Loss of camber + softening of flex

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

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

Post Reply
camhard
Posts: 125
Joined: Tue Dec 18, 2007 4:43 pm
Location: Vancouver, BC, Canada

Loss of camber + softening of flex

Post by camhard »

I'm sure this has been addressed, but searching hasn't yielded great answers. It seems like some people are seeing an immediate difference between mould and ski, when taking them out of the press. My skis come out just fine, but after 5 or so days of hard skiing, have lost a lot of their profile. They are also losing a lot of stiffness.

Using:
Entropy Super Sap 100/1000 epoxy, no heat
Have used 22oz triaz above/below, as well as 20oz below, 20oz above + 2" wide 9oz biax carbon above
Bamboo cores
Pressing at 55psi, will need to check gap distance, but it's pretty minimal

I just picked up silicone and glass today to make heat blankets, so I'm hoping this will solve my issues??
gozaimaas
Posts: 663
Joined: Fri Feb 10, 2012 4:17 am
Location: Nagano Japan

Post by gozaimaas »

I had the same problem with 1 board. I built 5 the same using west system and no heat, everything was the same except for the ambient temperature which I did not log, 4 boards are perfect and poppy, one lost its camber in a few days and feels soggy.

IMO heat is the only variable and must be the reason for my problem
knightsofnii
Posts: 1148
Joined: Tue Jan 08, 2008 6:02 am
Location: NJ USA
Contact:

Post by knightsofnii »

you all need to get on QCM/Forrest epoxy. :)
Doug
twizzstyle
Posts: 2207
Joined: Tue Mar 07, 2006 8:25 pm
Location: Kenmore, Wa USA

Post by twizzstyle »

How long did you let them cure before skiing? How warm was it? That sounds like un-cured epoxy to me. You sure it was mixed thoroughly?

I use Entropy's CPM epoxy, with heat, and I've never had any changes after cooling, and my skis get a ton of abuse.
camhard
Posts: 125
Joined: Tue Dec 18, 2007 4:43 pm
Location: Vancouver, BC, Canada

Post by camhard »

hmmm, it might not have fully cured. i'll have to look at my log sheets to see when they were pressed, and hopefully i can figure out how long they sat before being skied. I know some of them were definitely border line, I always just figured the issue would be delam, if it weren't fully cured.

I got into Entropy years ago, because I wanted to use something different from everyone else, when QCM was pretty much THE company to use. Now I guess it doesn't really matter. I still really like Entropy as they have been great to deal with, and I can easily get their product in Canada, now that Fiberlay rebrands their stuff for sale up here.
User avatar
vinman
Posts: 1389
Joined: Fri Nov 09, 2007 4:16 pm
Location: The tin foil isle
Contact:

Post by vinman »

I can also back QCM plus heat. I just to inspect a pair I made for a friend last year. They hare just as stiff as they were on day 1 out of the press and retained their rocker/camber after heavy use/abuse for a full season.

But I have also used Entropy with heat to basically the same result.
Fighting gravity on a daily basis
www.Whiteroomcustomskis.com
User avatar
SHIF
Posts: 280
Joined: Sat Jul 14, 2007 7:43 pm
Location: Wasatch Mountains
Contact:

Post by SHIF »

I also support the QCM + heat = ski durability. I have achieved similar results using Resin Research Composites Pro epoxy system. So far skis made with RR have been just a durable and maintained their shape as those made with QCM.

I really think the key to any epoxy is post-cure heating for a long duration to ensure adequate cross-linking within the resin.

I now prefer the RR system for two reasons; water-clear color, and no Haz Mat fees for shipping the stuff.

-S
petemorgan(pmoskico)
Posts: 85
Joined: Thu Dec 22, 2011 8:41 am
Location: Tacoma, Washington, USA! USA!
Contact:

Post by petemorgan(pmoskico) »

I use the slow cure west systems, and I add a little bit of heat during pressing. i have a some 1 inch insulation sheets that i inclose the press with and then put a small space heater in there. it gets up to 100 degrees ambient temperature and i am never in a big hurry and i usually leave them in there for 48 hours.

over the years, i have not noticed any "relaxing" of camber, and i honestly expected to see some after a while because i was guessing that the wood would be the thing to relax. but i believe the epoxy and fiberglass matrix is otherworldly and really as much abuse as i try to inflict on them skiing, that matrix doesnt give a shit.


im guessing twizz is onto something.... process problems
Post Reply