hi folks,
do your tips come out the same height/bend radius as the mold when using full woodcore, just some sidewalltype spacer for protection?
my snowboards tips lose about 15-20mm (1/2'' - 3/4'') height compared to the mould... GRRRRRR..... full wood core 2mm in the tips,, heat top and bottom, 80°C/175°F, 6bar/85psi, shut down heat after 1hr, let it cool down under pressure over night.
first i thought the cattrack might not bend in/press the flat layup properly down the curve, but i checked the distances next time and it seemed ok. also the partial cambers (3mm) under the feet came out spot on, whereas the total mould rocker (6mm/ 1/4'') came out about flat, i would think the latter due to the wood tips pulling it down?.. i do not want to overengineer the tip curves, would be quite inconsistent in results i guess.
any ideas anyone? couldnt really find any post regarding this?
cheers
relaxing tips less curvature than mould
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relaxing tips less curvature than mould
- skiers, come to the dark side, we have girls and beer -
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MontuckyMadman
- Posts: 2395
- Joined: Fri Jun 20, 2008 9:41 pm
cheers.
mm,
i remember a post where you said you let cool dwn under pressure over night and had warped results, so you are now pulling out hot? what temp, after how much time? what differences did you notice? do you put your skis in a stressing rack like doughboy to get the right camber/curvature etc??
brazen,
actually i did some tests to try different bases & different topsheets with a scrap core (the ones where my cnc f*#%d up the sidewalls
) cut in quarters. same layup without edges, used a flat mould in the centre, same tip blocks, with the exact same result at the tips. centre came out flat spot on. so i suppose the partial cambers did not have any noticable influence on the tips.
mm,
i remember a post where you said you let cool dwn under pressure over night and had warped results, so you are now pulling out hot? what temp, after how much time? what differences did you notice? do you put your skis in a stressing rack like doughboy to get the right camber/curvature etc??
brazen,
actually i did some tests to try different bases & different topsheets with a scrap core (the ones where my cnc f*#%d up the sidewalls
) cut in quarters. same layup without edges, used a flat mould in the centre, same tip blocks, with the exact same result at the tips. centre came out flat spot on. so i suppose the partial cambers did not have any noticable influence on the tips.- skiers, come to the dark side, we have girls and beer -
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MontuckyMadman
- Posts: 2395
- Joined: Fri Jun 20, 2008 9:41 pm
theres multiple problems created when allowing the lam to cool under pressure. Inconsistent results is the main one.
I think you have allot of different factors with relation to your "tip fall" problem.
You you prebend the base with edge attached?
Are you cooking long enough for your resin system?
Are you using enough longitudinal fibers to hold that orientation.
Are you pressing with enough pressure at the actual laminate? Not just the pressure in the bladder.
Unfortunately without super fancy analysis, trial and error is where you land.
Temperature and ramp speed and the difference between top and bottom temps can also dramatically affect rise and camber.
Perhaps your pressure in the tip and tail is weak and not pressing it all down enough.
Try and square core with tip and tail plastic and see what you get?
I think you have allot of different factors with relation to your "tip fall" problem.
You you prebend the base with edge attached?
Are you cooking long enough for your resin system?
Are you using enough longitudinal fibers to hold that orientation.
Are you pressing with enough pressure at the actual laminate? Not just the pressure in the bladder.
Unfortunately without super fancy analysis, trial and error is where you land.
Temperature and ramp speed and the difference between top and bottom temps can also dramatically affect rise and camber.
Perhaps your pressure in the tip and tail is weak and not pressing it all down enough.
Try and square core with tip and tail plastic and see what you get?
sammer wrote: I'm still a tang on top guy.
mm, thanks for your thoughts.
so what diferences did you notice when pulling hozt?
no i do not prebend edges, but considering that my tests without edges turned out the same, i would say they are not the issue. also, you do not need much force to bend a base with attached edges into the mould compared to the core, so that can hardly be the problem right?
yes i cook according to resin spec sheet, actually a little longer when taking cooling down into account..
triax 800grams/28oz makes the board not on the soft side, would need to look up how much fibre in the 0 direction, i think it was ca 280g/10oz.
i have one very wide bladder, which is nearly the same width as the cattrack/board when inflated, so nearly no losses.
