hemp , again.......

General Discussion
21

well, your question prompted a “google australia” search , 2cold ,

so thanks for asking !

… I wouldn’t mind “talking” to Jim Banks , and also the guy here in west oz , whose board I was admiring in the shop the other day [better return there with my digi camera soon , methinks , in case the board is just “on loan” !]

anyway , here’s some of what I found “on the 'net” …

"

Surfboard makers in Sydney and Byron Bay are making fibreglass-free surfboards, which are instead sheathed in a knitted hemp fabric, ***

sourced from Eastern Europe, Nepal and China, and knitted in Melbourne. The surfboards also have biodegradable polystyrene cores and biodegradable resins which have minimal environmental effect when they break down (although they are still toxic materials ­ research into hemp surfboard blanks and glues continues…). With more than 80,000 surfboards built annually and enormous health hazards associated with traditional surfboard manufacture, this is a great step ahead.

NSW finally has had trials of industrial-grade hemp fibre crops: the first was grown (not very successfully) near Armidale and was overseen by the University of New England.

If there is any justice, once the issue of growing low THC hemp*** is resolved, we can look forward to seeing an ever-increasing amount of real Aussie industrial hemp being converted to paper, fabric and construction material. The NSW Dept of Agriculture wants people interested in establishing further trial plots to contact their head office in Orange.

* For more info, see chapter 3 of the booklet Industrial Hemp, titled Hemp’s 25,000 Practical Products "

*** so , you were pretty on track , after all , Hicksy . [I thought it was just …well… you know …your "mad scientist " brain going off !!]

cheers

ben

22

Update !

Well, I went and got the hemp cloth this week .

I settled on 1 metre [x 150cms [5’] wide] of the MR11 6oz hemp , and 1/2 metre of the MR01 8oz cloth .

So far , I have cut out 2 fins worth [ 30 layers each fin] of 6oz fibreglass cloth , and will be inlaying between 1 and 4 layers of the 6oz hemp in them .

I also have 30 layers of 4oz fibreglass cloth , which I will probably inlay 2 layers of the 8oz hemp cloth in [these are for TINY fins]

…I wanted to leave a sample with the girl at the hemp shop because , guess what ?

… she told me her boyfriend makes boards ? [and , no…he HASN’T tried hemp cloth yet ?? So , I figure maybe we can “persuade” him to give it a go !]

Anyway ,

…here’s a few thousand words worth [pics] , showing where I am up to with it so far. (Hopefully , while people are gone from here during the weekdays next week , I can get all three panels laid up and cut out , at least )…we shall see …


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"I’d be very interested to see some pics of a board glassed with hemp, preferable without glass cloth and a board that’s been ridden. "

hi mate !

…next time I go back to the shop , I’ll try to remember to take my camera with me , to get some shots of the board in question … yes , it is used , but looks in GREAT condition . It has a layer [at least] of fibreglass cloth over the hemp on the deck and the bottom [and , it doesn’t look as though the hemp lapped the rails , by the way ]

I want to contact the guy who makes the hemp inlay boards in Margaret River , at some stage …

cheers

ben
26

So, hemp is strong in a different way than fiberglass right? It’s not as stiff/hard but it is very resistant to breaking?

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" So, hemp is strong in a different way than fiberglass right? It’s not as stiff/hard but it is very resistant to breaking? "

I’m not sure …

Yoshio ? others ?

your findings , please ? cheers !

that’s why I want to test it out in fins first , I figure they cop a fair bit of pressure / abuse , eh ?

I will be combining a few layers of hemp with LOTS of layers of fibreglass , so hopefully , the best of BOTH !!

cheers for asking !

…to be continued …

ben

28
Quote:

So, hemp is strong in a different way than fiberglass right? It’s not as stiff/hard but it is very resistant to breaking?

Nathan,

no, hemp is only a cloth and therefore cannot be “hard”. You have to consider the interaction with the matrix, i.e. epoxy or poly resin.

Hemp has a specific tensile strength and a specific young´s modulus that are close to e-glass. Its density is lower than glass, so you can - in theorie - achieve the same strength with hemp (being able to use heavier cloth) as with e-glass. But due to the treatment of the fibers the real strenght of the cloth can vary.

Ben, looks good so far, can´t wait to see the finished ones. Make sure the resin is fully cured before foiling, I had the impression the natural fibers don´t bond to the resin as well as glass.

Did you wash the cloth before use?

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“Did you wash the cloth before use?”

no, I didn’t . I wondered about that , though , actually !

…what are people’s thoughts ?? [I was thinking of just ironing it , to get any wrinkles out]

One of the things the girl in the shop told me , which I found interesting , was " it becomes softer , yet stronger the more you wash it " [She WAS referring to clothes made of the stuff of course , but I just found that different .]

The other thing , which I “may” explore , was she also mentioned it accepted normal material dyes , too.

