Best cut of wood for core wood

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Sailor Pronk
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Best cut of wood for core wood

Post by Sailor Pronk » Wed Mar 27, 2019 11:34 am

Hello everyone
This is my first post as I have just came across this group and have joined!
My question is what is the best lumber cut for cores, plain, quarter sawn or rift sawn?
I have a poplar log, an ash log and some iron wood that I was going to cut for side walls.
This will be my first pair of skis to build. I’ve built standup paddle boards and I’ve rebuilt sailboats so I do have experience working with epoxy and fibreglass. I also have a friend who is an engineer who works mainly with carbon fibre and I hope to pick his brain.
Thank you in advance.
James

MadRussian
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Re: Best cut of wood for core wood

Post by MadRussian » Wed Mar 27, 2019 1:09 pm

if I have a choice would always use quarter sawn wood.
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison

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chrismp
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Re: Best cut of wood for core wood

Post by chrismp » Thu Mar 28, 2019 1:50 am

This depends on how you plan to make your cores. Your goal is to have the grain running the lenght of the core as straight as possible with the grain being vertical in the ski core. I often buy plain sawn wood that I glue up into a large core block with the grain running horizontally over the width of the core block and then I resaw the core block into boards. This leaves me with core blanks that have the grain vertical over the thickness of the board.

Sailor Pronk
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Re: Best cut of wood for core wood

Post by Sailor Pronk » Thu Mar 28, 2019 2:47 am

That is awesome thank you. I was out at the farm yesterday and I think I have found my core material. It’s the poplar growing out of the birch.
36A1C0B9-B77C-45FE-90E0-1833C0E06018.jpeg
New skis?
36A1C0B9-B77C-45FE-90E0-1833C0E06018.jpeg (203.73 KiB) Viewed 879 times

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chrismp
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Re: Best cut of wood for core wood

Post by chrismp » Thu Mar 28, 2019 5:35 am

Nice! Always good to see people using local woods to make their cores!

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vinman
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Re: Best cut of wood for core wood

Post by vinman » Thu Mar 28, 2019 6:28 am

the specific cut of wood does not matter as much as the direction of the grain when you lay up your core. You can buy flat cut wood (much cheaper), rip it into strips and turn it 90 deg to place the gain as close to vertical as you can. You might look for portions of the flat cut plank that already have vertical or diagonal grain and cut those out and not turn them.

My suspicion (read no real evidence) is that if you flex tested a ski core or an actual ski to failure with vertically oriented grain and a ski core with horizontally oriented grain you you probably see that the vertical grain is stronger. Or you might see that the vertical grain is somewhat stiffer in the overall flex pattern of the ski. However is is pretty unlikely that you'll be flexing your core or your skis to failure in the real world. If it is not perfectly vertical or if you accidentally place a horizontal grain stringer in the core (been there done that), don't stress over it. I'm not sure any one could actually tell by how a ski performs if you grain is running vertically or not.
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MadRussian
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Re: Best cut of wood for core wood

Post by MadRussian » Thu Mar 28, 2019 4:37 pm

MadRussian wrote:
Wed Mar 27, 2019 1:09 pm
if I have a choice would always use quarter sawn wood.
I should've clarified. I built each core individual… 1/4 sawn work best for this method
I have not failed. I've just found 10,000 ways that won't work.
Thomas A. Edison

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MontuckyMadman
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Re: Best cut of wood for core wood

Post by MontuckyMadman » Thu Mar 28, 2019 5:32 pm

Lamination is the destination.
sammer wrote: I'm still a tang on top guy.

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