Bamboo backing sapling bow

[Roballa]

Hi everyone,
I’m very new to the world of bow making, but it’s safe to say I’m completely hooked and loving the variety of different techniques, and making small improvements along the way. My first bow was made at a workshop, and developed a small crack on one of the limbs. I recognise now it was because the board I was given had some grain run-off, and I salvaged it using linen thread and a linen fabric backing. My next two bows were a pyramid board bow design, with leopard print linen backing on instruction from my youngest son! 40Lb @ 27 inches for me, and 15Lb at 22 inches for my son.

I’ve been using spotted gum boards, which is one of the best bow woods in Australia. Unfortunately, none of our wood suppliers have even heard of Osage!

Chinese Elm is a pest species here, but there are some trees growing near my place, and I have two saplings drying in the garage. As a white wood, I thought it might be interesting to try a bamboo backing this time. I’ve seen a few videos where the back is fairly flat, so the bamboo can be thinned, tillered and applied. My question is regarding sapling bows. I understand the aim is to not violate the 1st growth ring below the bark. However, this will make a very curved back after tillering.
Has anyone applied bamboo backing to a sapling bow? Does the curved back make it too difficult to apply the bamboo, or if the bamboo is thin enough, can it still wrap itself to the back? I could easily leave it bare, or use my usual linen technique - however I thought it might be interesting to try something different, especially on a wood variety that is prone to set.

Sorry for the long post! Hope that makes sense. Thanks for any tips.

[Pat B]

Welcome to PA, Roballa. Do you have any pics of your bow(s).

[Hamish]

Hey Roballa, fellow Aussie here. Plenty of bows have been made out of Chinese elm. It doesn't need a backing unless the stave has been damaged.
Either take the bark off and use the surface just under it, or go down to a lower growth ring if you choose.

Bamboo backing needs a flat surface to glue it on to the stave. You need to plane it or rasp it flat, otherwise you would get poor adhesion. If you try and force the bamboo flat from clamping, it will split lengthwise.

Too reduce set in whitewoods you can heat treat, and or reflex the stave over a form.

A lot of chinese elm grows around northern NSW, and southern QLD. If you let me know what State you're in I can recommend some places that sell suitable species of wood for bows?
                                                    Hamish.

[willie]

welcome Roballa

if your elm is prone to set, heatreating will help as Hamish mentioned, although perhaps he can clarify how reflexing will help reduce set also.

putting a stiffer materiel on the back (which I assume bamboo is) will actually cause more set

[Hamish]

Heat induced reflex...  The reflexing if done 1-2" will not stop set but it will compensate for apparent set. The bow will now  perform better in cast and speed than if you hadn't reflexed it. Combine that with a deep heat treat on the reflex form, which will drive out moisture and temper the wood, giving you the best chance to minimize set during tillering.