Bass or Balsa Wood Fins

[Scode68]

I got to thinking and was wondering if Bass wood would be better to use for the fins on a rocket. It definitely is stronger but might be heavier.

[Gillard]

I got to thinking and was wondering if Bass wood would be better to use for the fins on a rocket. It definitely is stronger but might be heavier.

it is stronger, but it is heavier.
balsa wins on low power cos its the lightest

[bradycros]

I look at it this way. I am not trying to set a record with how high I get rocket "X" to go. I want the least damage done when the fins hit the ground. If rocket "X" climes to 800 feet with balsa fins and olny climes 795 feet with bass wood fins because they weigh 1 gram more ( just an exsample ), big deal. And with a hard landing, bass wood does better.

[Micromeister]

Yes: Basswood offers several advantages over balsa, but is a bit heavier. it's generally possible to reduce the thickness of basswood making the weight trade-off almost a wash.
Generally if the kits supplies, 1/8" balsa we can reduce it to 3/32" basswood without another thought, 3/32" balsa you can easily use 1/16" basswood, etc. Sometimes if you like the look of the thicker fin just use a direct replacement thickness really doesn't add all that much extra mass.

Basswood requires far less finish filling and/or sanding. or can be "papered" for additional strength.

As a scretch builder I almost never use Balsa for fins anymore, Basswood is always my preferred 1st choice.

[powderburner]

Have you tried all the varieties of balsa? Have you checked out the high-density end of the range? (I'm not saying you have to stick with balsa at all costs, just asking.) Some high-density balsa will be pretty close to basswood in strength, density, and fine-ness of wood grain.

If you really need the extra strength, probably the simplest, cheapest, fastest option is your basswood idea. Select a good grade and it will be one of your top options.

You could use fiberglass over balsa but this could easily get to overkill for your application. You would definitely get more strength but you would get quite a bit more weight also.

If you are worried about weight you could also use model airplane construction techniques and build with some spruce spars (at maybe 30% and 60% chord), a root rib and a tip rib, cover with thin plywood (1/32nd or 1/64th), bend the plywood so the leading and trailing edges touch, and glue everything in place. If you don't go glue-crazy this could be a weight-competitive design option. If you are really worried about panel stiffness you could foam the voids with a low-density foam (this foam is merely for panel support, not for any significant structural strength) but the foam will start adding weight again---and you might not want a fin airfoil with a sharp trailing edge (prone to damage?).

Or, a very soft (and light) balsa core for carving to the desired fin shape, and laminated with thin plywood (1/64). Definitely a heavy construction technique.

Not quite so good for strength or weight, but another option worth mentioning, use a thin plywood core (1/16th?) and laminate some balsa on the outsides to give you some material for shaping.

Is your rocket a mid- or high-power design? How long is the root chord, and how thick will the fin be? If it is low-power, a good piece of medium or high density balsa will likely work just fine.

[Boosterdude]

Basswood does offer a lot of advantages over balsa. No doubt it reduces the damage from landings. For most LP shape fins the weight gain is minimal, and finishing is much quicker because of the tighter grain.

[MarkII]

Absolutely agree with powderburner's post. But you can significantly increase the strength of balsa fins, and still have them be lighter in weight than equivalent ones made from basswood, by gluing paper onto both sides of them. Some people bond regular printer paper to them using white glue; others swear by using sheets of adhesive-backed address label stock. I just used a technique that worked really well to reinforce the balsa fins for my clone of Estes Industries' The Bat. These fins were long, thin and upswept, so they were prime candidates for reinforcement. I used a sheet from a roll of Reynolds Freezer Paper (http://www.reynoldspkg.com/reynoldskitchens/en/product.asp?prod_id=1798) for the reinforcement. This is heavy kraft paper, similar to butcher paper, but what is really neat about it is that it has a smooth coating of plastic on one side. You glue the uncoated side to the fin, and have the plastic coated side as the new surface for the fin.

Now people who reinforce balsa by gluing paper on with white glue warn about the moisture in the glue causing the fins to warp, but that is because they apply the glue to the fin surface, and then stick the paper onto it. What I did instead was to spread the glue onto the paper, and then stick the fin down onto the paper. Applying the glue in a thin, smooth layer makes it similar to self-adhesive address label stock. I took the sheet of freezer paper and taped it, shiny side down, onto a smooth table. Then I applied a thick bead of white glue to the edge of a craft stick, and used it squeegee-style to spread a thin, even coat of glue onto a section of the paper that was just larger than the fin. Then I pressed one side of the fin down onto the glue-bearing surface. After doing this for all three fins, I did place a light book over all of them, just in case the paper decided to wrinkle (it didn't).

