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Thread: Alternative Fabrics for composite hulls?

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    Member arizonaguide's Avatar
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    Default Alternative Fabrics for composite hulls?

    I've got my wooden framework complete, and I'm getting ready to glass...then I got thinking. I want this thing light.

    It's a lake and gentle stream rig, not something to bounce off rocks.
    FLAT water photography platform only. So, I'm hesitant to use the heavy woven glass fabric, if there's something else out there that's lighter that could be a good lightweight yet strong base for the resin.

    I wondered if perhaps something that would even heat-shrink, similar to the fabric used on SuperCubs.

    Anyone have any suggestions?

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    Member cristancanoe's Avatar
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    I have no idea, but I would love to see what you're creating. Can you share some progress pics?

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    Moderator Alaskacanoe's Avatar
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    Default PVC

    You can get the PVC materials rafts etc are made from and glue them together. We used to use canvas and then paint it with water proof paint years ago.. our scout troop made a dozen kayaks some years ago using a PVC cloth and glue and many of them are still in use..
    light and water proof.
    When you come to a fork in the trail, take it!

    Rentals for Canoes, Kayaks, Rafts, boats serving the Kenai canoe trail system and the Kenai river for over 15 years. www.alaskacanoetrips.com

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    I'll look into PVC cloth...that sounds like it could work!
    Thanks AKCanoe!

    I remember my Dad and his buddy made one 30years ago, and used canvas, but I didn't know what they coated it with.

    Funny story, cuz my Dad got a ticket for testing it out in the Spenard Lake swiming area after hours (in maybe 1969). It didn't leak...but it cost him a park violation to find out.

    I'll get some pic's posted.

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    Lighter-weight yet super strong threaded 'fabrics' of choice are of Kevlar and Spectra. Some are used in carbon and ceramic applications. They come in certain oz./yard, in several weaves and even locked weaves.

    WWII days there was a practice of coating canvases with rubber and plastic coatings for quick use an toss out boats... but temporary is not the answer you likely seek! These concepts were short term use... make a frame and skin in a day or two, repair often yet easy always getting a less than perfect coat (leaks).

    Inexpensive PVC coats even worse and pretty much the WWII process and issues.

    Today, Urethane coatings are a possibility better served than WWII stuff... but as tough as this stuff can be, it's expensive plus similar problems will arise.

    Spectra base fabric and slow going with high attention to detail is the ticket... you can make a glass fiber process or plastomer application for by far strongest, highest strength to weight, and watertight boat skin.

    PM if you would like me to lend a hand or point you in many of the essential directions on choice fabrics.

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    Moderator Alaskacanoe's Avatar
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    Default PVC materials

    The kleeper Kayaks, ( folding boats) use Hypalon for the material. I see no reason to not try either PVC or Hypalon materials cloth for your boat.
    http://www.klepper.com/en/faltboote_...k_material.php
    They also glue rubber strips ( bumpers) on the keel for added beech landing protection.
    the Kayaks we made with the PVC were extremely water tight. We would pull the material as tight as possible and staple it to the top of the wood frame of the kayaks, then where it had folds, we carefully cut the folds out and patched with glued strips of the same material using the Clifton Glue. From a distance you could not even see the seams, but up close you could see them. We were concerned at first that these few seams wold create some resistance to smooth paddling, but we noticed none when in the water and they were fast little boats. (12 ft long) and one 14 footer..
    When we finally got all the kayaks done, we practiced on Scout lake here on the kenai for several nights, and then we took our big trip, from Moose pass down the river to Kenail lake, camping on the lake for two days.. then crossing kenai lake and then down the kenai river to Jims landing. then we unloaded all the gear from the kayaks and some ( about half ) of the boys paddled on down to Skilak lake in the kayaks as the rest towed the kayaks behind and along side the 15 foot raft we used to go thru the canyon.. All made the trip from Jims to skilak with out a hitch.. we then camped on Skilak lake at the river out and waited until the next day when the lake layed down in the morning, we paddled to the lake out lower section of skilak and camped in that section then out the next moring to Bings landing just above Naptown rapids..
    The boys were owners of there own kayaks as they all raised money by doing car washes to buy the materials, and after the trip took them home.
    Several of the kayaks are still in use now 18 years later.. I know of only one that died, He took it down Swanson river and wrapped a rock in the lower section with the man hole up stream, and it filled with water and wrapped around a rock
    These kayaks are very light and easy to make.. we bought 4 colors of fabric and some of the boys mixed the colors from top to bottom and made them quite the sight,, some even used different color strips for the seams etc... lots of fun , lots of great memories and a project that empowered the boys in many ways..
    Just last night I completed the book ( 99 days on the Yukon) An account of what was seen and heard in the company of Charles A. Wolf Gentleman Canoeist).. it was written by Thomas McGuire, and they did the trip in the early 1970's, on the trip they encountered several groups of people ,,,and actually traveled for a time with one fellow that used the Kleeper Kayaks in the 1800 mile trip from headwaters in Canada to the ocean..

