how to add spray rail to composite fiberglass deck

B

bob Petritsch

Active member
My fiberglass Higbee has a a sandwich construction. Two thin layers of fiberglass with a foam or balsa center core. It is registered as a 1986 Rays Plastic boat. I do not want to but any screws through the fiberglass into the sub layer. I am thinking of just epoxying a strip, either PVC or oak to the deck.
My other option was to run bungee cord from the bow eye back to the decoy rack. I've tried this out and it keeps a tight fit to the deck. The dodger might look a bit strange out that far but it would leave a good sized storage area on the front deck.
Any suggestions would be appreciated.
 
My fiberglass Higbee has a a sandwich construction. Two thin layers of fiberglass with a foam or balsa center core. It is registered as a 1986 Rays Plastic boat. I do not want to but any screws through the fiberglass into the sub layer. I am thinking of just epoxying a strip, either PVC or oak to the deck.
My other option was to run bungee cord from the bow eye back to the decoy rack. I've tried this out and it keeps a tight fit to the deck. The dodger might look a bit strange out that far but it would leave a good sized storage area on the front deck.
Any suggestions would be appreciated.
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Bob got any pictures of your boat and its construction? Would love to see it, the Higbee is our next project.
 
Bob, If the core is end grain balsa the balsa alone can with stand 350LBS per square inch of compression. If it's foam it won't be that high. If you can access the deck under where you want to locate the spray rail then I would drill through the deck using 3M 5200 to seal the holes. The key is weather it's balsa or foam core you will want to use large stainless fender washers or better yet aluminum plates under the deck for each through bolt. Good luck.

Tom
 
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I am thinking of just epoxying a strip, either PVC or oak to the deck.
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I would think that would be just fine. As long as you have a good fit and enough surface area, mechanical fasteners should not be required.
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If you decide to through bolt and it appears that it still wants to crush the core another option would be to sleeve the holes making the sleeves a bit shorter then the thickness of the deck so you can tighten the bolts good but not crush the core. Just another thought.

Tom
 
Bob, I found a composite material at HomeDepot that is rather dense. IT is white and has a hard shell but is rather dense throughout, not to be confused with the light Azek trim that you can dent with a finger nail. While I don't know how you might attach it to hold it while the epoxy cures wihtout screws, I would use that material. I used it for my coaming for the dodger. It holds screws well. I used a wire wheel on my grinder to make some tooth on the bonding surface, and thickned epoxy to secure it. I also screwed mine through to the deck beams below. I think the coring suggestion is sound. Some over sided holes where you entend to install fasteners, Duct tape on the inside and fill with thickned epoxy. Allow to cure and fair, no you can screw in and not compromise the foam core.
 
Bob, wondering why your concerned with screwing through your laminate? If its balsa core or foam as long as you seal it up all is good. Balsa will break down before the foam core but were talking many many years unlike lesser woods. Also depending on the foam core it could have a stronger compression ratio than balsa but that will depend on what it is. Balsa
core will be around 9lb to 10lb density. Coosa and divinecell makes some of the greatest foam core available and many foam core manufacturers exceed 10lb density now days. Coosa makes 15lb to 26lb density. we use 5lb density core in our boats laminated between each laminate and it can be screwed through or into with mo worries of pulling under normal use. I wouldn't worry to much about drilling through this laminate i would simply seal each hole as stated before with 5200, backed with larger fender washers and all is good.
 
I guess I am the odd man out on this issue. We build entire boats with stitch and glue only, no mechanical fasteners.

Bob wants to use epoxy to glue on a spray rail with out mechanical fasteners. I don't see a problem with that. What am I missing?
 
I, and a couple of my buddies have been using products similar to this-

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Maybe not necessarily this exact manufacturer, but this product. It's an industrial strength, professional grade epoxy adhesive used for securing anchor bolts in concrete. A standard caulking gun is all that's needed, (and a LOT of elbow grease). Research shows it is quite weather and moisture resistant, sets up quickly, and is extremely strong. It has the consistency of toothpaste with a little grit in it. It normally comes with one or two static mixing tubes, but for small batches, we just squirt a bit out on a piece of scrap cardboard and mix with a small popsicle type stick. The tube automatically dispenses the proper ratio.

I know for sure, this stuff is stronger than whatever you put together with it.

Jon
 
I guess I am the odd man out on this issue. We build entire boats with stitch and glue only, no mechanical fasteners.

Bob wants to use epoxy to glue on a spray rail with out mechanical fasteners. I don't see a problem with that. What am I missing?
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I wouldn't think he is simply going to lay a bead of glue down and stick a piece of wood into it and try to get a good bond? especially if the deck isn't perfectly flat.

Depending on exactly where and what he plans to use will determine how it can be done. which is why I asked for some pictures. How to clamp the piece down or hold it securely while curing is a concern for me.
 
Dave, you are not missing anything. A clean and well scratched surface glued with epoxy igives a chemical bond that is far superior to mechanical bonding especially when dealing with the he draw backs to piercing core materials. Where improper sealing and /or eventual working will permit water intrusion.
Best, Frank
 
Dave, I'll second Frank's comments, particularly his statement regarding fasteners "working" over time to defeat any sealing compound used. I would add that any applied load would also be spread over the entire surface area of the chemical bond between the laminate materials.
 
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