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David Geiss
11-30-2011, 09:42 AM
http://greenlightsurfsupply.com/naturalbambooglassingfabricpackagesurfboards9-11.aspx

I (http://greenlightsurfsupply.com/naturalbambooglassingfabricpackagesurfboards9-11.aspx) searched prior threads and did not find anything on this bamboo alternative to glass or xynole cloth.
I emailed seeking a small sample and any product spec sheet.

I am considering various fabrics for sheathing the outer hull of a small 10' ama for a sail canoe that I need to finish this winter.

Has anyone out there had any experiences, good or bad,with bamboo cloth as an epoxy resin infused sheathing. Seems that it could be most popular with surfboard makers.
:D
Thanks in advance.

Hal Forsen
11-30-2011, 10:32 AM
I suspect you will get more responses on Swaylock's Surfboard Forum.

http://www2.swaylocks.com/forum/general-discussion (http://www2.swaylocks.com/forum/general-discussion)

David Geiss
11-30-2011, 10:57 AM
Thanks Hal! With our erudite group still hopeful that someone has tried it on a small craft.....
Best,
D

David G
11-30-2011, 11:58 AM
I'd be curious as to what you find out - esp. if anyone has done any testing comparing the bamboo cloth in epoxy resin to fiberglass in epoxy.

Gib Etheridge
11-30-2011, 12:02 PM
Traditional bowyers sometimes use linen threads bedded in hide glue to back their bows. I once saw a knife handle that was shaped from blue denim vacuum bagged in epoxy. Just think of the colors/patterns available! Not muc, if any help, I know, just thought I'd say.

David Geiss
11-30-2011, 01:37 PM
Well I'm learning that Xynole is just a re-badged polyester fabric so the whole topic of how various cloths work when impregnated with epoxy resin is pretty interesting. Have not head back from Greenlight (link in OP) concerning a sample......

Nicholas Carey
11-30-2011, 05:48 PM
Bamboo fiber has a pretty high tensile strength, some claims say that it has a tensile strength comparable to mild steel. I'm not sure I buy that. But, googling shows claims as high as 23,000 psi per square inch. I found a Powerpoint deck from a USC engineering student who actually did some destructive testing against bamboo samples:

http://www-classes.usc.edu/engr/ce/334/2002_10.ppt

His tests show tensile strengths in the 11k-15k PSI per square inch.

Not sure how that might translate into knit cloth made from bamboo fibers, though.

One thing to note, though: like cotton or other spun cloth, bamboo cloth is likely to require far more epoxy than fiberglass cloth for saturation.

WX
11-30-2011, 05:54 PM
As long as the fibre ends are sealed I can not see a problem with it. I am also curious about any info you find.

David Geiss
11-30-2011, 06:35 PM
Spoke earlier today from Mike@ Grain's Surfboards in Maine http://www.grainsurfboards.com/
He was very enthusiastic about bamboo cloth.
Less prone to dinging as compared to boards finished with glass cloth.
Indicated however that it does not finish quite as pure transparent as sheathing with glass cloth......just ever so milky.
Maybe for those intending to finish with paint, it's a non issue.
Also he turned me on to another source of the bamboo fabric here in NJ:
http://www.bamboofabricstore.com/

Some experimentation in order....

seedy
11-30-2011, 11:18 PM
Wonder if a version could be used with skin-on-frame construction. Either way, veddy in-teresting.

David Geiss
12-01-2011, 07:16 AM
I was wondering that as well.....if the bamboo cloth can be impregnated with epoxy resin I imagine it will take paint as well.
I am very happy with the polyester fabric and exterior grade latex I used on my SOF. That bamboo cloth store is close enough to me to buy some samples and have at it with some paint.........

P.I. Stazzer-Newt
12-01-2011, 04:49 PM
[QUOTE=Nicholas Carey;3216294.....
Not sure how that might translate into knit cloth made from bamboo fibers, though.
......[/QUOTE]

KNIT!!!

