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Boundary Waters Quetico Forum Gear Forum Kevlar canoe |
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09/24/2019 10:30AM (Thread Older Than 3 Years)
I need technical advice from people having experience working with Kevlar. I plan to make a kevlar canoe myself. The plan is for an 18' canoe with 3 or 4 layers with vacuum epoxy infusion. But I recently got over pretty inexpensive kevlar sheets 3 ft x 5 yd pieces which means it will be made from many pieces.
From your experience, how much may it affect hull strength? Is it worth it to consider making it from pieces or better not to take a risk and go with one piece per layer?
Thank you for your time.
Andrei
From your experience, how much may it affect hull strength? Is it worth it to consider making it from pieces or better not to take a risk and go with one piece per layer?
Thank you for your time.
Andrei
09/24/2019 01:20PM
Partials will be fine for the internal layers as long as there is sufficient overlap between pieces (8-10 inches perhaps) But I would want to have a full blanket for the most outer fabric layer: both for strength and aesthetics. Infusion would work fine in a female mold: infusing partials over a male mold would leave an irregular surface on the outside of the boat. Partials should not affect the infusion too much, though if the overlap areas are all on top of each other it may be slower to infuse in that particular place.
I infused a boat Earlier this year.
Strength for regular Kevlar canoe use should be fine. I have seen partial layers delaminate at the seams when rocks/rapids come knocking on the hull, though. Remember, Birchbark canoes of old were made of partials stitched and pitched together and they worked well enough to develop the entire fur trade industry.
I infused a boat Earlier this year.
Strength for regular Kevlar canoe use should be fine. I have seen partial layers delaminate at the seams when rocks/rapids come knocking on the hull, though. Remember, Birchbark canoes of old were made of partials stitched and pitched together and they worked well enough to develop the entire fur trade industry.
"Everybody needs beauty as well as bread; places to play in and pray in, where nature may heal and give strength to body and soul" -John Muir
09/24/2019 02:24PM
Hi muddyfeet, I read your thread on canoetripping. Amazing work, really inspiring. I plan just for one canoe, at least for now, so I thought about male mold.
With fiberglass as outer layer, next 2 layers of 5oz kevlar, next foam core and kevlar over core.
It will be my first serious project, so I'm not really run for perfection, just to have decent view.
How it all sounds for you, if I do it from pieces, doable?
With fiberglass as outer layer, next 2 layers of 5oz kevlar, next foam core and kevlar over core.
It will be my first serious project, so I'm not really run for perfection, just to have decent view.
How it all sounds for you, if I do it from pieces, doable?
09/24/2019 03:18PM
How this plan looks for you: On male mold put full sheet of kevlar and on kevlar put fiberglass - it will be first two outer layers. Infuse it, let it cure and take out from mold. Put inside of first two layers partial sheets, foam core, cover it with kevlar and infuse it second time.
Can two infusions make overall weaker hull?
One more question: I see people usually doing thwart and gunwale from carbon fiber. Why not kevlar?
Can two infusions make overall weaker hull?
One more question: I see people usually doing thwart and gunwale from carbon fiber. Why not kevlar?
09/24/2019 04:39PM
ak44: "
One more question: I see people usually doing thwart and gunwale from carbon fiber. Why not kevlar? "
Kevlar only surface bonds with the resin (the main reason that a kevlar hull is lighter than fiberglass is due to the reduced need for resin rather than the weight of the cloth), the fibers don't "wet through"- any abrasion that goes through the resin results in the exposure of frayed fiber.
Nobody exists on purpose, nobody belongs anywhere, everybody’s going to die.
09/24/2019 06:49PM
Yes, the two-infusion technique would work on a male mold, But:
-you will use twice the infusion consumables (peelply/mesh/tubing/vac bag).
-you will need to finish the outside of the canoe to a gloss by ‘filling the weave’ with epoxy and then sanding/polishing to a gloss.
Given the complexity of infusion, you might want to reconsider if it is the right technique for your build. I can recommend the James Moran book on building a Kevlar boat over a male mold- I’ve seen some very functional boats built with that technique.
-you will use twice the infusion consumables (peelply/mesh/tubing/vac bag).
-you will need to finish the outside of the canoe to a gloss by ‘filling the weave’ with epoxy and then sanding/polishing to a gloss.
Given the complexity of infusion, you might want to reconsider if it is the right technique for your build. I can recommend the James Moran book on building a Kevlar boat over a male mold- I’ve seen some very functional boats built with that technique.
"Everybody needs beauty as well as bread; places to play in and pray in, where nature may heal and give strength to body and soul" -John Muir
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