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Several repair questions
http://www.hobie.com/forums/viewtopic.php?f=20&t=1329		 Page 1 of 1
Author:  sliceofpi137 [ Thu Nov 04, 2004 4:52 pm ]
Post subject:  Several repair questions
Greetings! I just found this board and am hoping I can find answers to some of life's questions. Or just to tackle some repairs on a 1977 H16.

1.) Deck delamination:
I've succesfully done the "drill hole pattern, inject epoxy" method of delamination repair on a friend's Hobie. In working with other projects I've started to get into vacuum bagging. Is it possible/reccomended to use a bagging system in conjunction with the hole pattern method? I am thinking along the lines of drilling the holes, injecting epoxy, and covering with a half a bag sealed around it's perimeter to the deck. I am hoping this would evenly distribute the epoxy and hold all the layers together better than clamping without causing deformation. Please advise.

2.) Holed hull:
My trailer has caused some damage to my starboard hull, which when loaded with 3 people on a very windy day gave out in the water without any impact. We got towed back in and the hull is dried out (2 months) and on blocks in my shop. I've done repairs to plywood cored decks on bigger sailboats, how crucial is the fitting of new core material where this split has happened? I am installing a deck port at the same time so I can access the inside and put a few layers of glass on the inside but the core is badly damage from the break and I was thinking of replacing a patch of it as well. Is it just styrofoam or some funky corecell/divinycell material?

3.) Hull to Deck Joint:
My hull to deck joint (before the hole) was the main cause of water getting into the hull, or at least I assume it is because everytime we'd flip water would come streaming out of some of the depressions in it. I had patched some of the obvious "bad spots" before but I am thinking now a better idea might be to grind the entire length of the rail into a "v" and fill the whole shebang with thickened epoxy or epoxy paste (to save some sanity). Thoughts?

Thanks for your help!

~Kevin
Author:  JaimeZX [ Sat Nov 06, 2004 3:25 pm ]
Post subject:  Re: Several repair questions
sliceofpi137 wrote:
1.) Deck delamination:
I've succesfully done the "drill hole pattern, inject epoxy" method of delamination repair on a friend's Hobie. In working with other projects I've started to get into vacuum bagging. Is it possible/reccomended to use a bagging system in conjunction with the hole pattern method? I am thinking along the lines of drilling the holes, injecting epoxy, and covering with a half a bag sealed around it's perimeter to the deck. I am hoping this would evenly distribute the epoxy and hold all the layers together better than clamping without causing deformation. Please advise.

I'm not experienced with vacuum bagging, but I would think it would be difficult because you'd be sucking air up from inside the hulls, making it difficult to get a good seal. Am I missing something?

Quote:
2.) Holed hull:
My trailer has caused some damage to my starboard hull, which when (snip)it as well. Is it just styrofoam or some funky corecell/divinycell material?

I'm not clear on exactly what happened to you here, but anyway you have some hull damage, right? If you remove the damaged bits and apply a suitably strong repair it should be fine. Take, for example, the repair we made to the keel of my friend's Sunfish. (link)

Quote:
3.) Hull to Deck Joint:
My hull to deck joint (before the hole) was the main cause of water (snip)
sanity). Thoughts?

I have a very similar repair in mind for my boat. I dunno about grinding a V in the joint because I wonder if it wouldn't screw up the lamination some (I could be wrong) but I plan to lay a bead all the way around the joints on both hulls. Hopefully that will stop my leakage as well.

Good luck!
Author:  sliceofpi137 [ Mon Nov 08, 2004 12:16 pm ]
Post subject:  Re: Several repair questions
Quote:
I'm not experienced with vacuum bagging, but I would think it would be difficult because you'd be sucking air up from inside the hulls, making it difficult to get a good seal. Am I missing something?


