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How critical are soft spots
http://www.hobie.com/forums/viewtopic.php?f=17&t=2271
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Author:  Ukexpat [ Fri Aug 19, 2005 4:39 pm ]
Post subject:  How critical are soft spots

Now that my Ebay Hobie 14 is almost ready to sail, I am of course tempted to rush out there.

There are soft spots on the top of both hulls, mostly in front of the forward cross beam.

Am I risking disaster if I sail the Cat, even in light winds, without filling these soft spots with epoxy ?

I have no idea how many years it is since the Cat was sailed. I know it was "stored" on waste ground in the open in Clearwater FL, so it must have got very hot at times.

Thanks,
Terrence

Author:  JaimeZX [ Fri Aug 19, 2005 10:51 pm ]
Post subject: 

Depends on how soft they are, but I don't think you're in iminant danger unless you're planning to go out in rough seas. I would, however, fill them at your earliest convenience.

One thing though: don't use "Gorilla Glue." I ran out of epoxy and decided to try that. Bad idea. Apparently "foaming" is part of the curing process and I spent an hour wiping sticky foam off the hull after the job. I still have some sanding to do now also, as I didn't get it all. :roll:

I have heard "Git Rot" is a very fluid epoxy (prior to curing) and that's just what you'd want to use. And what I will use if I ever have to do it again.

Author:  Hobie Nick [ Mon Aug 22, 2005 6:07 am ]
Post subject: 

I used Git Rot on my H18 soft spots. I liked it because it comes with everything you need to do the repair. It is very fluid, easy to mix, and about the same cost a buynig West Systems after you get all of the extras needed to apply the epoxy. Plus, there is no mixing in the correct amount of filler with Git Rot.

Good luck.

Author:  mmiller [ Mon Aug 22, 2005 2:43 pm ]
Post subject:  Soft Spots

Soft Spots

Doesn't really need rough seas to cause issues with soft decks in the bows. You can sheet hard and break a bow I think. Basically the structure is weakened and the lateral stiffness is degraded. When you sheet the bows are pulled towards the center. This can further delaminate the bow until failure.

Check the delam FAQ for repair ideas:

http://www.hobiecat.com/community/viewtopic.php?t=1156

Author:  Ukexpat [ Mon Aug 29, 2005 4:42 pm ]
Post subject:  Git-rot

It may sound like a silly question to you afficianados but:

How do I ascertain/guess how much Git-Rot I need ?

I looked in West Marine this afternoon and they only have what seem to be very small quantities at about $40 a pop.

Pressing on my decks I think that I may need a large quantity.

Any bright ideas welcomed.

I gather that using an expanding foam is not a bright idea.

Author:  Hobie Nick [ Tue Aug 30, 2005 7:41 am ]
Post subject: 

I bought twice what I thought I needed with the intention of returning what I didn't use. I'm glad I did, becasue I would have been short by about half a box. Also, like Matt has said before, you are not filling a large volume of open space. You are just rebonding two layers of the hull. I had a fairly large area (about 18" by 6") on my deck. I used 1.5 of the small git rot boxes.

Author:  Ukexpat [ Thu Sep 08, 2005 1:37 am ]
Post subject: 

I used 32oz of Git Rot in the Port hull. It did not get warm in the bottle when I was shaking it so I was a little concerned, however in a few minutes the deck in the effected area got too hot to touch.

The Git-Rot hardened in an hour or so (air temp 90F).

I figure it wil take another 16oz in the Stbd hull.

Thanks for all your help and advice.

Terrence

Author:  mmiller [ Thu Sep 08, 2005 10:20 am ]
Post subject:  How much and how hot?

How much and how hot?

How much? The delamination is typically just a thin seperation like two pages in a book, there is little space between them, but if you force resin in it will spread out the void and fill with resin. Resin by itself is not as strong as just enough to bond the original layers. Less is better. Also, if you drill into the inner hull, you will be pumping resin into the keel. Pump/squeeze slowly, pour in more places and you will use less resin.

How hot? The resin doesn't start getting warm till it starts curing, so getting warm early is NOT a good thing. You should also avoid doing it in warm conditions and in direct sunlight. Resin that curse before you are done... not good. Resin that heats up so much that it damages the foam and glass... not good.

Author:  Ukexpat [ Thu Sep 08, 2005 1:35 pm ]
Post subject:  Applying Git-rot to a large soft spot.

I was working on the Port hull which had a soft spot about 18 - 20" long by the full width of the hull, just in front of the raised molded area in front of the forward post. Pressing on this depressed the deck markedly.

Four 1/4" holes were drilled in the deck, forward and aft and athwart the soft spot just through the first layer. I could see the separated glass layer through each hole. I also drilled an exploratory hole forward of the soft spot. This went straight through into the void space implying that there was no seperation in this area.

The Git-rot had been stored for a few hours in a refrigerator to chill it as per Git-rot's own instructions.

Using the first of 2 x 16 oz bottles of Git-rot I mixed the 2 parts in several batches (6 or 7 ?) as per the marks on the Git-rot mixing bottle. The aftermost hole was injected first until I saw liquid oozing from the inboard hole. I then plugged this with duct tape and started injecting the outboard hole until liquid oozed from the aft hole, which I then patched with duct tape. This was repeated on the forward hole/outboard hole. Finally I topped off the soft spot space using just the forward hole on the soft spot.

The epoxy resin flowed quite freely and it was not necessary to apply any pressure to "pump" the liquid in.

No Git-rot penetrated into the void of the hull so far as I could tell.

At about the time I was topping off the forward hole I felt the hull and noticed that the approximate area of the soft spot had increased markedly in temperature. It was quite hot to the touch, but not enough to burn. From this I determine that all the Git-rot remained in the soft spot cavity. If it had drained into the hull void the deck would not have been hot.

The following day I removed the duct tape and could see that the Git-rot surface had hardened in the drilled holes. There had been no drainage. Pressing on the former soft spot showed that the whole area had been stiffened up. There was no marked depression in the deck.

The soft spot in the port hull is in the same general area but is much smaller. I anticipate that one 16oz bottle of Git-rot may be enough.

Thanks to everyone for your helpful comments.

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