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Posted: Fri Jun 10, 2011 11:24 am
by twizzstyle
sweaterskier wrote:what is a better way of learning than being tested on what you are learning about. I say bring it on.
1) Describe how uneven or asymmetric heating can cause changes in camber. If you heat only from the top, will camber increase or decrease after curing/cooling?
2) Describe how an asymmetric layup (different number of layers or orientation of layers top and bottom) can cause changes in camber.
3) When vacuum bagging, how much pressure is exerted on the laminate?
4) Describe how to get a good bond between a wood core and UHMWPE sidewalls. (no seriously, I still need to figure this out
)
Posted: Fri Jun 10, 2011 1:07 pm
by sweaterskier
Just going to guess from what i have gather so far.
1. un-even heating will cause the top half to dry faster, and it will cause the camber to raise up further more after it cools.
2. some of the wood might mold different than the other which would cause the camber not to match up.
3. 40psi?
4. wood sidewalls.
Posted: Fri Jun 10, 2011 1:51 pm
by twizzstyle
sweaterskier wrote:Just going to guess from what i have gather so far.
1. un-even heating will cause the top half to dry faster, and it will cause the camber to raise up further more after it cools.
2. some of the wood might mold different than the other which would cause the camber not to match up.
3. 40psi?
4. wood sidewalls.
Nice work
You got #1 right, except nothing is "drying" it is "curing". Solvent-based things dry, epoxy cures. Two different processes!
For #2 I was really referring to the composite layers. Having different layers top and bottom will cause different tensile forces after cooling, and camber can/will change.
#3 = ~14.5psi (atmospheric pressure)
#4.... Dang it!
Posted: Fri Jun 10, 2011 4:25 pm
by sweaterskier
1.good to know that curing and drying are different.
2. You mean using different glass for top and bottom? I never even thought anyone would do that. maybe with carbon fiber on top of the core but thats it.
3. ok, but say for a Pneumatic press 40 to 60 psi is the norm .. right? still learning the presses.
4.
Posted: Fri Jun 10, 2011 4:32 pm
by MontuckyMadman
Wait, heat top only will reduce camber in increase rocker. Heat bottom only will increase camber decrease tip rise/rocker.
THis I am positive of.
Put the plastic sidewalls sandwich in between wood sidewalls. profile, press and cut flash.
Check the Folsom vid on the cnc.
Posted: Fri Jun 10, 2011 6:15 pm
by Brazen
^ what he said. For sure.
Posted: Sat Jun 11, 2011 1:16 pm
by sweaterskier
MontuckyMadman wrote:Wait, heat top only will reduce camber in increase rocker. Heat bottom only will increase camber decrease tip rise/rocker.
THis I am positive of.
Put the plastic sidewalls sandwich in between wood sidewalls. profile, press and cut flash.
Check the Folsom vid on the cnc.
what if u use no heat at all?
and where is this vid?
Posted: Sat Jun 11, 2011 1:26 pm
by twizzstyle
No heat at all should cause no changes in camber since the curing temp is consistent. Just make sure you are using an epoxy that is a room temp cure epoxy
Posted: Sat Jun 11, 2011 2:02 pm
by Brazen
so, here...in Google. Type in your search word Heat Cure space site:skibuilders.com
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