in this viewtopic.php?t=992 i stumbled across wooden sidewalls... and i begann to think more about this issue.
on my previous project the sidewalls were not a big problem. but now that i`m using a vertical core, as most of you, i started thinking about the sidewalls again.
if you don`t glue any sidewall stuff and just take the normal core material as sidewalls you get some endgrains exposed on the sidewalls. anyone experienced some troubles with this? ripped out little grains, low durability of the edges... or something like that?
now, if you put some "bent" wooden sidewalls on your skis you`d reduce the exposed endgrains. is this really "necessary"? does it really improve the durabilty of the sidewalls? is it worth the extra work?
durability is a general topic for me next projects... i know kingswood is using wooden sidewalls on their megafats, i think there was a serie of völkl gotamas with wooden sidewalls - which actually cracked and made serious troubles... are there any other manufacturer which are using wooden sidewalls? do they have any special threatments?
special threatments in general? if you just seal the sidewalls with epoxy i guess you have to repaint them after every stonegrinding to make sure they are sealed...
is sealing really necessary?
what about the wood you chose for the sidewalls? oak is said to be decent for building stuff in water - could we use this ability for skibuilding?
never ending questions - let there be light!
wooden sidewalls
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wooden sidewalls
plywood freeride industries - go ply, ride wood!
Plywood, Igneous skis use a wood sidewall (wood tipspacers as well). I will have to look closely at my friends to see the grain direction. Igneous skis also seem to be some of the toughest out there, based on my friends that ski them and shop guys here at Jackson Hole that repair skis. The edges are sealed. I think you just need to check them every once and awhile and re-seal any bad gouges. You are also right about the Gotama's with wood sidewalls having problems, the wood was rotting real quick after the seal was broken. I haven't finished my press setup yet, but I do plan to use wood sidewalls.
yeh, i forgot igneous! in an older posts they are also said to be pretty tough.
@windego: i`d say these people told you shit. as you can see on this forum, wooden sidewalls get used in quite a lot of skis. on my first pairs i used and abused wooden sidewalls, coated with epoxy. i learnt how to rail with these skis, so the got beaten up quite often. you mostly hurt the sidewalls when you bang the skis togheter. then the edges of one can damage the sidewalls of the other. but if you angle the sidewalls with 20° this won`t happen.
i think an important factor is the type of wood that is exposed. softer/ligher woods normally absorb water better than hard woods. this leads me to an other question: the people who don`t seal the sidewalls, which wood are you using?
up to now i used ash. it feels like it wouldn`t take up much water. but i can imagine that völkl used a lighter wood on the gots that couldn`t withstand water that good.
@windego: i`d say these people told you shit. as you can see on this forum, wooden sidewalls get used in quite a lot of skis. on my first pairs i used and abused wooden sidewalls, coated with epoxy. i learnt how to rail with these skis, so the got beaten up quite often. you mostly hurt the sidewalls when you bang the skis togheter. then the edges of one can damage the sidewalls of the other. but if you angle the sidewalls with 20° this won`t happen.
i think an important factor is the type of wood that is exposed. softer/ligher woods normally absorb water better than hard woods. this leads me to an other question: the people who don`t seal the sidewalls, which wood are you using?
up to now i used ash. it feels like it wouldn`t take up much water. but i can imagine that völkl used a lighter wood on the gots that couldn`t withstand water that good.
plywood freeride industries - go ply, ride wood!
I think it will depend on the kind of wood you use. If you use a wood that degrades fast in outdoor conditions, it will also start to rot as soon as the seal is broken. If you use wood that can be used outdoor without threatment there should be no problem.
I have only made a prototype ski (a single ski) so far, the ski had wooden tipspacers. I tested it using the Karhu tip delam test and de sandwich remained intact, I had edge delam problems tough. The edge delam was caused by careless cleaning of the edges before lay-up, so it should be an easy fix.
If you select the right kind of wood I think there should be no problems, as always material selection is a crucial point.
I have only made a prototype ski (a single ski) so far, the ski had wooden tipspacers. I tested it using the Karhu tip delam test and de sandwich remained intact, I had edge delam problems tough. The edge delam was caused by careless cleaning of the edges before lay-up, so it should be an easy fix.
If you select the right kind of wood I think there should be no problems, as always material selection is a crucial point.
