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Discussion Starter #1
Shiva has acquired over the years nicks, scratches and assorted "breaches" of the gelcoat. I have a friend who does commercial fiberglass work (amazing things) and he was nice enough to mix up a color matched repair kit for me... but the weather is only now becoming "cooperative".

Watched some YouTubes.... but they seem quite elaborate and it would be very time consuming. I haven't inventoried all the nicks... there are 3 scratches gouges which need attention.. not thru the gelcoat... but YUCKIE looking... but scores of small blemishes

I am thinking.... can I mic up small batches... clean the nick w/ acetone and then paint the gelcoat on the defect. If the dab stands proud I can sand it flush and polish it. Done! If it's dimpled I can leave it or add another dab. I am not looking to restore the gelcoat to pristine as new condition.

I, of course, can do some experiments before I take on the whole lot of these buggers.

Has anyone done quicker (paint on) gelcoat repairs? Any suggestions?
 

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Yes, what you describe will result in an OK at 10' repair, particularly if you do not buff it to a high shine. I do this often for old screw holes, removed fittings, etc. I'm assuming you plan to fill the defects first. Don't rely on the gelcoat for that. It helps if you sand back the fill below the surface slightly, as well as sand the edges into the old gelcoat slightly.

One trick I do is use gelcoat putty as a filler and mix it with some color matched gelcoat. This gets the fill color close to the finish color. Don't use dark filler under light gelcoat finish - you will always see it.

A better way is to spend time as you have it filling, fairing, and sanding all the gouges and nicks, then when they are all ready for finish coat, get a Preval sprayer and do them all. This will put a smooth coat on them that will only take a bit of 600/800 wet sanding to look great. You will need to thin it a bit for the sprayer.

If your friend can part with a small amount of Duratec, that helps tremendously with getting a good finish. It is also a perfect 1:1 thinner for a Preval sprayer.

Mark
 

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You need to know if the stuff you have has wax in it or not. If not, it needs to be covered with something like plastic wrap or it will never harden. If it has wax, the wax will seal it for hardening.
 

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Discussion Starter #4
Thanks for the comments.... I don't know what the gel he supplied is made with/contains. I am trying to avoid plastic wrap or perhaps clear packing tape???? I can do a proper repair and the 2 or 3 nasty ones... but the plethora of little nicks I just one a quickie 10' repair.
 

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Don't cover with plastic wrap because that makes finishing harder - it is difficult to not get creases in it. Clear packing tape is a bit better but will still likely cause you more work. Wax/no wax is really not a problem for the method of repair you are doing, where gelcoat will be built up above the surface then sanded back down. The gelcoat will cure and harden just fine without wax - only the very thin surface layer will remain a bit tacky, but you will be sanding this off anyway. Underneath this thin surface, everything will be fully cured and hard.

If you are going to spray with a Preval, then it is good to add wax or spray PVA over it (don't use a covering at all or it will mess it up). If you get some Duratec from your friend, that will also fully cure the gelcoat surface with no other additive needed. Otherwise, just get some good coats on and sand the tack layer off with 400/800 grit (wet sanding helps here, but isn't necessary).

Just spent the last couple of months applying gallons of gelcoat - using spray gun/compressor, Preval sprayer, roller, and brush. The best results are in that order, with brush meaning you will be doing a lot of wet sanding and 2nd/3rd coats to get it right. Spray gun is, of course, complete overkill and silly for what you want to do.

Preval sprayer would be my choice, and I'd hit my friend up for a pint of Duratec. Preval 9 oz. Complete Spray Gun-267 - The Home Depot

Mark
 

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Discussion Starter #6
Mark.... Why not dab the nicks with a small artist's brush? Doesn't spray over coat the surrounding gel coat? and get sanded off???
 

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Mark.... Why not dab the nicks with a small artist's brush? Doesn't spray over coat the surrounding gel coat? and get sanded off???
Yes, you can do this. In fact, I'm doing just that right now! I have some horizontal bolt holes that I've filled, ground the surface of the fill just below the deck level with a slight bevel into the old gelcoat, and dabbed gelcoat in the dimples so that it flowed and leveled. Waiting for it to kick to sand flush now.

You haven't described fully the nature of the nicks and gouges, nor where exactly they are. If deep, then they need filling first. If vertical, then running can be a problem even with dabbing with an artist brush. Otherwise, it can work fine for a 10' job.

Spraying allows one to feather into the old gelcoat to get a more seamless repair. It also requires less finish sanding than brushing. You will definitely see the transition from old to new with a brush dab. But only up close or while squinting at a sharp angle, which is fine for many things.

Mark
 

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Discussion Starter #8
very few are deep... no holes to file.. chopped gelcoat... and the worst are a few scratches on the hull at the beam and a the bow. Transom edge needs attention.
 

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Here is what I do; and on my 34-year old boat, it is good enough.