    Max
    When you come to a fork in the trail, take it!

    Rentals for Canoes, Kayaks, Rafts, boats serving the Kenai canoe trail system and the Kenai river for over 15 years. www.alaskacanoetrips.com

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    Member arizonaguide's Avatar
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    Great words of advise!

    The main issue is that I would like something for the first layer that will possibly "heat shrink" with no wrinkles or sag. Put a light coat of resin on THAT and let it harden. Then the next layers of heavier Kevlar, Spectra, or Carbon won't sag because its got a good hard base to build upon.

    Wrinkles and sag in the wet cloth, as well as weight are my enemy!

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    "Ceconite".

    Nonheat stabilized dacron fabric is used to cover "cloth" airplanes. After it is glued in place it is heated to specific temps to tighten it, Then UV protectors are applied and (normally) paint after. I of course would use epoxy resin rather than paint, if dacron is able to handle it.

    I'm thinking this would ensure a nice flat wrinkle-free initial layer to build upon with further composites. (Carbon fiber or Kevlar).

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    Alaskacanoe... I was referring to applying coating to a base fabric.

    I agree (to certain extents like availability, expense, industry standards) that the rubber Hypalon and plastic PVC 'already made' fabrics are not a bad idea at all... BUT no Feathercraft or Klepper is light by any 'stretch'. The lighter-weight these fabrics get in base-cloths, mm thickness of rubber or pvc, and so on --- the substantially weaker they are. These are principle reasons why pack-rafter manufacturers fabricate using Urethane material over all the rest in today's construction.

    Kevlar base fabric construction is stronger than 'Typical' fiberglass... So the Kevlar boat of same dimensions can be lighter-weight yet just as strong.

    Spectra fibers 1-up Kevlar in lightening same dimensions while keeping strength.

    Spectra lends itself to glass and ceramic applications to maximize impact protection, cut protection... all sorts of useful properties to stretch over a boat frame.

    Expensive Supercub Skin like Ceconite doesn't fit the shrink wrap boat application... would not be a good idea as a suitable boat fabric... you'd wind up duct-taping daily.

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    Quote Originally Posted by Brian Richardson View Post
    Expensive Supercub Skin like Ceconite doesn't fit the shrink wrap boat application... would not be a good idea as a suitable boat fabric... you'd wind up duct-taping daily.
    No, not as a stand-alone boat fabric...but as a FIRST layer "shell" to then build upon with other good composites.

    See, I've built a kayak out of Kevlar and Fiberglass, and it was a royal pain to lay the first layer of cloth, and keep it wrinkle free and not let any parts of it sag from the weight of the resin.

    I'm thinking about covering my wooden frame thus:

    1. apply ceconite fabric, and heat shrink to perfect shape.
    2. apply THIN (I said THIN!) coat of epoxy resin to ceconite fabric.
    3. allow to harden.

    Now I have a nice form-fitted "shell" that I can apply further Kevlar/Carbon/Glass layers to that will still hold it's perfect shape.
    Yes, I will have to give the dried ceconite shell a light sanding "prep" before adding new layers.

    That being said, I WILL look into the SPECTRA. That's something I'm NOT familier with. Thanks Brian.

    And a good "stretchable" PVC fabric COULD have the same "form fitting shell" effect as the "heat shrink" idea, so that warrants looking into also.

    You folks are giving me some GREAT food for thought. MUCH appreciated. ALL ideas are welcome, as I like to think "outside the box" for new ideas. ALL ideas are welcome.

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    Thumbs up Ahhhhhh Now I got Ya...

    You want a forming fabric to act as base to form other materials around it --- yes?

    OK now I can really help ya out:

    The Ceconite would work providing you should know a couple of specific properties...

    Ceconite is relatively cheap (with regards to all the other fabrics we've been talking) at about $10/yard.

    The glue is often going to be sold at same places and again cheap by comparison to glues, resins, coatings and so on we've been also talking... lets say $20 will due ya.

    Working with Ceconite requires knowing the real temp of your heat shrink gun/iron... you'll need a thermometer to verify no more than a 300 degree F temp. Any hotter --- you'll ruin it.

    NOW FOR THE BIG ISSUE --- MEK is an airplane eater!!!! It should not be used in your process and Toluene can also damage properties. MEK is often used when working with plastic and Toluene with rubber.

