new to building

Hello I have been reading around a bit and looking at information. I see composite being talked about in larger applications and not really getting a good idea of the route I want to go.

First off I will say I have worked with fiberglass and carbon on small car parts never with building large scale pieces.

I am looking to build a small hunting scull boat from a male mold. Mostly this will be used under a single oar or a kayak paddle or oars. I may throw a electric trolling motor.

The boat will be carried and dragged at times so I am looking for light weight and durable.

I have been reading about kevlar, carbon and different fiberglasses. Also epoxy and poly resin

From reading I am leaning towards Kevlar for the hull and adding closed cell foam ribs on the inside with carbon over the top of them in cased in Kevlar to provide ridgidy while keeping the weight and number of layers down.

Also I have been told when Kevlar get rubbed it frays and then is able to absorb water. if this is true would a layer of another material be needed where things will contact the hull.

I am trying to figure out the best route to go and what products would be best for my application. I realize there is a difference in price going to composite material and epoxy resin bit am willing to go this route to insure I get a good long lasting final product.

lastly I have read using peel ply to help with excess resin. Is this done by laying the fabric and adding the resin?Then laying the peel ply and going over the peel ply with a solid roller to allow the excess resin to seep out? Lastly pulling the peel ply before or after the resin has set? I may not have the actual process down just my understanding.

thanks for any help in advance
Josh

 

First, Josh, welcome to the forum.
A mold for a one of a kind boat is an expensive way to go. You might want to consider stitch and glue for a good serviceable boat for a lot less money.
Have you picked any specific designs?

 

Just one of a few sources for plans: http://www.bateau.com/products.php?cat=26#.UkNBeIabPUU

 

I have the hull layout from a guy that pulled them off a Lyn lee (similar to a Hayden) boat. He also built a male plug and is able to talk me through it. I have looked at the stitch and glue method and the reason I'm leaning towards a mold is if this boat pans out I will be building a second one.

The guy I got plans from he built his all glass and poly resin and it weighted in around 125 pounds. I'm trying to get down around the 60 range due to me not being able to put the boat straight into the water.

That being said I am shooting for a light boat but would still like it not to flex a ton. Now that I'm looking at building it for structural strength and not aesthetics is when I'm not informed when it comes to composites and resin. What to use where and why. I would be will to have a phone conversation if that would simplify things for anyone.

 

The plug already having been built should save a lot of money. Make the chines, floor and gunwales a little thicker but the hull should be okay with the same thickness as a standard fiberglass canoe. You should be able to reach your goal.

 

I will be building the plug, he will be sending me the layout for the hull as tempelates at one foot sections. Sorry for the mix up.

 

Good luck with your project. Make sure there are not any intellectual property issues to haunt you.

 

The lightest way to build a boat like that would be use a foam sandwich with carbon on the outside and inside. to make it more durable you can put a light layer of fiberglass over the outside.

Seems a pretty costly way to go however.

you can build a skin-on-frame canoe of similar size, with a doug fir frame, and 12 oz polyester skin, that would weigh about 45 lbs and cost about $100 in materials. And it would take about 100 hours or less to build. It would be much lighter and still be real tough for dragging through the woods. If necessary you could add a hard wood rub strip down the keel line. I have built something like 19 or 20 skin-on-frame kayaks, canoes and sailing dinghys, all came together quickly and are much lighter and less costly than their "hard shell" equivalents.

There are few structual deisgns that are inherently lighter than a well designed skin-on-frame. Modern commercial aircraft are built in almost the exact same way, frames, stringers, and a very thin skin.

It will not look like a modern composite, and there is a little less room inside because of the frame structure, but it can be made to look attractive if the frame is finished "bright" (clear marine varnish), and than paint the skin in a traditional "duck boat" camouflage.

 

what type of foam is used? i would need something that does complex shapes. here is a picture of what i am looking to build

 

Are you going to be making the top and bottom? Looks like you will need 2 molds, then glass the finished parts together. I used to build kayaks for a company in the Florida Keys.

 

Yeas it will be 2 molds a hull mold and a deck mold. Then with a shoe box style flange to fit the 2 together.
I have done a bit of talking and reading about resin infusion. The only thing that has not been answered is the mold will be insulation foam with drywall mud to smooth it all out. Then paint. When they hand laid over the male plug they put a layer of plastic down then pva. If I go infusion I need a product to apply instead of plastic that will not hurt the foam/mud mold.

 

Forgot to add I do not have a mold a guy in California has built the same style mold of another guys boat and is sending me the drawings to do the same at my house in Ohio

 

Ok after talks with a few places I have decided on using 2 layers of s-2 8.9oz hexcel then plulling off the mold.then using 3-4" strips on 1 foot centers of 3/8" divinymat and 1/2" on the deck. Then another layer or 2 of the s2 on the inside. A few have talked using a layer of 3/4oz mat inbetween the s2.

I'm looking to use 635 epoxy resin with fast hardner but have been suggested to use vinylester. Not really sure which is the better route. It seems the epoxy is stronger but a bit more expensive.

Lastly looking to see if there is a local place that can spray a thin gelcoat on the bottom of the hull with a graphite filler.

 

Do a little test with vinylester before a big project, as the stink is awful.

I tried a small bit for a little job, and could never use it again. Epoxy is much more bearable than Polyester too.

 

Thanks for letting me know. I don't even like the smell of poly resin. I would gladly spend a few dollars more and get epoxy