When the glue was set an hour later, I cut around each fin with scissors, leaving a bit of margin around each one. Then I repeated the process to adhere the freezer paper to the other side. I placed a book onto top of them (again, I'm not sure if this was really necessary) and left them overnight. Again I cut around them to free them from the paper.

Finally I fitted my craft knife with a new blade and carefully cut off the fringe of paper from each fin. The result was three strong and warp-free but very lightweight fins with sealed smooth surfaces that were ready for priming and painting, once I had attached them to my rocket. I did apply water-thin CA to all of the edges except the root edge in order to seal the edges of the paper as insurance that they wouldn't subsequently lift up.

MarkII

[luke strawwalker]

Absolutely agree with powderburner's post. But you can significantly increase the strength of balsa fins, and still have them be lighter in weight than equivalent ones made from basswood, by gluing paper onto both sides of them. Some people bond regular printer paper to them using white glue; others swear by using sheets of adhesive-backed address label stock. I just used a technique that worked really well to reinforce the balsa fins for my clone of Estes Industries' The Bat. These fins were long, thin and upswept, so they were prime candidates for reinforcement. I used a sheet from a roll of Reynolds Freezer Paper (http://www.reynoldspkg.com/reynoldskitchens/en/product.asp?prod_id=1798) for the reinforcement. This is heavy kraft paper, similar to butcher paper, but what is really neat about it is that it has a smooth coating of plastic on one side. You glue the uncoated side to the fin, and have the plastic coated side as the new surface for the fin.

Now people who reinforce balsa by gluing paper on with white glue warn about the moisture in the glue causing the fins to warp, but that is because they apply the glue to the fin surface, and then stick the paper onto it. What I did instead was to spread the glue onto the paper, and then stick the fin down onto the paper. Applying the glue in a thin, smooth layer makes it similar to self-adhesive address label stock. I took the sheet of freezer paper and taped it, shiny side down, onto a smooth table. Then I applied a thick bead of white glue to the edge of a craft stick, and used it squeegee-style to spread a thin, even coat of glue onto a section of the paper that was just larger than the fin. Then I pressed one side of the fin down onto the glue-bearing surface. After doing this for all three fins, I did place a light book over all of them, just in case the paper decided to wrinkle (it didn't).

When the glue was set an hour later, I cut around each fin with scissors, leaving a bit of margin around each one. Then I repeated the process to adhere the freezer paper to the other side. I placed a book onto top of them (again, I'm not sure if this was really necessary) and left them overnight. Again I cut around them to free them from the paper.

Finally I fitted my craft knife with a new blade and carefully cut off the fringe of paper from each fin. The result was three strong and warp-free but very lightweight fins with sealed smooth surfaces that were ready for priming and painting, once I had attached them to my rocket. I did apply water-thin CA to all of the edges except the root edge in order to seal the edges of the paper as insurance that they wouldn't subsequently lift up.

MarkII


Hey, I LIKE that Mark!!

Got a pic of the paper box (and rocket)?? I'd like to get some of this stuff and play around with it... :)

How'd the paint bond to the coating?? Just wonder because some of those plastic coatings on stuff can be kinda waxy and paint doesn't really like that... (polyethylene??)

Later and kudos on a great idea! OL JR :)

[MarkII]

Hey, I LIKE that Mark!!

Got a pic of the paper box (and rocket)?? I'd like to get some of this stuff and play around with it... :)

How'd the paint bond to the coating?? Just wonder because some of those plastic coatings on stuff can be kinda waxy and paint doesn't really like that... (polyethylene??)

Later and kudos on a great idea! OL JR :)So far my Bat has two coats of primer on it - 1 coat of Krylon Gray and 1 coat of Dupli-Color Black Sandable Primer. I sanded the Krylon smooth with regular 320 grit before applying the Dupli-Color. Everything is looking good so far. The Krylon had no problem sticking to the freezer wrap fin covers. The plastic coating on the freezer wrap is very, very smooth, very thin, and very durable and well-bonded to the paper. It has a dry plastic feel to it - no waxiness or oiliness. It seems to accept paint well.