I've seen that done for crash helmets - but never for sheathing.

Bamboo is horrible to hand spin - requires careful lubrication. There may, or may not, be a lubricant residue in any commercially spun and woven cloth - be especially wary if buying undyed.

David Geiss
12-01-2011, 05:02 PM
I have arranged for a sample of Entropy Resins Super Sap 100/100 product, 2 to 1 ratio...they utilize a proprietary formula involving approx 50% bio content (pine sap apparently and by products of pulp mills) with significantly reduced VOC. WIth it, I plan to make some samples using sapele ply as substrate, identical resin/hardener and 3 different cloths....glass, polypro (Xynole) and bamboo cloth...should be interesting.....

http://www.entropyresins.com/

Best,
David

BrianM
12-01-2011, 05:12 PM
Ask for a sample and do your own comparitive testing. All you need to do is cut the material into samples of the same width and length and along the same weave of the cloth.

Clamp one end on something stout, then start hanging weights on the other end and keep track of how much you've piled on.

You can do the same with an awl or other piercing object to see how well it will protect whatever you glue it to.

David G
12-01-2011, 05:20 PM
David,

If you're going to do some testing... which I applaud... I'd say minimize the variables as much as possible.

That is - I'd test some bamboo cloth with a standard epoxy (West System, System3, RAKA, etc.). Then, I'd do the same tests using this new 'green' resin you've discovered. But doing the testing with both and experimental cloth and an experimental resin is likely to leave you up in the air as to what performance to ascribe to which factor.

Todd Bradshaw
12-01-2011, 07:03 PM
Xynole is polyester, not polypropylene (there is a fairly major difference). Considering the already vast differences in tensile strength, modulus of elasticity, rigidity and abrasion resistance between the known fibers, it will take a pretty widespread array of tests to figure out which uses the bamboo might be good for and then how it will compare to other fabrics which are known to be good at those particular jobs. I'd agree that you're probably better off doing your tests with a well known, established resin which yields predictable results.

I saw a bolt of bamboo fabric in a store the other day and it was pretty neat stuff. It was hard to believe that it was bamboo.

David G
12-01-2011, 07:16 PM
I bought my wife a turtleneck last xmas that is bamboo cloth. Could have been a cotton/rayon blend for all I could tell.

DerekW
12-01-2011, 08:29 PM
Isn't most 'bamboo cloth' basically just Rayon [viscose] anyway?

David Geiss
12-01-2011, 08:53 PM
...I meant polyester (Xynole)......

I'm not intending to undertake any major empirical testing, just subjecting the 3 types of cloth to impregnation with standard resin and the bio resin. I'll use identical substrate in all six samples, probably constructing a simple 3-5" loa compound chine with each of the substrates to see how the fabrics react differently to lay up over a rolling edge.

I'll torture all of them, by piercing, scuffing, abrading, boiling, painting, varnishing, whatever and reach some conclusions.
In the end, it may come down to what looks or feels best.......basically want to come up with a recipe that will give least trouble and most durability in creating various hull shapes going forward. If the sustainable materials work well all the better....

Thanks for the great suggestions.

David

Todd Bradshaw
12-01-2011, 11:26 PM
I'd think you would also need to test them for tensile strength, recoverability (or not) from being stressed and also find out how much rigidity they can add to the laminate as these things would be critical for sheathing or laminating. You would also want to keep track of how much resin they absorb, as strength-to-weight ratios are often an important factor on small boats.

Derek, I suspect it's pretty similar to the typical Rayon process of making cloth from cellulose (which is pretty crazy, by the way). Here are the Wikipedia instructions for making Rayon.

