I have been looking at a small company's skis that are made
at an OEM factory in Europe. They all seem to have problems with chipping of the topsheet materials. From what I understand they are using a polyamide topsheet from ISO sport. Does anyone know where I can
find out what about top sheet material that a less prone to chipping.
These skis are used alot in the park so they take alot of abuse.
Top Sheet Materials
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
Chipping
Hi,
I can tell you that when we designed our first Scratch skis at Rossignol, we made them flat on the top surface and chipping was the first problem. We tried many top sheet materials with no success.
We decided to modify the design of the top surface on each lateral side on the ski.
So if you want your skis look better, try to make a chamfer on each side of your top sheet on your skis. It will help a lot.
Jacques
I can tell you that when we designed our first Scratch skis at Rossignol, we made them flat on the top surface and chipping was the first problem. We tried many top sheet materials with no success.
We decided to modify the design of the top surface on each lateral side on the ski.
So if you want your skis look better, try to make a chamfer on each side of your top sheet on your skis. It will help a lot.
Jacques
J Lx
Voiron, FR
Voiron, FR
Re: Chipping
i just had my first time on rails - and the skis also suffered some chipping. so i thought about good solutions to avoid it...
the problem occured on my skis on the inner edges of the skis, the ones facing each others. it`s kind of logical - if you crash you hit the skis together and the edged damage the sidewalls of the other ski.
i think this is a general problem of sandwich construction. maybe there a cap construction would be more resistible. as far as i understood hiona you somehow constructed a combination between a cap and a sandwichconstruction, right?
an other solution would be to use some sort of metal under the topsheet. i think for example the stöckli-skis are made so. this way helps a little to prevent serious chips. the metal prevents deeper scratches and hits, but the topsheet still gets some chipps - not so nice to look at too, but better than serious injuries to the fibreglass or so...
the problem occured on my skis on the inner edges of the skis, the ones facing each others. it`s kind of logical - if you crash you hit the skis together and the edged damage the sidewalls of the other ski.
i think this is a general problem of sandwich construction. maybe there a cap construction would be more resistible. as far as i understood hiona you somehow constructed a combination between a cap and a sandwichconstruction, right?
an other solution would be to use some sort of metal under the topsheet. i think for example the stöckli-skis are made so. this way helps a little to prevent serious chips. the metal prevents deeper scratches and hits, but the topsheet still gets some chipps - not so nice to look at too, but better than serious injuries to the fibreglass or so...
plywood freeride industries - go ply, ride wood!
-
Cadman
bending them? how should they? i don`t get what you mean...Cadman wrote:The metal idea would also work but I am afraid that with the way people use these skis, they would end up bending them.
you just had to use the right metal, like titanal or other steel which they use for producing springs and stuff like that
i think metal would be a good proteciont which works fine. but the problem is that as soon as you use metal the ski get extremely heavy.
plywood freeride industries - go ply, ride wood!
Welcome hiona. Your expertise is much appreciated.
The top sheet damage that I notice on my skis is not so much an actual chipping of the top sheet material... it's more that I have been getting little micro fractures (3 or 4mm in size) along the top sheet/side wall junction, actually in the glass layer itself. Is that what you guys are talking about, or are you actually getting chipping of the top sheet material itself? As hiona suggested, chamfering will help, but, due to the stepped and angled side wall profile (and curvatures of tip and tail), chamfering with a simple bit/bearing combo is not as easily done as it might initially sound.
G-man
The top sheet damage that I notice on my skis is not so much an actual chipping of the top sheet material... it's more that I have been getting little micro fractures (3 or 4mm in size) along the top sheet/side wall junction, actually in the glass layer itself. Is that what you guys are talking about, or are you actually getting chipping of the top sheet material itself? As hiona suggested, chamfering will help, but, due to the stepped and angled side wall profile (and curvatures of tip and tail), chamfering with a simple bit/bearing combo is not as easily done as it might initially sound.
G-man
hi hiona, welcome as well.
the Scratch BC is one of my favorite skis. and here i thought the bevel was cosmetic. without knowing that it reduces chipping, we bevel all our skis.
