It's taking me forever to belt sand even very small amounts of UHMW side wall after initial trimming on the bandsaw. The literature says that UHMW is more wear resistant than steel, and believe me, it's true. Steel is much easier to belt sand than UHMW. It's got me wondering why I go to all of the bother to use plastic sidewalls. Wooden sidewalls would be so much faster and less expensive, but I just can't get past my concern regarding moisture penetration and sidewall damage. So, for now anyway, I'll probably stick with the UHMW.
I remember reading somewhere in the last couple of months that there was a particular type of sanding belt abrasive that was more effective for removing UHMW. I've tried doing a search and haven't had any luck finding anything. Can anybody out there point me in a hopeful direction.
Thanks much
Sanding belts for UHMW
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
Re: Sanding belts for UHMW
i agree about the moisture penetration, but then again, you're not building water skis. also, how long do you expect the skis to last? if you apply a descent sealant on the wood sidewalls and do it from time to time, they should hold up pretty well. for now, we build most of our skis with wood sidewalls because it easier, faster, and probably cheaper in the long run. we're more interested in prototyping the effect of shapes, core-materials, length, etc.. this could be a wrong assumption, but the sidewall materials may not have much of an effect. although you could argue that the sidewall material could help in terms of damping -- we'll investigate that later. anyway, most of our wood-sidewall skis haven't been treated with sealant and they seem to hold up well, but the trick of course is to dry them off and store them in a dry location.G-man wrote:It's got me wondering why I go to all of the bother to use plastic sidewalls. Wooden sidewalls would be so much faster and less expensive, but I just can't get past my concern regarding moisture penetration and sidewall damage.
Hey guys,
Thanks for the feedback and suggestions. Yes, using UHMW for side walls certainly does add to the cost of a pair of skis... about fifteen dollars... and using it takes a lot more time and sweat to get them finished. So, why use it? Okay, here's the deal... or at least a good part of it.
I live in Ponderosa pine country. Over the last 20 or so years, in my "spare time", I have built my own house from insect killed trees that I have cut and milled into lumber myself (with the help of a friends portable sawmill). I suppose that I have milled about 300,000 bd. ft. of lumber all in all. There was one batch, in particular, that I milled 1 and 1/4 inch thick and mostly 12 inches wide (about 3,000 ft. of it). Most of it was perfectly clear... no knots for the entire 16+ foot length. It was just too nice to build with, so, I just saved it, feeling that some good use for it would come along someday.
I love to ski... tele ski. For years I've longed to build my own skis, but, every time that I looked at a ski from the perspective of building one, the prospect seemed just too untouchable... not without a lot of special knowledge and equipment. Then, last November, I ran across this site... and I've hardly slept a wink since. The first skis are done now, but, due to a neck and shoulder injury from about a month ago (yardsale), I've not been able to get on them yet. And, yes, the cores are made of Ponderosa pine. When I first considered using pine, I was pretty sure that it would be much too soft. But at the same time, I knew that I'd always wonder if it would work or not, so I just decided to start with it... if nothing else, it would be a great baseline to work up from. And I have a very special sort of 'spiritual' connection with this wonderful little valley where I live, so it felt really good to be making a ski from wood that came from right around home.
I really like to work with pine in general, but one thing I've learned is that, when it comes to moisture, pine is a varitable sponge. So, I suspected from the start that I'd need to take extra care to prevent moisture penetration of the ski core. Hence, the UHMW.
Like I said, I haven't skied them yet, but, I'm really surprised how stiff the flex feels in hand. They feel every bit as stiff as my Jak Teams. My pine core skis are 140-106-130 and weigh in at 4 lbs. 2 oz. per ski (2 layers of 22 oz triax)... awfully light for a non-carbon ski. It's a bit early to draw too many conclusions about the use of pine as my standard core material, but, I'm really encouraged at this point. I also have a few thousand feet of clear vertical grain Douglas Fir that I could mix in... hhhuumm.
I'm not sure whether or not the UHMW contributes to the flex. I did try flexing some of the glass/UHMW trim waste (after bandsawing it off during the finishing stage) and found the waste piece to be really tough to bend/break.
Ya, I'm hopeful of building a lot of skis in the future... and I'm hopeful that I'll be using my good ol' pine as the core material, or at least a part of it. I'll feel a lot better about giving skis to friends (and maybe even selling a few???) if I can be confident that moisture won't be an issue over the long haul. So, sooner or later, I think I'm going to need to work out this UHMW thing, so, I'm starting now. By the way, I'm thinking silicone carbide abrasives are the way to go for removing UHMW during the finishing process.
