Bamboo Mast(?)

[Pernicious Atavist]

I need to build a mast for my 16' flat iron (sharpie) skiff. i was wondering if bamboo would do, then i found this info from a local harwood dealer:

Weiss Hardwoods is now featuring GUADUA BAMBOO poles also known as GIANT TIMBER BAMBOO with thick side walls. We are stocking 2" to 6" diameter poles in lengths 7' to 19' long.
Great for TIKI HUTS, GAZEBOS and INTERIOR DESIGNS.

i'm using a 84' sprits'l and the mast will be about 13' above the partners, where it should be about 3" dia. reckon if i mount hardware i'll need to tie it on instead of drilling holes that may encourage cracks.

input?

[Donn]

BambooFencer ("") sells bamboo for spars.

[N. Scheuer]

I thought "Bamboo" was more or less solid; and that the hollow stuff is some lower form of "grass".

I read this some years ago in an article about Bamboo furniture.

Moby Nick

[Donn]

All bamboo is grass. Most is hollow, but a few varieties are almost solid.

[Old Bingey]

We have used bamboo for spars for a long time. My son's proa's spars are all bamboo including the 26' yard. It is funny stuff. You just about have to add any additions by lashing. We have not figured out how to get a real strong epoxy attachment. You can glue on a snotter block or something but you can't epoxy two pieces together with a plug to make a double tapered spar like a proa yard. Any end fitting is best built so the bamboo sticks down in a hole in the fitting instead of having the fitting stick up into the hollow of the bamboo. If you don't like a lump on top of the mast, you can make a wire whipping to keep the tip thing from splitting out. Any place where you drill a hole or interrupt the continuity of the outer shell in any way will compromise the integrity of the spar. Duct tape will protect a mast where a lug sail yard or gooseneck jaws rub. If you don't mess up, a bamboo spar is hard to beat.

[Al Owen]

Bamboo flyrods anyone. All bamboo is hollow and it is a grass. The making of a spar does not differ all that much from the making of a bamboo flyrod.

[Bob Smalser]

Fly rod makers use plastic resin laminating glue to lay up those itty-bitty strips, so it should work for all bamboo applications that are protected from UV.

http://www.tools-for-woodworking.com /index.asp?PageAction=VIEWPROD&ProdID=1659 (http://www.tools-for-woodworking.com/index.asp?PageAction=VIEWPROD&ProdID=1659)

[ 01-02-2006, 12:13 PM: Message edited by: Bob Smalser ]

[Kim Whitmyre]

On the Wharram forum there was a discussion re bamboo for spars, and this link was posted:

Bamboo Info (http://www.bamboo.org/FAQ.html#HowDoIPreserveBamboo)

It has techniques for curing, preserving, and even when to harvest for the best result.

[Old Bingey]

Bob,

I am talking about gluing to the shiny, outer integuement. Fooling around we have found that it must be intact to get the most strength out of bamboo. You can cut the little limbs off at the partitions and it can be abraded a little bit and not hurt anything but it still won't glue reliably with epoxy. It might be something we are doing wrong with de-sugaring the green culms. We have tried all sorts of stuff (Weldwood, resorcinol, Titebond II etc....J.B. Weld, hot melt, 5200, foamy Gorilla spit) and nothing works. Cyanoacrylate works as well as anything but is still unsatisfactory. It is easy to glue back a split place with epoxy when you can get to the interior part but the outer skin treats glue just about like polyethylene. I hope some innovator takes this problem to fruition.

Also, bamboo spars have to be kept out of the weather. Plain old spar varnish will sort of protect them (or paint) but it skins off real easily. We use Penetrol thinned varnish and apply it with a rag but we still have to take care of the spar. A little sprit rig is easy to take home, though.

We have plenty of four different species growing on this old place and we have done a lot of experiments. The kind with the knots close together will heat bend most marvelously when green.

As an aside, we are having some real weather down here right now. I am going to unplug this durn thing.

[ssor]

Everything that you always wanted to know about bamboo but were afraid to ask. ;)

http://www.americanbamboo.org/

[Al Owen]

I don't know if this means anything to building spars from bamboo, but for flyrods the most highly prized bamboo is Tolkien cane from Southeast Asia growing along the Tolkien Gulf. (see boys, now you really know a good reason for the Vietnam difficulty).

[Donn]

That's Tonkin, Al. Tolkein is the Hobbit guy. ;)

[ssor]

Originally posted by Donn:
That's Tonkin, Al. Tolkein is the Hobbit guy. ;) Maybe Al knows somethin that we don't.

[Al Owen]

That's true I did know how to spell Tokin, but my spell checker said I got it wrong soooo....