Plywood, I think the water absorption is also going to depend on the woods structure. What I mean is some woods have bigger pores when you look at the end grain (ring porous). Ash, oak and a few others are very ring porous or open pores. Maple has very tight closed pores. You almost need some type of magnification to see them. I don’t recall how rot resistant ash is, but the ring porous nature can work to your advantage as long as you seal it up. The open pores will allow epoxy or spare vanish to penetrate the wood deeper so when ash is sealed that way small dents and scratches will have very little effect on the treatment of the wood. So the water absorption will be minimal to no problem. I have kayak paddles I made with ash shafts that are sealed with epoxy and a varnish treatment for UV protection that have several years of hard use before I see any signs of water getting into the wood. Maple, poplar are nice hard woods but lack the open pores so epoxy and varnish treatments just sit on top of the wood. Penetration is very shallow and when dented or scratched will not only let in water but will also cause the seal coat to peel away from that area opening the wood to farther problems. Ash is my main goto wood for toys like this for this reason and because it is very shock resistant, and bonding in the laminate is better because of the open pores. Its also less brittle than maple or poplar, and IMHO is better at dampening the ski.
I don’t know what wood folks are using that are not being sealed, but the biggest problem I see with wood kayak paddles is water getting under the glass. When that happens the wood will push whole thing apart if left unattended, and the water is also very difficult to get out of the laminate once it gets in.
On the issue of bent wood side walls. The only way I really see that being effective from a stand point of exposing less end grain would be to find and cut the tree down your self. Take a splitting fro and split the parts out you want with minimal use of cutting tools. That way every piece would have full length wood fibers with no end grain exposed at all. Once wood is cut with a saw you have exposed end grain. Look at an oak board. You can see the pores in the wood on a plain sawn piece, which are and grain openings. The plain sawn view is what you would see on a vertically laminated core from the sidewall.
I have another thought on side walls but it is labor intensive for skis. I use a fabric called Dynel to edge my paddle blades. It comes in two varieties: cloth and a 3/8” braded rope. Dynel is not good as a laminating material because it lacks tensile strength, but when backed by say wood it is very tough and impact resistant as good as any plastic I have every seen. It bonds very well to epoxies after it has cured so it could be put on the core profiled easily and laid up like any other sidewall material. I was thinking of making a sheet 10-12 mm thick several inches wide and as long as the ski. Cutting out a 6 mm wide strip for each edge of the ski and attaching that to the core that has been cut 5-6mm smaller in the plane top shape. Then profile as usual. I *know * that it would bond well to the core and to the glass laminates and be very tough as a side wall. The thing holding me back on this is it would take 20+ layers to make a sheet thick enough and dynel really likes epoxy so it can get kind of heavy. Vacuum bagging the sheet would help with this. Cost would be an issue also. Not in the dynel but in epoxy. It is also a bit abrasive when it is milled. I get little blue sparks from my ¼” ball end mill when I’m profiling my paddles. Its pretty but sure eats up the bit. I have also thought about using the braded rope, but it’s hollow and could prove difficult to get all of the air out.
As for issues with the ski I have made the pair with the treated wood sidewalls are doing fine… as far as the wood goes. What I am getting is some chipping of the glass on the top inside edge (I have no plastic top sheet). Even with a 18-20 deg bevel I’m getting some of this. One chip is into the top sheet about ½” I think I’ll increase my bevel a bit to see if that helps.
I seem to have bit of a case of on-an-on-an-on. Hahahaha That’s what I get from being bored at work.
Hafte
I don’t know what wood folks are using that are not being sealed, but the biggest problem I see with wood kayak paddles is water getting under the glass. When that happens the wood will push whole thing apart if left unattended, and the water is also very difficult to get out of the laminate once it gets in.
On the issue of bent wood side walls. The only way I really see that being effective from a stand point of exposing less end grain would be to find and cut the tree down your self. Take a splitting fro and split the parts out you want with minimal use of cutting tools. That way every piece would have full length wood fibers with no end grain exposed at all. Once wood is cut with a saw you have exposed end grain. Look at an oak board. You can see the pores in the wood on a plain sawn piece, which are and grain openings. The plain sawn view is what you would see on a vertically laminated core from the sidewall.
