How to make urethane sidewalls

For discussions related to the type of materials to build skis/snowboards and where to get them.

Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp

User avatar
falls
Posts: 1458
Joined: Tue Oct 27, 2009 5:04 pm
Location: Wangaratta, Australia

Post by falls »

One thing that I find interesting is the elongation at break for the chemtura is 350% and the smooth on 305 is only about 6%.
Will await your results eagerly.
Don't wait up, I'm off to kill Summer....
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

Its still very flexible nearly 48 hours later. Looks good so far.
prospectsnow
Posts: 141
Joined: Sun May 02, 2010 8:21 pm
Location: Sacramento, Ca
Contact:

Post by prospectsnow »

I'm using task 16 plastic. They market it as their durable product. I also like a softer sidewall, it is 80A hardness.

Freezing, I don't see much change in properties.

Bonding, after toying with it, my results aren't quite as consistent as I want. I think they need to be sanded rougher and flamed more than the alternatives?

Finishing, on dark colors is hazed. Maybe a buffing wheel would help?

It also doesn't stick to hot glue, but does stick well to CA glue.
We have snowboard and kiteboard build kits!
https://prtahoe.com/collections/build-kits
troublemaker
Posts: 217
Joined: Sun Jan 22, 2012 10:03 pm
Location: The Dalles Oregon

Post by troublemaker »

I wonder if you could de-gas the air bubbles out of the polyurethane just like I do with silicone for heat mats? I put the silicone in a vacuum pot for about 10 minutes and it pulls all the air bubbles out.
Image
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

the instructions for the smooth-on I used said that if you can let it set in a pressure chamber. I assume this would remove any bubbles from the mix.
User avatar
chrismp
Posts: 1443
Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Post by chrismp »

any resin can benefit from degassing in a vacuum chamber. commercial chambers are pretty expensive though. thats why i built one out of an old pressure cooking pot and a sheet of thick acrylic as a lid.
troublemaker
Posts: 217
Joined: Sun Jan 22, 2012 10:03 pm
Location: The Dalles Oregon

Post by troublemaker »

A pressure cooker would work great! Probably get one at a garage sale or second hand store cheap.

http://www.harborfreight.com/air-tools/ ... 66839.html
User avatar
MontuckyMadman
Posts: 2395
Joined: Fri Jun 20, 2008 9:41 pm

Post by MontuckyMadman »

10 minuts would be along time with a short pot life.
sammer wrote: I'm still a tang on top guy.
prospectsnow
Posts: 141
Joined: Sun May 02, 2010 8:21 pm
Location: Sacramento, Ca
Contact:

Post by prospectsnow »

I'm passing a flame over my setup to pull out the air bubbles, it works really well.

I don't think the vac setup is the absolute fix Plus 10 min in a pot with a 6 min pot life doesn't add up. I think it is the wood surface that is causes the air bubbles.
For a wood channel, I've heard the same from other guys outside of the forum having the same problem. What if you put a coating or release film to get rid of the surface with air gaps?

Maybe even sand the channel smooth and coat with some poly?

I just did a smooth on order and am going to try a few different products. I might give the channel method a try. I'll post some results.
We have snowboard and kiteboard build kits!
https://prtahoe.com/collections/build-kits
Guest

Post by Guest »

I've thought of using a flame as well, although I have not used the urethane sidewall yet. I've used Mirror Coat epoxy for top sheet protection and the directions say to use a flame/torch to remove the air bubbles. But Mirror Coat takes a very long time to set up so you have a very long working time.
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

prospectsnow wrote:I'm passing a flame over my setup to pull out the air bubbles, it works really well.

I don't think the vac setup is the absolute fix Plus 10 min in a pot with a 6 min pot life doesn't add up. I think it is the wood surface that is causes the air bubbles.
For a wood channel, I've heard the same from other guys outside of the forum having the same problem. What if you put a coating or release film to get rid of the surface with air gaps?

Maybe even sand the channel smooth and coat with some poly?

I just did a smooth on order and am going to try a few different products. I might give the channel method a try. I'll post some results.
Mine only seemed to bubble on the top and just as the stuff was going off.
skidesmond
Posts: 2337
Joined: Tue Apr 07, 2009 3:26 pm
Location: Western Mass, USA
Contact:

Post by skidesmond »

Anonymous wrote:I've thought of using a flame as well, although I have not used the urethane sidewall yet. I've used Mirror Coat epoxy for top sheet protection and the directions say to use a flame/torch to remove the air bubbles. But Mirror Coat takes a very long time to set up so you have a very long working time.
Is Guest a new feature to Skibuildiers? I thought something was a bit strange.
prospectsnow
Posts: 141
Joined: Sun May 02, 2010 8:21 pm
Location: Sacramento, Ca
Contact:

Post by prospectsnow »

I changed up the smooth on product I use from task 16 plastic to pmc 780 dry urethane rubber. Way better bonding in our testing. The rubber has transparency compared to the plastic was opaque. These both have the same 80a duro.

I used their florescent colors for some of these too. They come out looking pretty amazing.

My testing shows that the material actually compresses a fair amount. A little concerning in the long term that this stuff might deform. I'm also thinking I can get rid of the edge step because of this as well. hmm.

What do you guys think will be the best way to get a finished look on this after cutting out with a router?

Image

Image

Image
We have snowboard and kiteboard build kits!
https://prtahoe.com/collections/build-kits
User avatar
MontuckyMadman
Posts: 2395
Joined: Fri Jun 20, 2008 9:41 pm

Post by MontuckyMadman »

I think its too soft for sidewall material.
The edge will be able to deform to much.
You are essentially removing the main purpose of a sidewall, in my opinion, and making something softer for the edge to sit on.
When you hit something hard it will allow the edge to bend and dent.
Perhaps its edge cracking you are more concerned with?
Riding metal rails and not slamming into unseen rocks?
I want a super hard sidewall to prevent edge compressions, which will affect tunability and turnability on piste.
sammer wrote: I'm still a tang on top guy.
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

I profiled my core with the smooth-on today and unfortunately there were bubbles through the urethane. It will be ok for this (my first) build but its definately not a perfect job. Perhaps if it were put in a pressure chamber like they recommend everything would be fine but that defeats the purpose IMO.
It did machine perfectly though and has an excellent bond to the core.
Post Reply