Heat treating bamboo for backing ?

[Webradbury]

I am planning a bamboo backed bow build of some sort soon and was wondering about the proper way to heat treat the bamboo strip.

First, does the bamboo have to be heated to make a suitable back?

If so, how does one properly heat it and how much?

Lastly, my bamboo was cut about three months ago and is now dry. Do I need green bamboo to heat or can dry bamboo be heat treated?

Thanks and bare with me, I'm learnin!

[Dances with squirrels]

Bamboo isn't generally heat treated when used as a backing.

[Carson (CMB)]

I dont think you want to heat treat the bamboo if you are using as backing. Heat-treating or tempering the bamboo or other woods is done on the belly. Some folks use bamboo as both a backing and a belly laminate, so maybe this is where you got the idea to heat-treat your bamboo backing?
You do need the bamboo to be dry, and preferably somwhat seasoned. Drying wood, or grass in this case, is different than heat treating. You can dry your bamboo by placing in an environment that provides a heat 90-105 Fahrenheit and low humidity, 20-30 percent. Might take several weeks to become dry.

Hope that helps

[Webradbury]

I am glad I asked! Thanks a bunch!

[duke3192]

#1 DO NOT heat treat bamboo backing, makes it weaker in tension, if it is used on the belly, heat treat it to a golden brown, you can't go by temp. on bamboo it is too variable. Three months is not enough to properly season bamboo for backing, some of the serious bamboo bowyers season it for 6 mos to two years. You heat treat dry bamboo. For info on heat treating bamboo, google, rope and wedge bow building.

[Webradbury]

One more question, should I wait until the bamboo is dry before cutting it into strips or should this be done while its green and the strips left to dry?

[Eric Krewson]

Some of the best bamboo I ever backed a bow with was sold as "tonkin" bamboo by Mike Westavang, AKA Wingnut on the Trad Gang. Of course there is no such thing as tonkin bamboo big enough to back bows with. I suspect it was heat treated mosa, the back was dark brown, even had a little charcoal on the tips of the nodes.

Just curious Duke, where did you come up with that info you put out about tempering bamboo being a bad thing? There are plenty of videos on utube of classic Japanese bow makers heat tempering their bamboo, they have been doing it for hundreds if not a thousand years.

Your info on seasoning bamboo is way off as well, way out in left field. I don't know how much you have cut and seasoned yourself but I have cut and seasoned a bunch. I have made at least 50 bamboo backed osage bows.  Cut the bamboo, knock the nodes out, let it sit for month in trunk form so the slats won't cup when they dry, split or cut out the slats, flatten the belly on a jointer or belt sander, throw it in the hot box for a couple of weeks and you are good to go. Seasoned for two years.......... no way.

Here is my last bamboo cutting haul, one of many,very many.



I have asked in the past for folk to not give untested opinions as if they are indeed a fact. If anyone has tempered bamboo and had a failure because of the tempering let us know about it. If anyone has "seasoned" bamboo for different periods of time for up to two years and has seen any recordable difference in performance, we want to know all about the changes you saw.

Like Sgt Joe Friday said "just the facts Mam, just the facts"

[PatM]

 Tonkin certainly does get big enough to back a bow with. When will that myth die?
 As far as tempering versus not tempering the BACK strip you'll get a variety of opinions on that. No question about the belly though.
  The multiple year seasoning thing IS a tradition amongst the Japanese though.,

[Eric Krewson]

Tonkin does not grow big enough to back a bow with, 3" is about it. There is very good video out about an american guy who travels to Asia to buy Tonkin bambo for split bamboo fly rod builders world wide. The video follows his journey to the bamboo groves, the cutters, processors, shippers and back to his supply business in the US, then on to the best custom fly rod builders in the country. You won't see any  big diameter Tonkin bamboo in any of the groves.

They charge to watch the full length 47 minute video on Utube now, here is the trailer;

https://www.youtube.com/watch?v=rTM-apAh844

I have studied this stuff in depth, I was so impressed with my so called "Tonkin" bamboo I wanted more when Mike's supply dried up. I found out there is none to be had, it doesn't exist. Someone may say they are selling Tonkin bamboo backing for bows but they are not being truthfull or have been hoodwinked themselves.

