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Old 11-03-2014, 09:54   #1
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rebuilding bow section from sandy. your 2 cents greatly appreciated


I ordered a book on fiberglass repair that might clear up a few things but still I figured I would pic your brains. Im still wondering about...

1. Best matieral for the mold. Im thinking that skinny partical board(I forget the name of it). That's what I was told to use for another much smaller project...

2. whats the best type of mold release for such a project? saran wrap. hair spray?

3. Im imagining just building the mold on the outside then laying up the glass from the inside. Unfortunatly(as you can see) my buddy started sanding more than he needed to on the outside until I explained that were laying it up from the inside.

4. I have read about using the other side of the boat to make a mold. But then im a little worried that the other side wasn't perfectly the same as the bad side even from the factory mold right?

Thanks ahead for any help you can give me that helps me get this done right. If anyone wants to explain how they would do It im all ears! Oh and how many gallons of resin do you think ill need. Also what weight of csm. I figured the heavier the better.
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Old 11-03-2014, 10:13   #2
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

If I were you I'd see if I could make a mold from another Alberg 30. There are certainly enough of them around and it should give you a perfect form.
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Old 11-03-2014, 10:14   #3
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

First suggestion but may be too late. I can't tell much from just a photo of the bow, but unless this is a really nice and very valuable boat with much less damage inside that what I see on the bow, it will be cheaper in the long run to buy a boat that isn't smashed in.

If you are committed to the project, getting a good mold will be critical and save you huge amounts of work in the long run. There are commercial, mold release agents sold that would be a good idea. You should also start with a good layer of gel coat before starting the glass layup.

To get a good mold I would use thin, flexible plywood, start a couple of feet or more back of the damaged section so the ply follows the curve of the hull and fair it in to the stem. Then add bracing and stiffening outside before starting the layup.

NOTE. I have not done a project of this magnitude but there are some on the forum that have. Maybe wait to see if they chime in with some suggestions.
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Old 11-03-2014, 10:22   #4
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

I might be tempted to go the other way, build something to support new glass on the inside. Layup the outside, then remove the inside support and do the inside. The inside mold only has to support the glass until one layer is hardned up.... it could be foam with sheet wax on it. Or thin ply just braced in place etc. This meethod gets you going quick. Yeah, there will be some fairing and filling to get the outside nice, but building a perfect mold to avoid that takes alot of time too, and may not avoid fairing and filling anyway.
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Old 11-03-2014, 11:08   #5
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

I'd also build the support on the inside first since it won't matter if the interior shape is wrong in the anchor locker.

I'd also find an alberg 30 and make a bunch of female cardboard cross-section patterns that you transfer to 1/4" plywood. You can hold the patterns up to the hull as you layup the outside and do the filling and fairing.

Put some thought into engineering the forward chainplate and it's support. There's a lot of load here. Tie it all in to the hull below the damage (e.g. to the waterline). You wouldn't want the deck to peel back on the first sail!
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Old 11-03-2014, 12:10   #6
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Where are you located?

The best mold release for this type work is Partall Paste Wax #2. You can remove it with wax remover, where some of the more exotic silicone mold releases are harder to get rid of. The best way to go about using mold release, is not using mold release. Lay in peel ply in the form instead. I would wax the rest of the boat.

Also, think about laying down some plastic and outdoor carpeting on all surfaces of the boat so that you don't create a bigger new paint job than what will already be required.

Grind the bevel from the inside and cut the foredeck back far enough you can work from staging around the boat down handed. Cloth doesn't like to build up much thickness overhead. Lost a pony tail once...


You'd also be ahead of the game if you even up the bevels so the repair isn't something shaped like texas. Where the corners and humps are, you'll get air voids. Drop a plumb line down so that each stack of cloth is the same, just a scotch smaller than the last.

