A Stripper and a Composite Copy

[Jim Dodd]

Jim - really nice work (as usual). In terms of the composite copy, how much tumblehome is there in your hull? Is there a level of tumblehome that is just too much to make this workable when it comes to separating the copy from the cedar strip canoe?

I have a stripper hull hanging from my garage ceiling now that is waiting for gunnels and other final fittings when/if the weather warms up around here. It’s an Ashe’s solo trip that has a 30 inch waterline, growing to 33 inches at the max tumblehome point, and narrows down to 29 inches across the gunnels.

Do you (or others here who have done this) think this much tumblehome would give me a lot of grief in trying to get a composite copy off, assuming I leave both ends open as you are doing? Your project has got me seriously thinking about trying this before I finish things up on the stripper, but I have absolutely no experience here.

Thanks
Tony

Hi Tony !

The amount of tumblehome would not be a problem.

I'd go for it !

My advise at this point, is to be sure you varnish your hull first, and use Partal for a release !

I did this on a Royalex White Water hull, using Partal. The 6 oz Kevlar cloth, held tight to the hull.

Finished.




Jim

 

[Traveler]

Thanks Jim. I am going to scout out the Kevlar and glass cloth I would need (seems more difficult now to just find the material here in Canada, let alone at the basement price you scored).

Feel free to go into excruciating detail when you post on the composite copy part of your build.

 

[Cruiser]

Thanks Jim. I am going to scout out the Kevlar and glass cloth I would need (seems more difficult now to just find the material here in Canada, let alone at the basement price you scored).

Feel free to go into excruciating detail when you post on the composite copy part of your build.

You could always look at drop shipping harder to get items ... then just scoot across the border and pick them up. I used to have a drop ship place in Buffalo, now I ship to a friend there and they bring them back when they come up on a camping trip.

The border doesn't need to be much of a barrier IMO.

Brian

 

[Jim Dodd]

OK . At this point the Kevlar copy is off the stripper mold.

Next up is to sand the glassed stripper, before removing from the forms.

I love how easy it is to sand, the Tumblehomed area when I tilt the strongback !

Fresh off the forms. Take note how little glue I have to deal with ! One of the big benefits of Bead and Cove. Being minmal with the strip glue is also a big benefit ! I spent very little time scraping, and sanding.

I will set the stem forms, with the adjacent form still attached, into the Kevlar hull. This will insure the stems on the Kevlar, get glued perfectly vertical.

Next I set the forms back up on the strongback, minus the stem forms.
Instead of foam, like a lot of other composites, I'll make a 1/8" thick WRC insert.
This adds plenty of stiffness, and I like the look a lot better. It also costs a lot less than Structural foam.
I just edge the 1/8" thick strips. No need to spent time fitting such thin strips.
I staple the strips to the forms. Two reasons. It's quick, and when I install, epoxy will seep through, telling me I have a tight fit between the insert, and Kevlar hull.

Those "Jimmy clamps " are so quick and handy !

After I'm done stripping up the insert, I clamp on a Batten, so I can mark where to trim the insert.

The Jap saw is a great tool. It works perfectly, for trimming. A simple plane makes quick work o fairing the edge.

Here the insert is cut, and sanded, waiting to be Mated with the Kevlar hull. Just a note, the middle strips are Aspen. Aspen will stay white, long after the light Cedar turns redish.

Next I address, the wrinkles left by the plastic film. Again ! Partal would have made this step a lot easier !

I have the stems glued true at this point. Beings I built the insert on the forms, it has the curves and shape of the Kevlar interior. This aids in fitting everything together. I place Blue tape spots to show me where the insert needs to be !

With the interior of the Kevlar, sanded, and marked for the inserts. It's time lay out plastic that will go on top of the insert, while gluing it in.

Here I have things lined up. With the insert, and the interior of the Kevlar sanded. the plastic sheeting and straps are in place.

Next comes the Epoxy. I'm sorry, I don't have photos, of the application, but when I'm working alone ? My glues are full of epoxy.

Next, I mixed two 12 oz batches of resin, with Cabosil added to thicken the epoxy. The mix was way thinner than Peanut butter.
I spread it with a toothed plastic troll, in the Kevlar hull, up to the blue tape marks.
The insert is added. Making sure it is centered. The plastic is placed over the insert, and the forms are strapped in place. Lastly about 150# of sand is added to insure the insert is pressed tight to the Kevlar.

A Very important Note ! Don't forget to place some bracing between the hull and saddles, to support the hull ! I made that mistake only once !

Forms and sand.
The sand is my version of a " Poor Boy Vacuum bagging system."
A vacuum bag would be far better !

The plastic worked great ! After a couple of days, no hurry at this point, I unstrapped the forms, and scooped out the sand.

Next it was time to sand the insert, and feather the edges, so I could cover, with a cloth layer. I think I used 6 oz E-glass for this, because It was handy.

