It is a coextruded nylon. Isosport 6661 I think.
Clear top layer that the graphic is subbed into and a white back layer that is roughened on the bonding surface. No epoxy ink involved.
Not sure in the end but I am starting to think that the upper glass layer was too dry and the temperature in the press was too low for a reliable cure.
Have just sanded back the top glass layer and bonded a wood veneer on. Using the heat blanket at 30C to make sure things cure ok.
Hopefully will bond ok and skis will be displayable at least or maybe rideable by me to see if they fall apart or not.
Do you guys get the topsheets printed in the US? Or in Australia ?
Nylon Bonding Failure
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
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catalystsnowboards
- Posts: 7
- Joined: Wed Apr 20, 2011 2:02 pm
Since your not backing with ink then im not much help! when backing with ink sometimes we find the ink can appear cured but its either not or the substrate could be dirty and the bond with the ink is bad. Usually this happens to us if its winter in moist cold conditions when we havnt used heating. I think its more a case of it being to cold to cure properly than anything else.
We print all our topsheets in house, we use a flatbed heat press and at the moment outsource our printing to a local company which we find is much more reliable than messing about with our own printer!
We print all our topsheets in house, we use a flatbed heat press and at the moment outsource our printing to a local company which we find is much more reliable than messing about with our own printer!
I pressed on a wood veneer topsheet. Used the same epoxy but cured at 30C with heat blanket. Seems to have bonded well. True to form however for this cursed pair on one ski the veneer split and left a gap lengthwise along the ski. It filled with epoxy and is a cosmetic fault. I will paint a pinstripe or some other graphic to hide it before varnishing.
I need to do a test pressing with heat for the nylon topsheet, but am starting to think that at the end of the day even though the room air temp was 18C the temp in the press was lower and the cure was not reliable. Even 18C is not great for curing the epoxy. The skis have now had 8 hours at 30C so hopefully this has been a good post cure for the whole laminate. Definitely not a pair to be giving to anyone though as was the original plan.
Too cold for making skis, but not cold enough to snow
I need to do a test pressing with heat for the nylon topsheet, but am starting to think that at the end of the day even though the room air temp was 18C the temp in the press was lower and the cure was not reliable. Even 18C is not great for curing the epoxy. The skis have now had 8 hours at 30C so hopefully this has been a good post cure for the whole laminate. Definitely not a pair to be giving to anyone though as was the original plan.
Too cold for making skis, but not cold enough to snow
Don't wait up, I'm off to kill Summer....
I eventually got around to making a test pressing to check nylon bonding. I cleaned the original topsheets I had trouble with. Cleaned with water only. Then pressed normal layup just with 3mm plywood core and no edges. I did skim coat the backs of the nylon topsheet with epoxy. 80C cure with sicomin ski epoxy (different to the room temp cure epoxy I had tried originally). Bonding this time around seems solid.
So end of the story is? Resin poor/too much squeeze out on the original pressing + no skim coat + poor cure of epoxy at low temperature = delamination.
On the plus side I now feel confident of using the other topsheets I have with the heat curing sicomin epoxy.
Noodle flex - 3mm plywood core !
So end of the story is? Resin poor/too much squeeze out on the original pressing + no skim coat + poor cure of epoxy at low temperature = delamination.
On the plus side I now feel confident of using the other topsheets I have with the heat curing sicomin epoxy.
Noodle flex - 3mm plywood core !
Don't wait up, I'm off to kill Summer....
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twizzstyle
- Posts: 2204
- Joined: Tue Mar 07, 2006 8:25 pm
- Location: Kenmore, Wa USA
Glad you got it figured out!Just finishing off my testing
I considered Twizz's idea, but thought some destructive testing would be better.
Lifting topsheet
Lifts with fibreglass longitudinal fibres still adherent. Nylon bonded well to glass.
Interestingly on the lower side of the core the glass comes away from the plywood easily. You can see a brown discolouration on the surface of the glass. Dust!
The plywood I got was a cheap piece that had been sitting on top of a stack for a long time. It was covered with dust on one side. All I did was bush it off before laying up because I wasn't really interested in testing the bond to the core. I think the dust caused poor bonding
You can see in the next pic on an offcut how much dust was still on the wood after just brushing it, compared to the other side (on the right) that exhibited good bonding (upper side of the core).
Bonding to the base material was good also
Even with what you think is good wetout there were occasional void areas
I considered Twizz's idea, but thought some destructive testing would be better.
Lifting topsheet
Lifts with fibreglass longitudinal fibres still adherent. Nylon bonded well to glass.
Interestingly on the lower side of the core the glass comes away from the plywood easily. You can see a brown discolouration on the surface of the glass. Dust!
The plywood I got was a cheap piece that had been sitting on top of a stack for a long time. It was covered with dust on one side. All I did was bush it off before laying up because I wasn't really interested in testing the bond to the core. I think the dust caused poor bonding
You can see in the next pic on an offcut how much dust was still on the wood after just brushing it, compared to the other side (on the right) that exhibited good bonding (upper side of the core).
Bonding to the base material was good also
Even with what you think is good wetout there were occasional void areas
Don't wait up, I'm off to kill Summer....