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falls · Post by **falls** » Sun Feb 20, 2011 12:05 am

peer pressure!

doughboyshredder · Post by **doughboyshredder** » Sun Feb 20, 2011 2:31 pm

falls wrote:That's what I figured. I have read other theories too though that leaving them in the press brings uneven cooling and therefore can have some funky effects. They do seem pretty flat out of the press.

I read in the article on here where the QCM guy answers questions - he recounts what Morrow snowboards did. They cure for 19 minutes then took the board out and put it in a camber - actually he said it better

Q5: When a ski loses camber, is it the epoxy bonds breaking down or the fiberglass reinforcements breaking that causes this?

My belief is that the epoxy in the board has still not fully cured for camber to go South. Take Morrow for example they cured for 18 minutes at 180 deg F. The epoxy is 95% cured at this stage. Partly because warm epoxy can move somewhat freely, they then put their boards into a Post-Camber press for an additional 24 hours. Mr. Camber was saved. Even with a full cure at elevated temp, like above, the epoxy is still curing for the next 7 days. 95% to 96% to 97%, etc. All Epoxy companies do their data sheets based on a 7 day 70 degree F cure – to optimize results.

When I worked in production we took the board out of the press, checked the camber, then put it in a camber table that either increased or decreased the camber, and let it cool for another 15 minutes with fans on it.

Richuk · Post by **Richuk** » Sun Feb 20, 2011 3:01 pm

Falls,

I've noticed that it takes one hour to cool from 80oC to 50oC. External temperature was 10oC. AL is 16th x 1 inch. Just in case you get tempted to pull them out hot.

MontuckyMadman · Post by **MontuckyMadman** » Sun Feb 20, 2011 3:41 pm

we pull them hot.
not right at 180F let it cool for 20 min or so full at 140F.
We let others cool overnight under pressure and see no difference.
its 95% there either way.

powderho · Post by **powderho** » Sun Feb 20, 2011 10:02 pm

MontuckyMadman wrote:we pull them hot.
not right at 180F let it cool for 20 min or so full at 140F.
We let others cool overnight under pressure and see no difference.
its 95% there either way.

Funny you mention 140F. I pressed two pairs this weekend both of them pretty much identical. The first one I only let cool for 15 minutes and it is was right at 140F when I took it out. The second pair I let cool for 2 hours until it was 90F (this is what I normally do). My press only has heat on the bottom with a zero camber mold. My skis normally come out with around 3mm of positive camber and the tips and tails fall a bit. The skis I didn't let cool in the press came out with around 2mm more camber and almost 10mm less tip rise. They still have 70mm tip rise so they will be fine. There is also around 2 inches of running length difference between the two. In a way I'm sort of glad I did this because I wanted to add a bit more flat in mold for a while now. I just don't want the camber though.

powderho · Post by **powderho** » Tue Feb 22, 2011 11:59 am

powderho wrote: In a way I'm sort of glad I did this because I wanted to add a bit more flat in mold for a while now. I just don't want the camber though.

I am longer glad I did this in any way. I didn't realized it until I took them in for tuning, but they are way concave. Easily the most edge hi skis in around 20 pair. The other pair is not any more edge hi than normal.

MontuckyMadman · Post by **MontuckyMadman** » Tue Feb 22, 2011 1:35 pm

perhaps you are heating too quickly and getting a cure on the bottom layer before the top has a chance to catch up? We dont have those probs.

vinman · Post by **vinman** » Tue Feb 22, 2011 2:00 pm

MM what is the heat recipe you guys use?

I'll be using QCM EMV043 and ECA032 with dual heat blankets.

MontuckyMadman · Post by **MontuckyMadman** » Tue Feb 22, 2011 3:17 pm

we use the heat cure super sap and we take an hour to get to temp and an hour to cook at 180F bottom heat only currently one ski at a time right now.

vinman · Post by **vinman** » Tue Feb 22, 2011 4:00 pm

So if I understand you, it seems you are cooking for 2 hrs per ski.

I'm going to cook for 1 hr at 160F or 170F depending on some testing to see if my wooden cat track and some thin nylon coated rubber matting can insulate my bladder well enough. My bladder is rated for 170F.

I'm not sure what kind of ramp up I should be using.

MontuckyMadman · Post by **MontuckyMadman** » Tue Feb 22, 2011 4:14 pm

because we heat from the bottom only we go slow so it takes 1hr to get to temp about 10 degrees every 10 min and then an hour at temp to get the top to 175, maybe a little overkill but it takes awhile to get the heat all the way through the ski.
We don't want the bottom composite to cure prior to the top or you will get radical camber changes and cupping and concavity and other problems so we go slow.

Heating top and bottom you could get to temp in 15min and cook for 20 and you would be good.

vinman · Post by **vinman** » Tue Feb 22, 2011 4:48 pm

right on that's what I needed to know.

So something like three 5 min steps of something like 55 deg to get to 170ish. then cure at 170 for 20-30 min. I'll also be curing both skis in one pressing. I think I'd leave them under pressure to cool to 120-140. Then since I'm not in a hurry to cut the flash I might just leave them in the mold with no pressure until the next day.

Thanks for the info MM.

falls · Post by **falls** » Fri Mar 04, 2011 12:39 pm

http://vimeo.com/20636312
first test run, first chair bottomless niseko pow

skidesmond · Post by **skidesmond** » Fri Mar 04, 2011 12:49 pm

Nice powder! Looks like the ski turned out nice as well.

Brazen · Post by **Brazen** » Fri Mar 04, 2011 12:51 pm

hahaha that is awesome! Have fun man

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