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Main Boards => The Bowyer's Bench => Topic started by: Echatham on March 18, 2014, 08:34:00 PM

Title: Bamboo vs hickory backing for ipe trilam
Post by: Echatham on March 18, 2014, 08:34:00 PM
A friend just gave me a real nice ipe slat and ive got an elm slat for a core lam.  Im skittish of bamboo cause ive had problems with the two that ive done.  I was told you cant get the same speed out of hickory but i think that would just be a matter of controlling mass.  What say ye all?
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 18, 2014, 08:54:00 PM
I prefer hickory backings over boo mainly because hickory is more reliable. You won't notice the difference in performance between the two just by shooting them and in my opinion a reliable bow is more desirable than a few more FPS.
 Hickory backed ipe makes a great hunting bow. I'd make it 1 1/4" to 1 3/8" at the fades with a straight taper to 3/8" tips and put in 3" to 4" of Perry reflex at glue-up.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Echatham on March 18, 2014, 09:27:00 PM
Cool... Yeah im definitely big on dependable. Now heres another question.  I got a nice clean shagbark board... But it would have heartwood and sapwood both in it if i sliced off a backing.  Anybody ever use a hickory backing with heartwood in it?
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 18, 2014, 10:48:00 PM
I have heard that hickory heartwood is more brittle than the sapwood. I would use it for bellies but haven't used it for backings.
 Another plus with hickory backings is they are a lot less work to prep for backing. As long as you have two good glue surfaces it's good to go.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LESKEN2011 on March 19, 2014, 05:50:00 AM
I have used both with ipe, but Pat is right. The bamboo takes a lot more time to get right before glue up. The hickory is much easier to work with. I do like the way the bamboo looks, though, when the project is complete. They both seem to be snappy bows, if the design is right. I have made a couple with some heartwood without a failure, but never really thought about it since the grain was straight, but Pat may have a point about it being more brittle. Now in hind site, I will probably be a little more careful.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LittleBen on March 19, 2014, 07:36:00 AM
I've used both. Bamboo looks cool, but I like the look of hickory too ... I like a flatbow with flat back and belly.

I've used hickory with both sapwood and heartwood, and when it's half and half.

I have not noticed any decreased strength in heartwood. I ignore whether it's sapwood or heartwood. The only failures I've had with hickory are from grain runoff.

A straight grained hickory backing is super strong, quick to make (tablesaw), and easier to glue to the other lams IMO.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Echatham on March 19, 2014, 08:19:00 AM
i may give bamboo one more shot.  it gets pretty humid here for hickory.   white oak?  i got some clean white oak trees around....
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LESKEN2011 on March 19, 2014, 08:53:00 AM
I have used white oak with good success. Just make sure the grain is straight. Hard maple is terrific, too.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 19, 2014, 09:02:00 AM
You will never notice any adverse affects due to humidity on a hickory backing.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: 4est trekker on March 19, 2014, 10:53:00 AM
I'm not a self-professed expert.  There are many who make a fine BBB (James Parker, Eric Krewson, Walt Francis [I have one of his  :)  ], Roy, etc.).  However, I'm sure they'd tell you they've lost their fair share of BBB's along the way.  

That said, I agree with the above advice. Hickory selfbows or laminated bow with hickory bellies are more susceptible to humidity.  I've found that in our humid Nebraska summers, a hickory backing really doesn't suffer noticeably.  It's a bit heavier than bamboo when all is said and done, but I've found  boo to be really stinkin' touchy...but oh, so smooth!!!

I really worry when I'm shooting my BBB's in the woods about dinging or damaging the backing.  In fact, I've lost two super nice boo bows that I've babied due to unknown causes (boo imperfection, damage, poor construction, ???).   On the contrary, hickory is used for tool handles for a reason.  :)

White oak is a great backing choice, too.  Like hickory, it's also used in tool handles.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LittleBen on March 19, 2014, 11:22:00 AM
x2 what pat and 4est said.

Hickory is known to be mpoisture sensitive because it's compression strength changes alot and it will take more set in moist climates.

