Ironbark and bamboo project.

[nigelo]

Hi All, my son and I have recently moved to beautiful Eildon in Victoria and are planning a winter project, two bamboo Backed Ironbark Flat bows, we have bought the build guide from rudderbows but at the moment we are struggling to find materials?
So if any of you guys are local and have any ideas we'ed really like some advice..

[Stickbow Hunter]

Firstly welcome to Ozbow. I would suggest doing some searches on here for bamboo supplies etc and you should find a place to purchase it. The ironbark should be available at most sawmills or Aussie wood suppliers down your way. I have a mate who has bought quite a number of Rudder Bows bow blanks so I will give him a hoy to post here.

Jeff

[Gringa Bows]

Welcome to Ozbow

[nigelo]

Thanks for that, I'm heading into Melbourne at the weekend so I'll drop into some timber yards on the way.

[slayer]

welcome fellow bowyer, very interesred to see how you go and see the progress, keep us updatedif you can, has any one else used iron bark to make a bow??

[Dennis La Varenne]

NIgelo,

I am the said mate of Stickbowhunter above who has bought a few Rudderbows blanks. What materials do you NOT have to build your bow. Jim Boswell at Rudderbows sells a huge variety of bow blanks at very modest prices and the shipping is not too bad either. Did you buy only the plans plus a couple of bamboo backing strips or just the plans with absolutely no materials.

I have some experience with Red Ironbark, and it does not need any kind of backing in the least. Quite sound bows can be made from it with complete disregard to growth rings. A bamboo backing strip will have no performance benefit unless you use the bamboo to bend the stave into some degree of reflex to induce some preload on the limbs. With reflex, I would expect very good performance indeed because of this wood's great natural strength.

The other issue is that I have no experience about the gluing qualities of Red Ironbark, ie. how well it actually glues up. It is not a particularly oily wood, so it will probably glue up OK.

If you trawl through the following thread, you can get an idea of what it can be like to work with Red Ironbark -http://www.ozbow.net/phpBB3/viewtopic.php?f=34&t=7445. It can be quite challenging.

If you have an angle grinder and are a deft hand at using one, you can take off quite a lot of by-wood quite quickly, otherwise a farrier's rasp which you can get for about $30 at Horseland (who will also mail it to you) is an excellent tool for shaping the stave prior to tillering.

[yeoman]

And that be my thread about making the longbow!

If you can find a sawmill nearby that processes ironbark, go to them with a 6 pack of a fine beer and offer it to them in exchange for some fresh flitches. Some people recognise this name at least. Flitches are the bits of the log that the mill cuts off to make the log square. This is pretty much scrap for the mill so they chuck it or sell it cheap for firewood. If you can find some clean, knot free, fresh flitches you could make bows from them.

Dennis and I get along very well, but our opinions differ on some points. I am of the opinion that ironbark is brolliant because it is exceptionally stiff and has tremendous compression strength. However my bend tests have suggested that the tensions strength of ironbark is not in proportion to its compression strength. That is, samples I have tested will break in tension shortly after only mild chryssaling.

That being said, a selfbow from ironbark is still a fearsome thing. And very efficient. But where I think ironbark really shines is when its compression strength is matched by a tougher backing, and glued into reflex. For making a boo backed ironbark bow, here's another one of my threads:

http://www.ozbow.net/phpBB3/viewtopic.php?f=3&t=4295

I've found ironbark at a number of places about Melbourne, but the names evade me for the minute.

Titebond 3 I have found at Carbatec. Don't know where else to get it from though. Rubber innertubes can be had for zero dallrs per tonne from the local tire place.

Bamboo I get from Bunnings. The largest and longest poles they have with the nodes as far apart as possible, with as few cracks and grey rot as possible. Other similar shops likely have poles as well.

Any more questions, jump on here and ask away. More than happy to help.

Dave

[Dennis La Varenne]

Dave (and Nigelo)

However my bend tests have suggested that the tensions strength of ironbark is not in proportion to its compression strength. That is, samples I have tested will break in tension shortly after only mild chryssaling.

. . . which I will take under advisement of course. But in bows I have made, and those I have of others' make, this has not happened at all. I have had some small frets on the belly (compression side) which I have treated with pricking which has stopped any further problems occurring.

That said, I have not done breakage testing as you have done to the point of rupture of the sample, so it could be said that the bows I have are well and truly below the modulus of rupture point and only a smidgeon past the elastic limit of the wood . . the amount of string follow being around 10 - 15mm.

So, Nigelo could still make a quite serviceable selfbow as a beginner without beginning at the more difficult point of backing. This could be his second bow perhaps. He could just keep it a bit longer with fine tips.

As an aside to the above, Dave, I have recently obtained some samples of Tonkin bamboo from Howard Hill Archery - both inside lamination (no rind) and lamination with the nodes and rind still on. I want to do some bending tests on this stuff in preparation for finishing my all-bamboo lam early Howard Hill design bow which has no fibreglass. I will post these results.

[nigelo]

Thanks for all the advice, the bow is progressing ok! we are looking at 70inches because my son is 6'6", we have bought a marine 2 part glue and making a seperate handle out of red gum.. I will post photos when I'm a little more confident how its going to work out. I bought a cheap ryobi band saw and belt sander from bunnings which work really well but I maybe have gone to far with the width of the limbs, about 1" at the thickest, I have left them fairly thick though and hope that this will make up for it, a good reason to have the bamboo backing!!. On another note My partner has an outdoor business and she has just become an Australian for Brisa Fi a finish knife maker, they have lots of interesting bits and bobs for the bowmaker, woods, horn and bone for nocks etc I will be bringing over some supplies at the end of July and will happily add to the order. the advantage to you guys will be no silly international postage charges just what it costs to post within Oz or pick up from Eildon Vic. check out the catalogue at www.brisa.fi. you can email on nigel.charlie@googlemail.com

[yeoman]

Glad to hear it's all going well. Don't be self conscious about sharing in-progress pictures though, we might be able to spot a problem before it turns into something more serious.

When you say you've gone too far with the width, do you mean you've made it too narrow? 1 inch is quite narrow, but not overly so for ironbark, doubly so if bamboo backed. I have a bow in the shed that's 66 inches nock to nock, draws 30lb at 28 inches, and is 26mm wide. Bamboo backed spotted gum with no glued in reflex. At its thickest the stave (minus the backing) is only 19mm thick. With a bamboo backing, heavy Australian woods can do amazing things.

Looking forward to seeing some pictures.

Dave

[Dennis La Varenne]

Any more developments with your project, Nigelo???