    You'd have to choose and apply some first layer 'primer' that would stick to the Ceconite form material that would in doing so maintain its properties... allowing whatever second resins and fabrics like spectra you then begin the build-up with to also stick. Major dilemma being that the form material can do it's job --- but the glassing or whatever other fabrication may never adhere to the actual frame-like structure through Ceconite barrier.

    The reasoning behind AlaskaCanoe and some of my early suggestions were that these are traditionally tried, true and available materials and designs.

    The Ceconite may be a good strategy in forming and possible easier lay-up of whatever you decide. Just keep MEK outta the mix, watch temps on shrinking, and realize that whatsoever you lay-up may not stick to the ribs without having to rip Ceconite (where you can) out then doing inner lay-up connectivity that adds weight.

    Cheers - and best of progress with your project.

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    Thanks Brian, good info!

    Let me clarify my thinking, if I can?

    I was thinking of using small amounts (stripes) of glue along the ribs to hold the ceconite, but not so much that the ribs were completely covered. So, even after I shrink the ceconite, I'd still have part of the ribs exposed that didn't have the ceconite glue on them.

    Then, when I add the epoxy resin to the glued and shrunk ceconite, it would saturate the ceconite and adhere to the exposed (non-glued) part of the ribs as well, not only providing me with a hard shell to "form" (layup) with (exactly!) but also providing adhesion between the ceconite, the ribs, and future epoxy layers.

    But you highlight a good point that I need to make sure I get adhesion "through the ceconite" between the ribs and future composite layers. And I'm thinking if I don't completely cover the ribs in ceconite glue, but just enough to hold it in place properly, that it should still provide lots of exposed rib surface for epoxy adhesion, as well. Great Point, though!

    The whole "heat shrink shell" idea came about because of the way that most of "normal" fabrics tend to "stretch" a bit when you add the resin...and even if you have the fabric held tight and clamped along the ribs..when you add the resin it sorta expands and wants to induce "slack" (sags/wrinkles) in the fabric. I figured if it were already under some "mechanical tension" (from the heatshrinking), then if I next add a VERY light first coat of epoxy to the tensioned fabric, it would help minimize the problem and give a "perfect" shell to build (layup) further (Carbon Fiber, etc.) upon.

    I know I could just go get a Thermoplastic boat for $249, and MOLD off that, but what fun and satisfaction would that be?

    PLUS, this rig is going to break down into three pieces (bolt together) so that I can throw the full 16' (Rowing shell) in 3 pieces (5'+/- ea.) INSIDE the mini-van.
    I guess I've gotta post some pictures of the lightweight wooden frame I've got built, so you can see exactly what I'm doing. Sortof a Kayak/Canoe/Rowing shell ALL IN ONE (or actually all in THREE!)

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    Take a look at Geodesic AiroLITE Boats. They sell boat kits with wood frames, roving Kevlar tape under a heat shrink Dacron skin. Amazingly light weight, but no one's going to win a rough condition durability award with one. --- http://gaboats.com/

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    Thanks Jim, and also Thanks to Max! Thanks to you folks input I've got a lot to research now, and get strait in my mind! Any and ALL input is greatly appreciated.

    I knew this forum would help. It's nice to have folks that are willing to be a sounding board to some of my "crazy" and whacked out ideas.

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    Moderator Alaskacanoe's Avatar
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    Thumbs up wow

    Thanks Jim for that post about the Geo boats..
    they look like kites almost..
    The thing that struck me was that they say you can put them together in an apartment with no mess..
    about 70 hrs work total and you can get a boat that totals out at 30 lbs..
    what a fun project you have going on ..
    I have noticed that Kevlar canoes will cut easy just like the guy from Geo says will hapen to his boats.. a sharp piece of Glass etc..
    I had a Kevlar canoe that was pulled over a tailgate of a truck that had a sharp edge on it and it cut the canoe like it was a razor..
    but ,,, the are light and tough in other areas..
    Max
    When you come to a fork in the trail, take it!