I use gelcoat with wax (available through Jamestown Distributors), and mix the gelcoat with tint (in my case a little brown) to get the color exactly where I want it. Immediately before applying gelcoat, I sand the area with 250 grit sandpaper, or a Dremel with a grinding stone. I then clean the area with acetone. If I am filling something (an old screw hole or deep chip in the gelcoat, I mix in a little cabosil to thicken the gelcoat to the consistency that I want (usually ketchup). Then I add hardener at 10 drops per ounce of tinted gelcoat/cabosil and mix thoroughly for at least a minute. Apply the gelcoat/cabosil mix to the area that I have sanded with a flux brush and let it dry. If necessary, shape with the Dremel, then sand with 400, then 800 grit wet/dry paper.

I have a Preval sprayer, but the gelcoat in the can is too viscous, and I have therefore never used it.
 

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Also - I want to add that I started working with Gelcoat in 2011 when I purchased the first can from JD. I have used this quart can for several years, and finally had to throw it away this year because the gelcoat in the can hardened. That's 9 years of touch ups from 1 quart of gelcoat!
 

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I'm about to do some gel coat repairs. Is it ok to add 5 drops of hardener to half an ounce of tinted gel coat? I'm concerned that the tinted gel coat will change color as it cures. And when we talk about an ounce of gel coat we are talking volume, right?
 

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I'm about to do some gel coat repairs. Is it ok to add 5 drops of hardener to half an ounce of tinted gel coat? I'm concerned that the tinted gel coat will change color as it cures. And when we talk about an ounce of gel coat we are talking volume, right?
In my experience, and to be honest, I primarily mix up ½ ounce batches of gelcoat and tint. And, yes, I only use 5 drops of MEKP. I have read elsewhere of an 18 drops of MEKP catalyst (hardener) per ounce of gelcoat ratio, but the label on the gelcoat that I use says 10 drops.

Part of the beauty of gelcoat is that the color does not change as it cures! Therefore, you mix the gelcoat and tint till it matches. I simply paint it on the spot to test, then I wipe it off with some acetone on a paper towel. then commence surface prepping and adding MEKP as I outlined above.

Do as I outline, and you'll be just as bad at this as I am. :)
 

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How are you guys getting a close color match
My wife has a bionic eye for colors. That and the kit I have has a color card with a variety of colors and what dye to add to obtain the desired color. But I'm going with the bionic eye guided by the color card.
 

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Making a tiny batch of color match is almost impossible. A quart is more reasonable, and a gallon+ gets easier. The best and easiest way is to take a piece of existing gelcoat, like a small hatch or similar, to a supplier and have them match it. Then it is in their system and you can order more whenever you need. Make sure you compound all the oxidation off the match piece first.

However, don't be disappointed if in 2yrs the color changes and becomes more noticeable. New and old gelcoat ages differently.

Mark
 

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The hull is blue gelcoat and painted white
Probably original owner...35 years...probably something like awlgrip, very pro
I need to do a lot of paint touch up on the hull..fender salt rash mostly
The cockpit/top is white gelcoat and need small touch ups

A 10 or 30 ft job would be ok right now. Rattle cans dont scare me. Just dont want to look like jed clampett
Down the road i may commit to something more serious
Curious as to how you guys get close in color
 

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Discussion Starter #18
I'm about to do some gel coat repairs. Is it ok to add 5 drops of hardener to half an ounce of tinted gel coat? I'm concerned that the tinted gel coat will change color as it cures. And when we talk about an ounce of gel coat we are talking volume, right?
I have the ratio in the box for the repair... I'll check this weekend
 

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10-30 ft doesn't need to be very close in color. Otherwise you need to decide if you want to match the chalked old gelcoat, or seriously compound the old gelcoat back to somewhat near its original color. Then it is a matter of adding colorant pigments to white gelcoat until you get a match. Again, this is very difficult for small amounts because the pigments are intense. Dipping the very tip of a toothpick into a pigment and stirring it in the gelcoat often is too much here. Easier with larger batches. The pigment color you need is not always obvious or the one you think it should be, so reading or watching some tutorials help. When you think you are close to a match, put a dab on the old gelcoat, wet the old gelcoat next to the dab, and place a piece of clear cellophane over it so that the old and new are covered. You will immediately see any color difference at the intersection. Make sure you aren't in direct sunlight for this, and I find polarized sunglasses help me to see color differences better when outdoors.

If you have a lot to do, and will need at least a quart, then taking a part of the boat of the desired color to a supplier for a match is well worth it.

Mark
 

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Part of the beauty of gelcoat is that the color does not change as it cures!
This isn't completely true in general. If it is catalyzed too hot it will definitely change color during cure, or change in a short time after cure. Also, gelcoat repairs will change color over a year or so, and will unlikely still match the original since they both will be aging at different rates. Heck, everyone probably has original factory gelcoat on their boats aging differently with different colors in different places. For small nick repairs and the like, this will be mostly inconsequential. Larger repairs will not be invisible after a few years.

Mark
 
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