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S2 7.9 Bear Lake, UT
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Discussion Starter #1
On my last visit to the boat I put a hole in side. I will share the story later when I have full use of a computer.

The hull is balsa cored and I was planning on using Boat works today's method of tapering 6" around then filling with Matt using laminating resin then gel coating.
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Unfortunately the resin is a week away. I will check to see if the hardware store has any. Any other suggestions for making this repair either temporary or permanently using west systems which I have on hand.
 

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Suggest doing it once and correctly. One week away isn’t much time.
 

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Polyester resin used for laminating will always cure slightly tacky. The finish coat, or gelcoat, needs to contain a wax, or other aid-dry-curing-agent.
 

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Discussion Starter #4
Polyester resin used for laminating will always cure slightly tacky. The finish coat, or gelcoat, needs to contain a wax, or other aid-dry-curing-agent.
I got wax based gel coat coming also. Unfortunately its an 8 day journey to me.
 

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If you are grinding a taper, and using discs of fg mat (and you should) , and intend on covering with gelcoat .. I dont see why you can't use epoxy. I'e gotten away from using *esther resins because of the short shelf life, and prefer epoxy these days.

Epoxy wont hold up to UV so you need to paint or gel coat it. Of course you will need to wash away the amine blush and sand to prepare it for the gelcoat.
 

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I completely agree about using epoxy.
 

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gelcoat does not like to stick to epoxy without another special coating in between. a lot of work for a repair the size of a quarter. polyester product like bondo glass works well on this type of small repair. can be found at auto parts store in small quantities. dig out the loose stuff then fill and cover with a piece of wax paper untill cured, sand with no finer then 80 grit, leave the surface a bit low and apply gelcoat and cover with wax paper to keep from running and being exposed to the air. repairing gelcoat is more of an art then science. surest you practice with the materials on another surface before doing the repair on the boat. if the hole goes all the way through then add some fiberglass cloth on the inside of the boat.
 

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Discussion Starter #8
I have been disappointed in both materials.

2 years ago I bought laminating resin, last summer I opened the resin to find it a can of rock solidness.

So I switched to epoxy to finish a repairs in a lazarette. Using mat I managed to make the repairs but would not have been happy if it was anywhere other than buried in the bottom of a small cheap boat.

The mat was very stiff. Research told me there are fibers that melt with Polyester resin making it both pliable and stronger when done.

To add to this error I added expired west systems white pigment. While white in its container, expired it turns into a pepto bismo pink.

Overall this repair worked but not my best bit of handywork. I wish I had a photo to share to show why I am concerned about grinding a 12 inch hole in the side of my boat to repair a 1 inch hole.
 

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Discussion Starter #9
Thanks overbored
gelcoat does not like to stick to epoxy without another special coating in between. a lot of work for a repair the size of a quarter. polyester product like bondo glass works well on this type of small repair. can be found at auto parts store in small quantities.
This product is likely what I saw at the hardware store yesterday.

Willing to give it a try.
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Discussion Starter #10
My previous epoxy/glass repair. The pink color came from expired hardener not the pigment. This photo does not show how rough the glass work is.

I realize this repair has to be done right with a cored hull any water intrusion means an even larger repair in the future. Since the laminate resin is already paid and will go bad if not used. I will wait for it. I am also committed to getting the gelcoat color to match as there is a humongous repair on the opposite side of the boat needing gelcoated
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I would.. clean this hole out. Paint with epoxy... fill with "bondo" ... sand fair... then apply gel coat.
 

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You haven't said what caused the damage, or what type of damage it is (point puncture, gouge, etc). From the picture, it appears to be a puncture or gouge that doesn't extend inward past the outer layer of glass, and likely doesn't extend laterally past the damage seen. If so, grinding out 6" around is crazy. You will never get that faired and matched without a professional, and it doesn't look like there is any need to do so structurally. Without an experienced person using higher-end gelcoat, high-gloss additive thinner, a spray gun, wet-sanding, and compounding, you will have a very noticeable halo around a 12" diameter repair regardless of how fair it is - a bullseye on the hull.

Epoxy will make your problem worse. There is no justifiable advantage of epoxy on this repair, and many disadvantages.

Overbored gave the good advice. The only two things I would add is to do a bit more than digging out the debris - use a dremel to cut back a bit into solid laminate and apply a small taper. The taper is less for strength and more for a better finish with a feathered edge. Also, after applying gelcoat like he mentions (you will likely need to do this step twice to build up to the surface because the first application will shrink slightly), sand it as fair as you can with 400 grit, then hit it will another shot of gelcoat, only this time use a Preval sprayer to apply it. Just shoot it straight on and let the overspray feather to the edges. Not too much so it doesn't run. Maybe let it tack up and shoot another shot. Then wet sand with 800 to almost completely fair, being sure to lightly sand out over the feathered edge, then take it to complete fair with 1200 wet sanding. A buffing pad on a drill or buffer with compound will put the gloss on - or leave it uncompounded to match the rest of the hull finish.