I have another thought on side walls but it is labor intensive for skis. I use a fabric called Dynel to edge my paddle blades. It comes in two varieties: cloth and a 3/8” braded rope. Dynel is not good as a laminating material because it lacks tensile strength, but when backed by say wood it is very tough and impact resistant as good as any plastic I have every seen. It bonds very well to epoxies after it has cured so it could be put on the core profiled easily and laid up like any other sidewall material. I was thinking of making a sheet 10-12 mm thick several inches wide and as long as the ski. Cutting out a 6 mm wide strip for each edge of the ski and attaching that to the core that has been cut 5-6mm smaller in the plane top shape. Then profile as usual. I *know * that it would bond well to the core and to the glass laminates and be very tough as a side wall. The thing holding me back on this is it would take 20+ layers to make a sheet thick enough and dynel really likes epoxy so it can get kind of heavy. Vacuum bagging the sheet would help with this. Cost would be an issue also. Not in the dynel but in epoxy. It is also a bit abrasive when it is milled. I get little blue sparks from my ¼” ball end mill when I’m profiling my paddles. Its pretty but sure eats up the bit. I have also thought about using the braded rope, but it’s hollow and could prove difficult to get all of the air out.
As for issues with the ski I have made the pair with the treated wood sidewalls are doing fine… as far as the wood goes. What I am getting is some chipping of the glass on the top inside edge (I have no plastic top sheet). Even with a 18-20 deg bevel I’m getting some of this. One chip is into the top sheet about ½” I think I’ll increase my bevel a bit to see if that helps.
I seem to have bit of a case of on-an-on-an-on. Hahahaha That’s what I get from being bored at work.
Hafte
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MartinJern
- Posts: 48
- Joined: Sat Jul 28, 2007 1:27 pm
- Location: Sweden
I have used teak for sidewalls the way the way mark did on his board. (glued on after it's been cut out)
The teak gets kinda greasy when its wet so i guess it will keep the water out of the core.
another wood that almost never rot is larch (spelling?) what do u think about that? it would bee alot cheaper than teak or any other rainforrest wood. and ethicly more corect, the lungs of the world u know
The teak gets kinda greasy when its wet so i guess it will keep the water out of the core.
another wood that almost never rot is larch (spelling?) what do u think about that? it would bee alot cheaper than teak or any other rainforrest wood. and ethicly more corect, the lungs of the world u know
@martin: i visited my veneer supplier today and we had a pretty intensive discussion of woods.
he also said something about larch. actually our this discussion was that intensive that i forgot half of it. damn but if i remember right he said that they`re often using larch for outside, that it is a pretty resistant wood.
we also talked about the lungs of the world there are a lot of certificates for woods nowadays which should ensure sustainability and stuff like that. how can it possibly sustainable to cut down some 100year old tress in the midth of rainforest?! he also told me that his suppliers deliver him with together with the wood programs with which he can print out such certificates...well, so he theoretically has a certificate for every log he stores. so all these certificates about sustainability are pretty much...crap. that`s what he said.
so the whole discussion made my attitude to just use "local" woods even stronger.
but now back on topic
so in conclusion this guy said, that larch would be the only conifer wood that could be suitable for our use.
@hafte: i think on my second pair i tried something similar as you plan to do. if i got your idea i tried to build sidewalls out uf fibreglass. i was so stupid an thought that it would be no problem to build them during layup, putting the glass in its place and wettening the whole stuff... so at least you won`t make this mistake.
only the sidewalls consumed a good KG of epoxy. for one ski.
so it needs quite a lot of epoxy and quite a lot of fibreglass or whatever you`re using. but i was surprised of how easy i could rout/angle/whatever them. after some times the sidewalls showed signs of crackings.
so i think you should carefully consider this: thick layers of epoxy tend to crack, even with fibres in it. and bubbles are a problem on thicker layups.
the chipping of the topsheet is a tricky problem. i remember a discussion somewhere with a guy from rossignol who said that they were using all imaginable types of materials and all chipped. the only efficient way to avoid chipping is to angle the "edges" on top of the ski, as if you would pull down the topsheet a little on the sides, similar as the construction there on a cap ski. hope you get the point.
on my evil twins i used a really tough abs-topsheet. i`m still really surprised how good it withstands the abuse. i only have one single "big" chip, about 5mm. so i think the topsheet definately has an influence, but i don`t think you need a bigger angle than 20°...
he also said something about larch. actually our this discussion was that intensive that i forgot half of it. damn
but if i remember right he said that they`re often using larch for outside, that it is a pretty resistant wood. we also talked about the lungs of the world
there are a lot of certificates for woods nowadays which should ensure sustainability and stuff like that. how can it possibly sustainable to cut down some 100year old tress in the midth of rainforest?! he also told me that his suppliers deliver him with together with the wood programs with which he can print out such certificates...well, so he theoretically has a certificate for every log he stores. so all these certificates about sustainability are pretty much...crap. that`s what he said.so the whole discussion made my attitude to just use "local" woods even stronger.
but now back on topic
so in conclusion this guy said, that larch would be the only conifer wood that could be suitable for our use.
