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PostPosted: Tue Aug 20, 2013 7:56 pm 
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Slow progress, but here is what I have so far. The fiberglass was damaged along the bottom of the hull for nearly 2 feet. There are a couple spots (pics 2 and 3) where the glass may be a little damaged, but not too bad- not sure if I should cut those out and blind hole patch those as well. I'm doing what I can do to prep now, as my glass comes in a couple days, as well as my gel coat.
Hope these pics come through alright. Any and all suggestions/ tips are much appreciated.

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PostPosted: Wed Aug 21, 2013 4:51 am 
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I wouldn't cut any more away. If your repair is as thorough as your prep, you will have great results!

One thing you may need to do is find a way to keep the two sides aligned while the resin cures. Might not be an issue; depends how well they hold their alignment by themselves.

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PostPosted: Wed Aug 21, 2013 5:00 am 
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I doubt I'll have any problems with alignment. The sides are strong and stiff. I'll just need to hold them together just a little bit (5mm or so) and for that I was simply planning to wrap a tie down or two around the hull with a couple foam blocks to get the strap up off the resin.
Once I complete the patching, how many layers of 8.7oz glass would you use for the bottom job? I plan on doing about an 8' section of the bottom. May want to add an additional layer or two over the area that has the patch?
Thanks!


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PostPosted: Wed Aug 21, 2013 5:27 am 
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Looking at it again, I think you have not exposed enough of the surrounding fiberglass to get the right buildup of cloth. Not knowing much about this, I would think a thin layer of glass in the center, then a wider one on top of that, and another even wider one covering at least an inch on each side of the original opening. But there must be a good write-up on this somewhere.

In the middle of the second picture there is a lighter colored lump. Is that old filler? It looks like it is on top of the gelcoat.

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PostPosted: Wed Aug 21, 2013 8:26 am 
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Looks like you need to add more taper to the sanded area. The existing glass should be ground down super thin right at the edge of the hole and tapered back to the existing thickness. This will allow you to lay a stack of glass into the ground out area to re-build to the original thickness. The way you have it now, you will be laying new glass on top of the existing glass, so it's going to end up being a "hump". You want to grind away enough of the existing glass so the new glass lays down inside the ground out area so you can bring it back to the original thickness. Not sure if that makes sense.

I would think you probably don't need to do the blind hole repair, but that would be your call. If you taper it back enough, you can probably just drape the glass over the hole and it will bridge the gap. Then after it cures, build up with more glass.

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PostPosted: Wed Aug 21, 2013 8:59 am 
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Great info SM! Thanks!

I haven't heard anything about tapering, but makes total sense! I have glass tape 1", 1.5", and 2" wide. I've read that you can either put the narrowest down first and work wider from there, and vice versa. Any suggestions?

Also, I think I'm going to attempt a blind hole repair for the practice and as a backup in case I much up the bottom job, as this is my first time working with glass.

Sure would be easier if I had something other than a palm sander. This is hot abs sweaty with down here in south Florida!


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PostPosted: Wed Aug 21, 2013 9:07 am 
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SWFLChris wrote:
I haven't heard anything about tapering, but makes total sense! I have glass tape 1", 1.5", and 2" wide. I've read that you can either put the narrowest down first and work wider from there, and vice versa. Any suggestions?


From a strength standpoint, I don't think it matters what order you lay the glass down. If you end up with the widest piece on top, you will have fewer edges to blend in after it cures since the wide piece will act as a cap for all the other pieces, so you'll only have to blend in one edge.

Either way, I definitely think you will be better off by eliminating the step at the edge of your repair. A dremel with a sanding drum works well for removing material, just be sure to have a few extra drums handy.

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PostPosted: Thu Aug 22, 2013 8:33 am 
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Wow! That trick with the sanding drum on my dremel worked like a charm!
Now I'm all prepped and ready to start laying glass. I'm still slightly confused about the process though.
Do I need to sand between layers? There isn't any wax in my resin (Boat & General Purpose Resin, formulated with low viscosity for quick wet out of mat and roving, contains thixotropic agent to prevent drainage on vertical surfaces. Wax free to reduce sanding between coats.)
One layer at a time, right? Do I need to let the first one fully cure, or can I lay subsequent layers while the first is still tacky?

I'll post pics of my progress this evening.
Thanks
Chris


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PostPosted: Thu Aug 22, 2013 8:46 am 
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Generally speaking, you do not need to do one layer at a time. You can pretty much do the entire lamination in one shot. Figure out how many layers of glass you need to add for the repair and pre-cut them to size. Then set them on a piece of wood, cardboard, or plastic board. Prep the repair surface and mask off the area so you don't get resin drips running up the hull. After your repair surface is prepped (well scuffed up and cleaned THOROUGHLY with acetone) mix up your resin. For a repair this size, you will need several ounces (I would figure somewhere around three to five ounces, maybe more). Have your brush/roller ready to go. Once the resin is mixed, pour a small amount over each repair patch and spread it out using your brush/roller. Flip the patches over and work the resin in so the glass turns from white to clear. Then paint a thin layer of resin on the hull over the repair area. Take your first patch and place it on the hull. Use your brush/roller to work out the excess resin. Continue laying the patches on top of one another as you work out the excess resin and remove all air bubbles. Let the resin cure.

For your repair, if you're going to try to bridge the gap in the hull without doing the "blind hole" repair method (internal reinforcement), then you may want to start with just one or two layers of glass and let that cure. Then scuff it up, clean it, and add your additional layers. This will give you something firm to work against when you do your main lamination.

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PostPosted: Thu Aug 22, 2013 10:13 am 
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You might want to cut out a "Hull Template" to help with the final shaping of your repair.

You can download one from: http://www.hobiecat.com/support/hobie-16/
Under Care and Maintenance section: Keel Shape Templates

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PostPosted: Sat Aug 24, 2013 10:59 am 
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Thanks for all the help! Here are some updates. I have done the blind hole repair, filled the gap (as it was hard as hell to get the patch completely snug against the hull) glassed the entire bottom.

I did a good job of hosing out the inside of the hull and came up with this device to dry it out in a hurry.
Image

The resin curing. I made a filler with resin and chopped glass to fill any voids between the patch and the hull.
Image

Hole filled and sanded. Those white spots are just sanded resin dust.
Image

First layer of 1.5" glass over most of the bottom (around 8 or 9')

Now to add another couple/ few layers. It's 8.7oz glass. Any suggestions on how many layers?
Thanks all!


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PostPosted: Sat Aug 24, 2013 11:52 am 
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PostPosted: Sun Aug 25, 2013 3:04 pm 
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Looking great!

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