The insert was glassed, about 4" up the side of the hull, on each side. At this point, I will turn my attention back to the stripper. Flotation chambers, will be the next order for the Kevlar, and an additional layer up the side in the area of where the seat will be placed.

Next episode will be finishing the interior of the stripper.
Thanks !

Jim

 

[Boatman53]

Thanks Jim. Quite the post. I like how you used the station forms to press down the insert. Well done.
Jim

 

[Cheeseandbeans]

Thank you for all the detail Jim. It has got me thinking of a future project for sure.

Bob

 

[Jim Dodd]

Spring is here, and the shop is warm enough to make working on the canoes, tolerable.

One of the main things that motivated me to build these two canoes, was to reduce the weight.

I must confess, I'm not very successful at that.

Setting out to the weigh everything.
First the hull. It is glassed with flotation chambers, and a double layer of cloth on the bottom. I do this with all my canoes. Not willing to change. Also added an extra 1" to the shearline Height. Why I don't know !?

The hull weighs in at this time 33.5 # with the trim, and seat, cut and laying in the hull. It weighs in at 45.5#.
Not what I expected with 3/16" thick strips, and 4 oz S-glass.
Hull at 33.5#, plus 12# for Ash trim including decks and seat. The seat alone weighs close to 3#.

I pulled out a set of Aluminum, Bell contour gunnels, I purchased a few years ago, to compare.
They weigh .4 # per foot. That figures out to be 6.4# for a 16' canoe.
My Ash trim including decks weighs 9 #. 2.5 # difference.

Though I made a comparison, between wood and aluminum gunnels, I won't put aluminum gunnels on a stripper. They may end up on the composite.

So in conclusion. Thinner strips and more expensive S-glass really made little difference.
I'll go back to at least 6 oz E-glass from here on.

For my gunnels, I glue and screw the inwhales, and decks. The outwhales are just glued. The shear of the hull is capped and sealed by the outwhales. This gives me the strongest gunnel system. It becomes the canoe, not something just screwed on.

No screws, or plugs will be showing. This seals everything. I like the look too.

Here are some pics, of my progress so far.

The decks will get shaped after the gunnels are installed.

More later, I need to put the scale to the composite next.

Jim

 

[stripperguy]

Jim,
What did you make the flotation chambers from? I’m guessing they’re stripped and glassed on both sides.
Your 3/16” strips are coved and beaded, meaning you didn’t have to sand much off. You could have saved a few pounds with thinner strips, maybe, but not much.
Did you cover the weave on the inside? If so, that cost you a few pounds.
I love the look of your gunnels, but as you already know, they exact a price from your shoulders and back.
Have you tried foam and carbon or foam and glass (maybe innegra) composite gunnels? Alan did some carbon over cedar gunnels, man they looked nice and I’m sure we’re plenty strong.
Seat frame at 3 lbs is a bummer, but you know how to reduce there…
Anxious to hear the weight of the composite hull.
Thanks for posting your results.

 

[Cruiser]

Hi Jim, it sorta seems there is something funky going on with those hull weights, granted the .38 special is a foot longer, but your hull is ~10# heavier than my 3/16" solo ... granted different boats and a 1 foot difference. Mine is using 6 oz e glass, but 10# heavier at this point, seems to point the finger elsewhere.
I am praying this is true, as the extended version of my boat is starting early summer and will feature 4 oz S glass and be extended to 17' with the expectation that I can hold the 30 pound mark, much of the anticipated weight savings is based on glass epoxy weight reduction.

Brian

 

[Jim Dodd]

Jim,
What did you make the flotation chambers from? I’m guessing they’re stripped and glassed on both sides.
Your 3/16” strips are coved and beaded, meaning you didn’t have to sand much off. You could have saved a few pounds with thinner strips, maybe, but not much.
Did you cover the weave on the inside? If so, that cost you a few pounds.
I love the look of your gunnels, but as you already know, they exact a price from your shoulders and back.
Have you tried foam and carbon or foam and glass (maybe innegra) composite gunnels? Alan did some carbon over cedar gunnels, man they looked nice and I’m sure we’re plenty strong.
Seat frame at 3 lbs is a bummer, but you know how to reduce there…
Anxious to hear the weight of the composite hull.
Thanks for posting your results.

The flotation chambers were made with 3/16" strips and glassed both sides.
I was able to get by with one fill coat , on the inside.
For the extra layer over the football, I did use 6 oz E-glass.
Adding an extra inch to the shearline, making the hull deeper, could have added a couple of pounds.

I have yet to route the top edges of the gunnels. That should help a little.

As far as composite gunnels, on a stripper ? It's a bit far out .