All your jigs and fixtures can be built off of batten screwed directly to the hull from the outside, and the inside of the fixture becomes the work surface. Get the stem right. Loft 2 of them off the line plans. Bolt one to the outside of the boat, bolt the other to the inside of the boat. Use the inside stem to set the shape the battens... Leave them just slack of the inside stem, so you could slide a dollar bill past each and every one. Rabbit them in to the outside stem.

When you have it shaped correctly, remove the inner stem. That projects the inside of the stem ahead of the boat. Just farther ahead than it is supposed to be. Bog out of drywall mud the radius that you want, in its natural position. (this is after the foam...)

I would skin the outside of the form with cheap plywood or hard board and staples. I'd use use spray foam between the battens. I'd use a surform plane and a 16 inch long board against the inside of the form until I could just see the battens through the foam, but not touch them with sandpaper. That'll keep the repair a smidge low to the rest of the boat, so when you drop the form, your battens will show you low spots not high spots.

I'd roll the foam in resin and let it kick, I'd sand the resin and fill any low spots (they remain shiny) that the long board couldn't reach with bondo. I'd then wax it.

I'd lay peel ply up against the foam, even if I need some staples to hold it into place, and as many darts as required to get a "No Wrinkle" job.

I would use polyester for this, simply because you can get on with the job and its plenty strong. I'm pretty sure alberg 30's were already laid up out of two hull molds and tabbed together on centerline anyway.

I'd start laying up 2 layers of CSM 1 1/2 mat. I'd let it go hard, and shoot it with an infrared thermometer until it passed its peak heat and started coming back down... scuff any nibs with a 24 grit grinding disk by hand, and start laying up alternating chop and woven roving.

You might need to blend some cabosil into the mix to keep the resin from running down out of the cloth.

I'd strongly consider putting a lip on the top, at the deck line and rolling the cloth up overhead to make a shelf for the deck to bond back down to. Its not that hard to layup, but it would mean you could bond the deck back into place and not have to lay up near as much tabbing overhead.

Once the form comes off, I would lightly grind everything and trowel an even coat of Adtech P17 fairing putty over the surface. I'd finish it off with a coat of Duratech Sanding primer unless you like working with gelcoat.

If you aren't familiar with painting and best practices on longboard sanding, you can get yourself in a heap of trouble. You want to take nothing off of the existing fair hull, but still need to sand from the good onto the bad... never the other way around. You may want to hire on a fairing guy to get her straight even if you are going to do the structural repair and paint work yourself. There's a certain number of hundreds of hours it takes to get a feel for what is a high and what is hard edge on a really big low spot. The guys that are good are worth the day or two of labor it'll take to get her perfect once the glass work is done. Sometimes you need a few hands to look at the batten. Sometimes a string taped down to the side of the hull and wrapping around it to the stem will show you what a batten won't.

The fellow that taught me fairing, told me once "Don't paint outside the lines." If you don't know if it is a high or a low, don't put on more putty. Use the batten to show only where there is light, do you fill... and only after you've sanded until the batten touches a good majority of the surface.

When you are ready to prime it... shoot it with gloss black enamel, and let it sit for the summer in the sun. Two reasons, you get to "see" it before you spend the time painting it. The second... Let it post cure at high temperature so whatever shrinkage is going to happen, happens. Particularly with that navy blue paint. It'll be a season or two before things stay stable and you can get a good long lasting paint job that doesn't start showing "Stuff" that moves. I use PPG's 1 part paint gloss black enamel, as Awlgrip T0006 wipes it right off.

The best way to come up with resin quantity: Go get a piece of butchers paper and hold it up against the boat. Figure out the area of the surface you need to work with in square feet. Then calculate the thickness of the layup. Once you grind it back, count out the layers of mat and layers of roving. Mat takes more resin than woven roving. Mat is 1 1/2 oz per square foot. Figure 2-3 parts resin to 1 part mat. This is on the wet side... Woven is weighed per yard... 18 ounce to the yard. Figure 1 part resin to 1 part woven. This is on the dry side.

