White Oak as a backing?

[Wooden Spring]

OK, so someone told me that White Oak makes a good backing material, so I gave it a go. I had some red oak laying around so I thought I'd do two things, test out some Resorcinol Resin that I just got in the mail AND see if white oak makes a good backing material...

I made a Red Oak bow backed with White Oak, and both were quarter sawn. It was 2" wide and 70" long. I had it tillered beautifully on the long string to around 42 pounds, so I put a proper length string on it and started exercizing it on the bowflex, and when I had it tillered to 24" it cracked...

The quarter sawn white oak lifted a huge splinter.

So, trying to see if this was a fluke, or was rather what should be expected out of white oak, I flipped the bow over, stuck it in my vise, and bent it until I heard the first crack. The 4th picture where you see the limb bent to 90 degrees is where I heard the first crack. It exploded shortly after that.

On a good note, the Resorcinol worked MARVELOUSLY! It literally ripped the wood apart at the breaking point, proving that the glue is truly stronger than the wood.

OK, so DOES white oak actually make a good backing material after all, and I just had a fluke crack? Or should I just stick to hickory?

(PS, I do actually have a couple white oak trees in the yard that we need to fall, so out of curiosity, I may start on a selfie as soon as they're down and seasoned)

[DarkSoul]

That white oak clearly shows a razor sharp edge. You should round the edges of all woods, especially the edges along the back of the bow. A sharp edge concentrates the stress, so a splinter is likely to lift in any wood.

[Wooden Spring]

That white oak clearly shows a razor sharp edge. You should round the edges of all woods, especially the edges along the back of the bow. A sharp edge concentrates the stress, so a splinter is likely to lift in any wood.

I actually had all the edges rounded over quite nice, then I fine tuned the weight of the bow by reducing the width a bit, then apparently I forgot to re-round over the edge...  RATS...  I can't believe I made that mistake.

So would the White Oak have done alright as a backing if I had re-rounded the edges???

[Hrothgar]

I wouldn't give up on white oak. Your vice bend test shows the properties of the wood. JMO

[Joec123able]

Looks like a growth ring runs off the edge right where it popped a splinter. Either way the bend test proves something

[Cameroo]

I would agree that the square corners were likely the problem, and not the wood.

I've used quartersawn white oak backing on several ipe bows. and they are likely my best flat bows to date.  If you are doubting the tension strength of the wood, just take one of your backing strips before glue up, and give it a bend.  I'll bet that you can damn-near tie it in a knot

[bubby]

I've never had a good pc of white oak fail, now I'm on my phone so it may not be the best image. But the grain in the pic looks iffy to me,  with quartersawn you can't have any illregularitys in the grain as that is a violation and a weak point, in your bend test it clearly shows how good it is

[arachnid]

I`ve made several white oak backed bows and self bows (here`s one- http://www.primitivearcher.com/smf/index.php/topic,47175.0.html).
It has great elasticity. As Darksoul said, it looks like you didn`t round the edge. Just remember to use straight graind boards and keep
it thin (I had white oak backing overpowering an ipe belly... )

[Wooden Spring]

I`ve made several white oak backed bows and self bows (here`s one- http://www.primitivearcher.com/smf/index.php/topic,47175.0.html).
It has great elasticity. As Darksoul said, it looks like you didn`t round the edge. Just remember to use straight graind boards and keep
it thin (I had white oak backing overpowering an ipe belly... )

I've heard that phrase before, where a backing "overpowers" a belly wood, but it's never been explained to me.
Could someone tell me what it means when a backing overpowers a belly wood, and how do you know?

[bradsmith2010]

it will crysle the wood on the belly if the back overpowers the belly, or cause a hinge etc,,,

[bubby]

Personally I think it's a matter of the wrong design for the wood than the back overpowering the belly, but that's just me, with proper design for the wood and good tillering I'm not sure you have this problem

[Hamish]

Quartersawn doesn't necessarily mean the grain is straight on the edges of the backing, and growth rings on the side can give you a misleading opinion. You need to look at the grain, use a magnifying glass if necessary. If the backing is 1/8" thick, the grain should run at least 2.5" from the belly side to the back. 1 in 20 ratio. If the backing was 1/4 thick, the grain should run a minimum of 5". This works well for hickory, oak might need to be even straighter to work, I have no experience with it.

Like the other guys say, round the edges.
       Hamish

[mikekeswick]

Backings don't 'overpower' bellies.....either the design was wrong from the outset eg. not wide enough or operator error (bad tillering) causes hinges.
I've just got my first ever board of white oak to use as backings. Lovely and straight on the quarter but it has lots of medullary rays which are making me nervous....I need to do a bend test like yours!
Oh and resourcinol is one of the very best glues out there. Excellent stuff!

[bubbles]

Am I crazy or does that backing look a bit like hard maple? I can't see any of the squigglywhos that oak has.  I can see them on the red oak belly.

[Wooden Spring]

Am I crazy or does that backing look a bit like hard maple? I can't see any of the squigglywhos that oak has.  I can see them on the red oak belly.

It's not nearly as white as hard maple. Trust me, it's white oak. I bought some hard maple along with the white oak on the same shopping trip, and I can post pictures later for comparison if you want.