Twizz 2013/2014
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
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- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
Twizz 2013/2014
Nothing built yet, but it's coming soon!
I only have one pair planned this year... while I'm itching to build more, I'm having a hard time justifying building just for the sake of building. The foam core powder skis I did last year are still holding up and I'm loving them, so I'll just keep skiing on them!
So plans for this first pair were supposed to be some park/all mountain skis. Something a bit "skinnier"... unfortunately I'm so normalized to my VERY fat skis that these are still going to be pretty fat. It's been hard to find time to work on stuff, but a few weeks ago I CNC'd the cores and epoxied the sidewalls on. Today I epoxied the inserts in, and some night this week I will profile the cores.
I sent the graphics to Miller last week, and tomorrow I'm picking up some bamboo veneer. The graphics will be sublimated on clear nylon, put over the bamboo veneer.
Here is what they'll look like:
And here is a gratuitous shot from my "office in the sky" over some of the first snow of the year. This is the new 787-9, and one of the reasons I haven't been able to spend much time in the shop lately.
I only have one pair planned this year... while I'm itching to build more, I'm having a hard time justifying building just for the sake of building. The foam core powder skis I did last year are still holding up and I'm loving them, so I'll just keep skiing on them!
So plans for this first pair were supposed to be some park/all mountain skis. Something a bit "skinnier"... unfortunately I'm so normalized to my VERY fat skis that these are still going to be pretty fat. It's been hard to find time to work on stuff, but a few weeks ago I CNC'd the cores and epoxied the sidewalls on. Today I epoxied the inserts in, and some night this week I will profile the cores.
I sent the graphics to Miller last week, and tomorrow I'm picking up some bamboo veneer. The graphics will be sublimated on clear nylon, put over the bamboo veneer.
Here is what they'll look like:
And here is a gratuitous shot from my "office in the sky" over some of the first snow of the year. This is the new 787-9, and one of the reasons I haven't been able to spend much time in the shop lately.
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- Posts: 175
- Joined: Mon Oct 11, 2010 11:06 pm
- Contact:
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- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
-
- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
-
- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
These skis are finally done, I'm calling them the "Totem Sticks".
As tends to be with each new pair, these are the best I've done so far. Edge fit is excellent, base flatness was pretty good (I never get this perfect), no delam anywhere, no core shifting, etc. Pretty darn close to perfect.
The topsheets are sublimated clear nylon from Miller Studios, over a HG blonde bamboo veneer. This clear nylon is completely crystal clear with a perfectly smooth glossy surface. I am sure it will scratch up like mad, but for now it looks incredible. The photos below do not do it justice. When light hits the bamboo grain at just the right angle, the bamboo almost becomes reflective! Very cool. The black is completely opaque, but the red is slightly translucent (as expected). I have yet to find any bubbles under the topsheet, and I've been looking hard!
As for the construction, these have bamboo cores with 6" tip spacers on each end. 20oz triax fiberglass on the top and bottom (diagonal fibers out), with a 3" wide strip of carbon uni on the top and bottom. No edge rebate cut in the core (the CF strip takes care of this).
160cm length, 125-97-113
The few things that make them not entirely perfect:
- The topsheet on the right ski shifted slightly to the right. Not a big deal, the skis just don't look exactly symmetric.
- The sidewall finish isn't very good. Suspect my sidewall router bit is getting dull. When I do my sidewalls I cut it in a conventional milling direction, I wonder if climb milling would give a better finish, especially considering a dull bit? The lighting in the photo below exaggerates it, but it's still not great in real life.
I couldn't find the SD card for my nice camera, so cell phone photos will have to do for now.
Camber profile
The graphics on the right ski shifted slightly to the right
Examples of the bamboo veneer showing through the topsheet
Shiny!
As tends to be with each new pair, these are the best I've done so far. Edge fit is excellent, base flatness was pretty good (I never get this perfect), no delam anywhere, no core shifting, etc. Pretty darn close to perfect.
The topsheets are sublimated clear nylon from Miller Studios, over a HG blonde bamboo veneer. This clear nylon is completely crystal clear with a perfectly smooth glossy surface. I am sure it will scratch up like mad, but for now it looks incredible. The photos below do not do it justice. When light hits the bamboo grain at just the right angle, the bamboo almost becomes reflective! Very cool. The black is completely opaque, but the red is slightly translucent (as expected). I have yet to find any bubbles under the topsheet, and I've been looking hard!
As for the construction, these have bamboo cores with 6" tip spacers on each end. 20oz triax fiberglass on the top and bottom (diagonal fibers out), with a 3" wide strip of carbon uni on the top and bottom. No edge rebate cut in the core (the CF strip takes care of this).
160cm length, 125-97-113
The few things that make them not entirely perfect:
- The topsheet on the right ski shifted slightly to the right. Not a big deal, the skis just don't look exactly symmetric.