G-man: do you think the fractures are mechanically induced? could heat be a problem -- i'm assuming you're using a heated press. for example, do you think the heat has altered the topsheet material in any way?
you said the fractures are along the sheet/side wall junction. i'm having a hard time visualizing this. are the fractures distributed all over the ski or is it localized along the edge (where the sidewall joins the topsheet)?
the Scratch BC is one of my favorite skis. and here i thought the bevel was cosmetic. without knowing that it reduces chipping, we bevel all our skis.
G-man: do you think the fractures are mechanically induced? could heat be a problem -- i'm assuming you're using a heated press. for example, do you think the heat has altered the topsheet material in any way?
you said the fractures are along the sheet/side wall junction. i'm having a hard time visualizing this. are the fractures distributed all over the ski or is it localized along the edge (where the sidewall joins the topsheet)?
hi hiona, welcome as well.
the Scratch BC is one of my favorite skis. and here i thought the bevel was cosmetic. without knowing that it reduces chipping, we bevel all our skis.
G-man: do you think the fractures are mechanically induced? could heat be a problem -- i'm assuming you're using a heated press. for example, do you think the heat has altered the topsheet material in any way?
you said the fractures are along the sheet/side wall junction. i'm having a hard time visualizing this. are the fractures distributed all over the ski or is it localized along the edge (where the sidewall joins the topsheet)?
the Scratch BC is one of my favorite skis. and here i thought the bevel was cosmetic. without knowing that it reduces chipping, we bevel all our skis.
G-man: do you think the fractures are mechanically induced? could heat be a problem -- i'm assuming you're using a heated press. for example, do you think the heat has altered the topsheet material in any way?
you said the fractures are along the sheet/side wall junction. i'm having a hard time visualizing this. are the fractures distributed all over the ski or is it localized along the edge (where the sidewall joins the topsheet)?
-
Cadman
Normally in a layup to create balance in the ski, you do pretty much the same thing below the core that you do above the core. Therefore you have to put aluminum on the bottom as well as the top. The aluminum that they use in skis has a yield point and when you bend a ski with metal in it past the elastic limit, the ski takes a set and is considered bent. That would be the reason why alot of skis don't use metal sheets since the free ride market is a market that is pretty tough on skis. I personally like a ski with metal in it because it makes the ski torsionally rigid, damp and the bases tune really nice. However, they tend to be more on the stiff side to keep them from bending as well as making them heavy as plywood said.. Titanol is a trade name that they use in the ski industry but I don't believe it has any titanium in it. It is just high alloy aluminum if I am not mistaken. I do agree with you that the metal would definately help with the chipping.
Cadman: you're right. Titanal is a trade name, and it's an AL alloy, much like the 6 or 7k series.
my most recent ski has aluminum and steel. i enjoy them very much, primarily because of how solid they feel. the metal makes the ride feel more damp, especially at high speed. i can really let them run.
my most recent ski has aluminum and steel. i enjoy them very much, primarily because of how solid they feel. the metal makes the ride feel more damp, especially at high speed. i can really let them run.
Hi bigkam,
Yes, I'm quite sure that the fractures are mechanically induced. I think that I've mentioned before that I often test my skis by tossing them around in an asphalt parking lot. I also take a 16 inch long piece of 1/2 inch diameter steel rod and beat them along the sidewalls... and worst of all, I ski on them
. The only real damage I get from all of this abuse now-a-days are the small 'fractures' that I have tried to describe... if I only hadn't busted my camera, I could take a picture. I'll try to describe the situation a little better. Let's say that you have a ski that has a red, but fairly translucent top sheet. This same ski has blue sidewalls. Now, let's say that you take a length of steel bar and beat the ski along the corner where the red meets the blue. After beating the daylights out of the ski, you notice (through the translucent red) a number of small white-ish colored areas where you hit the ski with the bar. Upon close inspection, you note that the top sheet material itself is deformed only a little in the worst areas, and that the sidewall material is completely intact. You then probe the white-ish areas with the point of a small knife blade (via the fiberglass seam between the red and blue) and realize that the fiberglass layer between the red and blue structures is somewhat broken-up and powdery.
