The pouring urethane sidewall thread

For discussions related to ski/snowboard construction/design methods and techniques.

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

User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

No probs,

will put some in a freezer again...Results tomorrow.
User avatar
chrismp
Posts: 1443
Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Post by chrismp »

Just FYI, I hit samples of the Adiprene with a sledgehammer after leaving it in a freezer at -25 C over night and it didn't take any damage whatsoever.
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

I think sample size is important here guys.
How thick and how wide are the samples?
User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

The other parameters are equally important, hammer weight, distance etc.

As said "1/4" wide (my router bit) by 5-6mm high" for a pre cured rails.

This one is not pre made, so poured and cured, no pressure, etc, and is 4mm thick, glued 2 peaces with epoxy.


Image

The hammer weight is 1190g, I hit the sample from about 15cm with the hammer edge:

Image

Then hit it from about 30-40cm with a hammer head:

Image

Repeated the above after the sample was on the Sun for about 20min:


Image

Image

I recon the above does not mean much since not done in a lab...

The sample is also quite thin, not sure if you guys are making the same.

But this is interesting, when I bend it, it does not break! Not frozen sample breaks. Hm...Might try this again.


Image
User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

More tests.

Pre cured PU on 50psi, in a freezer for 12h, sample size 6.12x7.4mm:

Hammer edge from 10-15cm:


Image

Image

Bent sample, clear break (no visible air bubbles:):

Image

Bent sample not frozen - at this angle the frozen part snapped:

Image

Hope this helps...
User avatar
chrismp
Posts: 1443
Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Post by chrismp »

If I recall correctly I hit the sample (about 12x10x200 mm) with a 2500 g hammer that was dropped onto the sample from about 1 m. The sample showed no signs of damage. It also doesn't snap when frozen no matter how much you bend it...but I guess most of these properties can be accounted to the softness of the material at 95 shore A compared to the 70 shore D of the Smooth-cast 310.
User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

True.

For me it's abut the cost as well. One "trail" PU package ~1kg about AU$30.
And quite easy to work with since it's like water. PMC790 is like honey, for me, not easy to pour at all.
User avatar
chrismp
Posts: 1443
Joined: Fri Feb 13, 2009 9:00 am
Location: Vienna, Austria

Post by chrismp »

The Adiprene is like honey as well. I always heat the resin part in the microwave prior to degassing it to make it more liquid which helps with evacuating the air. Then I add the hardener and degas once more before pouring. With low workshop temperatures the resin starts to thicken again before pouring, so I pour honey most of the time as well. Mind you, the resin is supposed to be kept at about 60°C for the whole process, so in an ideal environment it would be more watery.

Problem with the Adiprene resin is that it needs to be sealed from oxygen pretty well, so always make sure to top up the container with some heavy gas (we use a propane/butane blow torch and just hold it into the container). If you don't do this the top layer will solidify and cannot be brought back to a liquid state by heating. In general the Adiprene resin part needs to be stored at quite warm temps (around 30°C) in order to stay liquid.
User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

I'll have some Smooth On PMC 790 samples soon as well. Pre casted on 60psi.
If someone is interested...
User avatar
backyardskier
Posts: 139
Joined: Sat Nov 05, 2011 10:26 am

Post by backyardskier »

dbabicwa wrote:I'll have some Smooth On PMC 790 samples soon as well. Pre casted on 60psi.
If someone is interested...
How did the test turn out?
User avatar
dbabicwa
Posts: 133
Joined: Tue Aug 28, 2012 5:16 pm
Location: Perth, Australia
Contact:

Post by dbabicwa »

The PU PMC 790 test, same size, cured on 50psi, same dimensions.

Hammer test, no visible break:

Image

The finger nail imprint:


Image

Bend test from a freezer after 2 hrs:


Image

No visible air bubbles, some marks duno what that is, almost transparent:


Image

Hope this helps to someone.
User avatar
backyardskier
Posts: 139
Joined: Sat Nov 05, 2011 10:26 am

Post by backyardskier »

dbabicwa wrote: Hope this helps to someone.
Stuff looks pretty tough, big thanks!
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

Yet soft.
User avatar
MontuckyMadman
Posts: 2395
Joined: Fri Jun 20, 2008 9:41 pm

Post by MontuckyMadman »

90 shore A should be harder than that.
sammer wrote: I'm still a tang on top guy.
gav wa
Posts: 381
Joined: Tue Feb 18, 2014 8:58 pm
Location: Perth

Post by gav wa »

Hi everybody, I'm a new member. Love the site.
Just wanted to ask dbabicwa, where do you buy your smooth on products?
I'm also in Perth WA and just paid $55 off ebay.

I'll be testing my pressure chamber soon and will post some results. I made mine a little different in that it is just made of timber but the side height is only 20mm to minimize the load along the edge and I then have it in my press with my layflat hoses and cat track all assembled on top. It all builds pressure at the same rate so the chamber is equal pressure inside and out. The sides are the only part that can possibly fail but these are 40mm thick and well bolted.
Hopefully testing it next week so we'll see how I go :?
Post Reply