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 Post subject: patch a hole
PostPosted: Tue Jul 05, 2011 8:26 am 
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Joined: Tue Jun 23, 2009 6:24 pm
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Location: Grand Rapids, MICHIGAN
Just a quick note... to share. I had a storm push the bow of one hobie into the back side of another's hull. Made about a 2" triangular hole.

I could see inside, foam sandwich etc. Not wanting a major repair job, I tried some epoxy that comes in 2 cans. It says you can apply it even under water! I didn't do that, but applied it with putty knife. Next day - looks great and feels super... feels like the rest of the hull around it. If you have a need- check the stuff out.


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 Post subject: Re: patch a hole
PostPosted: Tue Jul 05, 2011 8:57 am 
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Joined: Wed Aug 18, 2010 8:15 am
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Location: Saint John, NB Canada sailing on Washademoak Lake
Boat is not made with epoxy, you'll never be able to gelcoat that area properly now. The repair is also not structural, while the damage might be.

The best method would have been to follow the Hotline article from May/June 2008 "This Old Boat - Blind Hole Repair"
http://2010.archive.hobiecat.com/hobiec ... 6_2008.pdf

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 Post subject: Re: patch a hole
PostPosted: Tue Jul 05, 2011 9:13 am 
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Joined: Mon May 09, 2005 10:25 am
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Location: Jersey Shore
If the damage is severe enough that you can see the foam core then the outer fiberglass skin has been fractured/damaged and you need to repair using fiberglass cloth and resin (preferrably polyester or vinylester). Simply slapping some epoxy in the hole is not going to restore the hull to original strength.

sm


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 Post subject: Re: patch a hole
PostPosted: Tue Apr 17, 2012 7:08 am 
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Location: Grand Rapids, MICHIGAN
Thanks.. I ended up using a two part marine epoxy product. Came in two cans. You mix and apply it like spackle. It says you can even apply it wet to holes under water! Mine wasn't. Used a putty knife and am very pleased with the result and product! Hull was painted befor so gel goat not a issue. Cover with paint or vinyl graphics... Or sticker and good as new.


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 Post subject: Re: patch a hole
PostPosted: Tue Apr 17, 2012 7:12 am 
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Joined: Sat Jul 25, 2009 11:19 pm
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Location: San Diego
srm wrote:
Simply slapping some epoxy in the hole is not going to restore the hull to original strength.

sm



Not good as new, srm knows.

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 Post subject: Re: patch a hole
PostPosted: Tue Apr 17, 2012 9:25 am 
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Joined: Mon May 09, 2005 10:25 am
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Location: Jersey Shore
Sounds like you used Marine-Tex or another similar product. Your repair method is one that many Hobie sailors take, but unfortunately it's a poor shortcut for a proper repair.

Your putty job may look good for a while, but know that this is not the way to make a structurally sound, long lasting repair. The putty you used (epoxy or otherwise) is simply not equivalent in strength to the original fiberglass/foam sandwich hull construction. Epoxy putty has high compressive and shear strength, but nowhere near the tensile strength of fiberglass cloth. As a result, it will eventually crack out due to the flexing that occurs in a Hobie hull. Depending on where the damage is located, that may happen the first time you sail the boat, or it may not happen for years. Just know that eventually, it will happen. Once the putty begins to crack, it will allow water to seep into the damaged area and into the foam core. When the foam core is continually exposed to water, it will break down and the hull will begin to delaminate in that area. You'll have a bigger job on your hands.

The proper way to fix the hull- a method that will last the life of the boat- is to grind out the damaged outer fiberglass skin and remove any damaged foam core. Then repair any damage to the internal skin, bond in a new piece of foam core material, and then laminate new glass to the outside surface. Finally, gelcoat the repair.

Using epoxy on an outside surface of the hull is also a big no-no if you ever want to match the gelcoat and have a cosmetically finished repair.

sm


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 Post subject: Re: patch a hole
PostPosted: Tue Apr 17, 2012 2:31 pm 
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Joined: Mon Jul 14, 2003 7:11 pm
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Location: Detroit, MI
srm wrote:
Sounds like you used Marine-Tex or another similar product. Your repair method is one that many Hobie sailors take, but unfortunately it's a poor shortcut for a proper repair.

Your putty job may look good for a while, but know that this is not the way to make a structurally sound, long lasting repair. The putty you used (epoxy or otherwise) is simply not equivalent in strength to the original fiberglass/foam sandwich hull construction. Epoxy putty has high compressive and shear strength, but nowhere near the tensile strength of fiberglass cloth. As a result, it will eventually crack out due to the flexing that occurs in a Hobie hull. Depending on where the damage is located, that may happen the first time you sail the boat, or it may not happen for years. Just know that eventually, it will happen. Once the putty begins to crack, it will allow water to seep into the damaged area and into the foam core. When the foam core is continually exposed to water, it will break down and the hull will begin to delaminate in that area. You'll have a bigger job on your hands.

The proper way to fix the hull- a method that will last the life of the boat- is to grind out the damaged outer fiberglass skin and remove any damaged foam core. Then repair any damage to the internal skin, bond in a new piece of foam core material, and then laminate new glass to the outside surface. Finally, gelcoat the repair.

Using epoxy on an outside surface of the hull is also a big no-no if you ever want to match the gelcoat and have a cosmetically finished repair.

sm

+1


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 Post subject: Re: patch a hole
PostPosted: Tue Apr 24, 2012 7:16 am 
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Joined: Tue Jun 23, 2009 6:24 pm
Posts: 269
Location: Grand Rapids, MICHIGAN
Surly I'd do that on a better boat. The entire boat cost me 280. The repair would cost more than that... Hehehe. Looks great, if it cracks out in a few years will do it again! I have two cheap boats.. And one I keep really nice... My 82. Luckily it didn't happen to my good boat.
For the 5 bucks and 5 minutes time... I'm pleased so far, a year later looks the same.
But thanks for the info.


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