Anyone know if adding a another layer of kevlar to the inside of a kevlar canoe will double or near double it’s strenth? Weight not an issue.
If so, don’t even think about it.
First, it won’t work well even if you try it. Second, for the money of supplies and labor involved, you sell your boat and get a new one in the layup you need.
Summary: Bad idea.
Allrite Kanoo >>> Why not ?
Adding a ply of Kevlar is not a big deal to do and YES it will significanly increase stiffness and durability. I have done is many times to older boats that have seen a bunch of miles. A kayak is harder to work inside of, a canoe is a not.
Not as good as if the 2nd layer were
in the original layup, and would exceed my layup skills, but it will add strength.
I suggest considering whether smaller areas of reinforcement would cure impact problems or stiffness issues. For example, I added Kevlar layers in the cockpit area of an old Kevlar kayak because that area was too flexible to work with a foam seat and back bulkhead. Adding that relatively small area of Kevlar was easy and the added layers were properly wet out without pools.
If weight is not an issue
Then I use S glass. It is much easier to work with than kevlar and about as good in every other way.
If he can’t afford or doesn’t want to
work with Kevlar (hard to see when it’s wet out) then I would suggest polyester cloth rather than S-glass. S-glass is more of an “outside” cloth, where its compression strength and abrasion resistance are excellent. Inside, it doesn’t stand out. Another thing, glass inside the boat can mean itchy fuzzies.
While polyester is not as strong as Kevlar, it will be better than glass at preventing propagation of a break. It’s almost as light as Kevlar and fairly easy to work with. I think sweetcomposites.com still stocks polyester.
I sounds to me like the project will take more effort and expense than it is worth.
Yeah, Pat Onno, our anyone else who is really good, can hand lay in a Kev layer. It’ll cost, maybe $20 X 5 yds to buy the Kev, another $25 for the VE resin.
and another $50 for sandpaper and acetone.
The issue is lamination skill. I don’t know what Pat charges for a half day’s work, but it doesn’t make any difference, because he’s in the Western Islands, and it would cost thousands to transport the hull there and back. Lets just say we have a shop rate of $50/hr.
So we sand, acetone clean, wet out, lay the fabric in, peel ply edges in 4 hrs plus $175 in materials. You’ve just spent almost $400 on a hull that will probably not be worth that when the work is done?
Sorry! Don’t do it.
goes to what others have said here
YOU could probably do it without much problem, but I think 99.9% of the population would lay on a resin heavy job full of defects. In the end, I still say unless you’re an expert, it’s a bad idea. Plausible, I guess. Generally advisable, not so much. I’m of the mindset right boat for right job.