Using a 5.5 oz in a hybrid shouldn't be a problem. You could get a bit extra and add a second layer to the waterline area (football shape) just to be sure.
Even using a slightly heavier S glass for back up would make up for the difference but may add a few ounces to overall weight.

Not sure of the laminate schedule advised in the book. Does he suggest S glass first then carbon or is the carbon sandwiched between S glass?

The texalium is a new one on me but there are a number of new products coming out recently and it's hard to keep up with them all. We focus on infusion specific materials for really heavy lay ups in yachts.
There is a new polyester/ S glass hybrid know as "poor man's kevlar" for example. The fabric you mentioned may well be along that line but I will ask our materials supplier and see if I can't find out something on the texalium for you.

The layup calls one layer of Kevlar (49 – 50" wide, 8.9oz) followed by 5.6oz S-glass (30" wide) "One piece of S-glass will be laid from one gunwale over the bottom for the length of the boat; another will go from the other gunwale to overlap the first piece on the bottom; the third piece runs from bow to stern flat on the bottom. This gives the boat one layer of S-glass on the sides and two complete layers on the bottom".

Almost sounds like there may be 3 layers of S glass along the keel line which would give you close to 18 oz's along the keel plus the hybrid. That's a decent wear/stiffening strip.

Even if you were to use the lighter hybrid I doubt you would compromise the integrity of the laminate. You could also use a 4 oz E glass on the whole boat before the hybrid and your laminate would be the same thickness as is recommended in the book.
The E glass is quite affordable and shouldn't require any more resin than the heavier hybrid, likely a little less. This would also "bury" the hybrid a little deeper in the resin where it would act similar to a core. The E glass is slightly easier to wet out as well.

The texalium you mentioned is a carbon hybrid from what I've been able to gather so far. The silver color is actually aluminum powder applied to the carbon (or whatever) fabric.
Still looking for any strength advantage stat's on it, so far it seems it's more for the cosmetic look. I'm still digging.................

There will only be two layers of S-glass on the keel except a very small overlap where the S-glass comes from the gunwales on each side to meet on the bottom of the boat. The sides have one layer of S-glass, the bottom has two (except that very small overlap where there will be three layers). I hope this clarifies the layout a bit.

Clear as mud.......... (kidding !!)

Anything stopping you from allowing the overlap to carry a little farther out from the keel line ???

When are you going to get started on this project anyway?



Cheers,

He recommends not using wider S-glass because it would entail some difficult cuts of the fabric. The overlap amount is due the width of the S-glass. I would like to keep to the plan as much as possible yet have my own touches as well.

I started to cut the strong back to size yesterday, I had to stop to get a new saw blade. Today I was not able to work on it at all. Tomorrow I may get some time. I plan to document my progress. I have not settled on the cloth I will use, it will be enough for me to just get the mold ready. If I use the hybrid fabric I may get a bit more to add to the keel line.

A bit here and there and you'll have a boat before you know it...

Keep us posted.........



Cheers,

Raka (http://www.raka.com/Kevlar.html) carries 9 oz, stitched, biaxial kevlar in 64" width, which is what you want for at least one of the kevlar layers. They also sell s-glass. The biaxial kevlar has its fibers running at +45 & -45 degrees which will result in a stronger laminate if used in conjuction with standard weave (0/90 deg.) s-glass.

Personally, if I was going to build a kevlar canoe I would build a wooden strip plug just like John W. mentioned. It will be less work and a much fairer surface to mold the kevlar hull on. You don't necessarily have to make a beautiful looking plug, cheaper wood can be used and the finished stripper hull painted.

Also, my personal fabric layup would be outside s-glass(6 oz), hydrid kevlar/carbon layer (5.8oz), 9 oz biaxial kevlar, and the inside of the hull layered with s-glass (6oz). I would add some reinforcing layers in the bow & stern. I would use (4-6 lb density) klegecell, divinycell, corecell, or airex for the rib system . Google up Souris River Canoes to get an idea of what I'm suggesting.

Also, It's HIGHLY recommended to use epoxy resin with these fabrics. The resulting hull wil be very tough and light.

See if you can get an out of print copy of "Boat Builder Manual" by Charles Walbridge. The copy I have is a 5th edition from 1982. It's dated, but still has some very good instructions on the process of canoe & kayak hull building.

BTW, Texalium is aluminized fiberglass and has absolutely NO carbon it. It's, stiff and heavy - not recommended for light weight boat building.

Just my opinion - Bob

I second the recommendation for "Boat Builder Manual" by Charles Walbridge. I picked up a used copy on Amazon.com for less than $5.

