Gelcoat - where purchased, how applied.
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Mark Prouty
- Admiral
- Posts: 1723
- Joined: Mon Jan 19, 2004 8:52 am
- Location: Madison, WI Former MacGregor 26X Owner
Gelcoat - where purchased, how applied.
I have a fiberglass repair that is as smooth as a baby's butt. How do I apply the gelcoat and where can I purchase some that matches?
First thing: You say the fiberglass is smooth? Please don't tell me you smoothed the layup to the same level as the existing gelcoat. If so, then it is going to be impossible to make a smooth gelcoat repair. I am going to assume you are a smart fellow and have made the layup smooth, but not the same height as the existing gelcoat. 
West Marine, Boaters World, local chandlery have the Evercoat products. They work well for the home repair work.
There is a Large Gelcoat Repair kit, or pints of polyester gel paste. West marine also has their brand which comes in two varieties. Waxed which is used for touch ups of worn or scratched gel coat. Non-waxed is a laminating gel coat that is tacky upson curing so you can do several layers. You use this for gouges and scrapes. You should also get the PVA curing agent which is applied over the last layer of laminating gelcoat so it cures.
Of course you want to make sure the area you start with is very clean as this stuff is particular and would eventually bubble and break away if applied to a dirty surface. Then mask the area with tape. Remember you should have some overlap of the existing gelcoat (about 1/2 inch feathered outward is plenty). I then prep the area with 220 grit sand paper so the gel has something to bond to. There is some dicussion regarding how big of grit among people, but I prefer 220. The gouges aren't too big and still has a good surface to bond to. Clean with acetone once you have sanded the surface to be coated.
Matching is the hardest part, here's why. If you get the gelcoat to match perfectly once cured, it will age a bit in the first year to a shade darker. But it's really hard to try and compensate for that natural aging of the new gelcoat unless you use the product every day for years and know how it changes color. You will have to make several samples (write down the exact mixtures for later), add the hardner, then allow them to cure til hard. Unless you wait for a couple of months with the samples outside you will never know what it ages to exactly. It's not a huge color variation, but think of it like this: You go into Lowe's or Home Depot to look at white paint. How many different variations of white paint are there? There's milk, cloud, marshmallow, cream, buttermilk, divinity, cotton flower... the list goes on and on...... same thing with gelcoat really. The variations are endless, it just depends on your pigment blend.
So back to application. After the great gelcoat color debate, you want to force the gelcoat into the area you have prepped. Two things to make sure it is a good coat. 1. make sure there are no air gaps between the fiberglass and gelcoat. 2. overfill as gelcoat shrinks when drying. To harden the gelcoat you need to close it off from air, so either the PVA curing agent, or some people use plastic wrap. Honestly, I hate plastic wrap as I tend to get wrinkles in it no matter what I do. (Plastic wrap and i have never gotten along, not even in a kitchen setting)
Once the stuff has cured (time depends on brand and thickness) you will take 220 grit sand paper and wet sand it down. then use 600 grit to wet sand further, and I finish with 800-1200 to wet polish a bit more. The last step is to apply marine polish and buff the whole boat.
Easy Peasy!
West Marine, Boaters World, local chandlery have the Evercoat products. They work well for the home repair work.
There is a Large Gelcoat Repair kit, or pints of polyester gel paste. West marine also has their brand which comes in two varieties. Waxed which is used for touch ups of worn or scratched gel coat. Non-waxed is a laminating gel coat that is tacky upson curing so you can do several layers. You use this for gouges and scrapes. You should also get the PVA curing agent which is applied over the last layer of laminating gelcoat so it cures.
Of course you want to make sure the area you start with is very clean as this stuff is particular and would eventually bubble and break away if applied to a dirty surface. Then mask the area with tape. Remember you should have some overlap of the existing gelcoat (about 1/2 inch feathered outward is plenty). I then prep the area with 220 grit sand paper so the gel has something to bond to. There is some dicussion regarding how big of grit among people, but I prefer 220. The gouges aren't too big and still has a good surface to bond to. Clean with acetone once you have sanded the surface to be coated.