[Al Owen]

I wonder if the makers of split bamboo flyrods would have any useful information to offer the humble spar maker?

[ssor]

If you look at the way they attached the line guides(fair leads?) with seizings(whatever happened to "I" before "E" except after "C") I think I know how we would have to attach blocks and cleats and shrouds.

[Donn]

"seizings(whatever happened to "I" before "E" except after "C")" One of those anomalies they make memory for, like seismic.

I'm not certain about this, but I think one of the reasons fly rod makers glue up small splits, is to eliminate as much as possible, the damping effect that the nodes have on the blank's flexibility. A fly rod needs a parabolic action, and using a solid cane won't work because it gets less flexible toward the butt.

How does a mast want to bend? I think junk-riggers used solid culms of bamboo, and not refastened splits.

[Donn]

Originally posted by Al Owen:
That's true I did know how to spell Tokin, but my spell checker said I got it wrong soooo...."Tonkin cane" is a misnomer. That's a common name for the rodmaking bamboo, but it doesn't come from Vietnam's Tonkin Province, or anywhere along the Gulf of Tonkin. It's too wet there to grow the hardwood bamboo used for rods. That stuff, Arundinaria amabilisa, AKA Tonkin Cane, Teastick Bamboo or Ch'a kon chuk, comes from mountainous regions in China, primarily but not exclusively from the Kwangsi province, north of Canton.

[Pernicious Atavist]

thanks, all! i plan on lashing any fittings.
bing, how do you keep a 26' yard out of the weather?

happy new year!

[ssor]

Originally posted by Pernicious Atavist:
thanks, all! i plan on lashing any fittings.
bing, how do you keep a 26' yard out of the weather?

happy new year!In thirty feet of six inch PVC pipe with caps on each end.

[Old Bingey]

With palm mats like this:

http://www.wingo.com/proa/micronesia/marshall_isles_proas.html

Or blue polyethylene tarps.

[Al Owen]

Donn: I'm sure you are correct. I was relying on memory from an Orvis catalog from many years ago. Of course this was before I learned that it was Jim Payne's rods that ruled. "Tonkin cane" is a misnomer. That's a common name for the rodmaking bamboo, but it doesn't come from Vietnam's Tonkin Province, or anywhere along the Gulf of Tonkin. It's too wet there to grow the hardwood bamboo used for rods. That stuff, Arundinaria amabilisa, AKA Tonkin Cane, Teastick Bamboo or Ch'a kon chuk, comes from mountainous regions in China, primarily but not exclusively from the Kwangsi province, north of Canton.

[Pernicious Atavist]

would brass or copper reinforcing bands help? i dunno if they'd encourage rot or cause a hardpoint to break around. i'm thinking a band around the foot would keep an insert that mates with the step from splitting the 'boo.

[Figmental]

Bamboo is one of natures best engineered materials. At ground level the stalk is nearly solid with no center void. For the lower half of the culm or stalk the outside diameter stays the same but the inside diameter increases resulting in a thinner and thinnerwall thickness the further from the ground it is. In the upper half of the culm, the wall thickness stays generally the same but the outside tapers till just a point at the end.

So, cut close to the ground after putting on s couple of turns of electrical tape to stop fraying of the cut and your mast bottom will be nearly solid. Find the fight culm for taper and straightness first. This is where the relaxing pleasure is for me, in spending time in bamboo groves looking for the right One before doing any cutting.

Lashing is the best way to make attachments since it doesn't harm any fibers. I've not found any way to preserve bamboo in the weather but you should get a year or two before a fungus gets it. A mexican said once to me that tar off of the beach mixed with gasoline and rubbed on several coats works well. I bet you could use CPES and keep it longer if cracking could be avoided.
Do you have a scource located for a piece yet? It was planted for windbreaks in the Ft. Pierce area long ago.

David

[Donn]

Originally posted by Figmental:
Bamboo is one of natures best engineered materials. At ground level the stalk is nearly solid with no center void. For the lower half of the culm or stalk the outside diameter stays the same but the inside diameter increases resulting in a thinner and thinnerwall thickness the further from the ground it is. In the upper half of the culm, the wall thickness stays generally the same but the outside tapers till just a point at the end.
This is true of some Bamboos and not others. I have a few dozen 12-20' long culms of Yellow Groove Bamboo (Phyllostachys aureosulcata) curing under the carport roof right now. The base of the culms has ~1/8" thick stem walls, with ~1.5" of hollow inside. This wall thickness is constant in all but the top few feet of the culm. The taper is found in the diminishing diameter of the hollow, as you near the top, down to ~1/4". This is characteristic of Bamboos grown in wet temperate climates. It's a softwood Bamboo.

