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Bamboo backing sapling bow

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Hamish:
Hey Rob, The spotted gum bow looks really good.

I would put the elm stave on a form for heat treating, and just to even up the reflex, makes tillering easier. Yes, it is a fair bit of work, especially if you need to make a form, but it can be used on further staves.

For bow timber, I'd try Matthei Timber at Yatala. It's at the other end of Brisbane to you. I haven't been there for a while, (I live down in Sydney)but they stocked Bulletwood/Beefwood/Massandubra, locally called Pacific jarrah. I rate this as a top bow wood, when backed with boo, hickory, or even a strip of straight grained bulletwood, and reflexed 1-2" in glue up.
 They also stocked some lemonwood, I think that was called Pacific ash, or something similar. Again, another highly rated bow wood when used the same way as with bulletwood, backed.
They had a small amount of Ipe, another top bow wood.

There should also be some bow wood, growing around your region. Red/Pink ash, alphtonia excelsa. Its usually a small to medium understory tree in dry sclerophyll forests. In rainforest areas, Saffronheart is another great native bowwood.

Roballa:
Thanks for all the encouragement and tips! Hamish - I’ll definitely check out the Yatala place next time I’m passing by.

After taking on board your advice I’ll leave the boo backing for another board bow instead of trying to back the elm sapling. In that case I’ll definitely try the heat gun on the belly as Hamish suggested (another new technique to try out!).

Just a couple of quick questions re the heat treating…

1. Should I wait for the sapling to dry out to stable weight/moisture content, then roughly shape and floor filler before heat treating while clamped to a reflex mould?

2. Would you heat treat again in the reflex mould after final tillering to further reduce set and strengthen the bow?

I’ve heard heat treating is good for white woods like this one, but comes at the cost of weakening the fibres - too much of a good thing?!

Thanks again Hamish and co - Keen to hear your thoughts on the right ‘order of operations’ to approach the heat treating for the elm sapling.

Cheers, Rob

Hamish:

Keep the tips wide, and start to floor tiller the limbs, so you get about 4-6" of travel. It should reach ambient moisture content quite quickly. Check it after a couple of weeks. You can correct the reflex without a really deep heat treat, with a heat gun, it still should perform really well.
If it's starting to take more set than you like during tillering, you can put it back on the form and give it a really long toasting session. After a good even heating you then try for an evenly toasted belly, darkened look(though not charred). That would absolutely maximise the stave's performance.

There are plenty of good videos about fire tempering white wood bows in 24hrs. Clay Hayes has done some which from memory were pretty good.
Its a little riskier than using a heat gun. Never tried it myself, but by all accounts, if done properly works like a dream for whitewood bows. Hopefully some other guys that do it regularly will chime in for some more in depth help.

Looking forward to seeing your results.

Roballa:
Hi Hamish and others who helped me out on this. I know the topic was about bamboo backing but it evolved into a project about Chinese Elm! Anyway, this is the final result of the kids bow. Adults size will be the same but bigger and heavier draw. I thought I may as well combine a few different techniques I hadn’t tried before - hence the snakeskin back, leather handle, string silencers, horn tip overlays and recurve. All seemed to go ok - thanks to Weylin from Swiftwood Bows !
Thanks again to everyone who gave me great advice! I’ll repost the pics if they have any technical issues like last time!

Pappy:
Looks like some beautiful work to me, thanks for sharing. :)
 Pappy

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