Does that paint a little better picture? A long time ago, I used to surf and build surfboards. When a board would get away from me, while surfing, and crash into a rock (we didn't use leashes back then), it'd usually end up with what we called a 'ding' in the fiberglass layer (bummer dude). I don't know what surfers call that sort of thing now-a-days (yikes, just did the math... that was 40 years ago), but this sort of damage that I'm describing to the ski is basically the same thing that a 'ding' was on a surfboard. I can easily reproduce it on a ski, at-will, by whacking the corner edge of the top sheet with the steel bar. The epoxy resin is tough stuff, but it does have it's limitations. I think the fiberglass matrix just simply fractures when subjected to a big enough impact. Oh, I also get an occasional 'ding' in my ski top corner edge from banging my skis together when I ski... you know, from doing all the sick tricks that I'm always inventing.
For my sidewall finishing details, I use a 7 degree sidewall bevel with about a 2mm step above the metal edge, and lately I've been doing a 45 degree chamfer(with about a 4mm face) where the red and blue (from above descripton) meet. The chamfer pretty much eliminates the 'ding' problem, even when I beat the ski with the steel bar. As I said before, the chamfer is tricky to do well because of all of the angles, steps, curves, and varying thicknesses.
Yes, I'm still using the heated press. I don't think that the heat process effects the top sheet in any negative manner. If anything, and as Roy said, it improves the bond.
In 'normal' skiing mode (and pre-chamfer era), I would just get an occasional ding on the inside ski edge, along the first 12 inches or so of the tip... mostly just from whacking the skis together while skiing.
Well, that was a bit long-winded, now wasn't it.
G-man
Yes, I'm quite sure that the fractures are mechanically induced. I think that I've mentioned before that I often test my skis by tossing them around in an asphalt parking lot. I also take a 16 inch long piece of 1/2 inch diameter steel rod and beat them along the sidewalls... and worst of all, I ski on them
. The only real damage I get from all of this abuse now-a-days are the small 'fractures' that I have tried to describe... if I only hadn't busted my camera, I could take a picture. I'll try to describe the situation a little better. Let's say that you have a ski that has a red, but fairly translucent top sheet. This same ski has blue sidewalls. Now, let's say that you take a length of steel bar and beat the ski along the corner where the red meets the blue. After beating the daylights out of the ski, you notice (through the translucent red) a number of small white-ish colored areas where you hit the ski with the bar. Upon close inspection, you note that the top sheet material itself is deformed only a little in the worst areas, and that the sidewall material is completely intact. You then probe the white-ish areas with the point of a small knife blade (via the fiberglass seam between the red and blue) and realize that the fiberglass layer between the red and blue structures is somewhat broken-up and powdery.Does that paint a little better picture? A long time ago, I used to surf and build surfboards. When a board would get away from me, while surfing, and crash into a rock (we didn't use leashes back then), it'd usually end up with what we called a 'ding' in the fiberglass layer (bummer dude). I don't know what surfers call that sort of thing now-a-days (yikes, just did the math... that was 40 years ago), but this sort of damage that I'm describing to the ski is basically the same thing that a 'ding' was on a surfboard. I can easily reproduce it on a ski, at-will, by whacking the corner edge of the top sheet with the steel bar. The epoxy resin is tough stuff, but it does have it's limitations. I think the fiberglass matrix just simply fractures when subjected to a big enough impact. Oh, I also get an occasional 'ding' in my ski top corner edge from banging my skis together when I ski... you know, from doing all the sick tricks that I'm always inventing.
For my sidewall finishing details, I use a 7 degree sidewall bevel with about a 2mm step above the metal edge, and lately I've been doing a 45 degree chamfer(with about a 4mm face) where the red and blue (from above descripton) meet. The chamfer pretty much eliminates the 'ding' problem, even when I beat the ski with the steel bar. As I said before, the chamfer is tricky to do well because of all of the angles, steps, curves, and varying thicknesses.
Yes, I'm still using the heated press. I don't think that the heat process effects the top sheet in any negative manner. If anything, and as Roy said, it improves the bond.
In 'normal' skiing mode (and pre-chamfer era), I would just get an occasional ding on the inside ski edge, along the first 12 inches or so of the tip... mostly just from whacking the skis together while skiing.
Well, that was a bit long-winded, now wasn't it.
