Tom

: Not once have I said anything negative about graphite stringers. In fact, if
: you read my posts to Malcolm, you will note that I support his experiment
: with
: the material, and hope he can make it work as a folder frame.

But surely implied. My point is that I want to fill the breach with the pros of carbon fiber versus aluminum. You have designed and built and paddled yaks for decades and care for each one with the dilligence and committment that define those words. I can't think of anybody who knows folders more then you, and IMHO, you probably know more about folders then the folks at the companies.

Many others have issues with aluminun in salt water environments, and even dilligent care, frequent use in saltwater will eventually have problems show up. The ocean is a nasty place, and aluminum gets destroyed pretty damn fast, even the resistant alloys.

: My only comments about the material are that I haven't used it and am not
: qualified to talk about it. I am very careful to discuss " only"
: issues that I
: know from experience, not speculation.

Still, the tone in what I read is what I answered. For your feelings on aluminum, I shared my thoughts on carbon fiber, which I might add, I use quite a bit to build many things, involving kayaks, and for the boat and the car and trucks.

: That's why, when I do post information, it is usually supported by pics.

I have zero desire to build and screw around with webpages or post pics to hosted sites. Further, we get zero spam and I intend to keep it that way. A web presence opens the way to all sorts of problems. But most of all, I have little time to want to do so. I like to paddle, or dive, or surf, or climb, or sail, or jump but not mess around with the computer. This morning I was out at Black's whomping the breaks in my Crossover, this afternoon I'll be doing some work on the kayak loader design for truck and boat as soon as the marine layer clears and I can get the epoxy warmed up in the sun. You want to see what I build I'll send anyone images ad nauseum, or better, come paddle with us and look and try the things I built! Hopefully before we sail, I hope I'll have figured out how to make bent shaft graphite paddle handles (I'm having a hard time with the foam cores staying in shape when I slip over the carbon fiber tubes.

: Aluminum has to "me" been an ideal building material. The 10 or so
: kayaks I've
: made with it are "proof" of that statement. Plus, I've qualified
: that
: statement on several ocassions by saying that I paddle primarily in a fresh
: water enviorenment.

I know that. We're the opposite, and rarely find ourselves in fresh water. Saltwater is nasty stuff. Being in it all the time calls for constant attention or using alternative materials in which to be less dilligent caring for.

: There is, however, a huge difference between endorsing a particular building
: material, and transforming it into a folding kayak. My use of HDPE and PVC
: has been criticized also, but like aluminum, only by those who have never
: used
: them, or for that matter have never built a folding kayak.

Frankly, I discovered the joys of plastic partly in response to your discussions of those materials. For instance: in the bilge area of the boat lies the form-fitting clamshell dive tank brackets made with HDPE salvaged from two large shipping pallets. Every couple weeks I'm haunting the cut-off bins at Rid Out Plastics.

On folding kayaks, we inherited a K1 with the boat. It took some work and time, but I ended up replacing the tubing with hard anodized tubing from IMS. After messing with it for a while, we gave it to friend who likes to travel and fish as a retirement gift. We had thought of having two folded up on the boat, decided against it because fresh water was in short supply, that is, before we discovered the watermachines. Being in a salt water environment was simply hard on the aluminum. But it doesn't matter, folders can't compare to our yaks I built.

: I've seen numerous failures by otherwise competent kayak builders when using
: new materials that initially appear ideally suited to this unique style of
: building. However, until you build stringers using graphite, carbon fiber,
: kevlar, or even the often discussed PVC, you are simply dealing in opinion

All things take time to learn and perfect. Patience, testing and dilligence are key elements for success. The arrow of time moves forward. For instance, paddle shafts in euro paddles are made out of...as if I have to say it.

BTW: carbon fiber and graphite in most kayak applications are essentially the same thing. It's the form that differs, the name is often used incorrectly.

: If you like graphite so much, I suggest you build a folding kayak using it.
: You will have my wholehearted support, and if successfully completed, I will
: then have someone other than myself to learn from.

Well, I've come to like carbon fiber in many applications in which it is clearly better then other materials. That you said what you just said limits graphite to making a folder? First, do you think we want a folder or two? Why, when I spent so much time and effort designing and building the yaks we have? Second, that I took on the often downplayed and much abused carbon fiber/graphite issue doesn't denegrate you or your experience in any way, shape or form. It's about pointing out that there is a suitable alternative to aluminum in a saltwater enviroment and throwing in support for such material based on experience using carbon fiber and graphite powder castings. Even better IMHO is titanium tubing! Or how about good ol' heavy gauge walled fiberglass tubing to save money?

Let me tell you and everyone about carbon fiber applications: I built every rudder assembly out of multiple layups of carbon fiber. During the Lake Powell trip I was spun around in Davies Gulch by two idiots in Wave Runners racing up the narrow canyon. I fortunately wasn't run down, but had to brace hard in the waves and reflected waves in that narrow area. What got me was the reflected wave from the bend behind which me spun me around and the following wave slammed me backwards into the wall hard. Later, on landing the damage was a badly bent 5/8 inch stainless steel bolt that served as the rudder pin, a broken wood-core glassed rudder and bent rudder pin support brackets. The carbon-fiber shell that held the rudder, cast in a L-shape to also serve as arms survived the hit with just two scrapes (14 layers of 4 oz carbon fiber, total weight after sanding and cutting to desired shape: 1.2 pounds). In fact, the whack was so bad that on resupply I used Rikki's yak the remaining 1000 or so miles of the trip.

Other materials and uses other then kayaks:
I removed and replaced the inside shell of the 4Runner and formed a mold in which I vacumn bagged a lay-up of 12 layers of 4 oz carbon fiber. That wqas then sanded down and fitted against the inside roof skin aianst a 1/4 inch layer of closed cell foam, bolted in place then roof liner put back. This quited the ride down and if ever the truck rolls, we have an additional layer of armor.

Side impact panels: the heavy steel beams inside the doors were removed and a series of 4 molds made up out of styrofoam. Carbon fiber and glass layups were vacumn bagged down using 18 layers of 4 oz carbon fiber and 6 layers of 6 oz fiberglass. Installed they saved about 15 pounds per door (with the slim-jim deflection brackets also installed). The idea is that in side-impact the layups will fail absorbing energy. It's not a new concept, I got the basic design from mods done in armoring cars and trucks.

Aluminum tubing frame stiffeners: to save the frame in the event that our 4Runner or PreRunner are ever hit from behind, I built a series of pipe crosspieces that bolted on to the rear part of the frame versus the honking heavy and never-used steel trailer hitches. I used 5086 and had them welded using inert gas welding. The tubes were powder coated for corrosion protection and stainless steel fasteners used to mount the pipe crosspieces. A thin layer a teflon isolate the cross pieces from the frame.

: "Experience is knowledge. Everything else is just information"

Exactly!