Weighing Balsa

[Kevin Wright]

Hi folks,
I had an interesting experience weighing balsa this week.

On starting a new model (Stanislav Cec's 'UNO' 1983 European F2B Champ) I took out a number of sheets of 2.5 mm (3/16)
for the ribs and decided to try out my new digital scales. The first sheet came out at 23 grams and the other three at over 40 grams each!

I was supprised at the difference between one sheet and another.

Off to Bunnings hardware (like Home Depot) for more sheet with my trusty scales and went through their entire stock of 2.5 mm
sheet and took all the light ones.

I don't know who bought what I left but I know his model weighs more than mine!
Kevin

[Dallas Hanna]

Hi folks,
I had an interesting experience weighing balsa this week.

On starting a new model (Stanislav Cec's 'UNO' 1983 European F2B Champ) I took out a number of sheets of 2.5 mm (3/16)
for the ribs and decided to try out my new digital scales. The first sheet came out at 23 grams and the other three at over 40 grams each!

I was supprised at the difference between one sheet and another.

Off to Bunnings hardware (like Home Depot) for more sheet with my trusty scales and went through their entire stock of 2.5 mm sheet and took all the light ones.

I don't know who bought what I left but I know his model weighs more than mine!
Kevin

Hope you didn't use 3/16" for ribs Kev!!   


H

[GregArdill]

Naa, That's what 1/4's for. It saves having to use cap strips.

G

[Kevin Wright]

Herb,
Oops you are correct - I meant 3/32.
Kevin

[Brett Buck]

Hi folks,
I had an interesting experience weighing balsa this week.

On starting a new model (Stanislav Cec's 'UNO' 1983 European F2B Champ) I took out a number of sheets of 2.5 mm (3/16)
for the ribs and decided to try out my new digital scales. The first sheet came out at 23 grams and the other three at over 40 grams each!

I was supprised at the difference between one sheet and another.

Off to Bunnings hardware (like Home Depot) for more sheet with my trusty scales and went through their entire stock of 2.5 mm
sheet and took all the light ones.

I don't know who bought what I left but I know his model weighs more than mine!
Kevin

  Balsa is pretty notorious for having a massive variability in the density, the lightest you can routinely get is around 4 lb/cu in, and you can easily find 16 lb/cu ft just about anywhere.

   Brett

[Tim Wescott]

One of the oddly convenient coincidences in the English system of measurements is that a sheet of balsa that's one inch thick, three inches wide, and 36 inches long has a weight in ounces exactly equal to its average density in pounds per cubic foot.  Since wood comes to us in fractional sizes, and since 3/32 wood is, for all practical purposes, 1/10 inch thick, this makes it easy to figure out the density of a 3x36 inch sheet.

3x36x3/32 weighing 23 grams is about 8 lb/cubic foot, which is nice but no great shakes.

You can learn to grade wood well enough without a scale for the purposes of buying it.  Just start by buying whatever feels light, then when you get home write the density on each piece with a felt-tip pen.  To teach yourself to grade it, guess the density before you measure -- do that long enough, and you'll get the knack.

[bill bischoff]

Of course, if it was a 4" wide sheet, it would be 6 lb. wood!