Balsa Wood

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Where can good balsa wood be found online? The selection of balsa wood at the local Michaels/Hobby Lobby leaves something to be desired. Several users have mentioned using specific density/stiffness wood and I was wondering if there was a website where that can be found.

[bernard]

These are quoted from the Bridge Building threads.

Does anyone know the best place to get balsa and bass wood? :)

I've used National Balsa and Specialized Balsa. I like that with Specialized Balsa I can select densities and grain (but at a higher price). I've also found that the wood cut by Specialized Balsa is very consistent while National Balsa's wood sometimes has some unwanted tapers. But National Balsa's wood is generally a lower price which makes it good for building a bunch of wood and testing general designs until you find one you like.

If you have one nearby, a local hobby shop allows you to hand select your wood, which can be the best option if you know what you're doing. When you order online you don't see the wood so people usually order more than they need, and some of it becomes scrap because it doesn't match their needs.

We try to buy basla wood from Michaels' however.. the weight is too haevy.. Can anyone provide the good recommendation where to purchase good density with light weight balsa wood?? Thank you all !!

https://www.specializedbalsa.com/ is a good bet for high quality- but realize you will pay a premium. We achieve GREAT results with balsa just from hobby lobby/michaels for bridges. I would recommend practicing/prototyping with the cheap stuff first and only if need be get the expensive wood (not so much for Wright Stuff- it needs to be really light wood).

[jander14indoor]

Don't dismiss your local Hobby Lobby/Michael's too quick. While much of the wood is garbage for our purposes, I can usually find some useful stuff, and it doesn't take a lot for these things.
You'll need to take a scale of some sort with you, nothing fancy, I use a simple postal balance that fits in my shirt pocket, you are only trying to sort wood quickly into correct density ranges.

I used to take in a table of wood sizes vs weight until I figured out a simple rule of thumb. A 3X36 sheet 1/32 inch thick weight in grams is very close to its density in lb/ft3 (common density units for balsa). From there, 1/16 sheet density is half its weight in grams, 3/32 is 1/3rd, etc. Rest of that conversion left as an exercise to the students...

I also check local aircraft hobby shops if you have any around you. Still a lot of useless wood for our purposes, but better typically better yield.

Note, I don't like to buy mail order because while you can buy for density and sometimes A/C grain, you can't check or buy for grain straightness, or gross stiffness. Both very important as you get more advanced.

Jeff Anderson
Livonia, MI

[calgoddard]

I want to expand on Jeff's comments about buying high quality balsa wood in a store, and not on line.

I was in an ACE HARDWARE store earlier this year. Much to my surprise, I discovered a bin of various sizes of balsa wood. I am able to tell what pretty good balsa wood feels like without a scale. Right away I located what felt like very lightweight, high quality C grain sheets. I cannot remember the thickness off hand, but I think they were either 3/32 inch or 1/8 inch in thickness. They were 36 inches long, and of course, either 3 inches wide or 4 inches wide. I recall that I purchased two sheets for something like $3+ per sheet. I had not even intended to buy balsa wood upon entering this ACE HARDWARE store, but the balsa wood I found was too good to pass up, especially for the price.

Anyway, upon returning home, I weighed these balsa wood sheets and according to my chart (from John Barker I believe) they turned out to be 4.5 lb. density! This kind of balsa wood is not necessary for building Wright Stuff airplanes, but can be useful in building Limited Penny Plane and A-6 models, for example. My point is that you might try looking for good quality balsa wood at an ACE HARDWARE store.

Good luck to you.

[bjt4888]

I am definitely in agreement with Jeff Anderson and calgoddard that you can find usable balsa wood at a Hobby Lobby/Michaels/Ace Hardware. The rules are well designed to allow use of commonly found grades of wood and still meet the minimum weight. A good wing can be constructed of 16 lb/cu ft 1/16" stick wood. This density of wood translated to a 3"x36"x1/16" sheet that weights 28 grams. This is easy to find and will construct a wing that weighs about 1.1 grams using ultrafilm covering. If you use the best quality grocery store bags for covering the wing will only be slightly heavier and still around 1.5 grams.

