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I was wondering where to buy balsa from.

In structural events (Bridge Building, Towers, etc.), consistency in wood are very important. For flight events, it isn't as important, but a lot of the same material supplies can be used.

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Home Depot is a really good place to get wood, especially because they usually have random pieces of wood lying around the back of the store that they let you pick up for free.

I've been using Specialized Balsa. I've found that being able to choose specific weights of dowels has been incredibly useful. That, and grain selection can also be incredibly important.

People make a big deal of finding the best source for balsa. But frankly you can buy perfectly good balsa almost anywhere. The trick is knowing what you need and sorting through what is available to get it. You don't need super special balsa for WS.

-Have a scale when you go to your local balsa source (hobby shop, Michael's, Hobby Lobby, etc).
-Develop a table that shows the weight of common balsa sizes vs weight vs density.
-Use the scale and table to sort through the balsa to find the correct density first.
-Then sort through correct density to get straight grain.
-Then sort for stiffest pieces.

You'll only find a limited number of pieces that pass all those tests, but you don't need a lot of balsa for WS. And what you buy WILL be useful.

Jeff Anderson
Livonia, MI

I've used balsa for various projects, including Wind Power. I bought mine from Michaels- careful to check for weak spots in the wood though.

In my area there are not very many shops that sell balsa. Most of the time it is so picked over that it is worthless. I tend to go by the balsa shelves whenever I am in a shop that has it. I have on a few occasions found some good balsa, so pick thru it and buy a few. I have gotten some very nice and some sorry balsa from both Sig and Midwest. They are cheaper than specialized balsa who I have normally gotten very good wood from at a very high price. I have a sheet or two from time to time that is under their normal standard. Shipping runs the price per sheet/stick up unless you are buying a larger amount.
There is no quality control when you buy on line like ebay. You can frequently get good wood, but not high quality.

What do you mean when you say get the stiffest wood? I always thought grain affected the flexibility of wood the most.

Kyle,

Balsa wood is a natural matieral and it varies in many ways, including grain, density and stiffness. For the purpose of constructing a WS airplane, stiffness will be a factor to consider for some of the parts that require lower density wood (ex. Fuselage and ribs may need to be 6 - 8 lb/cu ft wood and the tail boom would be well served to be 6 lb/cu ft or less). The most important balsa characteristics to consider for your airplane will be density and overall part weight.

If you want to carry the analysis Of stiffness to a high level, I have an MSExcel spreadsheet developed by Slobodan Midic that calculates modulus of elasticity and stiffness relative to a maxwell solid based upon buckling force. I can guide you to this spreadsheet if you are interested.

Brian T.

"Balsa wood is a natural material and it varies in many ways, including grain, density, and stiffness. For the purpose of constructing a WS airplane, stiffness will be a factor to consider for some of the parts that require lower density wood (ex. Fuselage and ribs may need to be 6 - 8 lb/cu ft wood and the tail boom would be well served to be 6 lb/cu ft or less). The most important balsa characteristics to consider for your airplane will be density and overall part weight."

Isn't lower density wood more flexible? Are some pieces just naturally stiffer than others even though they are the same grain and density?

"If you want to carry the analysis Of stiffness to a high level, I have an MSExcel spreadsheet developed by Slobodan Midic that calculates modulus of elasticity and stiffness relative to a maxwell solid based upon buckling force. I can guide you to this spreadsheet if you are interested."

In a sentence I will understand (if I am right), this spreadsheet calculates the stress:strain of an elastic and viscous material.