I was in a hurry to get this rocket completely done (meaning painted, decals applied and everything) by last Saturday so that I could launch it at ASTRE's Spooky Sport Launch on Sunday, because flying The Bat (http://www.ninfinger.org/%7Esven/rockets/nostalgia/81est016.html) unpainted and without its decals just wouldn't have the desired effect. But the launch was postponed until next Saturday because of high winds. So I didn't take any pictures of the covered but unpainted fins. But actually, except for the shiny finish on the covers, they looked just like any other set of fins that had been papered. I didn't do much rounding of the edges except for taking the square edge off, so I just papered the entire surface of each fin, right up to the edge. (When I paper fins that are to have rounded edges, I cut out the paper covers in the exact shape of the fin, but slightly reduced in order to leave a small margin of bare balsa at the edges that are to be sanded round. I make the bare balsa margin on each side of each edge equal in width to the thickness of the fin. I paper right to the edge of the root edge, though.) I am attaching a photo of the primed rocket (on my very cluttered work bench) and a close-up of the fins.

The postponement of the launch actually helped me out because a warm front is moving into our area, meaning that it will be warm enough and dry enough tomorrow to spray on the topcoat outside. I am using Dupli-Color Gloss Black Acrylic Lacquer for the topcoat.

There are pictures of the freezer wrap box at the Reynolds link that I posted before. One thing about this paper is that the plastic coating on it makes it just a bit harder to cut with a hobby knife. Not real hard, just harder than it would be to cut uncoated kraft paper. The next time that I use it, I will trim off all of the excess from the first side before bonding the paper to the other side. Trimming the excess from the edges of both sides at the same time after both sides had been covered turned out not to be really feasible, even with a brand new sharp blade in my X-Acto knife. The thickness of the balsa (3/32") may have contributed to this, though, because the excess margins on both sides were that far apart. I ended up having to trim each side individually. This would have been much easier if I had trimmed the edge of the first side before I glued on the other side. As I mentioned in my previous post, I put a couple of drops of water-thin CA on the edge and then let it roll down the edge and around to the next edge, rotating the fin to keep the CA on the edge and keeping it off the papered sides. I did this in order to seal the edges (except the root edge) and help to prevent the paper from eventually coming loose and lifting right at the edges.

(Start of off topic comments): BTW, Jeff, I used Bondo Spot Putty (which you had recommended awhile back) to fill the spirals on this rocket. Oh, man, does that stuff STINK! Not in how it works but in how it smells! :eyepop: I would almost trade CA fumes for the smell of this putty. :eek: Almost. Have lots of ventilation when you apply it, or else do it outside. And it cures extremely fast - I had to mix up two batches to get the small spirals filled on the 12.7" long BT-50 because the first batch hardened on the plate before I could get all of it onto the tube. But you know what? The stuff worked really well! :) Sanding it down took me just about as long as it usually takes me to sand off Fill 'N Finish, maybe slightly less. It cures and is ready to sand much sooner than FNF. One thing that I have been wondering about lately is whether the water in the diluted FNF weakens the spiral-wound body tube by seeping in and causing tiny delaminations of the layers in the areas where it has been applied. I don't know right now whether this is a real problem or not, but another good thing about the Bondo Spot Putty is that it is waterless. (End of off topic comments)

Thanks for your kind comments about my new papering technique. Another thing about the plastic coating is that it makes the paper harder to tear, a feature which will probably add just that much more strength to the fin when you cover it with this paper. Give it a try; you can share a roll of the freezer paper with your spouse, or at least use it yourself in the kitchen, because you will never use up the entire roll just on papering rocket fins. Another tip - you can put a sheet of freezer paper down on your table or workbench to give it short-term protection from minor spills. I used some on my dining room table to protect it while I was coating my sheet of decals with Future.

Sorry for hijacking this thread - I really don't intend to turn it into a build thread.

MarkII

[shrox]

I like basswood, I used it in the kits I offered.

[Evo666]

A bit off-topic but how do you cut basswood? Use exacto knife? or do i need something more heavier? I'm still a newbie BAR

[Micromeister]

Generally 3/64" to 3/32" with a shape x-acto knife. Letting the knife do the work, sometimes takes 2 or 3 passes. Anything thicker then 1/8" cut on a Scroll or Band saw.
Really for most LPR and MPR models once you use a piece or two You'll never use Balsa again for fins.