I would be sealing the bag to the deck around the hole pattern. The glass/foam sandwich should be airtight if thoroughly adhered. I was surmising that using the vacuum system it would pull the layers tightly together in the areas where they are not adhered thus providing a clamping force while the epoxy sets. The only way air would be pulled from inside the hull would be if there were holes in the inside glass layer. I think? :?:

Quote:
I'm not clear on exactly what happened to you here, but anyway you have some hull damage, right? If you remove the damaged bits and apply a suitably strong repair it should be fine. Take, for example, the repair we made to the keel of my friend's Sunfish. (link)

In cored deck repairs in the past I have always used the same core material to avoid hard spots, stress concentrations and density/flex differences. I'm just wondering if anyone knows exactly what the core material was in the 1977 H16s.

Quote:
I have a very similar repair in mind for my boat. I dunno about grinding a V in the joint because I wonder if it wouldn't screw up the lamination some (I could be wrong) but I plan to lay a bead all the way around the joints on both hulls. Hopefully that will stop my leakage as well.


Is that the "standard" way to seal the joint? Can I use epoxy paste instead of a thickened resin? It all just seems too easy :D
Author:  JaimeZX [ Mon Nov 08, 2004 3:25 pm ]
Post subject:  Re: Several repair questions
sliceofpi137 wrote:
I would be sealing the bag to the deck around the hole pattern. The glass/foam sandwich should be airtight if thoroughly adhered. I was surmising that using the vacuum system it would pull the layers tightly together in the areas where they are not adhered thus providing a clamping force while the epoxy sets. The only way air would be pulled from inside the hull would be if there were holes in the inside glass layer. I think? :?:

Dunno. I guess it could work but I haven't drilled out the deck before so I don't exactly know your situation. If that doesn't work then you could always put a nail on a string through the center hole and then pull up on the inside of the deck while the epoxy cures in the surrounding area, then seal the center hold. :)

Quote:
In cored deck repairs in the past I have always used the same core material to avoid hard spots, stress concentrations and density/flex differences. I'm just wondering if anyone knows exactly what the core material was in the 1977 H16s.

Matt Miller would probably know this. He is teh smart. 8)

Quote:
Is that the "standard" way to seal the joint? Can I use epoxy paste instead of a thickened resin? It all just seems too easy :D

Well, mine is "sealed" with a bead of silicone which is slowly peeling off. In another thread Matt said in later models they switched from silicone to epoxy for the bead, so I'm willing to scrape off the rest of the silicone and re-seal with epoxy. Out of curiosity, why would you use a paste rather than standard epoxy? Seems that you'd want the "runniness" of epoxy to flow into all the tiny crannies to seal the joint better.

Anyway, good luck again!


Jim
Author:  mmiller [ Tue Nov 09, 2004 10:27 am ]
Post subject:  Questions
Vacuum bagging would be great if you can get it to work. When we build boats we bag the whole part. Hard to pull that off with a section of deck.

A bead of the "runny" resin seeps into the voids, so I suggest that. Of course, that is done with the boat upside down.

The foam core in 1977? Clark - Urethane, same as a surfboard. Now we use a PVC foam.
Author:  sliceofpi137 [ Mon Jan 24, 2005 2:16 pm ]
Post subject:  Some more questions
I've had varied success with vacuum bagging the deck delamination. If it's a small area that has delaminated and most of the deck is smooth I can get a seal using double sided foam tape and one "side" of a bag. If the area is large, there is too much air leakage but it still does help a little.

Now I am starting repairs on a holed part of my starboard hull. After grinding away all of the bad glass I am looking at a void about 15" long and 2-3" wide with the foam from the pylon about 2/3 of the way bow-side in the hole. Normally for a hole like this I would just glass the hell out of the inside with several layers of 8oz mat then grind a bevel into the foam/glass on the outside and finish up with a few more layers of mat then finish. I am looking into the hull and notice that the foam block at the bottom of the pylon is only bonded to the starboard side of this hull (the more rounded side not the vertical side). Is this normal or should I bond it to the other side while I am in here working? Also do you think it would be beneficial to separate the foam from the side it is bonded to so that I can glass in a continuous piece of mat?

Thanks! Please advise.

~Kevin
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