 

[Jim Dodd]

Hi Jim, it sorta seems there is something funky going on with those hull weights, granted the .38 special is a foot longer, but your hull is ~10# heavier than my 3/16" solo ... granted different boats and a 1 foot difference. Mine is using 6 oz e glass, but 10# heavier at this point, seems to point the finger elsewhere.
I am praying this is true, as the extended version of my boat is starting early summer and will feature 4 oz S glass and be extended to 17' with the expectation that I can hold the 30 pound mark, much of the anticipated weight savings is based on glass epoxy weight reduction.

Brian

Guessing my expectation of less resin usage, as a result of the 4 oz S-glass, didn't come true. I used MAS on this hull, but don't think that was a factor.
I liked working with the 3/16" strips. I will again ! This time I will try the 3/32" Radius bits, for bead and cove.

Planning to weight the composite, as soon as I get flotation chambers in.

Not making the mark as far as weight, is just incentive to keep trying.

Good luck on your next build ! Looking forward to your thread !

Jim

 

[Cruiser]

>.< now I am worried about weight ... you promised me that the S glass was the magic sauce ... now I have to buy that new Hydrogen wood to stay on the weight budget.


Brian

 

[Jim Dodd]

I'm thinking if you single layer the outside, skip flotation, and just wet out the inside. You will do far better than me.

Oh ! don't add any extra shear height.

I was surprised, how much weight difference there was between aluminum, and my Ash gunnels in weight.

The best of luck !

 

[Cruiser]

Jim, I have always found that sizing and wood selection for gunnels, is likely the single biggest source of unnecessary weight with a canoe build.
If you are watching weight then trimming the dimensions, tapering as you approach the bow and stern and wood selection are all critical areas for weight gain. Ash is a very strong wood, but also very heavy, so it likely can be reduced even further in dimension and still do the job, just fine. Reducing that deck thickness would likely save a pound, reducing it further and putting a light fiberglass on it, would likely save a lot more.
I will also be adding an extra layer to the inside football, so I will pay special attention to the squeegeeing ..... dang it, I had a whole plan worked out in my head, now you have created a whole new scenario to contemplate before I start, lol.

Brian

 

[Jim Dodd]

Brian

I make my decks rather small. For one, the flotation chambers adds a lot of strength to the ends. There fore I make my decks small.
The pair weigh in at 1 pd. 14 oz.
Yes I have a lot of shaping to do to those decks, that along with routing to top edges should save even more. I won't do that, until I have everything installed.
I guess I really expected the resin usage, with the 4 oz, to be much less. It wasn't.

If I get in gear, and finish these two ? I can start again, as I have plenty of cedar. Ha ! A vicious circle for sure.

Alan played with Peel Ply. If one can reduce the amount of fill coats ? There would be a significant weight savings. I struggled getting Peel Ply to conform to the hull shape, on an earlier build ( Vader ) That is an area you might want to also look into .

Jim

 

[Kliff]

Ok, as I'm getting ready for my next build, I'm getting more and more curious about s-glass and e-glass. Looking at the suppliers I've used in the past, which is a relatively short list, they all just list "fiberglass cloth". I'm assuming it's e-glass, but I can't find where it says so. The glass I bought for my one and only stripper was from Raka. Now searching, the only s-glass I've found is on surfboard suppliers, and has a max width in the 30-38" range. Is there a "one stop" source for a good selection of glass? So far, I can't find any s-glass wide enough for a canoe. Not saying I'd be using it, but I'd like to know where to get it.

 

[Kliff]

While this thread is a great read, and something to keep in mind, it is way beyond me at this point. I'm still learning to "walk" in the world of canoe building. Jim and others are walking, doing cartwheels, juggling, and swallowing fire all at the same time. I'll just stick to my one at a time stripper builds. You continue to impress me.

 

[Cruiser]

Ok, as I'm getting ready for my next build, I'm getting more and more curious about s-glass and e-glass. Looking at the suppliers I've used in the past, which is a relatively short list, they all just list "fiberglass cloth". I'm assuming it's e-glass, but I can't find where it says so. The glass I bought for my one and only stripper was from Raka. Now searching, the only s-glass I've found is on surfboard suppliers, and has a max width in the 30-38" range. Is there a "one stop" source for a good selection of glass? So far, I can't find any s-glass wide enough for a canoe. Not saying I'd be using it, but I'd like to know where to get it.

I found mine at Sweets Composites, I think you said it was out of stock there, but it is likely a temporary issue. I would call and talk with them, see when he will be getting more, I did and he was really good to deal with.

 

[stripperguy]

Soller, Fiberglast, Merton's, Sweet, RAKA...
Oh, and thanks for the "lessons learned" and costing breakdown, that will help many others that might be on the fence.

 

[Jim Dodd]

Sweets has S-glass, and that is where I purchased mine. Cruiser gave some good advise. Call and talk to them.
I believe I Talked to Jennifer, and one of the shop guys When I purchased mine.
As far as which to use ? Builders choice. I have built almost all mine with E-glass.
My next will likely be built with E-glass.