@hafte: i think on my second pair i tried something similar as you plan to do. if i got your idea
i tried to build sidewalls out uf fibreglass. i was so stupid an thought that it would be no problem to build them during layup, putting the glass in its place and wettening the whole stuff... so at least you won`t make this mistake. only the sidewalls consumed a good KG of epoxy. for one ski.
so it needs quite a lot of epoxy and quite a lot of fibreglass or whatever you`re using. but i was surprised of how easy i could rout/angle/whatever them. after some times the sidewalls showed signs of crackings.
so i think you should carefully consider this: thick layers of epoxy tend to crack, even with fibres in it. and bubbles are a problem on thicker layups.
the chipping of the topsheet is a tricky problem. i remember a discussion somewhere with a guy from rossignol who said that they were using all imaginable types of materials and all chipped. the only efficient way to avoid chipping is to angle the "edges" on top of the ski, as if you would pull down the topsheet a little on the sides, similar as the construction there on a cap ski. hope you get the point.
on my evil twins i used a really tough abs-topsheet. i`m still really surprised how good it withstands the abuse. i only have one single "big" chip, about 5mm. so i think the topsheet definately has an influence, but i don`t think you need a bigger angle than 20°...
plywood freeride industries - go ply, ride wood!
Hi Kids,
This is my first post here. I'm a crossover from the Grafs site. There seems to be a lot of interest in wood sidewalls, so I thought I would chime in.
Anyone considering wood/bamboo as a sidewall should research methods for creating a "wood polymer composite" (WPC). Here is a basic description, relying on my memory from several years back. The process involves impregnating the structure of the wood with a water diluted solution of plastic resin. After a 24hr "soaking", the strips of wood are slowly heated to 250-300 degrees for an hour or so. This drives out the water from the wood.
The temp. is then raised to 400-450 for a brief period of time. This elevated temp. polymerizes the plastic trapped within the fibers of the wood.
What you're left with is no longer simply wood. This wood polymer composite, when properly teated will be impervious to moisture. The wicking properties will have been eliminated. The bond with epoxy is exceptional.
For tough and light weight, try Tonkin bamboo. Makers of heirloom quality cane Fly rods use this material. Further info can be found by researching forums of bamboo fly rod builders.
As with everything else you've done, there is some fabricating and ingenuity required for this process, but nothing compared to what most of you have already achieved. A makeshift gas oven built from a section of insulated stove pipe will do the trick.
Sorry for such a basic description, but it gets rather long winded otherwise.
MikeC
This is my first post here. I'm a crossover from the Grafs site. There seems to be a lot of interest in wood sidewalls, so I thought I would chime in.
Anyone considering wood/bamboo as a sidewall should research methods for creating a "wood polymer composite" (WPC). Here is a basic description, relying on my memory from several years back. The process involves impregnating the structure of the wood with a water diluted solution of plastic resin. After a 24hr "soaking", the strips of wood are slowly heated to 250-300 degrees for an hour or so. This drives out the water from the wood.
The temp. is then raised to 400-450 for a brief period of time. This elevated temp. polymerizes the plastic trapped within the fibers of the wood.
What you're left with is no longer simply wood. This wood polymer composite, when properly teated will be impervious to moisture. The wicking properties will have been eliminated. The bond with epoxy is exceptional.
For tough and light weight, try Tonkin bamboo. Makers of heirloom quality cane Fly rods use this material. Further info can be found by researching forums of bamboo fly rod builders.
As with everything else you've done, there is some fabricating and ingenuity required for this process, but nothing compared to what most of you have already achieved. A makeshift gas oven built from a section of insulated stove pipe will do the trick.
Sorry for such a basic description, but it gets rather long winded otherwise.
MikeC
Why Buy it for cheap when you can build it for a lot more!!?