Also, instead of epoxy, I always thought that using Vinylester would work just fine and be plenty strong. And save some cash. And be less subject to UV.

Bayport Bob wrote;




Excellent point. One good wood to use in basswood. Easy to work with, easy to get clear wood, really cheap in most localities and you can build the boat using short strips and just butting them together. I have used 4' strips and they work fine. Just need to have enough length to bridge three or more frames.

It didn't look all that bad when varnished although if water gets into it it turns black (telltale signs of a crack or leak in the skin).

_________________
Cheers,

John Winters

If the truth be told, I do not see the point in making a strip canoe using an inferior wood as a mold. The purpose expending the energy and money to make the strip canoe would be to either have a second boat or sell it. Alas, making a strip canoe is not within my abilities (either financial or technical). I am at least for this project following the directions of Mr. Moran.

If you care to track my progress on this project you may check out the page I made for it on my website. http://www.microtek-inc.com/canoe/canoe.htm. Be warned however if you download the picture they are very large.

deleteriousone wrote:


Actually there are many woods you can use to build strippers. Keep in mind that the wood is a core (albeit a load bearing core where the wood is very strong) so the qualities one needs in the wood differ from an all wood boat.

For example, one would not likely build a boat out of balsa wood (ganted some have) but as a core it works quite nicely. The wood is not very strong and rots easily but when encapsulated in fiberglass it works well. The best examples are large boats that use balsa as a core regularly.

I have used balsa, sugar pine, basswood, white pine, redwood, sitka spruce and both white and red cedar in strippers with success. The biggest difference is in the appearance. Some people just don't like the lighter color or sundued grain of some woods.

In choosing a wood the biggest concerns are weight and the ability of the resin system to adhere properly to the wood. Keep in mind that, where the wood has a lot of strength you can rely on it to contribute strength and cut back on the glass a bit. I have used sitka spruce with only 2 oz. of glass on each side and local reinforcements in high wear areas (high cost but very stiff and durable).

Some builders do not have access to certain woods (or they are too expensive) but the should not let that stop them. The glass will protect the wood and the wood will stiffen the glass.

OK, just a long winded way of saying that woods other than red cedar are not inferior, just different and you can often save money by looking at locally available alternatives.

_________________
Cheers,

John Winters

As was suggested earlier, a strip canoe should be less work. It isn't all that technical & is well within the capabilities of someone capable of building a kevlar canoe. The process automatically results in fair curves that you would have to work to achieve if using drywall compound. The cost can be quite low. The cheap wood will affect the looks but not the strength because it's just the filling in a sandwich between layers of 'glass. I've read that some builders have used balsawood to build lightweight strippers.

I read a magazine article in about 1978 that reviewed a book on building strip canoes. The 4 page review was the only guide I had to build myself an 18' tandem strip kayak of my own design. I ripped the strips from 1x8 spruce, knots & all. I didn't know about bead & cove, so I left them square edged. The strongback was made of 2x6 spruce. Frames were 3/4" ply (medium density fiberboard is cheaper & much easier to work with). I used Canadian Tire fiberglass & polyester resin (don't use polyester).

There are many things I wold do differently now, but what I did worked. The boat looked good & was used for several years. If I can do it based on a review, you can do it based on the book Canoecraft. And you'll end up with 2 boats.

If you were to consider the wood plug as expendable rather than as a second boat there are certain merits to using wood. We've used wood plugs many times over the years in "one off" construction and found it an afforable method.

John W mentioned butting the joints of wood planks along the length but it's also possibe to run wood planking on a diagonal which allows for shorter length of strips and negates the need for butting on stations. That also allows the use of a shorter material stock.

Bottom line I guess is to use whatever method you feel most comfortable with. The folks here are simply attempting to help in any way they can because they've experienced the satisfaction of launching something made by their own hands.

Wasn't able to open the link you supplied but will keep trying. I'm keen to watch your progress.

II am not trying to start a fight here, please do not be upset if I do not take your suggestion to build a strip canoe for use of a mold to build my Kevlar/Carbon canoe. I do not have the tools, the money, the time, nor the skill set to perform fine woodworking. If you happened to read my webpage on this project you will see the difficulties which I have already encountered.
I am ignorant of the processes involved in building a strip canoe. My goal for this boat is to have a canoe which is large enough for three occupants yet light enough for me to load (on the minivan) and port solo. I suspect the drywall compound will be more forgiving than wood. I thank you for your suggestions. Now I am going back out in the heat to transfer the rest of the patterns to the plywood and maybe even start to cup them out. Wish me luck.