G-man
hi G-man:
dude
, i used to surf too, for a number of years. it's nice to have that in common!
what you describe is interesting. could it be that the matrix is brittle? have you done some tests with cured epoxy with glass and a hammer? i'll beat on some leftover cured epoxy with fiberglass after my next ski (next week).
i used to own an old pair of K2s, the 5500 to be exact, and i remember seeing fractures all throughout the top sheet, especially near the curved portion of the tip. if i remember correctly, it looked like a cracked windshield. i think the cracks were in the topsheet, caused by the effects of aging and UV exposure.
suppose the matrix is brittle and suseptible to high impact. i wonder if a layer of material can be added to help dissipate the energy to minimize the fractures....? what about foam.. oh, wait. Kelvin tried that and he ended up with a bow and arrow.
dude
, i used to surf too, for a number of years. it's nice to have that in common!what you describe is interesting. could it be that the matrix is brittle? have you done some tests with cured epoxy with glass and a hammer? i'll beat on some leftover cured epoxy with fiberglass after my next ski (next week).
i used to own an old pair of K2s, the 5500 to be exact, and i remember seeing fractures all throughout the top sheet, especially near the curved portion of the tip. if i remember correctly, it looked like a cracked windshield. i think the cracks were in the topsheet, caused by the effects of aging and UV exposure.
suppose the matrix is brittle and suseptible to high impact. i wonder if a layer of material can be added to help dissipate the energy to minimize the fractures....? what about foam.. oh, wait. Kelvin tried that and he ended up with a bow and arrow.
bigkam,
Isn't it kinda funny... I hear these young folks on the ski hill saying,"dude this", and, "dude that", and I laugh thinking that if they really knew how old that lingo was, they'd probably stop with the "dude" stuff. I wonder who was saying it 40 years before I was? Ya, I built a bunch of surfboards in the late 60's... was a Huntington Beach board building legend as a teenager because I was designing such radical stuff for the times. Then I had to do a stint in SE Asia, and when I came home, I grabbed my board, headed out into the surf, and all of these surfers that I'd never seen before got all hostile on me cause it was their surf turf. Actually, so much had changed while I was away, including me, I gave all my boards to my little brother and I headed for the deep woods. Sorta been there ever since. Dang... I should'a chosen the name 'rambo' rather than 'g-man'. Anyway, I haven't surfed since those early days.
Ya, I think that brittleness, at a certain stress level, is just the physical nature of the epoxy resin. I've tested samples of resin that I had left over in mixing cups (about 5mm thick). Non-heat cured stuff just crumbles really easily. When I heat cure the same sample, I have to bend it with two pliers to finally break it. It's quite tough, but it will break with a moderate flexing. It is, however, very stiff, which, as Roy pointed out, is why it works so well for ski production.
These fractures that I've been talking about are really quite small... they only penetrate into the ski couple of mm's from the edge. I think a layer of fabric material is helpful because it makes the little fractures invisible... outta site, outta mind. What I mean is that I don't think the fractures actually constitute any real deficit to the ski. I bet most all skis get little fractures, but because of all the colors and graphics in the top sheet, no one really ever sees them... so the skier doesn't ever have to wonder if they are bad or not. I happen to like clear top sheets cause I happen to like wood. I used to like graphics, but in this age of being able to do just about any top sheet graphic on a computer in a very short period of time, often without a real artist or craftsman involved... well, it's gotten a bit underwhelming to see really wild-ass computer generated graphics. A real artist I am not, so for now, I'm just doing wood... and the little fractures looked unsightly, so I chamfered the edges. For one, the chamfer routed away most of the existing fractures, and two, it prevented more from developing.
Later dude,
G-man
Isn't it kinda funny... I hear these young folks on the ski hill saying,"dude this", and, "dude that", and I laugh thinking that if they really knew how old that lingo was, they'd probably stop with the "dude" stuff. I wonder who was saying it 40 years before I was? Ya, I built a bunch of surfboards in the late 60's... was a Huntington Beach board building legend as a teenager because I was designing such radical stuff for the times. Then I had to do a stint in SE Asia, and when I came home, I grabbed my board, headed out into the surf, and all of these surfers that I'd never seen before got all hostile on me cause it was their surf turf. Actually, so much had changed while I was away, including me, I gave all my boards to my little brother and I headed for the deep woods. Sorta been there ever since. Dang... I should'a chosen the name 'rambo' rather than 'g-man'. Anyway, I haven't surfed since those early days.
