Hi all again, many thanks for all the advice and help over the year. A company in the UK, www.oceangreen.com, are producing boards using 4.5 and 7.5 oz cloth. I have managed to source some hemp cloth, 5.75 ounce in Romania via www.ecolution.com. Very hard to find a source outside of China. I just wanted an organic hemp produced outside the PRC. I am planning on building a board with www.bufoboards.com this January. I will be using at least 2 layers of hemp (top & Bottom) if not 3, (2 top, one bottom) The board will between 7’ and 7’6", big guy thruster/all rounder. Fin system from www.4wfs.com Blank is a 7’6 MDI from www.homeblown.co.uk This is what I have found out about hemp so far. When I get it I will need to wash it at 60-90 degrees centigrade to shrink it and tighten up the weave. These are my questions. Has anybody here used hemp? Any particular problems with hemp? How much extra resin should I expect it soak up? Do you feel 5.75 is too heavy for all 3 layers, should I stick with 2? The board will be stringerless so I am hoping to balance out the extra weight. All advice and comments are, as always, very welcome. Also, just to wish everyone a happy, healthy, progressive, positive and productive 2004. I know sometimes my questions may seem stupid, but surfing is still developing in Ireland and the Netherlands, so I do value all the advice and help. http://www.surfingireland.net
you might already be planning on this but- i first would get some foam pieces and do some small test panels first. check how it wets out and works before you use it on your blank. also, what resin are you planning on using ? i believe epoxy is the way to go on hemp, it probably needs the extra strength of epoxy. the test panels will give you an idea of the toughness of the laminate, and hopefull how many layers of cloth you will need.
I’ve been wanting to glass a board with hemp or any fabric other than fiber glass. I’m finding very little info out there on this topic and hopeful that a few questions get answered on this thread. I’ve found a 5.7 oz 55% hemp 45% cotten blend 52" wide in a variety of colors for $6 us dollars a yard. Can this stuff just be laid out on a shaped eps blank and coated with epoxy? The epoxy seems to form a solid matrix with my jeans where I’ve dripped some on them…Can any one recomend some inexpensive ready to go cloth options? Can you mix natural cloth and fiber glass for strength and appearence? What can you not use? As a side note: about 3 years ago I patched a hole in the plastice reserve tank for my truck’s radiator with a piece of my cotton shirt saturated in pipe glue and it is still going strong.
I’ve made a few hemp boards and here’s what I’ve found. First, use hemp in conjunction with glass. A layer of 5-6 oz hemp with a layer of 6 oz. glass over top. If you use all hemp, sanding will be a nightmare and that’s if sanding is possible at all. Iron the fabric before you use it. Otherwise wrinkles will not lie down. The 6 oz. glass will help here as well by holding the hemp flat. Don’t try to lap the stuff. It is VERY dimensionally stable and will not lap clean. It’s best to use a more flexible epoxy with hemp. It has better elongation than most high modulus composite resins and your laminate will shatter easily if you use one of these. We use our RR 2020 which worked quite well. The 2000 didn’t fair as well. On the positive side, hemp is some of the most attractive fabrics you’ll ever see on a board and strong as hell. Good luck.
“Don’t try to lap the stuff. It is VERY dimensionally stable and will not lap clean.” Greg, does that mean that you only use deck and bottom patches and reinforcce the rails with conventional glass? Would it be possible to do cut laps ? Thanks
For Confusion Hill, the combo your talking about is used by www.oceangreen.org in the UK. Brian, thanks a ton, we have test MDI from the first (broke in transit- Thanks a million DHL/UPS people) and so will be working with that as a test piece. Greg, as always, thanks. http://www.surfingireland.net
Hi Greg, Like Henning, it would be helpful to clarify those remarks, thanks in advance Simon
hello Simon, I know nothing about glassing with hemp, but came up with a couple of thoughts. Regarding your concern about resin absorbtion of hemp, I’ve found that resin absorbtion can be controlled with an adjustable vacuum bagging system - the greater the vacuum the more the bleeder will soak up. Regarding Greg’s experience with difficult lapping and sanding, again the vacuum bag does a great job of squeezing laps flat. Peel ply is a tightly woven nylon fabric and doesn’t drape round rails very well. However by cutting slits at 1ft or so intervals I was able to get the vacuum bag to wrap the peel ply round the rails without any wrinkles. So I’m thinking the bag might get the hemp lapped without much of a ridge to sand.
By dimensionally stable I mean that the fiber bundles within the fabric are tightly woven into place and won’t allow much movment within the fabric. This is typical of most textile fabrics as the manufacturers don’t want tread movement. Most surfboard cloths allow the bundles to move quite freely which makes them more three dimentional, allowing better drape. This is also why cut fiberglass cloth easily starts to unravel. Most fabrics don’t do this, at least not to the extent a surfboard fabric does. Vaccuum bagging will help with this but adds to the difficulty of producing the board and to the cost. On the hemp boards we built, we just cut the cloth at the boards edge and laped the glass on both top and bottom. The boards came out looking great. I could see inlays being a real great application for hemp as well.
Is hemp the same as burlap?I did a deckpatch inlay with bulap and it was tough and looked good. R.B.
heres a good one…Hemp woven in t-shirt style cloth, stretched, pegged, vaccuum bagged and then trimmed before the other side is done… http://www.speedneedle.com.au
Hi greg, The guy supplying me (www.ecolution.com) said the fabric already had a tight weave, so I think I will skip the hot wash to shrink it. This should allow more movement, what do you think? Simon