Question about bamboo

[paulsemp]

I found a suppler locally that sell bamboo slats for a good price. They need to be planed and that is not a problem. I believe that it is  tonkin bamboo. Is tonkin any good for bow backing? And would this need to be tempered/dried? Any other items to look out for would be appreciated. I have never made a boo backed bow and am getting the itch for this price.

[PatM]

Most slat bamboo is from Moso which resembles Tonkin the same way that Pine resembles Ipe.

[blackhawk]

Since its cheap Paul buy one slat and give it a bend test....I've been taught by someone who's been making bbos for ten years, that if you can bend it in a U that it should be good for bow backing in most cases.

[paulsemp]

thanks blackhawk, that is what I was thinking also. Plane it down and bend it in half and see what happens.

[PatM]

You don't even have to plane it down to see how it reacts. Most  bamboo is very tension strong. it's just the susceptibility to pulling up splinters at nodes or on tapered edges that are issues.

[paulsemp]

So Pat, you have tried it with poor results? And with moso the fibers are  more interlocked?

[PatM]

It's more the "glue"  binding the fibers that is the variance. Bamboo doesn't have interlocking fibers.
 Moso is the type that is known for popping up splinters. True Tonkin is used to make fishing rods where popping a splinter is even more likely than when making bows, and yet it holds up.
 Look up some pics of Tonkin online and you'll quickly see the difference in appearance.

[paulsemp]

Any one know anything about tempering? Is it even needed?

[PatM]

Temper a belly slat and perhaps force dry a backing slat in a heat box but not really necessary to directly temper a backing strip with heat, although some do with success.
 Some guys making fly rods flame the inside of the sections which heat treats the outside less directly. That's probably the best compromise.

[Pat B]

Bamboo tempering is only needed when using the boo for the belly. It increases the compression strength.

[PatM]

The main reason people have for tempering a backing strip or a rod blank strip is to dry and shrink the bamboo to the max which tends to improve on the tendency bamboo has to move dimensionally later on with moisture cycling.

[Roy]

Pat M. I have been making BBO bows for years with Moso. And the Biggest problem I have is the boo blows up a splinter and that whizzes me off. So are you saying here that Tonkin is the best boo for BBO bows? Thanks, Roy

[Eric Krewson]

Tonkin doesn't get big enough to make bow backing with 2 1/2" being about as big as it gets.

Anyone who is selling tonkin bamboo bow backing is probably calling some other variety "tonkin" because it has a pretty good name recognition from the flyrod industry and will sell better.

[Roy]

Interesting Eric.

[PatM]

That's not true. Tonkin reaches easily adequate size. You only need a virtual cable running down the center of a narrow Ipe bow for example. People use small bamboo garden poles which are often Tonkin with good success.
 If you want to back a really wide bow you'd be better off using a flat wood backing.