Heavier Wood in building!

[Andrew Tinsley]

Hello All,
   Over the years I have acquired various Job lots of balsa. I have used the lighter wood and am now left with a lot of 12 to 15 pound per cubic foot wood sheet.
  Tongue in cheek, what do you think of the idea of using 1/16 sheet instead of 1/8 etc when building the next few sports models? Any other suggestions apart from burning it in my shop stove next winter?

Andrew.

[john e. holliday]

Sell the heavy wood to your racing or speed buddies.  To me the heavier wood seemed to work okay as it took less finish for the base coats.  I know of an individual that used hard wood like spruce in thinner/smaller sizes to build with.  It is all in the construction.   

[Dwayne]

I've used heavier 1/16" balsa and 1/8" square bracing to build fuse sides and it worked fine but model met an untimely end so I don't know about longevity.
Dwayne

[sleepy gomez]

I build using NO balsa.  I use poplar and cedar from Home Depot and white foam.   Weight doesn't suffer at all.  I hot wire cut foam wings by myself with out a machine.  Fuselages are foam core with poplar or cedar cover.  Tail plane  is foam with poplar LE and TE.  Fin is foam with internal poplar spars.  Covering is clear sealing tape or silkspan.  Paint is Rustoleum or HD acrylic.  Minwax urethane clear for fuel proofing and shine.  Examples: 500 sq in Dragon Witch w/ OS 40 weighs 42 ounces, 390 sq in FireBelle w/ Fox 25 weighs 25 1/2 ounces.  Best yet I build a plane for under $20.

[Andrew Tinsley]

Hi Sleepy,
  Your no balsa regime sounds good to me. However I do have rather a lot of balsa that needs to be used or burnt. So until I have got rid of that, the no balsa regime will not be implemented!

Thanks,

Andrew.

[Clancy Arnold]

Sleepy
Sell it to some RC guys. 
Clancy

[Tim Wescott]

Tongue out of cheek, I wouldn't hesitate to replace ribs, capstrip & sheeting of 3/32" super-dooper-light balsa with the same of 1/16" harder balsa.  Ditto for fuselage formers, tail feather ribs, and even fuselage sides if they're meant to be flat.  Planking would be hard, because you do a lot of shaping.  Clearly, things like big blocks that are to be hollowed and shaped just need to be light balsa, or you need to replace them with molded -- which would require some significant redesign, and would demand 'A' grain, and gets harder as the balsa gets more dense.

(Stepping completely away from balsa for a moment -- has anyone tried shaped foam, with a hard fiberglass or CF shell?)

As balsa gets more dense its strength to weight ratio actually increases -- but there's less surface area for gluing, and less margin for sanding away strength in pursuit of a nice contour.

I weigh every piece of balsa I use, then decide where it's going to go.  Ever since I started doing this -- even without consciously thinking about it otherwise -- my planes have gotten lighter.  I suppose at some point I'm going to have a huge pile of balsa in the "use only for spars" bin and nothing in the "use for fairings" bin, but at least in the mean time I'm maximizing strength, minimizing weight, and not spending too much extra in the process.

[Wayne Collier]

  I use poplar and cedar from Home Depot and white foam.

  Fuselages are foam core with poplar or cedar cover.

  Best yet I build a plane for under $20.

How thin can you get the poplar or cedar?  The thinest I have seen in the local Lowe's is 1/4" thick.  I haven't thought of seeing if they have veneers.

[Garf]

At the end of one aviation job, I had little to do at night, so I went to the back and came up with some pallet wood that was clear and nail free. I then set up a rip fence on the 20" band saw. I proceeded to cut very thin wood from the pallet wood. Some pieces were better than others, but it was all usable. I like to use it as planking in high stress areas, like the center section front of combat wings. I just used some to repair damage to the Fronkensteen wing.

[phil c]

Hello All,
   Over the years I have acquired various Job lots of balsa. I have used the lighter wood and am now left with a lot of 12 to 15 pound per cubic foot wood sheet.
  Tongue in cheek, what do you think of the idea of using 1/16 sheet instead of 1/8 etc when building the next few sports models? Any other suggestions apart from burning it in my shop stove next winter?

Andrew.

Just keep an eye on the weight as you build Andrew.  Use thinner sheets, smaller spars and longerons, put on a light finish, and you can build a very competitive plane with heavy wood.

[Andrew Tinsley]

Hi Phil,

  Your advice seems pretty sound to me. I will give it a try. I always weigh my materials, because I usually finish up on the porky side if I use the TLAR method of selecting wood.
  In terms of finish, I am always amazed at the billion dollar finishes that you guys in the US seem to strive for. All that sanding and coat after coat of whatever the guy fancies. The results are stunning and I am in awe of some of the planes depicted on the forums. What is the added weight of these finishes? probably 6 oz in a 50 plus oz plane?
  I go for a neat lightweight finish, usually Mylar film with doped, dyed silk and the minimum of fuel proofer. I would use some of the 'cote finishes, but they impart no strength at all to a wing and hence you need to beef up the wing structure. As a weight saver they are a delusion!
  From what has been said so far, no one seems to think that using denser thinner wood has serious drawbacks. So I shall give it a try. Do we all just slavishly follow the recommended size of wood on the plan without too much thought?

Andrew

[Ward Van Duzer]

Ever since I got a raft of "stuf" from Hunt, I've built all my fuselages out of 3/32nd good light wood. Never had a problem! even some 60 sized monsters. Not my normal build! No reason I see that you couldn't use stif 1/16th as long as you can keep it straight. Also, think about butt gluing that 1/16th into wing sheeting, then sanding down to 1/20th. Good luck

W.

[Jim Thomerson]

I have a bunch of Testors wood.  It is amazingly heavy. This is a useful discussion.  Incidentally, have you tried burning raw balsa?  It does not burn well. 

[Tim Wescott]

I have a bunch of Testors wood.  It is amazingly heavy. This is a useful discussion.  Incidentally, have you tried burning raw balsa?  It does not burn well. 

Comet kits are frustrating, because they take these sheets of balsa that are better than spruce for spars, then they crunch them all up into really bad patterns for wing ribs and fuselage formers and whatnot.  Their printwood kits are much better, because you can transfer those patterns to paper then strip the wood into whatever you need for really high strength parts.