Filling material for a cored shaft.

[desi2960]

i have used

bamboo, its the strongest but not the lightest, and the home inprovement foam, not the strongest, but lighter, also balsa wood, hollow plastic tube, and carbon fiber tube, and air.

my best effort was the bamboo, but to get the weight down more if i remember i used a used a 6 or 7 inch hole

 

[the kidd]

Cork it like a bat.

 

[the kidd]

Or better yet helium !

 

[SwissChris]

Cork it like a bat.

Tony from black boar uses cork but I have no clue how he gets it in there .....lol

 

[Sloppy Pockets]

If you make the hole for the carbon fiber tube the right size, i dont see the epoxy being a factor. I bought some 6mm tube and am going to try it out soon. I also bought a long 6mm drill bit, so if I make the hole the right size, it would only take a very small amount of epoxy to hold the tube in place.

Joe

The OP was talking about the possibility of filling the entire hole with epoxy for about an inch. I was just pointing out that that for every gram of wood removed from the hole he'd be adding two grams of epoxy for equivalent volumes.

At first look I thought that the thin graphite tubing would be the nuts for the purpose, but it's hard to argue with Baba's math. :wink:

 

[Sloppy Pockets]

Tony from black boar uses cork but I have no clue how he gets it in there .....lol

Prolly uses something like the tool below.

Although, cork is normally denser than balsa and offers little in the way of strength, so...?

 

[JoeyA]

Joey, the whole point of drilling out the end of the shaft is to reduce deflection-causing end mass. Since cured epoxy is roughly twice the density of the hard maple it is replacing, using epoxy in this application will only increase the deflection.

THANKS!
jOEYa

 

[JoeyA]

Just calculated the mass difference when you use carbon fibre tube.
Example:
Carbon fibre tube: OD = 8mm; ID = 6mm --> Wall thickness = 1mm
Density: 1.5g/cm³
Lets say you core the last 10cm.
Weight of the carbon fibre tube (10cm long) is = Pi * (0.4²-0.3²) * 10 * 1.5 = 3.30 g

Removed weight of Maple wood (Density 0.65 g/ cm³) = Pi * 0.4² * 10 * 0.65 =3.27 g

I would say you add more weight as you remove, especially if your wood has a less denisty as 650kg/m³!

That is interesting. I certainly don't want to increase the weight.

Thanks!
JoeyA

 

[JoeyA]

Prolly uses something like the tool below.

Although, cork is normally denser than balsa and offers little in the way of strength, so...?

I need something that will provide some strength to the cored shaft but still reduce the weight/mass. Cork doesn't sound like the solution.
Thanks!


JoeyA

 

[Petros Andrikop]

Forgot to add that the silicon foam also deflected more...

 

[JoeyA]

Forgot to add that the silicon foam also deflected more...

hmmmm. Thank you.
JoeyA

 

[JoeyA]

bamboo, its the strongest but not the lightest, and the home inprovement foam, not the strongest, but lighter, also balsa wood, hollow plastic tube, and carbon fiber tube, and air.

my best effort was the bamboo, but to get the weight down more if i remember i used a used a 6 or 7 inch hole

Maybe you're making a joke about the bamboo, but I am ignorant so I will bite. :smile: Where do you get bamboo for an insert?

JoeyA

 

[desi2960]

from a stair banister

i bought a stair banister made of engineered strand woven bamboo. i made a one piece solid bamboo butt, it was just an experment. i had many smaller pieces , i made a couple shafts with bamboo ferrules, they play great. i also drilled a shaft, 6 - 7 inches i think it was 5 1/6, and pressed in a piece of bamboo, it also played great.

bamboo is stronger than steel by weight, it is also very light, they use it in the orient, to make scaffolding for building sky scrapers, it can be used to cook food, i believe it is a grass and can grow 1 ft in a 24 hr peroid.


now you know all i know about bamboo.