Bending Hickory?

[Kev2007]

Hi all

I'm just wondering if anyone's had experience bending hickory for bass sides? I've got a local guy here with some interesting hickory (pecan) and I'm thinking of trying it out. I'm well aware of its weight and difficulty working, I'm just wondering how it bends. Also, because of its weight and density, is it conceivable that I could reduce the side thickness by, say, 1mm as compensation?

This will be a sort of 'travel bass', so the sides will be more narrow (shorter?) than a normal DB. Also, because it will rely more on amplification, I'm less concerned about the acoustic/resonant characteristics of the wood.

Thanks for your input!

Kev

[1st Bass]

The following list was gleaned from the internet:

Stock Selection
The U.S. Forest Service has evaluated 25 hardwood species for relative bending quality. In their testing, the best 17 woods were:

Hackberry (Best)
White Oak
Red oak
Chestnut oak
Magnolia
Pecan
Black walnut
Hickory
Beech
Elm
Willow
Birch
Ash
Sweetgum
Soft maple
Yellow-poplar
Hard maple (Worst)

This ranking represents the results from one evaluation; variation in the results can be expected from tree to tree and site to site.

from:
http://www.woodweb.com/knowledge_bas...ding_Wood.html

What I see as interesting is that it bends much better than maple. Don't know why they picked that particular list-- I have been told that Chestnut is the best for bending, and that American Walnut is right up there with it. There is a book available from Stewart-Macdonald on wood bending-- you might have a look at it.

Chet

[forester]

judging from your location it is most likely hickory...which has been for years marketed as "pecan" in order to increase the value in trade.
sizable true pecan is rarely available since most of the trees are kept for nut production (s.e. us) and tend to remain "standard"size trees. i have seen some monsters though,big,tall and straight.
hickory/pecan does bend well...and it is frequently bent in the round ie.handles,furniture,etc. you can shape it like the other bendables with steam/heat and it can be quite strong even when cut thin. BUT...
it has to be free of:
knots
birdpecks
mineral/stain
and you have to be patient,i have blown some up bending it in a rush.
it is stringy and very brash as a wood in general,and the timber that has grown in poorly drained soil has some drying/stability issues the sapwood is white and the heartwood is brown with a distinct grain. and oh yea,they graft apple trees on the rootstock since it is one of the few trees with a taproot. try to pull one out of the ground...

[Kev2007]

Thanks for the input, guys. I hadn't come across that web page in my searches. Very interesting, how the density of the wood species doesn't necessarily correlate to their ease of bending. More research nis definitely in order.

It was my error in referring to the local wood as pecan hickory - the sawyer is selling it as 'hickory', I incorrectly concluded based on other reading that the species native to my area was of the pecan variety.

I'm beginning to have second thoughts about using hickory, and it's becoming evident that this is perhaps why you don't see many luthiers working with it. Still, I'm intrigued, and may pick up some just to try. All this guy's wood is nice and clear, and very inexpensive. Within 10km of my house, too.

Peace,

Kev

[Matthew Tucker]

Chet is that list based on tests on steam bending, or just "how far will it bend before it snaps"?

If you want to use it for the back as well you need to find out how it shrinks and expands with moisture, because (for a flatback) there's a long glue seam and transverse bracing to think about. And what does the grain look like?

I think, if you can get wide clear dry quartersawn hickory at a good price near you, you have little to lose giving it a try.

In terms of thickness, you need to make your bass as light as you can without it imploding. That's a balancing act! Get your ribs down to 2mm -2.3 mm and do a few tests.

[1st Bass]

No clue, Matthew! I googled "bending characteristics of wood" or some such thing, and found that list.

There is a book called The Wood Bender's Handbook" by Zachary Taylor, which, as I recall, has much more information than one really needs. But your point is well taken-- what does the wood do AFTER it has been bent?

Hickory is supposed to be pretty strong and springy, is it not? I think I recall people making archery bows of them...(?)

Chet

[Matthew Tucker]

and axe handles ...

[Kev2007]

Originally Posted by 1st Bass

No clue, Matthew! I googled "bending characteristics of wood" or some such thing, and found that list.

There is a book called The Wood Bender's Handbook" by Zachary Taylor, which, as I recall, has much more information than one really needs. But your point is well taken-- what does the wood do AFTER it has been bent?

Hickory is supposed to be pretty strong and springy, is it not? I think I recall people making archery bows of them...(?)

Chet

Still thinking about this...

