Solo expedition build

[Alan Gage]

If I may, I'd like to make a suggestion for someone to try...
What about using a plastic tube, like teflon, cutting a slit in it, and then epoxing it to the hull first. Then wrapping the CF tape or Kevlar over the top of it and down on the hull? Has anyone tried this? Does flexible tube or hose work with epoxy?
Maybe it's a dumb idea. I don't know.
What do you guys think?

So you're thinking the plastic tubing would take the place of the wood or foam core?

I don't think epoxy would adhere to most plastics, at least it hasn't in my experience, and I don't think you want the core to be able to move inside the laminate, which it might do when stressed if there's not a firm bond.

Alan

 

[Jim Dodd]

This is kinda a different direction, but the old Strip built C1s simply used a Thicker shear strip as their gunnel. One could Do this, wrap in CF, and what ever. and that would simplify having to Fit the cedar gunnel.

Modify your forms to accept your cedar gunnel as you've already done formed. Insert your first strip, and away you go !

Jim

 

[Jim Dodd]

One other thought that bothers me about the CF. It's black, and on a hot sunny day, might not be all that pleasant to grab.

Maybe you are going to paint it, or something?

Jim

 

[Alan Gage]

This is kinda a different direction, but the old Strip built C1s simply used a Thicker shear strip as their gunnel. One could Do this, wrap in CF, and what ever. and that would simplify having to Fit the cedar gunnel.

Modify your forms to accept your cedar gunnel as you've already done formed. Insert your first strip, and away you go !

Jim

That's a good idea, especially for a lightweight build. On an 18.5' solo I did I used oak as the shear strip, slightly thicker than the cedar and rounded over on top, as the gunwale. On the water it seems ok but on the roof rack there's way too much flex in the wind. I'm thinking it will get wrapped in CF.

One other thought that bothers me about the CF. It's black, and on a hot sunny day, might not be all that pleasant to grab.

I'm not too worried about it on the gunwales, though I might change my tune in August. I'm a little more concerned about the carbon decks/float tanks and they might get painted for that reason. I don't necessarily think they'll get hot enough to cause damage or too much pressure inside the tanks but I don't like the thought of it turning into a little oven inside there, especially since I might add a hatch and use it for small dry storage.

Alan

 

[Alan Gage]

Finally made a little more progress on the boat tonight. Last night I wimped out and went to bed early.

I got the decks/float tanks cut out for the bow and stern. I thickened some epoxy and glued them together so that they'll be an assembly. Then I'll finish shaping the corner and the seam where they meet. They're just sitting loose in the boat but it holds them in the proper position while the epoxy sets. Otherwise it was very difficult keep them lined up and sand the proper angle on the edge of the deck so that it transitioned smoothly to the front of the tank. Hopefully this will work and then I'll laminate both sides with carbon fiber. Probably two layers on the deck and one on the tank.


20150401_001 by Alan Gage, on Flickr

I wanted to have integrated handles and came up with some cool ideas but in the end decided they would either be too difficult to implement or would be more aesthetically pleasing than functional. Would have been easier if the deck wasn't integrated with the float tank. I'll either add a handle between the gunwales or might carve one out of foam and attach to the deck/float tank.

Also made up a couple more foam gunwales and laminated them with 18oz. carbon sleeve. I made one from EPS foam (others have been XPS) and I'm curious to see if it feels any different. The EPS foam itself, while the same density (2lbs/cu. ft), is slightly softer and flimsier. EPS foam seems to be the preferred foam for surfboard builders. I haven't read a lot about it but there seems to be some concern that XPS foam continues to outgas for years and that over time it may weaken the laminate. I don't know if there have been any actual cases of this happening or if it's only a hypothesis/old wive's tale. While harder to get locally the manufacturing process is a lot more eco friendly and I just happen to have 8 sheets of 4'x10'x4" laying around from when I built my shop. It's my sub-slab insulation and I ordered a bit too much.


20150401_002 by Alan Gage, on Flickr

Alan

 

[Jim Dodd]

Well thought out construction plan !

I like being able to access the flotation tank !

Wish I had more knowledge base on the foams ! It amazes me with the wide variety of technics commercial builders are using these days.

I've been viewing North West Canoes, work shop video. Wow !


Jim

 

[memaquay]

I gotta say Alan, you're the Thomas Edison of canoe building. I read his biography once, said he lived off apple pies and slept sporadically. Any similarities?

 

[seuss]

The fabric itself, once the final fiberglass layer was added, stayed in place pretty well and does not seem to have wrinkled As far as I can tell it was only the peelply that wouldn't conform and left wrinkles of epoxy.

Alan

Alan, are you wedded to vacuum bagging the gunwale? Maybe consider heat shrink instead?

https://www.youtube.com/watch?v=jwExI_vnchE

 

[Alan Gage]

I've seen that heat shrink on Soller's website. Nice to see a video of the process. I'd like to make some carbon tubing and it looks like it would be perfect for that.

As far as using it on composite gunwales it should work great if forming them off the hull and probably would eliminated the wrinkling problem from the peel ply. Less wasted materials as well (peel ply,breather, bag film, tacky tape). Definitely something to think about.

Doesn't work if laying the cloth on gunwales that are already attached to the hull, however. Yet another reason to try and figure out an easy way to do it off the hull.

Thanks for the idea!

