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Spruce or Basswood?

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Old 11-03-2004, 04:15 PM
  #1
Crash90
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Default Spruce or Basswood?

I am in the middle of building a Giant profile. The instructions call for a 1/4" x 3/8" x48" piece of Basswood for spar material. I don't have Basswood in that size but I do have Spruce.

Can anybody tell me if it will work?
What's the difference between the two? Thanks.
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Old 11-03-2004, 04:54 PM
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Default RE: Spruce or Basswood?

I don't remember the density of the different woods but spruce has a high strength to weight ratio. I would rather use spruce any day. I think there is a real shortage of spruce so basswood is used instead.

If you have time for some research check it out for different kinds of wood.

Carl
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Old 11-03-2004, 04:57 PM
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Default RE: Spruce or Basswood?

Thanks.
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Old 11-03-2004, 04:57 PM
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Default RE: Spruce or Basswood?

Basswood is hardwood. Spruce is softwood. I don't think I would want to use spruce for a spar. I haven't done a lot of building so I went looking and I found this:

Hardwood vs. softwood terminology is perhaps one of the most misunderstood concepts in regards to wood. Although most people assume that hard and soft refers to the overall strength of the wood, it in fact refers to the botanical grouping and structural differences of the wood species. In most species however, hardwoods (ash, oak, and maple, cherry) are more durable than softwoods (pine or poplar). Hardwoods for the most part offer greater choices in respect to natural finish, graining, texture and durability. Hardwoods are generally more expensive than softwoods, due to supply and workability (i.e. hardwoods are more challenging to work with).
For example:

Oak: Although over 60 different species exist, oak is separated into two main varieties: white and red (also known as black oak). Oak is heavy, durable, and light in color with coarse texture and highly visible grain. Of all of the hardwoods, oak is the most predominantly used.

Pine is a softwood, white or pale yellow in color. It is light in weight, and resists shrinking and swelling. Consideration should be given to the type of pine selected if it is to be used in residence hall furniture construction, as pine tends to be less durable and joints in pine furniture do not hold up as well as joints in hardwood furniture. Southern Yellow Pine is durable, although not as hard as oak or maple. Southern pine is strong enough to be used as flooring however. It is less costly in general than other hardwoods.

Do a search for hardwoods vs softwoods.
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Old 11-03-2004, 05:56 PM
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Default RE: Spruce or Basswood?

Years ago full scale airplanes were built with spruce spars. Other parts of the airplane too. No problem with spruce IMHO.

DaveB
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Old 11-03-2004, 05:59 PM
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Default RE: Spruce or Basswood?

Asked and answered:

[link=http://www.rcuniverse.com/forum/m_1684643/tm.htm]basswood or spruce?[/link]
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Old 11-03-2004, 06:28 PM
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Default RE: Spruce or Basswood?

Ah. Thanks.
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Old 11-13-2004, 03:19 PM
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Default RE: Spruce or Basswood?

Sitka spruce has been the choice of the aircraft industry for nearly a century.
One source for high-quality spruce is:
http://www.aircraftspruce.com/catalo...esparstock.php
You can get it to the thickness and length you need, and rip the width required for your particular model application. For example, ripping a half-dozen square spars from 3/8" x 3" stock would cost about $3 or so per 48" 3/8" sq spar. A bit more than basswood, I'm afraid...but not prohibitively so. Of course, continuous grain along the length of the spar is vital, and the member must be oriented with the grain vertical for maximum strength.
Although basswood is suitable for spars because it is relatively light, has nice, straight grain, and typically is resistant to warping, spruce is somewhat stronger and more elastic than basswood. It can flex more without failing - which is what you're looking for in a spar. It is more resinous than basswood, so you should plan on gluing with carpenter's glue (not CA) and reinforcing with shear webs.
For an exhaustive study on the mechanical properties of wood, check the USDA Forest Products Lab at: http://www.fpl.fs.fed.us/documnts/fp...tr113/ch04.pdf
A good example of spruce in a well-known model is the Sig Kadet Senior - where spruce is used in combination with balsa on the inboard section of the wing, where stresses are greatest...then balsa spars continue outboard.
Best...
pjw
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Old 11-13-2004, 07:29 PM
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Default RE: Spruce or Basswood?

Sitka Spruce is superior to Basswood for spars. It also costs a lot more which is why basswood is being substituted. Basswood is not the first choice, but used to keep costs down.

Even though bass is probably ok to use I either use balsa or spruce for spars in my planes and don't even consider basswood.
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Old 11-13-2004, 08:06 PM
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Default RE: Spruce or Basswood?

I think I read elsewhere in the forum that folks had some bad experience with Aircraft Spruce -- inconsistent dimensions? In that they serve the full-scale market, I suspect modeling tolerances are not something they think about too much. That's why I recommend ripping and finishing (joiner or drum sander?) what we want from larger stock. 3/8 sq or 3/8 x 1/4 spar stock typically...
;-)
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Old 11-13-2004, 10:22 PM
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Default RE: Spruce or Basswood?

