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harryproa

Infusing flax

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I have been given a couple of rolls of flax cloth.  Before using them on the boat Flax_glass_infusion_4.thumb.jpg.c233e0e55b11c1d85e7dd2f94ac09c90.jpgI infused a couple of stacks of flax and fibreglass.  Same weight of cloth, but the flax was a little thicker.  The infusion filled both stacks at the same time.  After half an hour, the flax side was about 2 degrees C warmer (21C vs 19C), which climbed  to 22/24C by the end of the infusion when I put  a heat blanket over the job to cure it.  

929575979_Flaxglassinfusion3.thumb.jpg.51dba501fafb2cb86f9ad4f96c9a9f0d.jpg
Any suggestions/experience as to what caused it?

Flax glass infusion 1.jpg

Flax_glass_infusion_2.jpg

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Guessing that the difference in temperature is due to the difference in mass and specific heat of the flax vs glass.  If the amount of flax used and its specific heat are lower than the glass, the amount of heat released by the resin will raise its temperature more.   

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My guess is the flax thickness and its' greater insulation abilities would cause more heat generation[exotherm]and insulatiom[higher R value].  I applaud your efforts in using flax.

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4 hours ago, Diamond Jim said:

Guessing that the difference in temperature is due to the difference in mass and specific heat of the flax vs glass.  If the amount of flax used and its specific heat are lower than the glass, the amount of heat released by the resin will raise its temperature more.   

This is my guess too. Any greater insulation abilities of flax versus glass under normal conditions would likely be due to entrapped air, which doesn't exist in the infusion.

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It absorbs more resin than glass, the flax is thicker for the same weight so the same weight of laminate is about 50% thicker and heavier.  However, the stiffness is greater due to the thickness and stiffness is what I want as I am trying to eliminate core. Similar thickness glass would be about the same weight and much stronger.   It is nicer to use than glass and not itchy when ground.  The stuff i am using is woven, the cut edges stay together better than knitted glass and it is more stable.  

The samples are being tested by the local University, the results of this and other tests and boat building progress will be posted daily when there is something to report on the harryproa Yahoo chat group and weekly(ish) on Cargo Ferry Prototype – HARRYPROA http://harryproa.com/?p=3788

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