Although a little moisture may slightly reduce tensile strength, you woin't notice. It won't cause the bow to take additional set like it would in a hickory selfbow or a hickory bellied bow.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: bubby on March 19, 2014, 05:42:00 PM
I personally use hard maple, I think it is a much better backer than hickory
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Zradix on March 21, 2014, 11:21:00 AM
Working with hickory now for the 2nd time Eric.
First try the hickory was junk. It was kinda golden in color..be warned.

The second time ( and current ) the hickory seems great.
This hickory is white..or just very slightly yellow.

So far I like it.

I will say this...I wouldn't really want to use hickory unless I had a way or a person to thickness taper it. I'm sure flat pieces work but it just would bother me seeing all that weight at the tips.

It's nice having a flat back to clamp when gluing and working the riser.

The nice thing about boo..even though it's some real work..is that once you width taper it, you have a nice automatic thickness taper guide.

Only working boo 3 times and hickory 2...and not having completed a hickory backed bow just yet...I'm liking the hickory route a lot.

...I'm just not feeling that constant worry about the boo.
...maybe I should be feeling the constant worry about the hickory...but I'm not...lol
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 21, 2014, 11:43:00 AM
One nice thing about hickory backing(and other wood backings) is you can reduce or taper the thickness after you glue it to the belly. You can tiller from the back also if necessary.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Zradix on March 21, 2014, 11:46:00 AM
neat thought.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LittleBen on March 21, 2014, 12:09:00 PM
On that note Pat, I have a bow I'm working on now, and I was cutting the limb profile out with a hand planer, and I slipped and the bow turned 90degreees and I gouged a notch straight across the back of the bow ~1/32" deep. Not good at all.

BUT thankfully it was hickory, so I just blended that dip into the rest of the backing with a scraper etc. and just proceeded as normally.

If that was bamboo, that would have been the end of the day for that bow. No way to recover that one.

So tillering on the back can be a valuable tool .... so can firmly clamping down the bow before applying power tools ....
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 21, 2014, 01:12:00 PM
Power tools don't take a second and an unsteady hand to ruin a good bow.
 You still need the backing to be even. A dip in the backing instead of just a tapered backing can result in a possible hinge or weak area.
 If you used TB glue and you need to you can remove the hickory backing. You can heat it up to 150 deg and the glue will release.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: LittleBen on March 21, 2014, 01:28:00 PM
I'm with you 100% Pat. Fortunately the backing was more than  thick enough. When I say I blended in the dip, I blended it over a length of maybe 10" or more so the whole backing on one limb is tapered for the length of the working limb. Also the backing was pre-tapered so I just ended up adding slightly more taper and the dip is gone ...

The backing is thinner than I'd like but I don't anticipate any problems.

The bow is also a full 1.75" wide and the backing is not trapped, so I believe the stress on the backing is fairly low. Also only 44#, so not a heavy weight rig by any means.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: oldway on March 22, 2014, 03:28:00 PM
Just a question Pat on the grain of the hickory backing.Do you use edge or flat grain,and also how thick would you go.Any info would be appreciated,Dell.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Roy from Pa on March 22, 2014, 04:13:00 PM
so can firmly clamping down the bow before applying power tools ....

DAH, there's your sign...   :)

Your not from Virginia by any chance, are ya, Ben?  :)
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Pat B on March 22, 2014, 04:22:00 PM
oldways, edge or biased grain I think are the best but flat grain will work. You want as few runoffs as possible. I usually cut hickory backing strips at 3/16" and they end up at 1/8" or slightly thinner after sanding out the saw marks.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Echatham on March 22, 2014, 07:12:00 PM
Well i got sold on bamboo by a reputable bamboo advocate who surfaced long enough to pm me.  I got two pieces on their way now.  So im gonna give it a go.  Might be a couple weeks.  Been sick a couple days and now my springtime honey do list is getting away from me.
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Zradix on March 22, 2014, 07:49:00 PM
it's spring there?
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Echatham on March 22, 2014, 08:33:00 PM
Well most of the snow has melted and it hit 58 today
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: Zradix on March 22, 2014, 09:49:00 PM
Cool!

It's uplifting to know it's spring somewhere...lol
Title: Re: Bamboo vs hickory backing for ipe trilam
Post by: oldway on March 23, 2014, 10:58:00 AM
Thanks Pat for the info.