That was probably me. I ordered some 1/8" x 1/4" and it was everything from 3/32" to 5/16". Not very well cut, but I can resaw it to the proper dimensions. Still annoying though.
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Old 11-14-2004, 10:29 AM
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Default RE: Spruce or Basswood?

Perhaps a bit of overkill for modelers, but R. Bruce Hoadley's book "Understanding Wood" is the de facto bible.

The 'debate' between hard woods and soft woods is largely irrelevant for our purposes, since balsa is technically classified as a hard wood.

Go figger.

Spruce is 'stronger' than basswood, and rider scale aircraft are still being built with the stuff.

Check http://www.aircraftspruce.com/catalo...s/capstrip.php

Plenty of sizes there for modeling needs.
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Old 11-14-2004, 10:32 AM
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Default RE: Spruce or Basswood?

Indeed Aircraft Spuce supplies the home-built market, and sometimes the smaller spruce sizes aren't spot-on for our needs, dimension-wise.

I dodge that issue by ordering planks, then ripping what I need.

Not many folks can do that, though.
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Old 11-14-2004, 11:25 AM
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Default RE: Spruce or Basswood?

With the shortage of spruce, at least in this area, I have found that some pine works out just as well. You have to be quite selective but I manage to find good close straight grained boards after diligent search through the lumber piles. These rip up into excellent spar material and, I think ever bit as strong as spruce and better than bass wood. If you have a good table saw and are willing to do some weeding out of stock lumber, you can have your cake and eat it too.
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Old 11-14-2004, 01:38 PM
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Default RE: Spruce or Basswood?

Has anybody done anything with bamboo? (Yeah, go ahead and laugh - ever tried to kill and pull out a patch of it?) Works fantastic for kites.... maybe good for stringers, etc? I saw some rather large blocks of it when I was in Japan, but didn't think to grab any at the time. No idea where you'd get it in the states... [&o]
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Old 11-14-2004, 09:30 PM
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Default RE: Spruce or Basswood?

Quote:
ORIGINAL: cwrr5

Has anybody done anything with bamboo?
My patch gets large doses of Roundup three or four times a year.

Ya want bamboo ? Come n' get it !!! I'll furnish the chainsaw.
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Old 11-16-2004, 09:08 PM
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Default RE: Spruce or Basswood?

Just to confuse the issue, I seem to remember several sources, including the Sig catalog and Thor Hyerdal's book 'Kon Tiki' mentioning that Balsa wood is actually a hardwood because it has true leaves rather than needles, and does seasonally shed them.
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Old 11-16-2004, 09:11 PM
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Default RE: Spruce or Basswood?

Almost missed the question about bamboo. In the days befor WW2, bamboo was frequently used for rounded outlines for wing and tail tips and even for struts and landing gear.
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Old 11-18-2004, 07:59 AM
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Default RE: Spruce or Basswood?

I would use the spruce as well. On my scale hydros, all the stringers are made from spruce. I read where someone said not to use CA when attaching spruce, but I've never had a problem glueing spruce to the birch ply framing and skin in my boats. Maybe it's the fact that I seal everything with a skimcoat of slow set epoxy that makes the difference. I've never found a good use for basswood, so I don't buy it
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Old 11-18-2004, 08:07 AM
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Default RE: Spruce or Basswood?

Plumber - If I happen to stop through there, I might take you up on that!

Actually, I'm suprised it's not used more in models.... I wonder why? After all, most of the arf's are contructed in the right part of the world....
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Old 11-18-2004, 11:59 AM
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Default RE: Spruce or Basswood?

I have a problem with the bamboo, no glue or epoxy seems to make a real good joint with it. As to using CA on any hardwood, this can be a problem as hardwoods tend to be acidic and CA's like basic materials. To solve this just very lightly coat your hardwood with plain old baking soda and it will help the CA bond. doesn't take much, just the barest brushing of soda.
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Old 11-18-2004, 01:33 PM
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Default RE: Spruce or Basswood?

I've used spruce and basswood, but it's always seemed to me that it's hard to get spruce to stay straight without twisting and building in delayed warps. I've built a lot of free flight hand launched gliders, and I use basswood for the fuselages even where spruce is called for just because iff I can find a straight piece of spruce, it doesn't stay straight long.
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Old 11-22-2004, 04:33 PM
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Default RE: Spruce or Basswood?

Pound for pound bamboo is stronger than steek!

The trick is getting long pieces. I have seen recently that they (whover that is) are making flooring boards out of bamboo. Now you can get long straight pieces that you can rip (carbide blade pls)
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Old 11-22-2004, 04:56 PM
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Default RE: Spruce or Basswood?

Just this weekend, I found a couple three-views in my files showing rubber powered free flight models from 1915. Fuse and wing spars from bass, spruce or boxwood, wing, stab and fin outlines and all wing ribs from BAMBOO STRIP, and props carved from pine or bass. Landing gear legs from bamboo or spruce. Horsehide glue, of course. You got your bamboo strip by CAREFULLY splitting a bamboo fishing rod. The bamboo was bent by forming it around a candle flame or a lighted electric light bulb. Covered by painting the wing frames with BANANNA OIL, and applying PACKING or GIFT WRAP tissue!
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