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Captain, we have a core meltdown in the drive
By:Paul G. Jacobson
Date: 11/10/1999, 5:05 am
In Response To: Hollow Tube Query (mike allen)

> Hey Shawn

> Any bright ideas on how to shop make hollow carbon shafts to get really
> light paddles? And how to mate to a paddle end - (insert in shaft?)

> Like saran wrap some rubber garden hose, tie a weight on one end and lay
> up. Then tie other end to car bumper stretch tight and slide off tube.

> What else could you do? Would you put expanding foam inside for a core
> separator?

> -mike

A few ideas here:

make a paper core that you leave inside. For large,cheap paper, get a hot iron and press out the wrinkles in a a few sheet of the morning paper. Roll them around any suitable form --PVC pipe, electical condit, iron pipe, broom sticks, closet poles etc.

ou can also wrap these with a couple layers of wax paper, which is resistant to epoxy, but is slippery enough to allow you to withdraw the support pole. Saran wrap is a bit too 'tacky' for this, I think. A layer of aluminum foil might be nice if wax paper is hard to come by.

If you want an oval cross section, use your plane, drawknife, spokshave, or belt sander to flatten areas along the length of a closet pole, Sand it smooth and maybe rub on a few coats of wax.

The support pole you use should be at least a foot longer than the length of the shaft (loom?) that you are making. That way you can us a dab or tape at each end of your paper to tape it to the support pole. also, the longer length ill let you prop the ends on a pair of saw horses so that the resin coated glass or carbon, or whatever is suspended horizontally while it sets up. And if it starts to drip or sag, you can rotate the support pole.

The foam pipe covers that insulate pipes can be used too. Cover them with a layer of waxpaper, then the resin and glass.

I dont think you want to wrap the carbon fiber tape barberpole fashion. the pictures I've seen of people making fly fishing poles seem to emphasize that the fibers run straight for the full length for best strength with lightest weight. Maybe they also do this for flexibility, though. You may want one layer wound in a helix, covered by a layer with the fibers in line. Or you amy want some combination for strength and flexibility. After you do the first layer you can pull out your support rod or tube ( so it doesn't permanently stay inside) and replace it with smaller diameter rod, or piece of electical conduit.

You night try reshaping a round tube into an oval by applying gentle pressure to it after the resin has set, and the assembly has been removed from the original support. It should still be workable for a few hours to a few days ( depending on resin/hardener and temperature). place a smaller diameter pole inside while you do this so you don't accidentally smash it.

There are soft foam tubes, kind of like the foam 'pool noodles' that are so popular with little kids, but these are sold in smaller diameters, and frequently used in construction as a compressible sealing material. They may ot be stiff enough to use as forms for yur hollow tubes, but if they are wrappe with 3 or 4 layers of newsprint they get pretty stiff and weigh practically nothing. Poke a hole in one end and you can hang these things from your garage rafters to help keep them straight while the glass/resin sets up.

I'm surprised Rehd didn't mention the dissolvable packing 'peanuts' that are made of cornstarch. Roll a tube of paper and stuff it with these to reinforce it before applying resin and glass. You may want to chop some of these into a smaller size so they fill your paper roll better. Warm water dissolves these things, and washes the center of your tube clean in minutes. Test a few to make sure you are not using expanded styrene! (if you get a mixture, you can get rid of the styrene ones with acetone)

Just few thoughts to keep you up at night.

Paul G. Jacobson

You can buy fiberglass and carbon fiber tubes already made. Search the web for antenna parts for amateur radio operators. (hams) Some people are using these for the longitudinal members on skin-on-frame kayaks, but I suspect they have an inexpensive supplier, or bought these as surplus.

Another material you can use for cores is available at fabric stores. It is water soluble( or 'rinse away') fabric stabilizer. This stiff, non woven material is used by sewers who do embroidery. In sewing it is placed behind the area where an embrodered design is located in thin or sheer materials. You would stitch through the fabric and this stabilizer. After finishing, you cut or tear off the excess stabilizer, and wash the area, or just spritz it with water and the stabilizer dissolves away. If you wrap some over the support rod, after you pull out the support you simply rinse the inside of your tube to dissolve away this material.

'Styrofoam' or other expanded styrene foams can be machined with sandpaper, knives, hot wires, etc. to make molds for more complicated pieces. You can use it for long rods or tubes, too. Styrene dissolves in acetone -- and it is amazing how much will dissolve in just a few drops of acetone. Cured epoxy will withstand the action of the acetone for wuite a while, so after the rod is formed, pour a teaspoon of acetone into it and slosh this around until the styrene is dissolved. (this makes a useful mix of dissolved styrene, so save it in a glass jar) Or. leave the foam in the middle o the tube. It weighs almost nothing and can add a bit of stiffness.

Messages In This Thread

Light paddles
Stan Woronko -- 11/9/1999, 1:49 pm
Re: Light paddles
Hank -- 11/9/1999, 11:07 pm
Re: Light paddles
Jeff DeJongh -- 11/10/1999, 6:42 pm
Re: Light paddles
Chris Luneski -- 11/9/1999, 8:36 pm
Re: Light paddles
Monte Rhodes -- 11/9/1999, 5:43 pm
Re: Light paddles
Don Beale -- 11/9/1999, 4:14 pm
Re: Light paddles
Shawn Baker -- 11/9/1999, 4:04 pm
Hollow Tube Query
mike allen -- 11/9/1999, 5:33 pm
Captain, we have a core meltdown in the drive
Paul G. Jacobson -- 11/10/1999, 5:05 am
Re: Captain, we have a core meltdown in the drive
Rehd -- 11/10/1999, 6:07 pm
Help Scotty!- the warp tubes are warping!
mike allen -- 11/10/1999, 12:59 pm
Hollow crank shaft thoughts
Ed Valley -- 11/10/1999, 3:28 pm
Was that your troop in Boy's Life?
Paul G. Jacobson -- 11/11/1999, 6:01 am
some more Hollow crank shaft thoughts
mike allen -- 11/10/1999, 4:24 pm
crank crank crank
Ed Valley -- 11/11/1999, 3:30 pm
Re: Hollow Tube Query
Preston Seu -- 11/10/1999, 12:51 am
Re: See WoodenBoat
Don Beale -- 11/9/1999, 6:27 pm
Re: WoodenBoat, Aug. '99
Mike Hanks -- 11/9/1999, 10:26 pm
Re: Hollow Tube Query
Dean Trexel -- 11/9/1999, 5:46 pm
Re: Hollow Tube Query
mike allen -- 11/9/1999, 5:57 pm
Re: Hollow Tube Query
Randy Knauff -- 11/10/1999, 1:18 am
Pls tell us more!
mike allen -- 11/10/1999, 2:06 pm
Re: Pls tell us more!
Randy Knauff -- 11/11/1999, 5:14 pm
Re: Hollow Tube Query
Gary Toffelmire -- 11/10/1999, 12:13 am
A Light Bulb Went On ...(hehehe)
mike allen -- 11/9/1999, 6:16 pm
a bit dimmer
Paul G. Jacobson -- 11/10/1999, 3:43 am
Re: No Merry Xmas Paddle :(
Rehd -- 11/9/1999, 11:54 pm
Re: No Merry Xmas Paddle :(
mike allen -- 11/10/1999, 2:00 pm
Re: No Merry Xmas Paddle :(
Rehd -- 11/10/1999, 5:40 pm
Re: A Light Bulb Went On ...(hehehe)
Dale Frolander -- 11/9/1999, 10:08 pm