I'm hoping that the shoulder is ready for a workout in a week or so. I'll post a ride report and some pictures at that time. Cheers.
Thanks for the feedback and suggestions. Yes, using UHMW for side walls certainly does add to the cost of a pair of skis... about fifteen dollars... and using it takes a lot more time and sweat to get them finished. So, why use it? Okay, here's the deal... or at least a good part of it.
I live in Ponderosa pine country. Over the last 20 or so years, in my "spare time", I have built my own house from insect killed trees that I have cut and milled into lumber myself (with the help of a friends portable sawmill). I suppose that I have milled about 300,000 bd. ft. of lumber all in all. There was one batch, in particular, that I milled 1 and 1/4 inch thick and mostly 12 inches wide (about 3,000 ft. of it). Most of it was perfectly clear... no knots for the entire 16+ foot length. It was just too nice to build with, so, I just saved it, feeling that some good use for it would come along someday.
I love to ski... tele ski. For years I've longed to build my own skis, but, every time that I looked at a ski from the perspective of building one, the prospect seemed just too untouchable... not without a lot of special knowledge and equipment. Then, last November, I ran across this site... and I've hardly slept a wink since. The first skis are done now, but, due to a neck and shoulder injury from about a month ago (yardsale), I've not been able to get on them yet. And, yes, the cores are made of Ponderosa pine. When I first considered using pine, I was pretty sure that it would be much too soft. But at the same time, I knew that I'd always wonder if it would work or not, so I just decided to start with it... if nothing else, it would be a great baseline to work up from. And I have a very special sort of 'spiritual' connection with this wonderful little valley where I live, so it felt really good to be making a ski from wood that came from right around home.
I really like to work with pine in general, but one thing I've learned is that, when it comes to moisture, pine is a varitable sponge. So, I suspected from the start that I'd need to take extra care to prevent moisture penetration of the ski core. Hence, the UHMW.
Like I said, I haven't skied them yet, but, I'm really surprised how stiff the flex feels in hand. They feel every bit as stiff as my Jak Teams. My pine core skis are 140-106-130 and weigh in at 4 lbs. 2 oz. per ski (2 layers of 22 oz triax)... awfully light for a non-carbon ski. It's a bit early to draw too many conclusions about the use of pine as my standard core material, but, I'm really encouraged at this point. I also have a few thousand feet of clear vertical grain Douglas Fir that I could mix in... hhhuumm.
I'm not sure whether or not the UHMW contributes to the flex. I did try flexing some of the glass/UHMW trim waste (after bandsawing it off during the finishing stage) and found the waste piece to be really tough to bend/break.
Ya, I'm hopeful of building a lot of skis in the future... and I'm hopeful that I'll be using my good ol' pine as the core material, or at least a part of it. I'll feel a lot better about giving skis to friends (and maybe even selling a few???) if I can be confident that moisture won't be an issue over the long haul. So, sooner or later, I think I'm going to need to work out this UHMW thing, so, I'm starting now. By the way, I'm thinking silicone carbide abrasives are the way to go for removing UHMW during the finishing process.
I'm hoping that the shoulder is ready for a workout in a week or so. I'll post a ride report and some pictures at that time. Cheers.
G-man,
Nice story. I great that your skis will have a extra special meaning to you. The first turns will be so much sweeter.
UHMW is really tough stuff and doesn't sand well. I found that using a wet belt sanders helps alot.
If you are worried about moisture, you might try a penetrating epoxy. It will soak into the wood and seal it from water.
-kelvin
Nice story. I great that your skis will have a extra special meaning to you. The first turns will be so much sweeter.
UHMW is really tough stuff and doesn't sand well. I found that using a wet belt sanders helps alot.
If you are worried about moisture, you might try a penetrating epoxy. It will soak into the wood and seal it from water.
-kelvin
ABS is a plastic. ABS is a harder but more brittle plastic. The black plastic pipe that is typically used in plumbing drain systems is ABS plastic.
UHMWPE and HDPE are both polyelthilynes and are what p-tex and many cutting boards are made of.
PEs and ABS have both been comercially used as sidewall material.
UHMWPE and HDPE are both polyelthilynes and are what p-tex and many cutting boards are made of.
PEs and ABS have both been comercially used as sidewall material.
-
o0norton0o
- Posts: 12
- Joined: Tue Mar 14, 2006 10:07 am
- Location: Seattle
hey g-man, what kind of mill do you have? I have a sperber mill, a high tech version of an alaskan style. It has two stihl .090 chainsaw engines on opposite ends of the cutting bar that pull together on .404 chain. Ever see one? I used to share a log dump with a few others. One guy had a woodmizer which was very efficient. I was wondering what you cut with.
norton
norton
est sularis oth mithas
Norton,
Yep, I had a mill very simular to that one... 5 foot bar, two big ol' powerheads, same .404 chain. But, I finally built a VW powered mill on a trailer... or I should say almost built one. Just about the time I finished it up (a two year long 'free time' project), a friend of mine bought a very simular new VW mill (MightyMite). I used his for about 15 years, and mine is still sitting over yonder rusting away.
