Problem with Entropy SS CPM

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prospectsnow
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Problem with Entropy SS CPM

Post by prospectsnow »

Hey guys, thought I would share.
I've been using Entropy for a bit now and have gone through about 15 gallons worth and it has worked great so don't think there it can't be used.

I was working a custom board project that had a tight radius on the tip and tail meaning short distance steep pitch like what you might see on a alpine carving board. It was a struggle just to get the tips to make good contact because a press presses down well, but not sideways if that makes sense.

Anyway, after pulling the boards out they all were coming out delaminated in a 1ish cm radius around most of the tip. And of all places it didn't lay up was between the bonding strip and edge. The bonding strip should stick to just about anything. It is hard not to freak out the first time let alone the 5th. Plenty of F bombs.

I did some test layups to make sure i was getting pressure uniformly in the tip tips and it came out flawless. I added more bonding strip, made sure there wasn't any foreign goo on the tips, added extra epoxy, put epoxy directly on the tip fill, gave it extra sanding, extra flaming, extra time it the press, extra luv, all of it, no luck, still delammed. FML moment.

I did some more research on here and didn't see anything, and was about fed up. I made some calls and found the answer that worked, although I'd like to leave this open for discussion as well.

It turns out that Entropy takes too long to set up. As we know when epoxy hits heat it thins out. This caused the epoxy to seep out of the tips and left it too dry to keep the lamination together.

The fix, I had some huntsman samples around. The 557/5049 combo. It sets up faster. The next pair of skis came out like a champ. The alternative I was told was to do a dipping heat schedule hot/cool/hot with entropy, which I wasn't able to try.

I still like entropy and is awesome to have some less funky resin around. Hope this helps someone diagnose problems down the road. Anyone have anything to add?

Oh, by the way, to get better pressure check out the 2nd bladder I added to get the layup tight.

Image
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twizzstyle
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Post by twizzstyle »

How hot were your curing the entropy at, and for how long?

What is a "bonding strip"? VDS?
prospectsnow
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Post by prospectsnow »

I'm pressing at 180F for 30 mins. tested up to 60min.
Yes, VDS is what I called bonding strips.
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Jekul
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Post by Jekul »

I've done a couple pair of skis with a really tight bend radius like that. I ruined a pair of sticks by not having enough pressuring in the tip, and I ended up doing something similar to you; using an additional filler piece in the tip.

They turned out great and I'm still using them (wife skied them today). I've gone to a much larger radius since, but at the time I was using QCM and didn't have any problems (did 3-4 pair with that sharp radius).

Sorry it's not much of a help, just confirmation of your method and an alternative epoxy resin that has worked for tight bend radius tips.
prospectsnow
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Post by prospectsnow »

Right on,
Extra fire hose and paint sticks made some good filler to close the radius.
To add, having protective tape over the topsheet gives a nice pressure indicator.
To add to pressure testing we have a rider that comes down to the shop that is a phd and does composite failure testing. He gave me this link to a pressure testing system. Looks pretty sophisticated, but it would be a great tool.
http://www.pressurex.com/
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threeninethree
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Post by threeninethree »

you could also take some pieces of the cat track out, so that it only is the length of your cassette.
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PTTR
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Post by PTTR »

I've had the same problem with entropy.
The alternative I was told was to do a dipping heat schedule hot/cool/hot with entropy, which I wasn't able to try.
Do you know how fast and to what temperatures?
rockaukum
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Post by rockaukum »

Reduce the width of the cat track in the contour areas. Same height, just narrower to allow for the bend to be accomplished. If this does not make sense, let me know and I'll get a pic to you.
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Brazen
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Post by Brazen »

Supposedly they have a new and faster hardener, might want to try it. At 180 for 15 minutes is quicker production time and would have probably nipped that problem right away. I would have hated to be you! Just UGH! Happy New Year BTW!
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ProbsMagobs
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Post by ProbsMagobs »

anybody have any ideas about how well this stuff cures at room temp? ill have it heated in hot water to mix first but just curious about some less pricey epoxy
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Brazen
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Post by Brazen »

It doesn't "cure" at room temp.
"86% of the time it works 100% of the time".
ProbsMagobs
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Post by ProbsMagobs »

ok thanks. getting a heat blanket is an expensive eventuality for everyone i guess
amidnightproject
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Post by amidnightproject »

What pressure are you pressing at? Also, after you put your board in how long does it take for your blankets to get up to temp?

It also looks like you have a gap where the tip is in your photo. It looks like the cat track is actually pushed up and away from the mold.

It takes me about 25 minutes to layup a pair of skis (and I'm using cpm also). The working time with this stuff is about 40 minutes. It takes about 18 minutes for my press to get to temp again after I have put the skis in. I also do some pretty tight tip radius and don't have any problems. Pressing at 80psi and 180F for 40 minutes.
prospectsnow
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Post by prospectsnow »

I've since done some upgrades and tweaks to try and get this to lay up a bit better. A lot of effort has gone into even pressure and good contact in the tips.

When the cassette gets pressed my temp goes down to 65c and is back up to 82 inside of a minute or 2.

I've pressed anywhere from 30 to 80 psi

tried jelled epoxy from the previous layup thinning it might not run, it did

doused the ends in extra goo

sanded, rubbed mek and rubbing acl, flamed

added the second bladder for better tip pressure and tried pressure variations between the 2

added shiims over and under the cassette to fill in any possible gaps.

The one thing that DID work is using huntsman resin. When I pull it, the laminate is perfect. Here the current setup.

I am pretty stoked on the second bladder. It opens up the cavity a lot more and it helps the track fit into tight corners

https://docs.google.com/file/d/0B0MF1yy ... sp=sharing

https://docs.google.com/file/d/0B0MF1yy ... sp=sharing
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MontuckyMadman
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Post by MontuckyMadman »

very weird.
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