Kevlar/Aramids

Where are all the Kevlar boards??? When kevlar can be purchased for only dollars more than good fiberglass, I fail to understand why this cloth hasn’t been adopted by even just backyard shapers. My Wee-no-nah racing canoe is made of a thin kevlar layer (maybe two layers of 8 oz. on the hull) and has repeatedly sustained direct collisions with sharp rocks, with a payload of over 300 lbs. This abuse seems to have absolutely no affect on the canoe, which deflects rocks like teflon. Is it too hard to work with/cut or is it too rigid or just cost prohibitive? I would like to make a bomb-proof board that I can use in the jagged, rocky downeast Maine coast and the aramids seem a likely canidate. Any ideas on the stuff? Matt

Matt, My wife just got a carbon/kevlar surfing kayak from Mega boats in England. It is 9’ 10" and weighs only 21 lbs (fiberglass versions of the same kayak weigh 35+lbs). I hear kevlar is hard to cut and laps don’t sand well. I think with the boats they use vacuum bags. I am also curious about making surfboards out of this stuff. I have heard stories over the years of it being tried but have seen no recent attempts. Any one out there tried it? Michael

Not only does it not lap well its somthing that was never intended to be sanded kevlar lay ups were intented to be vacumm baged so it will bond with the object your dealing with also its lite brown in color witch would not look so hot but it is posable to do it its just to much of a pain

Kevlar is a pain to work with, although it is workable. The problem with it is that it’s compression strength is low. We took a bunch of Kevlar boards to Mexico years ago. They all broke. Delamination under compression. Which is another issue, it’s hard to bond to. Epoxy works best. It also has serious UV issues. I do think the stuff has some great features, just not for boards.

Anybody ever seen a board done compleatly in carbon fiber? Its bad ass when polished but hard to keep wax on it. Strong as hell, when used with epoxy.

Another thing about Kevlar is that it absorbs water like a sponge! The lamination technique better be dialed in…in order to seal off any possible points of entry! Spectra is/was another prospect…but it too,like Kevlar is lousy in compressive strength and fantastic in tensile strength.At least Spectra cloth is white in appearance…where Kevlar is a loud yellow!

Ok, I’m currently going to abandon kevlar, but I am preparing to shape my second board from an EPS billet. The last one I made, in almost prison escape-type ingenuity, was shaped using dry cutting methods, ie: saws, planes, etc. I really need to make a hot wire cutter but am a little timid of getting zapped. I would prefer to use a partially spent car battery that I have instead of alternating current. I have read of your work and would expect that you know as much about hot wire cutting as anyone. Thanks for any advice

MKIA, Carbon is AWESOME. If it weren’t black, and a little expensive, that’s what we’d be using. But the price is going down. It’s about 1/3rd the price it was 20 years ago and continues to drop. And it should. It’s just rayon that’s been fired to remove the organics. It can be covered easily with silver paint, the kind you get at Michaels. Covers in one coat and then you can even airbrush over that. That paint contains aluminum powder which is very opaque.

Matt, the hot wire loom is relatively easy. First, take a piece of plywood and make a big U with atleast 25" clearance across and 12" clearance from the opening. Take a couple of eye hooks and attach them to each side of the U (I attached springs for wire flexibility to the eyehooks but do not think it is completely necessary). String nickle-crominum wire across the loom. The wire is available at hobby stores. Get an old extension cord and cut off the female end. Strip the wires about 18" and attach the ends with wire nuts to the NiCr wire. In the middle of your extension cord, wire in the biggest wattage bulb you can find. I used a single 250w. Make two cross section templates, nail them to your billet, plug in, and slice away. Just hold on to the wood! The 250w bulb adds just enough resistance to cut 1" every three seconds. To go faster add more bulbs next to the other one. For the stringer cut, to make things easy, snap a chalk line or make any other straight edge, cut with a saw and true each cut with a planer (I use a woodworking jointer.) Good Luck, Gary Geist

Or you can buy a nice variac from wicks aircraft supply. They are online at wicks.com. They have one for about $120 that works great.

Greg, Both Carbon and Kevlar pricing will be going up dramatically over the next year. A lot of manufactures won’t be able to even get Carbon this year and the ones that do will be paying dearly. The few years of low Carbon pricing are going away. Cause, some major aircraft projects are sucking all the carbon demand up and Kevlar is being consumed by the balistics industry due to 9/11. Supply and Demand!! This might take a while to effect some of the larger weavers due to year long contracts, but prices are going up now on both Carbon and Kevlar. Sluggo

greenough has been using carbon and epoxy on his stuff for at least 15 yrs.super strong and light should be painted with a good L.P coating to protect from UV.Almost all modern racing sailboats are carbon fiber and titanium–pricey!!Too bad the surf industry is still in the late fifties with the techniques and products.Hey even the thruster is a 20 yr old design–so much for free thinking souls!!My tennis racket has been carbon fiber for 20 yrs --sorry to labor my point.The tow in surfing seems very futuristic though very inovative stuff coming out of those guys.Maybe some new stuff will come out of it for us mortals

George has been using carbon and epoxy for well over 30 years… applying inexpensive rattle can aerosal paint (as Krylon) for U.V. protection. Shown are three carbon graphite-epoxy-EPS edgeboards (for standing use), shaped and fabricated by George Greenough, circa 1984, photo/collection courtesy of Charlie Coffee.

i have made a couple of boards out of carbon cloth the first was a 6/4 thruster with epoxy over a poly clark blank and the second a 6/0 traditional fish using poly over a poly blank ,the first is over a year old and still going strong and in good condition and the fish is still like new . my thinking in makeing them from carbon was purely from an extra strengh point ,exposure to the sun is a problem but you just have to be sensible ,straight into a board bag as soon as possible. the extra cost of carbon is/nt that much if you make them yourself and they do look good .

If you are painting over carbon with a paint that contains aluminium. Be 100% shore there is no carbon exposed to the paint.Carbon will react with the aluminium. Two dissimilar metals in a saline solution and whamo you have a battery.The aluminium being the least noble of the two will be attacked by the carbon.In the 1980’s a Sydney Harbour 18ft skiff was built using a aluminium honeycomb core and glassed with carbon. Within a very short period of time the skiff fell apart,due to the carbon attacking the core.David.

carbon’s not a metal! chemistry 101

Ok, maybe my choice of words was wrong.May be I should have said two dissimilar elements.But it dosent change the fact that carbon will attack aluminium if they are placed in a saline solution. I have seen this first hand.Talk to any boatbuilder who uses carbon, if aluminium is to be used near carbon it HAS to be isolated from the carbon. Usually a layer of E-glass layed up wet will do the job.

See link below. Graphite/carbon is the most noble at the bottom of the scale.Aluminium being less noble is almost at the top of the scale.This is why you get a reaction between the two. http://http://www.corrosionsource.com/handbook/galv_series.htm

Hop I got it write this time .David. http://www.corrosionsource.com/handbook/galv_series.htm