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Plastic ski bottoms

Dont forget there is virgin and recycled UHMW. White is Virgin, Black is recycled, white is slicker on the snow and dirt.
 
can you tell the difference from UHMW to High Density Poly Ethylene (HDPE)

I am not sure I have had both materials at hand at the same time
 
I've been meaning to try out Tivar-88 UHMW. It has a lower coefficient of friction than other brands of UHMW and is very wear resistant. We use it quite a bit in the mining industry.
 
buckchop said:
Dont forget there is virgin and recycled UHMW. White is Virgin, Black is recycled, white is slicker on the snow and dirt.
Click to expand...
Interesting- hadn’t heard that the black was not as slick. Have heard it’s more UV-resistant; the white does seem to suffer UV degradation over time…
 
The white UHMW bottoms on two sets Aero skis weathered out and cracked at the rivets. I painted the edges on my third set to slow the process.

Gary
 
You can buy “virgin” black UHMW, not recycled…better UV protection built-in…
 
I have replaced three sets of skies worth of the white UHMW. My observation of it is that it is "hard"... as in it will crack before it wears out. So yea it slides real nice on snow or gravel, appears to take wear/abuse well. I think i will try the black as it appears to be "softer" not sure if that's true or not but i recall being able to put a mark in the black with my thumbnail? So, if that's true then maybe I'll have a chance to wear the plastic out vs it cracking? Could be i was just looking at different types of plastic again just an observation.
 
It seems to me like the black Carbon fiber skis I have that also have black UHMW plastic bottoms like to freeze to the snow easier and quicker than my white LW2500s with white UHMW. Especially on a sunny day. Some winters, like this one I’ve had both types on the same plane, switching to the LWs when the valley snow is marginal. So a fairly good comparison time wise and similar snow conditions. Has anyone else noticed this?
 
My white UHMW plastic Datum skis have worn very well, (hangared) it took a Idaho rock with a sharp projection on it (that would have damaged anything short of 16 gauge sheet steel) to poke a 50 cent piece sized hole in one. On the other hand, all my snowboards for the last 15 years at least, have all had the black stuff on the bottoms.
 
My mother-in-law's brother-in-law's team (worked for Phillips Petroleum) invented UHMW production in the 1950's. Support the family and use it. Actually the best plastic I've seen was the blue colored stuff. Slick and tough as a weasel.

Gary
 
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Interesting thread that only addresses the main skis, wonder how many folks have UMHW on their tailskis?
Lots of Cubs running Aero 3000 penetration tailskis, of course they will bond down being aluminum same as the main skis do. Pita when heavy to get em broke free.
UMHW on aluminum tailskis is a great option. Here is one modified for "deep powder" conditions, heavily loaded application. It's 15" wide.
IMG_20230302_113308.jpg
 

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Big Bob puts UHWW on his tails skis. I have some on mine. I usually don't put the tail ski on as with a C-90 on the -11 one keeps the tail up most of the time to ease turns and keep in motion.

UHMW will definitely get brittle if left out in the sun for an extended period, though.
 
Left in the sun? You park with the ski bottoms up? ;)

I've used lots of plastics on skis. HDPE is very tough. UHMW is more slippery. White lasts the longest. I'd bet that lots of guys who think they bought UHMW actually have HDPE. For most guys it wouldn't matter. For snowgo freight sleds where my runners may see dirt and rocks? No reason to spend more for UHMW. In fact I believe HDPE has a tougher surface, but neither is up to running on gravel. For my Trickair skis? Ground clearance is so low hitting gravel is inevitable. UHMW would be expensive for expensive's sake. The plastic is sacrificial.

Black hasn't served me well at all. It abrades on snow and ice and grows and shrinks with heat changes.
 
Those that like to extend the ski bottoms beyond the edges can eventually have them crack. It takes a few years and sun exposure, but I had that happen on three sets. They crack to the rivets or hardware that holds them on, then eventually across the ski's bottom. They're a wear item so replacement is expected.

Gary
 
I have a lot of time on the freight sleds and building them, I have used the red/blue HDPE with great results. My favorite though is the black umhw, does not crack until -40, and still wear resistant and slippery. The HDPE seemed "harder" like the white umhw, and was also very slick. For extended edges on skis we tried the white and it cracked a lot when it was very cold, went to the black and no issues now. For skis kept in a hangar or out of the sun, any of it will work great. Also of note, the black umhw is softer is seems but it would deform when drug over gravel, whereas the hdpe would just cut. Still both were very slippery even when scratched completely up. Some dress up and that takes care of that.
 
JP,
The 11 is a fantastic skiplane lite, and my 18 has a very lite tail, and comes up instantly lite. But my hunting n fishing pardner, weighes 275 lbs. With him in back seat and full tanks, survival gear, bait, ice augers, pack baskets,
(Yukon Jack) and all the other trash we lug around. Not running a tailski ( With UHMW) in 2' of spring snow is just NOT an option for us! With him aboard till the tail comes up, the tailwheel is alot like a Danforth �� anchor! Lol.
E
 
I know one pilot I respect has removed plastic from his hydraulic skis and opted for an applied anti-friction coating. He raves about it. I have a couple of log skidder-type freight sleds with steel skis I’m going to try it on. I had a chance to buy some old Fernandez skis that it would be perfect for. If you use plastic for slipperiness and not wear? A coating may be a better, and certainly lighter weight solution.

https://wetlander.com/
 
Over the decades, there have been "coatings" which were promoted as being slick and tough. I've seen these (and had to remove them) from a set of floats and a couple sets of skis. The problem with coatings is that they can invite and hide corrosion underneath the coatings. As I noted, I bought a set of floats on which the bottoms had been coated with some nasty, very hard black coating, the former owner apparently thinking that the stuff would make the floats slide better in water. Back then, this black stuff seemed to be all the rage in Alaska, because I subsequently ran into the stuff on the bottoms of two sets of skis.

I worked really hard with lots of very toxic liquids to try to remove the coating from the bottom of the floats, only to find ultimately, that corrosion had nearly destroyed the metal under that coating. So, I then replaced the bottom skins.

With skis, the risk of corrosion is certainly lower, but there are other functions that the plastic affords in that realm that a coating doesn't. High on that list is protection of the ski structure itself from rock damage, which is very common in skis. The UHMW bottoms absorb all that punishment, and are relatively easy to replace. Replacing plastic bottoms is a lot easier and less expensive than replacing ski bottoms.

As noted earlier in this thread, the plastic bottom coverings on skis is a sacrificial material, intended not just for better performance, but to protect those ski bottoms.

MTV
 
Back in the 1970's there was a product commonly called Concresive (this?)>(https://rlrowan.com/products/concresive-paste-spl/ or maybe https://www.bestmaterials.com/PDF_Files/135_tdg.pdf) was applied to ski bottoms. It was a black slick covering that I assume was thinned with solvents for easy application and self smoothing. Landes skis primarily had the application, but I saw metal bottom Atlee Dodge and Northland Aviation made of wood use it. That was before Landes started using plastics (yellow for example) as an anti-wear substrate.

Gary
 
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