Hose-man and chugach,
ABS is certainly worth a consideration, although some past info on this site reports that it may be prone to chipping (as you say Hose-man "harder but more brittle"). But, thanks for the reminder that it is a possible option.
On the subject of sanding/grinding UHMW, even if I did decide to go with some other method of side wall construction, I'd still have the UHMW base material to deal with, as pretty much all ski builders must do because I've never heard of any other material that is being used as a base material. Fortunately, my bases, so far, have turned out really flat. But, it seems that the UHMW base material may be just a few thousands of an inch (or 2 or 3 tenths of a mm) thicker than the relief area provided in the steel edge. My base ends up just slightly higher than the edge. On a 140mm wide tip, that's a lot of material to remove. Yes, I know that a number of builders have reported that they have taken their skis in for a stone grind with good results, but, I'm really just not very eager to hand my newly built skis over to someone else to grind on. Also, I'm so far out in the sticks that the nearest town that would offer a base grinding service is about 3 hours away... and to go there, I'd have to face civilization... yikes!! So, it still remains that my ski building endeavor would really benefit from my figuring out how to effeciently grind and sand UHMW.
Kelvin,
Thanks for the comments and THANKS SO MUCH FOR THIS SITE!! I've been so obsessed with the ski building process since finding skibuilders.com that I haven't taken the time to express my appreciation. Of course, ditto to the Kams. I hope to get to meet you all some day, maybe at a ski builders gathering, eh.
Over the past week I ordered, received, and tested some wet/dry silicon carbide belts on a 4x36 inch sander... very promising. So, in the last couple of days, I built a wet belt sander 6 inches wide and adjustable for up to 132 inch belts... powered by a VW motor... just kidding... about the motor, I mean. I found a source for the belts, I just have to get them ordered... at least I hope it's that easy.
Thanks again to all [/url]
Yep, I had a mill very simular to that one... 5 foot bar, two big ol' powerheads, same .404 chain. But, I finally built a VW powered mill on a trailer... or I should say almost built one. Just about the time I finished it up (a two year long 'free time' project), a friend of mine bought a very simular new VW mill (MightyMite). I used his for about 15 years, and mine is still sitting over yonder rusting away.
Hose-man and chugach,
ABS is certainly worth a consideration, although some past info on this site reports that it may be prone to chipping (as you say Hose-man "harder but more brittle"). But, thanks for the reminder that it is a possible option.
On the subject of sanding/grinding UHMW, even if I did decide to go with some other method of side wall construction, I'd still have the UHMW base material to deal with, as pretty much all ski builders must do because I've never heard of any other material that is being used as a base material. Fortunately, my bases, so far, have turned out really flat. But, it seems that the UHMW base material may be just a few thousands of an inch (or 2 or 3 tenths of a mm) thicker than the relief area provided in the steel edge. My base ends up just slightly higher than the edge. On a 140mm wide tip, that's a lot of material to remove. Yes, I know that a number of builders have reported that they have taken their skis in for a stone grind with good results, but, I'm really just not very eager to hand my newly built skis over to someone else to grind on. Also, I'm so far out in the sticks that the nearest town that would offer a base grinding service is about 3 hours away... and to go there, I'd have to face civilization... yikes!! So, it still remains that my ski building endeavor would really benefit from my figuring out how to effeciently grind and sand UHMW.
Kelvin,
Thanks for the comments and THANKS SO MUCH FOR THIS SITE!! I've been so obsessed with the ski building process since finding skibuilders.com that I haven't taken the time to express my appreciation. Of course, ditto to the Kams. I hope to get to meet you all some day, maybe at a ski builders gathering, eh.
Over the past week I ordered, received, and tested some wet/dry silicon carbide belts on a 4x36 inch sander... very promising. So, in the last couple of days, I built a wet belt sander 6 inches wide and adjustable for up to 132 inch belts... powered by a VW motor... just kidding... about the motor, I mean. I found a source for the belts, I just have to get them ordered... at least I hope it's that easy.
Thanks again to all [/url]
G-man. I've got a 6x36 bench top belt sander that I envisioned using for base flattening when i finally get the time to put allthe material I have laying around together in a shape that resembles a ski.
