Bayport_Bob wrote:
Baixial with stiched matt would not be recommended. It would create bulk, but at the expensive of lots of extra weight. The mat portion will soak up resin lke a sponge.
There are basically two standard stiched biaxial fabrcis available... E-glass (6 oz, 9 oz, 12 oz, etc.) or Kevlar (but I don't see anyone stocking it anymore).
There is a huge shortage of performance fabrics at this time. The major aircraft manufacturers and the military has put a huge crimp in the carbon & kevlar markets. Prices for many carbon weaves has doubled in the last 6 months. Kevlar isn't as bad, but availability is very spotty. If you plan on building in the next 6 mo. to year you will be paying a premium and you may have to wait to get your orders filled.
A & P technology does make a biaxial carbon 9 oz fabric, but they may require a minimum order size (way beyond what a typical canoe would need).
Thank you for adding to the thread
I have been searching for a biaxial S-Glass without success. The book calls for use of "5.6 oz S-Glass three times the length of the canoe + 6 feet". The Kevlar called for is 8.9 oz the length of the canoe + 2 yards. He states that using a more heavy cloth will results in air bubbles in the laminate. (that is not a quote, just a paraphrase)
I have been trying to stay as close to those weights. As I have stated most venders just call it biaxial fabric (I have seen the term biaxial Knytex). Being my first attempt at building a boat I am trying to stay close to the technique and materials suggested in the book. I thought that even using the hybrid Kevlar/Carbon Twill was getting of the beaten path just a bit. Now I have this discussion of biaxial fabrics. Smell the smoking neurons now.
VectorPly has a cloth which is Aramid/eglass/carbon (+45,90,-45) of which they state:
"
Total weight refers to reinforcement material only.
Stitching weight ranges from 0.15 - 0.97 oz/sq.yd. (approximately 2% of total weight) based on the stitch density. Stitch weight for multi pass infusion specific reinforcements ranges from 1.0 - 2.0 oz/sq.yd"
I must confess I do not understand this statement nor have I any idea of the cost.
This is without a mat (I did not really want a matted cloth just for the extra weight)
As it stands I am thinking about building a boat like this:
Version 1
1) Hybrid inner layer bow to stern (
a deviation from the book, not 8.9 oz Kevlar and 5.5 oz)
2) Hybrid football layer at a 45 diagonal (port to starboard) to the inner layer. (
a deviation from the book, and extra layer)
3) 5.6 oz S-Glass bow to stern on each side overlapping on the keel.
4) 5.6 oz bow to stern over the keel covering the side S-Glass cloths
Version 2
The changes I would like with similar weights:
1) Stays the same
2) Hybrid +/- 45 (like the VectorPly fabric without the e-glass) football layer (bow to stern)
3) Biaxial 0 / 90 S-Glass bow to stern on each side overlapping on the keel.
4) A biaxial +/- 45 S-Glass bow to stern over the keel covering the side 0 / 90 biaxial cloths
I can not find the fabrics for the 2nd version for steps 2,3,4
Komatiq’s point is take about inner layer of 45/45 and outer layer of 0/90, however I like the idea put forth in the book about overlapping the thee layers of s-glass on the bottom of the boat and I am trying to keep the weight down.
If I am unable to find the fabrics needed for version 2 of the canoe I think I would guess that even version 1 would be stronger (however not as light because of the extra layer of hybrid) than the materials called for in the book. Those being:
1) 8.9 oz Kevlar bow to stern (no detail given on weave)
2) 5.6 oz S-Glass bow to stern on each side overlapping on the bottom (no detail on weave)
3) 5.6 oz S-Glass bow to Stern the bottom (football) over side S-Glass(no detail on weave)
If anyone knows where I can find the fabrics for version 2 it would be a great help.