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Building Tips and technical articles. => Building techniques => Topic started by: Gary Anderson on February 25, 2010, 08:35:00 PM
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Hi guys,
I need a little help from y'all balsa wood people. A friend gave me some balsa wood blocks, I'm not sure if they're any good, weight wise???? One of the blocks is 30" long 4 1/4" wide and 2 1/8" thick. The big question, is this wood any good for building models, how can ya tell when the wood is light enough for our use???? Man I hate to use this stuff for firewood. My friend gave me, I believe 12 wood block close to this size?????? Help Help (some of the blocks are just a little lighter but most are close to 9 3/4 ounces per block????? A little help from my friends, Gary
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Google the "Barton Model Flying Club", a really good Australian site that is also a forum. Click on forum, click on general, look under 'sticky' for balsa weight calculator. It really works. I use to use it for balsa now I use it for poplar and cedar since I no longer use balsa.
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Google the "Barton Model Flying Club", a really good Australian site that is also a forum. Click on forum, click on general, look under 'sticky' for balsa weight calculator. It really works. I use to use it for balsa now I use it for poplar and cedar since I no longer use balsa.
Barton: a good site. http://www.controlline.org.uk/phpBB2/portal.php
Australian: not so.
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I guess there are a lot of people not aware of the download area here:
http://stunthanger.com/smf/index.php?board=14.0
According to this , a little less than 4 pounds per cubic foot. That makes it Contest grade as most see it.
Robert
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Well bust my bubble! So the Barton site comes from England?
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If math doesn't make your head spin, and if you don't want to drag a computer into the workshop, just divide the weight of the wood in pounds by its volume in cubic feet. This is a bit of a pain because you'll weigh it in ounces and measure it in inches, but for your block it works like this:
(9.75 oz / (16 oz/lb)) = 0.6 lb
(30 in / (12 in/ft)) = 2.5 ft
(4.25 in / (12 in/ft)) = 0.35 ft
(2.125 in / (12 in/ft)) = 0.18 ft
(0.6 lb) / ((2.5 ft)(0.35 ft)(0.18 ft)) = 3.8 lb/cu ft
Or you can find the density in oz/cu in and convert:
(9.75 oz) / ((30 in)(4.25 in)(2.125 in)) = 0.036 oz/cu in
(0.036 oz/cu in)(108 (lb/cu ft)/(oz/cu in)) = 3.9 lb/cu ft
I get two different answers because I was rounding -- but that's close enough.
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If you have 36 x 3 sheets, you can divide the weight by the thickness to get density in lbs/ft*3.
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If you have 36 x 3 sheets, you can divide the weight by the thickness to get density in lbs/ft*3.
That's very clever. Now if only I can remember it...
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If you have 36 x 3 sheets, you can divide the weight by the thickness to get density in lbs/ft*3.
. . . the weight in ounces . . .
Larry Fulwider