It works out to be... just about right.

Once you know your area, know how many layers, you can figure out how many ounces of resin you'll need per square foot. Then multiply by area. Then add a gallon or two.

Cheers,

Zach
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Old 11-03-2014, 13:14   #7
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

The easy way is to find another boat and take a female mold from the front of it,
then make your new bow from it, and attach the new one.

If there is no boat to take a mold from, shape a new one from foam
then make female mold from it and use it to make new one, which can all be done on a workbench on the ground, which makes it go faster and easier.
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Old 11-03-2014, 18:48   #8
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Im in cleveland. The boat is not an alberg. I sold that, bought a bayfield 32, and now i just bought a westsail 32 which i am keeping. A friend helped me pay for the westsail so im helping him fix this 35ft dufour. That was exactly my plan to make the form of the hull from the inside, put a cuple layers of glass, then lay it up real heavy on the inside. Instead of laying it all on the inside and praying its right when u take off the mold. Today we were playing around with mold matierial and we needed something to make that curve in the front and it hit me...poster paper. I drove up to staples and sure enough it formed perfectly the missing hull section i cant think of anything that would have worked quite as well for the very front.
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Old 14-03-2014, 19:05   #9
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

1st watch a million youtube videos.. i would screw a piece or formica to the hull from the inside.. put a couple layers on and move the formica over some more just keep working it over until you bridge the hole .. then layer the hell out of it.. the key to glass is dont mix too much resin at one time.. little bit at a time and make sure you push out the air bubbles.. i fixed my boat myself as well .. took a lot of time but it came out great
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Old 29-03-2014, 13:03   #10
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Got sum pics for u guys been meaning to post these. We did this in the cold lol. Of course theres sum low spots that need to be filled with more glass but were gettin er done! Thanks guys! It should be stronger than origional
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Old 29-03-2014, 14:57   #11
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

No pics........?
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Old 30-03-2014, 11:24   #12
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

I know you've already started your project ... way to go ... I'm doing a lot of glass work on my boat. Who wants to just buy a new boat anyway. Do a project and learn ... then you've created your own work.
Ok, since you're asking for 2 cents ... here's my 2 cents:
1. Polyester resin has NO strength of it's own. Resin saturated glass does. That being said, make sure you have a good roller to not only roll out bubbles but also excess resin. There is a weight formula for mat:resin ratio. To much resin and you layup will be weak.
2. Overlap between your original boat and the new lay up is important. Your friend didn't grind back to far. The long strands of glass going even a foot to 18 inches will give you a very strong structure.
Enjoy your project
Here's a very good link ... scroll to the end and watch his techniques
https://www.youtube.com/user/GasserG...lf_id=1&view=0
Lowell
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Old 30-03-2014, 21:11   #13
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Sorry i cudnt figure out how to post the pics last nite. But ya it took like 4 days to get that much done. And remember that was in ice cold conditions. Fun fun fun. Already laid it up pretty heavy on the inside but were not done adding layers. To give u an idea of the enormity of this at one time i laid up 24 large pieces on the inside that were already cut up to shape. Its gonna be way stronger than origional. I kno that first layer of the mold didnt look soaked enough but i can assure you the rest are ; ) oh and i kno fiberglass is flammable. We bought 6 more gallons of resin. We have used 5 already. Will be sure to post more pics as we progress. Thanks for all the input..

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Old 31-03-2014, 07:18   #14
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Do you have an woving or biax in there or is it all mat?

Zach
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Old 31-03-2014, 10:17   #15
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Re: rebuilding bow section from sandy. your 2 cents greatly appreciated

Hey ... that looks really great. Glassing is fun, huh. Now the yucky part begins ... sanding it out. After a rough shape with 25 on an anglegrinder on glass that obviously need to come off anyway ... I use 40 grit on a random orbit for the rest.
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