Matching is the hardest part, here's why. If you get the gelcoat to match perfectly once cured, it will age a bit in the first year to a shade darker. But it's really hard to try and compensate for that natural aging of the new gelcoat unless you use the product every day for years and know how it changes color. You will have to make several samples (write down the exact mixtures for later), add the hardner, then allow them to cure til hard. Unless you wait for a couple of months with the samples outside you will never know what it ages to exactly. It's not a huge color variation, but think of it like this: You go into Lowe's or Home Depot to look at white paint. How many different variations of white paint are there? There's milk, cloud, marshmallow, cream, buttermilk, divinity, cotton flower... the list goes on and on...... same thing with gelcoat really. The variations are endless, it just depends on your pigment blend.
So back to application. After the great gelcoat color debate, you want to force the gelcoat into the area you have prepped. Two things to make sure it is a good coat. 1. make sure there are no air gaps between the fiberglass and gelcoat. 2. overfill as gelcoat shrinks when drying. To harden the gelcoat you need to close it off from air, so either the PVA curing agent, or some people use plastic wrap. Honestly, I hate plastic wrap as I tend to get wrinkles in it no matter what I do. (Plastic wrap and i have never gotten along, not even in a kitchen setting)
Once the stuff has cured (time depends on brand and thickness) you will take 220 grit sand paper and wet sand it down. then use 600 grit to wet sand further, and I finish with 800-1200 to wet polish a bit more. The last step is to apply marine polish and buff the whole boat.
Easy Peasy!
-
Mark Prouty
- Admiral
- Posts: 1723
- Joined: Mon Jan 19, 2004 8:52 am
- Location: Madison, WI Former MacGregor 26X Owner
-
Mark Prouty
- Admiral
- Posts: 1723
- Joined: Mon Jan 19, 2004 8:52 am
- Location: Madison, WI Former MacGregor 26X Owner
It is only about 3" in diameter. I left the rudder down and went into full power mode which is pretty fast in my boat. The top of rudder bracket tore clean off and the bracket looked like a pretzel. I also ripped the top of the rudder off about 3 inches down. I did a real nice job fixing it smooth. The fiberglass is actually thicker than before.
OK my dear.
1. Get your dremel tool out and put a tapered grinding stone on it.
2. On low speed with a mask and safety glasses on, gently grind down 1/16 to 1/8" out of the nice glass job you did, and while you are at it, gently feather back the existing gelcoat about 1/4-1/2" as well.
3. Follow the directions previously posted.
Since your layup is thicker than existing it won't be a big deal to grind down some of the resin and glass.
Sudie
1. Get your dremel tool out and put a tapered grinding stone on it.
2. On low speed with a mask and safety glasses on, gently grind down 1/16 to 1/8" out of the nice glass job you did, and while you are at it, gently feather back the existing gelcoat about 1/4-1/2" as well.
3. Follow the directions previously posted.
Since your layup is thicker than existing it won't be a big deal to grind down some of the resin and glass.
Sudie
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Frank C
Dee,Mark Prouty wrote: ... I left the rudder down and went into full power mode which is pretty fast in my boat. The top of rudder bracket tore clean off and the bracket looked like a pretzel. ....
That story obviously couldn't happen in a Tripp 42 at full power ... but OTOH, unless some other problems were possible on a Tripp, you wouldn't have nearly so complete a grasp on the repairs procedure ???
Let's just say I have learned quite a bit about repairs over the years.
We ran youth sailing programs with 420's, Optis, and Flying Scots. Children + boats = lots of repair work.
I have raced and lived aboard a Hunter 34 while on a poor college kid budget. That means I did quite a bit of work myself. I recall a rather large gouge to a keel from the Bump& Tack method of short tacking a rocky beach. A note of reference: Bumping while tacking through is acceptable, bumping before tacking is not the best method.....
The T47 is a bit more work when it comes to repairs, and luckily we just haven't had that many. I love the fact she may be light but is built like a tank. She isn't all glass, but a wild composite mixture of foam core, glass, and exotics. Her bow is glass and where the keel attaches is glass but the rest is specialty.
We ran youth sailing programs with 420's, Optis, and Flying Scots. Children + boats = lots of repair work.
I have raced and lived aboard a Hunter 34 while on a poor college kid budget. That means I did quite a bit of work myself. I recall a rather large gouge to a keel from the Bump& Tack method of short tacking a rocky beach. A note of reference: Bumping while tacking through is acceptable, bumping before tacking is not the best method.....
The T47 is a bit more work when it comes to repairs, and luckily we just haven't had that many. I love the fact she may be light but is built like a tank. She isn't all glass, but a wild composite mixture of foam core, glass, and exotics. Her bow is glass and where the keel attaches is glass but the rest is specialty.