i preheat to 40°C/104°F then ramp up to 80° /176°F in ca 5minutes, tried different temperatures along and between top and bottom, differences were minimal, even with a delta T of 40° C.
hmm reagrding the pressure in the tip and tail i'll triple chack that one again.
yes maybe a tip fill test might be interesting.
so what diferences did you notice when pulling hozt?
no i do not prebend edges, but considering that my tests without edges turned out the same, i would say they are not the issue. also, you do not need much force to bend a base with attached edges into the mould compared to the core, so that can hardly be the problem right?
yes i cook according to resin spec sheet, actually a little longer when taking cooling down into account..
triax 800grams/28oz makes the board not on the soft side, would need to look up how much fibre in the 0 direction, i think it was ca 280g/10oz.
i have one very wide bladder, which is nearly the same width as the cattrack/board when inflated, so nearly no losses.
i preheat to 40°C/104°F then ramp up to 80° /176°F in ca 5minutes, tried different temperatures along and between top and bottom, differences were minimal, even with a delta T of 40° C.
hmm reagrding the pressure in the tip and tail i'll triple chack that one again.
yes maybe a tip fill test might be interesting.
- skiers, come to the dark side, we have girls and beer -
Went back and re-read your post. The full wood tip is likely too strong for your glass and is flattening. Try some plastic in the tip and maybe thin the tip out a little.
I pull my skis hot after cooling to 140 deg and place them on their sides so gravity can't effect the camber. Allow them to cool to room temp then cut them out.
I pull my skis hot after cooling to 140 deg and place them on their sides so gravity can't effect the camber. Allow them to cool to room temp then cut them out.
Fighting gravity on a daily basis
www.Whiteroomcustomskis.com
www.Whiteroomcustomskis.com
so that means that the industry are all overengineering? most videos i saw had flat layup!?
regarding thickness/fibre weight, pop/stiffness is about right so making the tips thinner (or the taper from end of effective edge to tip shorter )is not an real option unless using carbon , also because my tip protection spacers are 2mm standard..unles i thin them out to 1.5mm .. not using full woodcore is not really an option neither due to various reasons. i might do a test anyway...also a little bit of tension is desirable in my opinion to reduce vibrations in the tips...hmmm..
regarding thickness/fibre weight, pop/stiffness is about right so making the tips thinner (or the taper from end of effective edge to tip shorter )is not an real option unless using carbon , also because my tip protection spacers are 2mm standard..unles i thin them out to 1.5mm .. not using full woodcore is not really an option neither due to various reasons. i might do a test anyway...also a little bit of tension is desirable in my opinion to reduce vibrations in the tips...hmmm..
- skiers, come to the dark side, we have girls and beer -
off topic, but...........http://www.sisco-sports.com/factory/presses.html
someone seen this? bloody hell, just a couple of presses. think i'll have a wet dream about this next night;)
someone seen this? bloody hell, just a couple of presses. think i'll have a wet dream about this next night;)
- skiers, come to the dark side, we have girls and beer -
changes with temperature
hi everyone,
i pretty much solved the losses by overengineering. using wooden topsheets also helped, depending on the veneer type they make the board's top laminate quite a bit stiffer.
one thing i still experience is changes in tip height and overall rocker depending on temperature of the board, i do not mean the curing heat, but if i leave a finished board in the house overnight it will have a couple more mm of rocker and up to 10mm more tip height than when measuring it being cold from staying outside.
obviously different temp. elongations of the edges and laminate will make some difference, but then with most industry boards i could not see any or only small differences?? of course i use vds.
any ideas?
cheers
i pretty much solved the losses by overengineering. using wooden topsheets also helped, depending on the veneer type they make the board's top laminate quite a bit stiffer.
one thing i still experience is changes in tip height and overall rocker depending on temperature of the board, i do not mean the curing heat, but if i leave a finished board in the house overnight it will have a couple more mm of rocker and up to 10mm more tip height than when measuring it being cold from staying outside.
obviously different temp. elongations of the edges and laminate will make some difference, but then with most industry boards i could not see any or only small differences?? of course i use vds.
any ideas?
cheers
- skiers, come to the dark side, we have girls and beer -