Alan

 

[Alan Gage]

I gotta say Alan, you're the Thomas Edison of canoe building. I read his biography once, said he lived off apple pies and slept sporadically. Any similarities?

Well, I do eat a lot of cookies and have had trouble sleeping the past couple weeks but I think that's where the similarities end.

Alan

 

[Alan Gage]

Decks/float tanks are now a module:


20150402_001 by Alan Gage, on Flickr

This made it very easy to sand the correct angle for a smooth transition at the joint and to round over the edge. Foam sure is easy to work with.


20150402_002 by Alan Gage, on Flickr

Added a thickened epoxy fillet to the inside corner and put the first layer of carbon on the decks. A second, full layer, will cover everything. Will I add the 2nd layer before or after it's been installed in the boat?


20150402_003 by Alan Gage, on Flickr

Alan

 

[Mihun09]

Well, if you put the second layer on while in the boat you could wind up with a really ugly frayed edge of carbon on the nice wood. How difficult is it to trim the carbon after the epoxy has hardened? If you do the second layer off the boat, trim the edges nice and clean and use a fillet to install the tanks, should look better in the long run. Can you get a black pigment for the epoxy so the fillet is black, not some other colour?

 

[Alan Gage]

Yes, beforehand seems like it would be the best option. Sometimes in the morning I forget my reasonings from the evening before but there must have been a couple reasons why I thought laminating after install would be an option. Hmmm.....what were they?

Oh yeah! I'm not sure how much, if any, flexing or tweaking may be required to get the tanks to fit just right. Leaving off one layer of lamination might let me move it a little if needed. I'll know for sure after I laminate the inside of the tanks and try a test fit.

Having the tanks in place would be a handy way to hold them still while I applied the last layer of carbon. But surely I could come up with some other way to hold them in place without installing them in the boat.

I don't know if I'll be using carbon or fiberglass tape to secure the tanks in place. If carbon then any ugly edges don't matter since it will be covered by the tape. Fiberglass seems like it might be a better choice though and would give a cleaner looking transition between the hull and tanks. Fiberglass tape would also give me the option of painting the tanks.

I could also try Holme's tape method to trim the stray edges of the carbon if I laminate them in place.

I figured I could use powdered graphite to blacken the epoxy and if I look on the shelf I think I bought a little bottle of black epoxy coloring as well. I bought some graphite powder at the hardware store the other day and even after thickening the epoxy with cabosil (which turns it white) a little graphite powder still turned it pretty close to black.

Alan

 

[Mihun09]

Considering the thickness that is available on the edge of the foam, what I would do is... put them in place where they are to go and outline on the hull with masking tape the outer edge. Remove the tanks and scuff the area where the foam edge meets the hull. Mix up thickened epoxy and slather the edges of the foam and push the tanks into their respective positions. Any epoxy that oozes out can then be formed into a fillet. That would give maximum adhesion and strength of tank to hull. Now, if you felt that wasn't enough of a bond, you could still put glass tape around the edges to further enhance the bond. All of this assumes you contoured the edges of the foam to fit the hull shape of course.

 

[wysedav]

I may have missed this but I think you still have to fiberglass the inside before you put the tanks in place. Another option to blacken your epoxy is black chalk line chalk it's cheap readily available and works great.

 

[wysedav]

One other question. Why the second layer of carbon? I doubt it is needed structurally the decks are supported all around so they shouldn't need much. Seems at odds with the construction method. Using foam and carbon is great for lightness but then a second layer just adds unnecessary weight.

 

[Alan Gage]

I may have missed this but I think you still have to fiberglass the inside before you put the tanks in place.

You mean the inside of the tanks? Yes, they'll get a layer of carbon as the next step. Or maybe it will be fiberglass. Oh geez, more decisions.....

One other question. Why the second layer of carbon? I doubt it is needed structurally the decks are supported all around so they shouldn't need much. Seems at odds with the construction method. Using foam and carbon is great for lightness but then a second layer just adds unnecessary weight.

Good question. With one layer of carbon (5.7oz/yd) I can still feel the squishiness of the foam when pressing hard. With two layers I can't, at least not much anyway. I worry a little about abuse the decks might take when rolling the canoe upside down or when running into obstructions while portaging. I wouldn't expect them to break with just one layer but I hope the second layer ads a little more puncture/dent resistance. So the second outside layer is only on the upper/deck section.The vertical surface will only have one layer inside and out.

I also expect a final layer of fiberglass over top of the decks after install and probably an extra layer at the stem tips.

Alan

 

[wysedav]

Ok. I thought it might be dent resistance. I think fiberglass will be plenty on the inside even 4oz

 

[wysedav]

Don't forget to weigh them and give approx size before installation. I was thinking foam might be a good way to go but because of the squishyness I ll probably go wood with fiberglass. Thanks for going into detail about what you're doing I'm learning a lot.

 

[Jim Dodd]

OK Beings we have TAKEN OVER your build Alan

I'd put a layer of glass say 4 oz on the insde, one complete layer of carbon (Trimmed before putting in )
And a layer of 4 oz over that, and a 1" skirt to seal against the chamber. You can feather the edge of the skirt, and no one will know it's there. It will seal your chamber to the hull !

This is how I do my flotation chambers, minus the cabon.

Any other changes you will need to confirm with us !

Looks Great ! May be using some of this on my Kevlar !

Jim