The fuselage and tailboom will most likely require a little better wood of up to 8 lb/cu ft density. A 1.75 gram fuselage can be cut from a 42 gram sheet of 3"x36"x3/16" balsa (dimensions 3/8"x12"). Also, easy to find wood. The tail boom can be cut from this same piece of wood and the stabilizer and fin can be stripped from the lightest sections of the 16 lb 1/16" sheet to achieve an airplane with overall weight of about 6.0 grams (with a trimmed Ikara prop).

Remember that any sheet of balsa wood is made up of varying densities. An 8 lb/cu ft sheet may have sections as light as 6 lb/cu ft and sections that are much heavier than 8. With a sheet 1/8" thick or thinner, you can hold the wood up to a light bulb, letting the light shine through the wood and see lighter and darker sections. More light through a section equals lighter wood. With a thicker piece of wood, you can sometimes identify the more dense sections by darker or grainier appearance of the surface. You can also flex a thicker piece of wood and possibly identify which edge is stiffer. Which usually tells you which edge is more dense.

Good luck and good science.

Brian T.

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Thank you all for your responses, they have been extremely helpful. I had not realized that Ace Hardware stocks balsa wood and will definitely have to check that out.
The problem I've encountered is that the wood I've been using to build spars was small sheets of very high grade and light 1/64" that came from a company that stopped selling supplies (A2Z I believe). The narrowest sheets I've been able to find are the standard 1/32" sheets at Michaels/Hobby Lobby, but these don't perform as well as the other wood. I've had several issues with wings either snapping at random points or bending upwards under any kind of aerodynamic load (lighter wood) or ending up at least a gram too heavy (denser wood). There doesn't seem to be an in-between with the wood locally available.

[Less_Incidence]

1/64" thick wood anywhere on a Wright Stuff airplane doesn't seem right to me. The smallest pieces of wood on my model are the wing and stab ribs, which are 1/16" square and about 5.5 lb/ft^3 density. Before I switched to carbon spars, my spars were all 1/16" high by 1/8" thick (cut from 1/16" sheet) of about 7.5 lb/ft^3 hobby-shop-grade wood, and the overall weight of my model was still barely over 5 grams. If your wings are buckling under aerodynamic load then there is a lot of structural rethinking to be done.

For reference, here are all the wood sizes from my 5.3-gram model, if I recall correctly:

Spars: 1/8" x 1/16", 7.5#
Ribs: 1/16" x 1/16", 5.5#
MS: 3/32" x 3/8", 8.0# (Braced with basswood post and nylon string)
TB: 3/32" x 1/4" taper to 3/32" x 1/16", 8.0# from same sheet as motor stick
Posts: 1/16" x 3/32" basswood

I was using a trimmed Ikara propeller at the time, and I think it was covered with SuperUltraFilm. Unfortunately I can't actually measure or look at the model as it was destroyed in transit between Lakehurst and my home and ended up in the garbage bag.

P.S. There is also the option of using carbon tubes for wing spars. Carbon fiber is more consistent and more resilient than balsa, and the weight penalty is nil on a Wright Stuff model.

[_deltaV]

Thank you Less_Incidence. I should have clarified that the spars were made by laminating two sheets of 1/64" together.

[Less_Incidence]

Again, even laminated spars of that thickness are, as you've found, not going to be able to handle the aerodynamic loads on a relatively high-speed Wright Stuff airplane. My F1Ds are more than twice the size of Wright Stuff models and less than 1/5 the weight, and I still use spars more than 1/32" thick on my F1D wings.

I'd be curious to see the full list of specifications of wood dimensions and densities you are currently using on your models, if you wouldn't mind. Having to have such flimsy wing spars, even with high-grade wood, means there is probably a lot of weight to be saved elsewhere.