Is bending wood over an iron (or with a heat mat) the same (to the wood, that is) as steam bending? I suspect perhaps not, or we'd be doing it that way. If so, why aren't we doing it that way??

Thanks for your thoughts.

Kev

[1st Bass]

Some do use steam...but steam is a real bother, compared to a bending iron of any sort. You heat the whole piece in a steam box, then move it out and onto your bending mold (or what have you) and quickly roll it into the shape you want, then allow it to cool. With the bending iron, only the portion you want bent gets heated, at any one time.

My bass-bender is aluminum, and a monster, that I heat with propane. For violins, etc, I make wooden molds, and dampen the ribs, then use a flat bending iron (literally, an upside down clothes-iron), and bent the wood around the forms. For a celloor a guitar, I would use the bass bender, OR, as my son does, build a guitar-side bender. (look up Charles Fox side bender on Google...)

Chet

[Matthew Tucker]

if you heat a 2mm rib in a steam box, by the time you get it near a mould it will have cooled down past bending point. So, like Chet says, we heat and bend a bit at a time, UNLESS you use a silicone blanket (search this forum) in which case the whole rib is heated at once. It is the heat that allows wood to bend, not the steam. The steam is just a way of heating the wood evenly, and maybe protecting against scorches if the wood is heated by contact with hot metal.

if you are boatbuilding, the wood is significantly thicker, and holds its heat well enough to be bent out of the steam box. But you still have to be quick.

[Kev2007]

Originally Posted by Matthew Tucker

if you heat a 2mm rib in a steam box, by the time you get it near a mould it will have cooled down past bending point. So, like Chet says, we heat and bend a bit at a time, UNLESS you use a silicone blanket (search this forum) in which case the whole rib is heated at once. It is the heat that allows wood to bend, not the steam. The steam is just a way of heating the wood evenly, and maybe protecting against scorches if the wood is heated by contact with hot metal.

if you are boatbuilding, the wood is significantly thicker, and holds its heat well enough to be bent out of the steam box. But you still have to be quick.

Hmm. Very useful info, guys, thanks. So I guess if you had a positive and negative form all ready to clamp the steamed wood in, there still wouldn't be time?

Yeah, I've read all about the silicone mats - they look great but beyond the parameters of my budget right now.

I've been researching DIY bending irons; I can't think of why steel pipe would be better than aluminum if they're heated to the same temperature - am I correct?

Kev

[1st Bass]

Steel is not as good a thermoconductor, so it heats more slowly, cools more slowly, (and more evenly, I think)...BUT, if you are continuing to apply the heat, Aluminum is easier to keep it hot, plus guaranteed not to make rust stains.

Steel is much cheaper...easier to come by, etc.

[Matthew Tucker]

If you're prepared to make a positive and negative mould for each bout of a double bass then you could consider making your own laminated ribs from veneers without steam or heat. But there's a heck of a lot of work in making those positive and negative moulds! Think about how much that will cost! Suddenly the cost of a silicone blanket has dropped ...

[RCWilliams]

if you consider laminating the ribs a positive mould is all that is neccessary to vacuum bag them, another way is to use a thin strap made fom aircraft alu and pull the veneers down from the ends, like a belt. we use alu forms I made years ago. I stuffed bent up oven heating elements in them and used range top controls to contro0le the temp. we spritz the rib with water tuck it in the bending form and pull it down with the alu strap. we let it bake dry and then we move it straithe into the mould to cool. it works pretty well. the wood always relaxes a bit afterwards in this type of bending so I think it is best to over bend the c's about 10%, it is easier to bend them straghter to align with the plates than to bring the corners in tighter.

[forester]

http://www.tai-workshop.com/english/tech-2(b)-e.html
the strap method seems less likely to rupture the grain.

[uprightben]

In responce to Mathew's question about how hickory moves with changes to moisture:

I recently refloored my entire house in hickory. On the downstairs I made the mistake of not using a sanding sealer, and I get a lot of moisture induced movement. I was older and wiser when I did the upstairs and properly sealed it, and I haven't noticed much movement at all. My impression is that if you plug up the large open pores in hickory, it becomes very stable.

[forester]

+1 for stable when dry,conditioned and sealed..
it however,is subject to a very high % of shrinkage,(radial/tangential) in the drying process,more so than most hardwoods.it has many qualities, and is overlooked too often these days since man-made materials are subsituted in it's place.
long day= 20,000 bdft. of frozen hickory logs(any good sawyer will tell you to swedge a lead into the headsaw for frozen hickory ) to be sawn 4/4 ,5/4 etc. ahh... that smell.