Next project for indoors, Dagger board end repair.

shorefun

Well-Known Member
The dagger board came broken at the tip. I used what I had on hand which is Kwik Poly.
It was something I had laying around for making dry rot wood able to be structural and take fasteners.

I put some nails in and made a loose form and layered it in place.
I made a critical error.
The kwik poly cant bond to itself unless roughed up. I thought it might have a recoat window and did it pretty quick, but I was wrong.

So during the season the tip area broke, but the bit of glass cloth held it together. I put in some epoxy and made it the rest of the season. Now I have fiberglass and poly resin. I made a mold of sorts from a good dagger boards I now have from buying too many sunfish cheap.

In the picture you can see the dagger board tip after I have sanded back to the nails I put in to stabliize the Kwik poly. I have also sanded the surface of the kwik poly back to the edge of the factory material. The lower 1 1/4" or so will have to be made up. I am trying to think of the best way to make things up. You can also see the fiberglass mold I made along with lines showing a factory edge, the end I sanded to and the top edge

My plan is to drill in and put some long nails or stainless wire for some support. But my lack of experience has be wondering what would be the best filler for the open area. Do I make up a block of glass with a few layers of glass and roughly shape it and glue it in place then build up both sides. Or put the nails/ wires in and just start laying up glass from there. I am thinking get a base flat area with a piece of card board and put like 2 layers on the cardboard and push against the wires and put 2 layers on top. Then peel away the card board and start building glass on either side. But I need to build up like a 1/4 so is there a filler I should use?

A new challenge to keep me busy.

I am kind of annoyed it is too cold to do the boats, but it is months away from actual sailing. Well unless I come across some sort of suit, finding one cheap when you are 6' 6" is not easy.
 

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Shorefun,

I thought you would never ask! I have made a bunch of these Sunfish daggerboard tip repairs and finally wrote an article for Duckworks, see at this link:

We are very much on the same page. A key step is making a lot of "saw cuts" in the damaged area to get a lot of contact area for the thickened epoxy to adhere to and be sure to glue in some stainless screws as "rebar" reinforecement.

Hope this is helpful.

Alan Glos
Cazenovia, NY
 
Alan's approach looks good, especially when the whole tip is gone. Here is an approach I've used for some "shark bites" on my Laser board.
Note the Laser board in the video is made the same way as the Sunfish ones that are made of the yellow high density foam. Both Laser and Sunfish boards are now made from more of a fiberglass material - I hope not to have to find out how to fix those!!!!
 
Slight change in scope.

Had to remove the area of repair that was left behind. It was not well bonded and did not have the structure needed.

So I am doing the Alan repair.

I need to figure out the most economical epoxy to buy. I need it thick enough to form the whole area.

White Marine Tex? Is that thick enough?

What are my other options? I am not familiar with the marine compatible products.

Thanks
 

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I need to figure out the most economical epoxy to buy. I need it thick enough to form the whole area.

White Marine Tex? Is that thick enough?

What are my other options? I am not familiar with the marine compatible products.

Thanks
That was wise to remove the older attempt. :cool:

Shop around for Marine-Tex. Prices vary, and I don't know if that one small treatment will have sufficient content for the job. :confused: Marine-Tex is not very thick, but sculpting with the tip perfectly upright might get it done. I'd use tape, and sculpt with an aggressive grit. ;)

Y'know, dentists drill vertical holes in the tooth they are capping, then cast remotely for insertion. (With the post sticking out). I'd drill a few 3/16" holes, at least one inch deep. (English measure).

Other options:
A retailer has just announced a fully-transparent surfboard. Maybe find out what was used--for surfers to watch the sharks? :eek:

View the video. He seems to know what he's doing, except for not using English measure. 20mm nails? :confused:
 
MarineTex is great stuff but is rather expensive for the amount you would need for a repair this large. I use WEST two-part epoxy, the fast cure type in winter and the slow cure type in summer thickened with the WEST low density thickener powder.

Alan Glos
Cazenovia. NY
 
Looks like you’ll need about $80 with of West supplies, more if you buy the pumps for the resin and hardener. Jamestown Distributors has what you need. West Epoxy plus 403, 405 or 406 fillers are required - I don’t know which of the fillers is best for you the job. I think Alan’s approach is good, although that Laser video has a good approach too - I’d use the stainless screws Alan recommends if you try the Laser fix.