So , if it doesn’t go the nice “golden yellow / brown” colour that the board I saw was , I could always dye the material , I suppose …or do a tint .

cheers

ben

30

Hemp under glass? Wicked cool, pal.

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Hemp has a specific tensile strength and a specific young´s modulus that are close to e-glass. Its density is lower than glass, so you can - in theorie - achieve the same strength with hemp (being able to use heavier cloth) as with e-glass. But due to the treatment of the fibers the real strenght of the cloth can vary.

So if the tensile strength is similar to glass, does this mean it would have the same flex characteristics? Or would lower density = more/heavier cloth mean it’s stiffer? Can you tell from riding the skate? (Which is really nice looking by the way) I’m guessing the strength increase from washing happens because the fibre becomes more compressed when washed so maybe that’s part of the technique. I’m stoked on the idea of at least hemp fins, if not a board (get some production going Ben, I’ll find something to trade for a set o’chipemp fins!) I was given a hemp shirt a while back, rolled my eyes ike the aging cynic I am and then found it’s not only insanely comfortable but really hard wearing. Keep the pictures coming post-a-day Ben, this is an interesting thread.

32

hi chip, here is a link that might be of some use,

www.oceangreen.org

33

What I meant was that, once combined with the resin, is it as hard as fiberglass? Ding resistant etc.

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Quote:

hi chip, here is a link that might be of some use,

www.oceangreen.org

nice !

thanks for that Pete !

I guess they

a] use the heavier hungarian green cloth

or

b] tinted / pigmented it green ?

thanks for the feedback , Kirk consafos , and others !

I’m new to this , so , ANY other info / advice …yoshio , greg loehr , anyone else who has glassed boards or fins with hemp inlays ? …please keep the elp '/ thoughts / questions coming !

cheers ,

(HOW MANY posts a day ??!! ) ben

35
Quote:

(No , this has NOTHING to do with drugs at all.)

HEMP IS THE ANSWER !!!

Does…an--------y---------one…

Rem-m-m—ber…th-e-e-e…

,QUESTION ???

36

Hey all,

hemp is awesome, and I’d love to see more of it everywhere–like right here right now

but the shopgirl was sweetly hyping it–it does get softer, but it doesn’t get stronger as you wash it. Washing is just wear, and wear is wear. I had some hemp tennis shoes and they were nice, got soft and then faded and wore out quick–frayed, holes–had a wallet, got soft, faded, worn, dog collar, same story, it fades out pretty bad, so ah, hemp is good stuff, but not defying-the-laws-of-textile-physics good. Maybe the coarser more straw-like mat stuff is stronger for lams, but would soak up a lot of the goop.

I’d look to sheet bamboo for thin tensile strength, but I saw where it doesn’t wet out too good, or de-lams or something. 1/16 aircraft grade birch plywood? Good stout stuff and bendy. Ya know, rayon is cellulose…

37

hi Janklow !

so, what is your experience of using hemp in fin panels and boards , did you have trouble laminating it , or not ?

got any photos please ?

I would be very keen to see them , and hear a riding report of how they went .

cheers,

ben

38

consafos,

the skateboard with flax cloth has similar flex to my glass ones (same core thickness). But I did use glass on top of the flax and the wood core affects the flex, too, so that´s not a fair comparison.

Generally, flex (or bending stiffness) is determined by core height and tensile strength and the young´s modulus of the outer layers. So I guess hemp and glass would have the same flex characteristics (due to roughly the same tensile strength/ modulus). But as mentionned above, glass is man-made and its possible to dial-in the properties, while hemp is a natural fiber (that means shorter fibers, variations due to growth, region, treatment of the fibers etc.).

Washing makes the cloth softer (easier to lap??) but there is no increase in strength. The fiber absorbs water, so it should be dried completely before lamination. I had difficulties to iron it flat after washing, so I would prefer to skip the wash. But I imagine there are a lot of oils/ sprays/ lubricants involved while making the cloth (which may affect resin adhesion)???

39

hi faded !

did the flax go lighter or darker when the resin hit it and the fibreglass ?

I ask , because someone wanted to know how / if hemp will do the same when glassed and resined .

I’d also like to know if epoxy or polyester will have different colour effects ["hues’?] on the hemp .

But I guess I will soon [?tomorrow?] be the answer to my own question…

…I’m still thinking of going with the MR01 [8oz] hemp for my first panel …I may have to do the tiny [blue template] sized side fins with that first , and then , if I like it , do a pair of fcs G3’s , with that 8oz hemp [yes , with maybe ?2-3 layers of that , I figure around 25 layers of 6oz fibreglass over it . [Single foiled side fins]

cheers !

ben

I’d like to eventually do a big single fin , with a middle layer of 8oz hemp material between about 38 layers of 6oz cloth , too.

40

Dear Ben

Did you try water to get a preview of the wetted colour?

Just a thought

ENJOY!!!