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ABS or UHMW?

Posted: Tue Sep 25, 2012 4:21 pm
by MBsnow
Just curious what type of sidewall materials people are using? I have been using ABS for years but have not been able to get solid bonding, on a 100% consistent basis. Thinking about trying UHMW, but I am not a fan of the price? Let me know what you all think. Thanks

Posted: Tue Sep 25, 2012 7:30 pm
by SHIF
How about neither of these plastic materials for sidewalls?
I gave up on UHMW a long time ago; can't get reliable bonds and it’s heavy.
I now only use Amazon rainforest hardwoods for sidewalls, specifically Ipe and Massaranduba. This wood bonds perfectly and looks great. It does not absorb moisture and so far has not delaminated in my skis.
Plus it adds to the structural stiffness of the ski core.
It is commonly used as decking boards so it’s relatively easy to source.

Cheers,
-S

Posted: Tue Sep 25, 2012 7:34 pm
by switzch
Lots of success with IPE.. No issues at all other than its tough on the blades.

That said, we are going to try UMHW this season but are considering changing the way we do things.

Posted: Tue Sep 25, 2012 8:20 pm
by Dr. Delam
SHIF, care to share where you are finding your sidewall material? I haven't found any locally yet but would like to try some ipe out. I see you are in the Wasatch. I thought you were in Cali?

Posted: Wed Sep 26, 2012 2:40 am
by falls
Do you seal the ipe/massaranduba with anything SHIF? or just leave it raw?
Is it an oily wood? No issues with epoxy?

Posted: Wed Sep 26, 2012 7:02 am
by SHIF
Dr. Delam wrote:SHIF, care to share where you are finding your sidewall material? I haven't found any locally yet but would like to try some ipe out. I see you are in the Wasatch. I thought you were in Cali?
Massaranduba purchased in San Jose, California at "The Decking Superstore" although I don't see it listed on their website anymore:
http://www.thedeckingsuperstore.com/

Ipe purchased in Pleasanton, California at “Richert Lumber”
http://www.richertlumber.com/

After 28 years in the Bay Area, enduring that long drive up to Squaw and longer drive back home, we finally got outta there. Moved to Utah this past spring, up near Park City. The mountain biking out here is amazing and you all know about the skiing. And there are plenty of excellent local microbrews out here too, douple IPA etc., not 3.2!
falls wrote:Do you seal the ipe/massaranduba with anything SHIF? or just leave it raw?
Is it an oily wood? No issues with epoxy?
It's not particularly oily wood, it bonds extremely well to my bamboo cores using regular Titebond wood glue. It also bonds very well to the other ski materials during the lay-up using epoxy. I’ve used both QCM and Resin Research epoxy with equally excellent results. So far no delaminations. In the past my UHMW sidewalls always develop cracks just above the ski edges, from the bindings aft.
Using my cantilevered router set-up I put a bevel along the top edge of the side walls, leaving a 6mm tall vertical wall above the ski edge. Then I apply a thick coat of ebony colored Minwax stain. It barely penetrates this hardwood, just enough to give a little color.
http://www.minwax.com/wood-products/sta ... ood-finish
Then when tuning the skis (Wintersteiger micro 71), the edge grinder reveals raw hardwood on the vertical face. I leave this alone and it weathers nicely, looks great.

Image

Cheers,
-S

Posted: Wed Sep 26, 2012 8:37 am
by MontuckyMadman
we did some test layups with 8mm wide ipe sidewall. the core was so stiff at 11.5mm with the ipe we would have to completely retool to get the flexes right. I doubt we could get a soft enough core with 9mm core and 22oz glass. maybe good for a skinny gs ski.
Shif you must weight 300lbs.
uhmw, consider bonding to a substrate prior to attaching to your core works very well.

Posted: Wed Sep 26, 2012 10:33 am
by SHIF
MontuckyMadman wrote:...Shif you must weight 300lbs...
MM
Close, about 230lbs :)
We like a stiffer ski than the typical rocker-powder variety. Not using 22 oz triaxial FG, we're using 19 oz. Some carbon-uni top and bottom gives them plenty of pop too. Our skis are not super stiff GS sticks, not even close, they flex more like a soft slalom ski. Plenty of edge hold on the hard pack and they float up nicely in the deep stuff. Made a couple pair thinner and softer flexing for my lighter friends to use too.

Posted: Wed Sep 26, 2012 2:43 pm
by vinman
I agree with MM, I bonded all my sidewall this year to VT grown cherry that was given to me. After trimming out he tips try to rip the sidewall away from the wood when it is down to 2-3 mm thick, the wood fails before the epoxy does.

But it sounds like you are talking more about the bond between the edge and the base layer of FG.

Posted: Wed Sep 26, 2012 3:10 pm
by More
I just got a quote back on a full sheet of UHMWPE and I died a little inside... Full width cores are the go for now it seems :)

Posted: Wed Sep 26, 2012 3:51 pm
by skidesmond
I use wood sidewalls, usually maple or ash but have used cherry too. I'd like to try ipe this year. Also might try pouring a urethane sidewall (Chrismp style) if time and $$ permits.

Shif I like the look of your stained sidewall with bare ipe. Great contrast.

Posted: Wed Sep 26, 2012 4:04 pm
by vinman
Shif, those are beautiful by the way. Great job on the edge wrap and how clean the core profile looks. How ae you doing your full edge wrap?

Posted: Wed Sep 26, 2012 4:43 pm
by MBsnow
I have not heard of IPE I might have to take a look. Shif those sidewalls look phenomenal I have been thinking about using wood sidewalls for awhile but have not given it a try yet. Not exactly sure what type of wood to try?

Posted: Wed Sep 26, 2012 6:53 pm
by falls
More - what was your quote? I was informed it is about $900 a sheet over here for 3m x 1m + shipping.
I enquired about some ABS once and was shocked - the guy then said he might have an offcut which I thought was hopeful. Turned out he did have an offcut but then wanted twice as much per square metre for the smaller piece.
Vinman - check out the link to SHIF's website on his posts. It is an untapped goldmine of great building pics/journalling.

Posted: Wed Sep 26, 2012 7:43 pm
by More
Yeah, and what good is a 3m length??!! too short to make 2 sets of skis but WAY too long for one.
3000 x 1220 x 15 UHMWPE was going to be ~960NZD plus GST (15%) and freight. at that rate it would be better for me to get ski lab ones, although I bet freight would be a pain and they aren't quite long enough for some of my plans. There's got to be a better way to buy this stuff. Whatever happened to 8'x4' sheets?

Guess I'd better look into urethane resins. Chrismp seems to get his cheap, somehow!