I don’t see a way to do this with inexpensive materials. Evercoat used to sell some West knockoff epoxies and fillers, which probably were fine, but I don’t know if they are still offered.
 
I put my math to work and came up with an estimate for the volume of tip I need to fill. It looks like a great place for me to use my calculus I have not done a triple integral in ages (like 35 years), but being the lazy engineer I just guessed 2 boxes to get me in a ball part. The front rectangle was sort of the same average thickness and the rear one tapered some so I went thinner.

I came up with 10cu in of material.

The 14 oz Marine Tex is about 15.5cu in of material. It is in white and best I can tell less expensive then other epoxies. Keep in mind to go the west system or other I would need fillers and such. So price wise and structure wise it appears that Marine Tex is my best candidate at this point. Still looking.
 
Marine Tex probably will work. It hardens to about the same hardness as a rock! Here is info from their site. http://marinetex.com/products/marine-tex-products/marine-tex-epoxy-putty/

Note the working time - you may need to do your work in smaller increments to avoid the product kicking before you have gotten everything done.

I don’t think I’ve heard of anyone building something so big with this stuff - I’d be sure to use Alan’s screw idea for support and to increase the bonding area.
 
According to the Marine Tex site, users can mix Marine Tex easily at 55F and have 20-30 minutes to form it (to the board). It heats up internally, so further temperature changes should be kept to a minimum.

Marine Tex is touted as very strong, so any breakage will occur at the line that forms the repair with the board.

Thinking about the nails, they shouldn't be made of materials that could bend. I'd be tempted to use longer hardened steel, such as what is used in drill bits. (Start saving those broken drill bits! ;) ).

The length of the board permits flexing, so further thinking about Marine Tex and dentistry is essential to a long lasting repair--IMHO.

I'm neither an engineer nor dentist :oops: , but in addition to the nails, I'd prepare disposable syringes containing prepared Marine Tex paste, and inject the paste into deeply-drilled holes.

The trailing edge repair should go without adventure.

L&VW, DDS

:)
 
MarineTex will probably work, but might be considered more a filler vs something to build up bulk. The attachment wil be your weak point, given that the stuff us pretty rugged. I extended a daggerboard (With pics in a thread) and used some aluminum L brackets, to "splice" things together. I just used regular fiberglass resin and cloth/mat. Then my choice of fairing compound to finish off the surface inperfections. The 10 inch extension wasn't going to come off, without taking some wooden board above it.
 
I am keenly aware of edge bonding. Over the years I figured that out with various repairs.

The bars you see sticking out are the original harder steel bars that are factory and run most of the length of the board. I expect those bars to form the brunt of the structure and will work hard to fully encase them with the epoxy. The nails to me are a way to control breakage from side hits towards the rear. I have been debating if I might want to use something other then nails.

I picked up the marine tex and tomorrow I start killing some use or lose leave. I may work up a plan in the next few days. I will try to record what I do.
 
I expect those bars to form the brunt of the structure and will work hard to fully encase them with the epoxy. The nails to me are a way to control breakage from side hits towards the rear. I have been debating if I might want to use something other than nails.

I picked up the marine tex and tomorrow I start killing some use or lose leave. I may work up a plan in the next few days. I will try to record what I do.
A hybrid suggestion:

Rout inside the torn edge to get a grip.

Drive 2 or more long and fat lag screws (not bolts) approximating the existing steel reinforcement locations.

Then, wrap several layers of 2-inch fiberglass tape between them, (coat with resin).

Allow to cure, then continue with Marine Tex forming, sculpting, and fairing.
 
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Drive 2 or more long and fat lag screws (not bolts) approximating the existing steel reinforcement locations.

Then, wrap several layers of 2-inch fiberglass tape between them, (coat with resin).

Allow to cure, then continue with Marine Tex forming, sculpting, and fairing.

Something along these lines seems to make more sense than just adding a huge glob of Marine Tex. It would also be much easier to get the right shape to the tip.
 
Here's a pile of pictures on my extension project...probably in that older thread too. I extended it twice.
 

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