Ya, I think that brittleness, at a certain stress level, is just the physical nature of the epoxy resin. I've tested samples of resin that I had left over in mixing cups (about 5mm thick). Non-heat cured stuff just crumbles really easily. When I heat cure the same sample, I have to bend it with two pliers to finally break it. It's quite tough, but it will break with a moderate flexing. It is, however, very stiff, which, as Roy pointed out, is why it works so well for ski production.
These fractures that I've been talking about are really quite small... they only penetrate into the ski couple of mm's from the edge. I think a layer of fabric material is helpful because it makes the little fractures invisible... outta site, outta mind. What I mean is that I don't think the fractures actually constitute any real deficit to the ski. I bet most all skis get little fractures, but because of all the colors and graphics in the top sheet, no one really ever sees them... so the skier doesn't ever have to wonder if they are bad or not. I happen to like clear top sheets cause I happen to like wood. I used to like graphics, but in this age of being able to do just about any top sheet graphic on a computer in a very short period of time, often without a real artist or craftsman involved... well, it's gotten a bit underwhelming to see really wild-ass computer generated graphics. A real artist I am not, so for now, I'm just doing wood... and the little fractures looked unsightly, so I chamfered the edges. For one, the chamfer routed away most of the existing fractures, and two, it prevented more from developing.
Later dude,
G-man
Hey G-man, you beat your skis with a metal bar and they show cosmetic damage? You must be ashamed.
I would be interested to hear a little more about your chamfer process if you are willing to share. Are you using a specialty bit on one of your many routers or can this be accomplished with a mill or plane. Imagining how you would guide a router bit is in my head is getting very complicated.
I would be interested to hear a little more about your chamfer process if you are willing to share. Are you using a specialty bit on one of your many routers or can this be accomplished with a mill or plane. Imagining how you would guide a router bit is in my head is getting very complicated.
- Ben
I knew if I didn't keep my big mouth shut, I'd end up in this predicament. Actually, I really like to share... but don't we all, at some point, have our little secrets?
Okay, here's kinda the story. As so many of us have learned since discovering this site, going through the process of setting up all the steps required to build a pair of skis is a lot more difficult than we ever initially thought it would be... lots of time, work, and money. I also think that most of those who have actually managed to build that first pair of skis would say that the journey was entirely worth the effort. The K's set the ball in motion in a really huge way... I mean look at us... we're building skis in our home workshops, garages, and (some I think) living rooms. Together, we've shared successes and failures, and I think that at this point in time, all the necessary information for obtaining materials and building a darned good ski is somewhere on the site.
In general, the ski industry, like most others, is quite secretive regarding manufacturing processes. The positive side of this is that (however frustrating it may be at times) it causes us want-to-be ski builders to come up with our own (at least in or own minds) original methods for accomplishing a particular process. On those very rare occasions, what we come up with may be even better than a long adhered to industry norm.
I'm absolutely sure that many of the ski building processes that I've come up with in order to get a pair of skis on the snow are far, far inferior to what the general industry is commonly using. Some, too, may be on par with the industry, but not affordable for someone like myself (like an integrated plasma analyzer flame treating system for 50 grand). But there just might be a couple of items that I've stumbled across that the big boys haven't picked up on yet. As I've mentioned before, I've spent much of the last 10 months testing (over a hundred now) different plastics for bond ability, flexibility (at sub-freezing), impact resistance (at sub-freezing), environmental friendliness, workabilty, and affordability. Have I come up with something? Maybe, but it needs more test time... so far, so good. Many of these new things that I'm working on are intertwined with other interesting new processes... the new sidewall treatment is one of them, and yes, I had to build a pretty elaborate machine for the process, which is still undergoing fine tuning. Am I ready to share all this stuff? Not just yet. For one thing, the secrets help to drive my creative side. I also think that a little secrecy helps to stimulate the creative nature in others.
