Making a laid-up kneetube..
  Also functions as a glove compartment!...



I thought that a place for small items that are accessed while paddling, would be handy. I got the basic idea for this Kneetube from the Kayak BBS.
The application of the concept is my idea of how to do it. I have experience making composite wings and floats for radio controlled aircraft.  I thought I would apply the technique I used for models, to this project. I decided to use a Kajak-Sport 4" hatch for the kneetube. I got this from
Newfound Woodworks. I got the cover and rim.
I started by laying out the ends of the tube, using the hatch rim as a pattern. I cut the ends from some left over ply from the hull. One end was cut in the center to accomodate the rim, the other, left solid.



Using the ply ends as a pattern, I cut sections out of foam building insulation. These were "stacked" together like a loaf of bread.Hot-melt glue holds everything together.
I taperer the form so that the forward end is smaller.




I wrapped the foam in packing tape as a mold release, so that I could get the tube off the form later.
The ends were hot glued to the tape-covered form.
The foam was hot glued to the packing tape covered deck.


The tube after glassing. The 'glass was laid over the form while on the deck. I used 6 layers of 5 and 3.75oz glass in the layup. I don't remember how many layers of what weights were used. I colored the epoxy with graphite powder.


The rims are made of ABS plastic. I wasn't sure how strong the hatch/tube joint had to be, so I drilled flaired (with a countersink) holes around the rim for epoxy to fill through to help bond everything together.


I glued the rim to the end of the tube with thickened epoxy tinted black. A paint can serves as a "clamp" while the glue sets up.


After the layup was cured to a "green" stage, I removed the form (chipping the foam away) and cleaned up the tube. I then glued it to the deck with schmutz. Ankle weights serve as a clamp for this job.


The kneetube, ready to cover with a layer of minicell to make bracing against the tube a little easier on the knees!


The finished product! I covered the tube with a minicell "skin", that is, a thin layer (1/4") of minicell which is cut fron the outside of a block of foam. The outer surface is black, and smooth. It's a little easier feel on the knees, also, more durable. Got the foam from kayakoutfitting.com.
I used 3-M spray adhesive to glue it on.



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Page created Sept 08, 2004  Last update, Jan 05, 2008

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