The Tonkin Cane Bamboo mentioned above, on the other hand, is a hardwood Bamboo, grown in higher and dryer climates. It's wall thickness and hollow diameter are amost uniform for the entire length of the culm.

Other Bamboos have much thicker walls and smaller diameter hollows. These are usually genus Dendrocalamus, characterized much shorter internodes and averaging a total wall thickness greater than the diameter of the hollow. D. asper, D. latiflorus and D. strictus are the most commonly used building material varieties. They are hardwood Bamboo, very resistant to splitting.

The most common large and long (big mast size) Bamboo is Moso (Phyllostachys pubescens). This is the stuff that can exceed 8" in diameter at it's base and 80' in height. It's the most commonly grown timber Bamboo, and is a softwood variety. Even an 8" diameter specimen will seldom exceed 1/2" wall thickness.

[MarkC]

Preserving bamboo - might be of interest. I took this from the network-earth building site.

Bamboo Architecture and Construction with Oscar Hidalgo


For longer lasting structures it is important to treat bamboo against rot and insects. One method is to cure the bamboo by standing cut culms on a stone for a month amongst the living culms. The leaves are left on as they continue to remove starch from culm. When air curing bamboo it is best to keep it vertical, as it takes half the time to dry as horizontal storage. Once the bamboo is cured it is soaked in water for approximately four weeks. It is then soaked in the fumes of a .3 solution of caustic soda.

Perhaps the best way of treating bamboo is to force a solution of 3-10% of half borax and half boric acid through bamboo using an air compressor to create 20-30 lb of pressure. The bamboo is left on a slight incline with the base closest to the tank (though it is also possible to do it in the other direction) and the chemicals gradually move through the vascular system.

Structural Characteristics of Bamboo

Bamboo is unique in that it is strong in both tension and compression. While tensile strength remains the same throughout the age of the bamboo plant, compressive strength increases as it gets older. There is some controversy in determining proper testing protocols, as it is important to test bamboo which is at least three years old, and that the test should occur on a piece of bamboo with an entire internode and two intact nodes. Some testing research has not used these criteria, and thus the results are not as useful.

To utilize bamboo to its best capabilities, several conditions are important to consider. One consideration is that bamboo grown on slopes is stronger than bamboo grown in valleys, and that bamboos that grow in poor dry soils are usually more solid than those grown in rich soils. Bamboo will shrink diametrically, so Oscar does not recommend tied connections. Bamboo takes at least four months to dry, and should not be kiln dried, as the moisture inside leaves mostly through the ends.

There are certain limitations of the use of bamboo in construction. The starchy interior is attractive to insects. In addition, because bamboo has a slick waterproof coating, it cannot be painted. However, this coating allows bamboo to be used as water pipes.

Using Bamboo

Bamboo is useful for different things at different ages:

<30 days it is good for eating
6-9 months for baskets
2-3 years for bamboo boards or laminations
3-6 years for construction
>6 years bamboo gradually loses strength up to 12 years old
from:

http://www.networkearth.org/naturalbuilding/bamboo.html

[ 01-07-2006, 02:14 PM: Message edited by: MarkC ]

[Pernicious Atavist]

so far i've found two sources, weiss hardwoods in largo, near tampa (where i'm moving nearto in a few weeks) sells "GUADUA BAMBOO" and Bamboo Fencer in GA., which sells bamboo for spars (as suggested in an earlier post here), but i need to talk to their "sailing" guy. ...and i just found a place here in orlando! companies advertise borax-treated wood that is bug resistant, and i plan on soaking the 'boo in either cepes or linseed oil as well. beats hell out off making my own, and should work very well and be fittin' for this boat!

[ 01-09-2006, 09:52 PM: Message edited by: Pernicious Atavist ]

[cedar savage]

I'll bet you can find a nice piece of bamboo just growing out there somewhere in a field that's waiting to be developed.

[Ronin NW]

For what it's worth, when in Seattle visit Bamboo Hardwoods (www.bamboohardwoods.com). A few years ago we entered the Quick and Daring boatbuilding contest at the Center for Wooden Boats, and built a canvas-covered bamboo canoe, complete with a Chinese lug sail. The keel was 3" tre gai, the rest of the hull framing and mast was about 1" tam vong, and the sail battens were skinny tonkin cane. Much of the tam vong was virtually solid. She was the fastest boat on the water by far (with two kayak paddlers and a good downwind sail), but we took forever to build and the bamboo was quite a bit more expensive than I'd expected. Never did get a photo from CWB of it. Construction was mostly socketed with various hole saws, and I can't tell you how many rolls of duct tape. It certainly wouldn't have lastes for any time with that damage to the cane. Recycled it into a few nice pieces of furniture, though ;)
-Scott