- The sidewall finish isn't very good. Suspect my sidewall router bit is getting dull. When I do my sidewalls I cut it in a conventional milling direction, I wonder if climb milling would give a better finish, especially considering a dull bit? The lighting in the photo below exaggerates it, but it's still not great in real life.
I couldn't find the SD card for my nice camera, so cell phone photos will have to do for now.
Camber profile
The graphics on the right ski shifted slightly to the right
Examples of the bamboo veneer showing through the topsheet
Shiny!
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- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
Now the one embarrassing admission...
After trimming the flashing off I was inspecting things, and noticed on the tail of one ski one edge appeared to be longer than the other, by a good 1/2cm or so. I couldn't tell if my eyes were playing tricks on me. I started trying to figure out if the base and edges could have warped that much, but then it should have looked twisted. It just didn't make sense. So I checked the other ski, and it looked the same! The tips were fine, but on the tails one edge was longer, and wrapped around the tail slightly more.
So I checked my CAD file... oops. Turns out I hadn't mirrored both sides of the ski, and in my haste I rushed it and just eye-balled it, and was way off. I drag-knived the bases on my CNC, and it did exactly what it was told to do.
A CNC machine is only as good as the crappy engineer programming it At least this doesn't effect the skis at all, and my secret is safe with you guys
After trimming the flashing off I was inspecting things, and noticed on the tail of one ski one edge appeared to be longer than the other, by a good 1/2cm or so. I couldn't tell if my eyes were playing tricks on me. I started trying to figure out if the base and edges could have warped that much, but then it should have looked twisted. It just didn't make sense. So I checked the other ski, and it looked the same! The tips were fine, but on the tails one edge was longer, and wrapped around the tail slightly more.
So I checked my CAD file... oops. Turns out I hadn't mirrored both sides of the ski, and in my haste I rushed it and just eye-balled it, and was way off. I drag-knived the bases on my CNC, and it did exactly what it was told to do.
A CNC machine is only as good as the crappy engineer programming it At least this doesn't effect the skis at all, and my secret is safe with you guys
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- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
I got greedy grinding the bases tonight... at least it won't effect how it skis, and once they're waxed it won't be as noticeable. Glad I saw it when I did, or I would have kept going! On the plus side, the bases are completely dead on flat!
You can also see the difference in edge length in this photo.
You can also see the difference in edge length in this photo.
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- Posts: 66
- Joined: Fri Jun 01, 2012 5:54 pm
HONEYCOMB!
Well, I don't know if you have any intentions to resurrect the honeycomb idea from the grave. If you are still interested though, I think I have a solution which spawned from taking a one week composites course in Winnipeg MB that is identical to an intro course given to the Boeing manufacturer facility employees. Aha, so you can indirectly thank the company you work for, should the idea work. And hopefully I did enough reading and research to ensure that I'm not reposting something that has been suggested or tried...
At our composites course we were building parts from pre-preg and honeycomb. Now we would lay down the bottom layers of pre-preg on a flat caul plate and then we would add the honeycomb core in position on the plies and apply vacuum to seat the core and compact the plies. Applying this process to your problem brings me to a solution to create a great bond and reliable epoxy seal for your honeycomb.
Take some like 10oz. biaxial and wetted it out on a flat plate, then sit your honeycomb core down on top of the wet glass and put a weight on top of the core to seat it into the glass.
(Really neato illustration that sums it up better than my wordiness)
-WEIGHT-
-HONEYCOMB-
-WET FIBERGLASS-
Let the epoxy cure, remove the weight, and repeat the process on the other side of the honeycomb. Boom, sealed honeycomb. And if you left the glass resin rich, enough epoxy would likely flow up into the root of the honeycomb's cells to create a reliable bond.
Thoughts and idea's on that? Sucks that it's a multiple step process but if that's what it took, id imagine it would be worth it.
At our composites course we were building parts from pre-preg and honeycomb. Now we would lay down the bottom layers of pre-preg on a flat caul plate and then we would add the honeycomb core in position on the plies and apply vacuum to seat the core and compact the plies. Applying this process to your problem brings me to a solution to create a great bond and reliable epoxy seal for your honeycomb.
Take some like 10oz. biaxial and wetted it out on a flat plate, then sit your honeycomb core down on top of the wet glass and put a weight on top of the core to seat it into the glass.
(Really neato illustration that sums it up better than my wordiness)
-WEIGHT-
-HONEYCOMB-
-WET FIBERGLASS-
Let the epoxy cure, remove the weight, and repeat the process on the other side of the honeycomb. Boom, sealed honeycomb. And if you left the glass resin rich, enough epoxy would likely flow up into the root of the honeycomb's cells to create a reliable bond.
Thoughts and idea's on that? Sucks that it's a multiple step process but if that's what it took, id imagine it would be worth it.