    Rentals for Canoes, Kayaks, Rafts, boats serving the Kenai canoe trail system and the Kenai river for over 15 years. www.alaskacanoetrips.com

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    a completely carbon fiber hull would be extremely light and durable too. I'm studying the vacuum bagging method right now.(countless hours and dozens of scholarly articles) It's a process that bonds the layers together and while drawing out excess resin. this process allows you to get the most out of the carbon fiber. kevlar also has a tendancy to fray under severely abrasive conditions (running shallow rivers) and is something that carbon fiber doesnt do. costs aside.....there's also a custom coating that i've been studying too. the coating is usually applied to industrial augers. you need a 40,000 dollar piece of equipment to even spray this stuff but it's the ulitimate coating. I've found some folks who have the equipment to spray this coating. although I'm going to mantain a level of secrecy regarding this coating.....the two combined would be mind boggling in theory. constructing a mold and coating it with gel coat (male of female mold) is the route I'm going. you can coat a mold with a release wax and reuse the mold multiple times. vacuum bagging the layup requires more detail into the constuction of the mold.....but allows you to get everything you could possibly get from the carbon fiber layup. special valves, bagging urethane, a vacuum pump, or special valve operated by a compressor are avail at a decent price. carbon fiber is the way to go.....and it's getting more affordable as we speak.

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    Quote Originally Posted by mainer_in_ak View Post
    a completely carbon fiber hull would be extremely light and durable too...
    Yup, you're on the right track, Mainer. I've worked with each of the materials, and I'm leaning toward Carbon Fiber for it's strength, abrasion resistance, light weight, and the fact that it doesn't transfer/hold water (much) if it does get punctured and wet. But, looking into that Spectra material sounds like worth looking into also.

    It's pretty easy to make a mold from an existing hull, and most folks use thick Fiberglass to do that for max. durability and repeated use (many layers, say 3/8" thick total..also vacuum bagged for a precise "perfect" mold). Exactly as you mentioned with an initial GEL coat over a waxed original part. Once that's made and seperated, you now have a form that it's pretty easy to layup whatever combination of materials you choose (kevlar/Carbon/glass) in whatever order you choose, and then use a vacuum bag system to compress the fibers/resin into the form for maximum strength. And the waxed form can be repeatedly used.

    I will end up doing that eventually for future Boats. I have all the composite tools/fittings/vacuum system from composite Aircraft Repair work that I used to do. I will probably buy a thermoplastic HULL I really like, to use as an initial form. Since you can "top" the hull in any way you like, it can be a small Canoe OR Kayak, or whatever configuration you like. The beauty is that once the form is made, it doesn't destroy the original part...and hey, it's always good to have an extra Thermoplastic "beater" Boat sitting around once your done with it as a mold. I don't BELIEVE that violates any patent laws, and you (pretty much) have a hull that was even hydrodynamicly engineered at one time.

    But this current rig is a custom "multi-use" rig Canoe/Kayak/Rowing Shell/Duck Boat, and there just wasn't an inexpensive alternative to actually building the frame, and doing a (non-vacuum) wet layup. The type of Rowing Shells that would have been close to what I want are in the SEVERAL THOUSAND $$$ price range, and then I would have had to buy a long 16'+ trailer to transport it. This way, I can break it down as a "custom" bolt together unit, in various configurations depending upon my use for that day.

    I'll post some pic's tomorrow.

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    Quote Originally Posted by mainer_in_ak View Post
    I'm studying the vacuum bagging method right now.(countless hours and dozens of scholarly articles)...
    Mainer, I got thinking you may be interested in a class and if so, this place is the Best of the bunch.
    http://www.abaris.com/IndividualCoursePage.asp?CRSID=1

    I'm sure you could also get just the study materials from them, if interested.

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    Default Pic's of the project rig...

    Here's the basic idea. (just gotta do the Glasswork, and sheetmetal "bolting" bulkhead work)

    Here's the FULL 16' rowing shell configuration. (all three sections to be bolted together) with a 5' OPEN center section with a (removable) sliding seat and oar outriggers (also to be removable). Center section will be open for rowing, the two end sections will be enclosed KAYAK configuration with "hatches" big enough to open and sit comfortabley OR covered with a hatch cover for storage...depending upon what configuration I'm using that day.


    Or, bolted together in just the 11' Kayak/Canoe configuration (center 5' rowing section removed)...for basic paddling with either Kayak paddle or Canoe oars. (again, these end sections will be covered Kayak style, but with LARGE hatches big enough to sit/paddle in comfortably)


    Or, Bolted together in the Duck Boat configuration with the rowing seat and the outriggers removed and a possible "electric kicker" motor attached.


    Because of the way I'll build the enclosed (and hatched) end sections it should be almost impossible to sink (then again, I hope I don't have to find out!), AND it will all unbolt and fit (just barely) in the minivan with the seats folded forward.

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    Default Previous (first) project...

    Here's a picture of my FIRST project.
    This is my PHOTOGRAPHIC platform, and is layered Kevlar AND Carbon Fiber, covered with a couple layers of Glass. It's ****ed HEAVY (like 50+lbs), but it's also ****ed near "bulletproof".

    It's amazing the way that animals don't seem to "spook" when you paddle near them, I guess they just think you're a BIG bird or fish or something.

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