As for seasoning, I am a bit of a hoarder when it comes to osage and bamboo. If I use a bamboo slat I cut 6 months ago or one that has been on my rack for years, I see no difference in performance.

[Eric Krewson]

My point is; lets not interject random snippets of bow making lore as necessary components of the bow building process, these snippets complicate the simple process of bow making unnecessarily for beginning bow makers who are collecting knowledge for their first attempt.

Get some materials, cut out a bow, floor tiller it, take it to the long string then the short string, do your final tillering, shoot that sucker and enjoy it.

[Stefan]

I did read something over bamboo backings being steamed. Sugars in the bamboo caramelise and that process should make it stronger and give the bamboo a browner colour.

Not sure if that's true/tested

[PatM]

Tonkin does not grow big enough to back a bow with, 3" is about it. There is very good video out about an american guy who travels to Asia to buy Tonkin bambo for split bamboo fly rod builders world wide. The video follows his journey to the bamboo groves, the cutters, processors, shippers and back to his supply business in the US, then on to the best custom fly rod builders in the country. You won't see any  big diameter Tonkin bamboo in any of the groves.

They charge to watch the full length 47 minute video on Utube now, here is the trailer;

https://www.youtube.com/watch?v=rTM-apAh844

I have studied this stuff in depth, I was so impressed with my so called "Tonkin" bamboo I wanted more when Mike's supply dried up. I found out there is none to be had, it doesn't exist. Someone may say they are selling Tonkin bamboo backing for bows but they are not being truthfull or have been hoodwinked themselves.

As for seasoning, I am a bit of a hoarder when it comes to osage and bamboo. If I use a bamboo slat I cut 6 months ago or one that has been on my rack for years, I see no difference in performance.

      What makes you think that 3" is not big enough? People use 1.5" Tonkin successfully.
 Not sure why you are saying that people selling Tonkin are hoodwinking when Mike was doing that and you bought it

[Badger]

  Eric is correct in that a lot of bamboo has been sold as tonkin cane. I don't think anyone was being dishonest as much as just misinformed. As long as the bamboo doesn't break I don't think it will make much difference in performance. Most of the magic is happening in the belly of the bow. Wet bamboo is stronger in tension than dry bamboo as all natural fibers are tension strong at higher humidities. But stronger isn't always better if it carries more histerisis. Strong enough is probably what we need to look for in backings.

[dragonman]

according to things I have read by japanese bowyers and confirmed by my own experience, bamboo keeps hardening with age....10yr old bamboo is a lot harder than 1 year old bamboo. In japan they use new bamboo on the back and harder old bamboo on the belly. They also recommend smoking the bamboo for several days before use.
It certainly  isnt conclusive proof and it shouldnt realy be so, but before I learnt this, ( off the internet), I was using harder old  bamboo as a backing for ipe and these bows appear faster than the fresh bamboo  backings I used afterwards on the same desgn of bow...just some food for thought

dave

[Eric Krewson]

Don't know if Mike knew his bamboo was something other than Tonkin, few people know the true nature of the stuff. I bought what he had because I found it to be good bamboo, didn't care what it actually was. I had just run through a bundle of 25 slats  from Frank's, beautiful stuff but every bow I made from it had a bamboo failure. My next bundle arrived waterlogged and covered with mold, it went to the burn pile. I was hungry for good bamboo and Mike's filled the bill.

It has been my findings from cutting complete 50' tall clums that anything less than 4" gives you a very high crown and limited width once you flatten the stuff. You can use any width of course, you can radius the core wood to fit the inside curvature of the bamboo if you like but you will end up with what I call an osage belly bamboo bow, mostly bamboo and very little wood.

Japanese bow makers take their craft to a different level, they know what they are doing and produce a superior bow. 

Dragonman, is the age thing standing bamboo or cut and seasoned bamboo? I have found the longer the bamboo stands in a grove the harder it gets as well. I wouldn't cut a clum that I know is one year old.

I watched  Jap Kopedryer's presentation on yumi bows at the Hill shoot a couple of times. He said that Japanese arrow bamboo is too soft until it has been growing for three years and to hard for arrows if it has been growing more than three years. Three years is the optimum for producing the best arrow shafts.

My point is; ordinary wood hacks like myself can make pretty good bows with out getting into century old traditions and practices.