Regular rayon (or viscose) is the most widely produced form of rayon. This method of rayon production has been utilized since the early 1900s and it has the ability to produce either filament or staple fibers. The process is as follows:

1.Cellulose: Production begins with processed cellulose
2.Immersion: The cellulose is dissolved in caustic soda: (C6H10O5)n + nNaOH → (C6H9O4ONa)n + nH2O
3.Pressing: The solution is then pressed between rollers to remove excess liquid
4.White Crumb: The pressed sheets are crumbled or shredded to produce what is known as "white crumb"
5.Aging: The "white crumb" aged through exposure to oxygen
6.Xanthation: The aged "white crumb" is mixed with carbon disulfide in a process known as Xanthation, the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon disulfide under controlled temperature (20 to 30°C) to form cellulose xanthate: (C6H9O4ONa)n + nCS2 → (C6H9O4O-SC-SNa)n
7.Yellow Crumb: Xanthation changes the chemical makeup of the cellulose mixture and the resulting product is now called "yellow crumb"
8.Viscose: The "yellow crumb" is dissolved in a caustic solution to form viscose
9.Ripening: The viscose is set to stand for a period of time, allowing it to ripen: (C6H9O4O-SC-SNa)n + nH2O → (C6H10O5)n + nCS2 + nNaOH
10.Filtering: After ripening, the viscose is filtered to remove any undissolved particles
11.Degassing: Any bubbles of air are pressed from the viscose in a degassing process
12.Extruding: The viscose solution is extruded through a spinneret, which resembles a shower head with many small holes
13.Acid Bath: As the viscose exits the spinneret, it lands in a bath of sulfuric acid, resulting in the formation of rayon filaments: (C6H9O4O-SC-SNa)n + ½nH2SO4 → (C6H10O5)n + nCS2 + ½nNa2SO4
14.Drawing: The rayon filaments are stretched, known as drawing, to straighten out the fibers
15.Washing: The fibers are then washed to remove any residual chemicals
16.Cutting: If filament fibers are desired the process ends here. The filaments are cut down when producing staple fibers

MN Dave
12-02-2011, 12:07 AM
Isn't most 'bamboo cloth' basically just Rayon [viscose] anyway?

That seems to be the case for the Chinese fiber. The Swiss(?) material is apparently a cellulose fiber like flax. http://www.litrax.com/materials.html

Viscose, according to a 1990 source has much lower mechanical properties than E-glass or Kevlar, with the exception of elongation. Mechanically, it should be a lot like Dynel or Xynole.

These are all dry properties, wet can be lower, but usually not that much lower once it is encased in epoxy. Don't ask what grams per denier means, higher is stronger.
I hope this lines up.
__________________________BREAKING
FIBER_____________________TENACITY_____TENSILE____ _STIFFNESS______STIFFNESS______ELONGATION
___________________________g/denier______1000 psi_____g/denier________1,000,000 PSI____%______
Kevlar________________________22__________410_____ ____525____________15____________3.6_____
Polyester reg. tenacity___________3-5 _________0-100 ______0-65 ____________- ____________4-42 _
Polyester high tenacity __________7-9_________100-170_____65-90___________--____________9-27____
Viscose reg. tenacity (bamboo?)___3___________30-50_______6-17____________--____________15-20____
Viscose high tenacity (bamboo?)___5___________56-88______13-50____________--____________14-34 _
Cotton _______________________1.5-6__________--________60-70__________--_____________7-10____
Silk___________________________4 ____________--________100____________--____________25-30___
E-Glass_______________________15____________500_____ ___--____________10.5____________5____

If you make a beam with fabric on the top and bottom of a strip of wood and hang a weight on the end, the fiber type, cloth weight, weave and orientaion will make a lot of difference in the deflection. Glass has a density of about 2.5 g/cc, and most of the organic fibers are close to 1.4, so the resin to fiber weight ratio looks better for glass.

wharf rat
12-03-2011, 10:20 PM
I too am interested in the results of any tests of the fabric for use on/in hulls.

If you're interested in an alternative to conventional epoxy, I found this http://www.ecopoxysystems.com/ a while back and plan to try it, but my projects lately (and unfortunately in the foreseeable future) don't use any adhesives. It's made from nuts, IIRC. This and bamboo could be one of the greenest combinations ever.