applied and let cure in the same way.

I never noticed any of this stuff for sale in the states, but it may be out there. I came across it when I bumped into a promo team that was traveling around the country exploring the possibility of marketing these products in the U.S.

They gave me some free samples, which worked very well, but over a period of time everything cured, even if it had not been opened. I guess it had a short shelf life.

Tony "