Log Ski Press idea

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skibum
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Log Ski Press idea

Post by skibum »

Okay so this may seem completely weird but I have seen some pretty bad questions asked before so I thought I would throw it out there. So I was thinking of making a pneumatic press out of a tree. Yes I know laugh it up. Okay so rip the log down the middle length wise and pour some kind of self leveling concrete or I forget the other epoxy kinda like material onto the bottom half of the log (with a form around it to hold it in). This will then leave one half of a log with a smooth surface (bottom half to hold the mold on a level surface) and the top half, which will be a bit rough but will not matter because it will have the bladder and cat track below it. So the log would then be held together with rock climbing slings. These slings are static and can withstand 22kn (4945lbs) http://www.mec.ca/Products/product_deta ... 4302691525. So the idea would be to put a sling every foot or even every 6 inches along the length of the log. To open the press easily the ends of the slings could be connected with a carabiners. The question is how much would the log distort? I would plan to press to about 50 psi, creating about (yikes I just worked this out) 32000lbs. Sounds like it might be a good way to make toothpicks but I did test one log to 50 psi already and all was good, but I didn't check for deflection.
Hopefully this isn't the dumbest thing you have heard today. The reason for not doing and I-beam one is because I may need to move in a year and moving 2500 lbs of steel up to a ski town would be hard enough, never mind moving again.
thanks for any thoughts
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chrismp
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Post by chrismp »

sounds like it should work.
we're using cordura bags for our frame. you might want to do the same since i guess it would distribute the pressure more evenly. just ask montucky, he's been so kind to sew us some bags for a nominal fee.

our press consists of form board and particle board, which i think is even weaker than full wood.
the only issue i see here is that the log could start warping.

here's a couple of pics of our press:

Image

Image
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skibum
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Post by skibum »

Yeah I saw your design and it got me thinking. I'm going to give it a try this way but if its not working for me then I'll consider what you have come up with.
thanks for the advice!
leboeuf
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Post by leboeuf »

Ending my lurking with this post...

I've been thinking of using numerous 15ft tow straps on my version of a fabric press. A whole lot cheaper than climbing gear and they come with hooks rated for load. My plan is to cut them in half and sew a loop into the cut end...

If the lumber is green it will move a lot after you mill it. Concrete will probably crack off even a fully cured log. It would be interesting to try, but a laminated beam is fairly easy to produce...

--Tom
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chrismp
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Post by chrismp »

well, you'd have to place them pretty close to each other (i'd say 5" spaces) and sew them all at the exact same length to get even pressure troughout the press.
for a 2 metre long press you would need seven tow straps with 2" width to cover the whole press. i looked them up at amazon and the cheapest offer for seven straps was 90$ without shipping.
for considerably less money (including shipping to europe!) Montucky has sewn us four cordura bags! ;)
leboeuf
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Post by leboeuf »

If you look around, 7 1.75" (~6000lbs break) straps can be had for $50-$60. For a single ski press @40psi this should yield a safety factor of ~2. Not great, but you could always add more.

Otoh if Montucky is really hooking it up I'll pm him before I buy anything :)
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chrismp
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Post by chrismp »

leboeuf wrote: Otoh if Montucky is really hooking it up I'll pm him before I buy anything :)
he is! might take him a while since he seems to be pretty busy most of the time, but he was happy to sew us up some remnants the company he works for produces.
there is even a thread where he offers to make the cordura bags...there you go: http://www.skibuilders.com/phpBB2/viewt ... ht=cordura
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MontuckyMadman
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Post by MontuckyMadman »

Got lots of scrap right now and some time. Not always the two go together like this. Let me know sooner rather than later.
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chrismp
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Post by chrismp »

btw, anyone interested in a cordura frame press should read this post: http://www.skibuilders.com/phpBB2/viewt ... loth+frame

some good info on there.
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