I was discouraged when I tested the belt out on an old dynastar, but I hadn't considered looking for a better belt until I read your post. Please let us know how the silicone carbide works.
To the K's: I saw that grindrite type belt machine in one of your pictures...... can you shed any light on the composition of the industry specific belts? Also to the run wet or dry? If wet, water or some sort of lube?
Most importantly, thank you guys for creating and mantaining this site.
I was discouraged when I tested the belt out on an old dynastar, but I hadn't considered looking for a better belt until I read your post. Please let us know how the silicone carbide works.
To the K's: I saw that grindrite type belt machine in one of your pictures...... can you shed any light on the composition of the industry specific belts? Also to the run wet or dry? If wet, water or some sort of lube?
Most importantly, thank you guys for creating and mantaining this site.
We have an older wintersteiger grinding machine. I believe the belts are aluminum oxide and needs be run wet. Dry grinding will heat up your edges too much. There is a emulsion that is added to the water bath and it protects against rust and is also a surfactant.
A good place for tools and grinding supplies is http://www.spirakut.com/
-kelvin
A good place for tools and grinding supplies is http://www.spirakut.com/
-kelvin
I am currently building a pair of skis out of pine as well, and so far I think it should work out alright. I am going to use knife threaded inserts for the bindings to make sure they don't pull out, but aside from that, they are looking good so far.
On sidewalls: I have only used wood sidewalls, but have done some experiments with different treatments. On "The Better Rockets" I coated the sidewalls of one ski with epoxy the same epoxy I used to make the skis (applied with roughly using my fingers) and I coated the other ski's sidewalls with a couple coats of polyurethane (applied with a paintbrush). I found that after 12 days on them, the polyurethane was holding up pretty well, and some spots of the epoxy had peeled off. What was most interesting though was that where the epoxy had peeled off, the wood didn't seem to have any issues with soaking up water. I think that the key is to let your skis "dry out" after each use by storing them inside where it is somewhat warm. Storing them inside also helps keep the edges from rusting.
On another pair of skis with an Ash core, I used polyurethane, but I didn't treat the base wood before applying the polyurethane and there was a little mildew that got under the coating. This turned the sidewalls a strange blackish green color in places, but again, the polyurethane coat seems to be holding up really well.
The best part about the polyurethane coating is that it takes about 5 minutes to apply, it doesn't smell bad, and cleanup is easy (unlike epoxy). I am sure that Kelvin and the Kams would agree with me that once you get several pairs of skis, the added durability that goes with umwhpe sidewalls is just not necessary. From my experience, the ski will completely delaminate long before the sidewalls become an issue
.
On sidewalls: I have only used wood sidewalls, but have done some experiments with different treatments. On "The Better Rockets" I coated the sidewalls of one ski with epoxy the same epoxy I used to make the skis (applied with roughly using my fingers) and I coated the other ski's sidewalls with a couple coats of polyurethane (applied with a paintbrush). I found that after 12 days on them, the polyurethane was holding up pretty well, and some spots of the epoxy had peeled off. What was most interesting though was that where the epoxy had peeled off, the wood didn't seem to have any issues with soaking up water. I think that the key is to let your skis "dry out" after each use by storing them inside where it is somewhat warm. Storing them inside also helps keep the edges from rusting.
On another pair of skis with an Ash core, I used polyurethane, but I didn't treat the base wood before applying the polyurethane and there was a little mildew that got under the coating. This turned the sidewalls a strange blackish green color in places, but again, the polyurethane coat seems to be holding up really well.
The best part about the polyurethane coating is that it takes about 5 minutes to apply, it doesn't smell bad, and cleanup is easy (unlike epoxy). I am sure that Kelvin and the Kams would agree with me that once you get several pairs of skis, the added durability that goes with umwhpe sidewalls is just not necessary. From my experience, the ski will completely delaminate long before the sidewalls become an issue
.It just occured to me today as I was going thought this site for a scrapper that a the structuring tool Item #SVN-RS2 Snowboard Base Skiver Tool might be useful to texture the UHMW for glueing.
http://www.tognar.com/base_flattening_t ... ml#SVN-BF1
Any thoughts
Hafte
http://www.tognar.com/base_flattening_t ... ml#SVN-BF1
Any thoughts
Hafte
Definitely. I stopped with the fancy sidewall business. Just too time consuming. I haven't noticed any significant damage to my wooden sidewalls and I tend to trash my skis a lot.Greg wrote:I am sure that Kelvin and the Kams would agree with me that once you get several pairs of skis, the added durability that goes with umwhpe sidewalls is just not necessary. From my experience, the ski will completely delaminate long before the sidewalls become an issue
- Kam S Leang (aka Little Kam)