Basically, it has been a personal goal of mine to contribute to this site to the degree that anyone who wants to build a pair of skis can do just that... always knowing that my contribution has been a drop in the bucket addition to what the K's and others done. I've just wanted to give back to the community that has given me so much. I also suspect that there are hundreds of people out there who have built skis (or are building skis) from the information provided on this site, but who have never contributed back to it. I think that is fine, but at the same time, I also think it's important that users realize that this type of forum exists for the benefit of all because a certain number of folks put in the energy to actively participate... without that, the site would cease to exist.
Anyway, I feel quite certain that the amount of information that exists on the site is plenty adequate to build a great pair of basic skis. I'm also glad that the lack of certain information has ended up pushing me to spend those hundreds (if not thousands) of hours pursuing answers where none were easily available. For those site users who aren't going to be satisfied with a 'basic' ski, it's probably better in the long run to have your creative juices stimulated by an info void anyway. Who knows what you'll come up with.
If I found out out tomorrow that I had 6 months to live, would I tell all? Ya, probably... at least some hints. Does any of it really matter? I think not... as long as we're doing the best we can everyday. As for my big secret?... I'll probably find some reason it doesn't work anyway.
Cheers,
G-man
Okay, here's kinda the story. As so many of us have learned since discovering this site, going through the process of setting up all the steps required to build a pair of skis is a lot more difficult than we ever initially thought it would be... lots of time, work, and money. I also think that most of those who have actually managed to build that first pair of skis would say that the journey was entirely worth the effort. The K's set the ball in motion in a really huge way... I mean look at us... we're building skis in our home workshops, garages, and (some I think) living rooms. Together, we've shared successes and failures, and I think that at this point in time, all the necessary information for obtaining materials and building a darned good ski is somewhere on the site.
In general, the ski industry, like most others, is quite secretive regarding manufacturing processes. The positive side of this is that (however frustrating it may be at times) it causes us want-to-be ski builders to come up with our own (at least in or own minds) original methods for accomplishing a particular process. On those very rare occasions, what we come up with may be even better than a long adhered to industry norm.
I'm absolutely sure that many of the ski building processes that I've come up with in order to get a pair of skis on the snow are far, far inferior to what the general industry is commonly using. Some, too, may be on par with the industry, but not affordable for someone like myself (like an integrated plasma analyzer flame treating system for 50 grand). But there just might be a couple of items that I've stumbled across that the big boys haven't picked up on yet. As I've mentioned before, I've spent much of the last 10 months testing (over a hundred now) different plastics for bond ability, flexibility (at sub-freezing), impact resistance (at sub-freezing), environmental friendliness, workabilty, and affordability. Have I come up with something? Maybe, but it needs more test time... so far, so good. Many of these new things that I'm working on are intertwined with other interesting new processes... the new sidewall treatment is one of them, and yes, I had to build a pretty elaborate machine for the process, which is still undergoing fine tuning. Am I ready to share all this stuff? Not just yet. For one thing, the secrets help to drive my creative side. I also think that a little secrecy helps to stimulate the creative nature in others.
Basically, it has been a personal goal of mine to contribute to this site to the degree that anyone who wants to build a pair of skis can do just that... always knowing that my contribution has been a drop in the bucket addition to what the K's and others done. I've just wanted to give back to the community that has given me so much. I also suspect that there are hundreds of people out there who have built skis (or are building skis) from the information provided on this site, but who have never contributed back to it. I think that is fine, but at the same time, I also think it's important that users realize that this type of forum exists for the benefit of all because a certain number of folks put in the energy to actively participate... without that, the site would cease to exist.
Anyway, I feel quite certain that the amount of information that exists on the site is plenty adequate to build a great pair of basic skis. I'm also glad that the lack of certain information has ended up pushing me to spend those hundreds (if not thousands) of hours pursuing answers where none were easily available. For those site users who aren't going to be satisfied with a 'basic' ski, it's probably better in the long run to have your creative juices stimulated by an info void anyway. Who knows what you'll come up with.
If I found out out tomorrow that I had 6 months to live, would I tell all? Ya, probably... at least some hints. Does any of it really matter? I think not... as long as we're doing the best we can everyday. As for my big secret?... I'll probably find some reason it doesn't work anyway.
Cheers,
G-man