Mark
 

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Discussion Starter #13
You haven't said what caused the damage, or what type of damage it is (point puncture, gouge, etc). From the picture, it appears to be a puncture or gouge that doesn't extend inward past the outer layer of glass, and likely doesn't extend laterally past the damage seen.
Sorry, I was posting from my cell phone from a campsite. Don't like typing on the phone but back home now.

Last month I got the boat in the water to camp on it for 3 days. We and the boat were not ready to sail. Being very rusty I had trouble controlling the boat but got it into the slip. I blamed it on not having sailed an outboard and tiller boat in a while. On day 3 I had to move the boat to another slip and had even more trouble. I was solo in the boat my wife was waiting on the dock. The boat slipped and slided and I ended up bouncing off a ski boats boarding platform and the hinge hit the side and punctured the side. On the return to the dock I lowered the centerboard and solved my control problem.

I am pretty sure the puncture is deeper than the surface and likely into the balsa core. My concern for anything other than 100% repair is any leak will causes a leak into the core which is a problem with these boats. I would really like to not grind out a massive hole but want to make it sure it is done right so no leaks occur to the core.

I woke up this morning feeling less than perfect so decided not to do any hull work, at less than 100%. I addressed some electrical issues and went home. Tonight the laminate resin showed up on my porch. Since it is paid for and on hand I would hope to learn and use this resin to make this repair.

As far as gelcoat work the boat already has a huge patch badly color matched so I need to learn gelcoat or paint the boat.
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On the repairs that turned out pink, did you add sandable thickener? That stuff is often a pink/brown color.
 

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Discussion Starter #15 (Edited)
On the repairs that turned out pink, did you add sandable thickener? That stuff is often a pink/brown color.
No I had no plan to fair or finish this job. It was a hole made in the locker by an anchor flute and another hole left to route a cockpit drain in a $1000 Potter 14, I just wanted to prevent the leaky locker from filling the boat with water.

Looking back at my photos reminds me of the process. I opened up a can of laminating resin to find it completely hardened. I turned to west systems, the expired hardener caused the mixed to have a maroon tone. Combined with white pigment gave me a Pepto Bismo colored repair.
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The boat slipped and slided and I ended up bouncing off a ski boats boarding platform and the hinge hit the side and punctured the side. On the return to the dock I lowered the centerboard and solved my control problem.
I feel your pain. We recently moved onto a daggerboard catamaran from our previous keeled catamaran. Our keeled catamaran turned and danced and crabbed and moved on command in complete control. The first time I went to move our daggerboard boat to a dock (daggers up), I was in a panic as the thing just slipped and slid and felt like I was controlling it though a huge time and space delay. And we have two engines 24' apart to work with!

Learned to put them daggers down for slow maneuvering around docks and such.

Mark
 

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Polyester resin is good for ~1yr and gelcoat for ~4-6 months, both depending on storage conditions and formulations. Epoxy a bit more, but don't get fooled. Poly cures in time and can't physically be used after. Epoxy oxidizes, but still appears usable. Until it makes a mess of a project. Many people are confidently carrying around epoxy that is just waiting to make a royal mess of their next project, or leave their repair at unknown peril.

Resin systems are designed to be used fresh. The advantage of polyester resin is that it is available almost everywhere in the world in hardware and other common stores. Epoxy mostly, but not as much, and usually only in specialized stores. Polyester catalyst is good for much longer time periods, as is epoxy resin itself, but epoxy hardener is not. I used general terms poly and epoxy above, but it really is the poly resin and epoxy hardener parts that are the issue.

Use fresh(ish) resins for repairs. Refresh onboard stores accordingly.

Mark
 

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Discussion Starter #18
Learned to put them daggers down for slow maneuvering around docks and such.

Mark
Live and learn. I thought it was just me being rusty, but after a few beers that night and sitting up contemplating I realized I know how to operate a sailboat rusty or not, without a keel down I was operating a weird powerboat.

I still struggle with a dinghy. I shut off the power as I approach expecting the momentum and the rudder (outboard) to steer me in.
 

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Discussion Starter #19
Man that was easy. I so overthought that.

Ground out and beveled the hole, damage did not make it to the core. Now I got to figure out what to do with the leftover Polyester resin 1 gallon minus an ounce.

Thanks all for the advice.

Note to all I did not color match the gelcoat because I have a huge patch to match on other side of boat and will touch up this patch then.
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Discussion Starter #20
Next question: sanding gelcoat?

I purchased some 400 wet dry sandpaper. I also had my 5" random orbital sander and was going to put 220 on it to get the first couple of layers sanded down towards the boat's contour. I will be hopefully returning next week to sand this smooth. I also have 280 and 320 grit for this sander.

Can I use the palm sander or should I stick with hand sanding with 400?
What is a good sanding regimen for gelcoat? What is the final grit I should aim for? What step down between grits?

My expertise is in woodworking, I am lost after 220 grit.
 
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