Bass vs Obechi

Hi,
I bought a couple of strips each of 1/8" x 3/8" obechi and bass wood today to
use as servo bearer reinforcements having got tired of slicing up 1/8" plywood
into strips. I didn't buy spruce because it has a tendency to split when you
put screws into it.
I know it doesn't matter much for this application but can anyone tell me the
differences in these two woods (obechi and bass) when it comes to aeromodelling
? Bass seems like a vewry good quality quite hard balsa and I would seriously
consider using it for wing spars and fuselage longerons where balsa's
variability can be a nuisance. I know obechi is used for skinning foam wings
which presumeably means it's good for making into veneer but what is it good for
in strip form ?
Any comments welcome (probably :-)
Cheers,
Reply to
Boo
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I have never used obeche or basswood...simpler to use spruce and pre drill the servo screw holes with a 1/16 drill bit...no splitting in many decades of r/c installations.... I use 3/8 square spruce...and sometimes I cut strips of 1/4 inch five ply plywood and make servo bearers out of that....all predrilled with 1/16 bit...never any problems...no splitting..no pulling out of the wood...why do it the hard way searching for obechi and basswood and other somewhat exotic woods?? Frank
Reply to
Frank Schwartz
Well this is the easy way now I've bin and gone and bought it :-) (Two 3 ft lengths should reinforce all the servo mounts I'm likely to need for a bit ;-).
Seriously though, I did hunt around and it seemed just as easy/hard to buy the bass and obechi as it would have been to get spruce. I just want it to reinforce the typical ply radio trays you get in ARTFs so 1/8" thich does me fine. The splitting problem with spruce does go away if you drill pilots as you say, but I just thought it'd be easier and safer to try another type of wood.
Cheers,
Reply to
Boo
Bass is not a 'flavor' of balsa, it's a completely different species. Spruce, and perferrably Sitka Spruce, is considerably stronger tha bass, and is the wood of choice for structural components.
Obechi is somewhere between bass and spruce in hardness, which makes i suitable for sheeting. OTOH sheeting with balsa and covering wit epoxy/glass results in a less expensive and more durable skin.
Bass isn't really all that good for our sort of modeling because it' more brittle and less tolerant of bending loads than spruce, an because it's heavier than balsa.
I use plain old Red Oak for servo bearers. It's not all that muc heavier than spruce or bass, and it's a good deal harder and stronger. The weight penalty for Red Oak mounts is negligible, and you can make -lot- of mounts from a 1x12x48 Red Oak plank from The BORG.
I also use 'these
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serv mounting screws. The socket head makes it a lot easier to drive tha standard servo mount screws.
You should be using a hard wood for servo bearers, not bass or spruce although you can 'get away with' the softer woods.
You won't split any more bearers if you pre-drill the screw holes a Frank pointed out
-- the-plumbe ----------------------------------------------------------------------- the-plumber's Profile:
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Reply to
the-plumber
There's nothing wrong with spruce, except that it's a bit slow to stick with cyano. You should drill pilot holes in servo bears whatever they're made of, I just hold the servo in place and drill through the centre of the mounting hole with a small dremel type drill.
Greg
Reply to
Greg
One final gasp about basswood. Back in the thirties and early forties, it was the specified wood of choice for engine mounts for gas engines in the old free flights...often scratch buiilt from magazine plans and basswood was always specified... things change.... Frank
Reply to
Frank Schwartz
Bass is about as good as it gets for hard balsa replacement - its a fine grained stiff and even wood. Makes great struts and spars.
Obeche is lighter and not as strong. I have used it on very small models to make e.g. wing and tail outlines..its very fine grained and sandable, and in fact I reckon that 3/32" obeche sanded well down weighs the same a 1/8" hard balsa, and is more reliable and sands better.
Reply to
The Natural Philosopher
I say the grain is seldom straight and it tends to split. Its not as stiff either.
I'd use bass every time rather than spruce.
Reply to
The Natural Philosopher
Actually I thought beech was what they used.
Bass (Lime or linden tree, wood) is used a LOT these days in electric models. Its possible to get great stiffness in a small dimension. Spruce is to my mind inferior - its heavy, rough, doesn't sand well, isn't as stiff, has a grain running every which way and it's coarse to boot.. and tends to split. It PROBABLY has greater TENSILE strength, so if that is what you want go for it. But usually I want a predictable wood which is straight grained and stiff. Bass is it.
Obeche is light and not hugely strong, but its one of the few woods that approach balsa weights, its very even grained and very fine grained, and if you want fine detail on thin bits of balsa, obeche makes a decent substitute.
Spruce may be the king of 'structural lumber' as bought for making houses..although pine is in many ways a better finish, but in terms of real hardwoods, it isn't in the running. Oak, mahogany, Iroco, Bass obeche, ramin, beech..even poplar as used in lightply or birch as in standard ply - these are all in many ways better woods.
Reply to
The Natural Philosopher
Bass is a great, straight-grained wood and is commonly used for servo rails, spars, etc. Of course, you should always drill pilot holes for servo screws.
Obechi is a pretty wood if clear-coated, and is most often used as a veneer sheeting. It's biggest problem is the wavy grain it has -- it's horrible to plane or carve. It's also quite light.
Someone else mentioned Spruce as being slow to accept CA glues; to fix this just sprinkle some baking soda in the palm of your hand and run the strip through the powder, just get a thin coating then wipe most of it off.
Cheers -- \_________Lyman Slack________/ \_______Flying Gators R/C___/ \_____AMA 6430 LM____ / \___Gainesville FL_____/ Visit my Web Site at
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Reply to
Lyman Slack
I haven';t found it nearly as hard to work as spruce..seems to have a very nice close grain to me.
> > Someone else mentioned Spruce as being slow to accept CA glues; to fix this > just sprinkle some baking soda in the palm of your hand and run the strip > through the powder, just get a thin coating then wipe most of it off.
Reply to
The Natural Philosopher
Baking Soda is like Viagra to CA, if you know what I mean.... ;-)
I once tried making home-made, low-budget CA accelerator by putting a baking soda solution in a little pump spray bottle. It didn't work real well so I spend the few dollars on the real thing.
Good flying, desmobob
Reply to
Robert Scott
Obeche was often used as a balsa substitute in just post WW2 kits. It is much harder and heavier and more brittle. I would go for Bass which, if I remember correctly, is another name for lime - not the citrus variety.
Malcolm
Reply to
Malcolm Fisher

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