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  #16  
Old 11-27-2010, 02:48 PM
Coen Coen is offline
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The shear modulus of a balsa 100 kg/m3 is around 110 N/mm2. PET (Airex T92) will give you a shear modulus of 21 N/mm2.
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  #17  
Old 11-27-2010, 02:59 PM
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Herman Herman is offline
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Manufacturers. (edit: Thank you, Coen)

For moulds stifness is what counts, more than impact resistance (people working your tool with a sledgehammer should be ehhmm, eliminated).


But as I stated: All types of stiffening is better than no stiffening at all.
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Old 11-27-2010, 03:05 PM
Coen Coen is offline
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Sorry, I didn't see / forgot that it was concerning the mold. I thought it was about the hull. Sorry for that.

For the mold, go with balsa.

Cheers
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  #19  
Old 11-27-2010, 03:55 PM
War Whoop War Whoop is offline
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Quote:
Originally Posted by Coen View Post
Sorry, I didn't see / forgot that it was concerning the mold. I thought it was about the hull. Sorry for that.

For the mold, go with balsa.

Cheers
Never will use wood , but see post #9
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  #20  
Old 11-27-2010, 04:00 PM
War Whoop War Whoop is offline
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Quote:
Originally Posted by Herman View Post
Manufacturers. (edit: Thank you, Coen)

For moulds stifness is what counts, more than impact resistance (people working your tool with a sledgehammer should be ehhmm, eliminated).


But as I stated: All types of stiffening is better than no stiffening at all.
I have built a lot of first rate molds and chose to use first rate material every time,Yes balsa will work but why use a second rate core in block form of varying density.
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  #21  
Old 11-27-2010, 04:39 PM
War Whoop War Whoop is offline
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Originally Posted by Coen View Post
The shear modulus of a balsa 100 kg/m3 is around 110 N/mm2. PET (Airex T92) will give you a shear modulus of 21 N/mm2.
Point is some of the testing methods do not work on the resilient cores. Once again, when they do what you pay the big money for the test will indicate that movement as failure and mark that as a absolute value.
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