[luke strawwalker]

So far my Bat has two coats of primer on it - 1 coat of Krylon Gray and 1 coat of Dupli-Color Black Sandable Primer. I sanded the Krylon smooth with regular 320 grit before applying the Dupli-Color. Everything is looking good so far. The Krylon had no problem sticking to the freezer wrap fin covers. The plastic coating on the freezer wrap is very, very smooth, very thin, and very durable and well-bonded to the paper. It has a dry plastic feel to it - no waxiness or oiliness. It seems to accept paint well.

I was in a hurry to get this rocket completely done (meaning painted, decals applied and everything) by last Saturday so that I could launch it at ASTRE's Spooky Sport Launch on Sunday, because flying The Bat (http://www.ninfinger.org/%7Esven/rockets/nostalgia/81est016.html) unpainted and without its decals just wouldn't have the desired effect. But the launch was postponed until next Saturday because of high winds. So I didn't take any pictures of the covered but unpainted fins. But actually, except for the shiny finish on the covers, they looked just like any other set of fins that had been papered. I didn't do much rounding of the edges except for taking the square edge off, so I just papered the entire surface of each fin, right up to the edge. (When I paper fins that are to have rounded edges, I cut out the paper covers in the exact shape of the fin, but slightly reduced in order to leave a small margin of bare balsa at the edges that are to be sanded round. I make the bare balsa margin on each side of each edge equal in width to the thickness of the fin. I paper right to the edge of the root edge, though.) I am attaching a photo of the primed rocket (on my very cluttered work bench) and a close-up of the fins.

The postponement of the launch actually helped me out because a warm front is moving into our area, meaning that it will be warm enough and dry enough tomorrow to spray on the topcoat outside. I am using Dupli-Color Gloss Black Acrylic Lacquer for the topcoat.

There are pictures of the freezer wrap box at the Reynolds link that I posted before. One thing about this paper is that the plastic coating on it makes it just a bit harder to cut with a hobby knife. Not real hard, just harder than it would be to cut uncoated kraft paper. The next time that I use it, I will trim off all of the excess from the first side before bonding the paper to the other side. Trimming the excess from the edges of both sides at the same time after both sides had been covered turned out not to be really feasible, even with a brand new sharp blade in my X-Acto knife. The thickness of the balsa (3/32") may have contributed to this, though, because the excess margins on both sides were that far apart. I ended up having to trim each side individually. This would have been much easier if I had trimmed the edge of the first side before I glued on the other side. As I mentioned in my previous post, I put a couple of drops of water-thin CA on the edge and then let it roll down the edge and around to the next edge, rotating the fin to keep the CA on the edge and keeping it off the papered sides. I did this in order to seal the edges (except the root edge) and help to prevent the paper from eventually coming loose and lifting right at the edges.

(Start of off topic comments): BTW, Jeff, I used Bondo Spot Putty (which you had recommended awhile back) to fill the spirals on this rocket. Oh, man, does that stuff STINK! Not in how it works but in how it smells! :eyepop: I would almost trade CA fumes for the smell of this putty. :eek: Almost. Have lots of ventilation when you apply it, or else do it outside. And it cures extremely fast - I had to mix up two batches to get the small spirals filled on the 12.7" long BT-50 because the first batch hardened on the plate before I could get all of it onto the tube. But you know what? The stuff worked really well! :) Sanding it down took me just about as long as it usually takes me to sand off Fill 'N Finish, maybe slightly less. It cures and is ready to sand much sooner than FNF. One thing that I have been wondering about lately is whether the water in the diluted FNF weakens the spiral-wound body tube by seeping in and causing tiny delaminations of the layers in the areas where it has been applied. I don't know right now whether this is a real problem or not, but another good thing about the Bondo Spot Putty is that it is waterless. (End of off topic comments)

Thanks for your kind comments about my new papering technique. Another thing about the plastic coating is that it makes the paper harder to tear, a feature which will probably add just that much more strength to the fin when you cover it with this paper. Give it a try; you can share a roll of the freezer paper with your spouse, or at least use it yourself in the kitchen, because you will never use up the entire roll just on papering rocket fins. Another tip - you can put a sheet of freezer paper down on your table or workbench to give it short-term protection from minor spills. I used some on my dining room table to protect it while I was coating my sheet of decals with Future.

Sorry for hijacking this thread - I really don't intend to turn it into a build thread.

MarkII

That DOES look good Mark... congrats. Kewl rocket design to boot... :)

I'll have to give it a try. I'll pick up a roll next time I'm in Wally World...

Ummm, you had to MIX the spot putty?? I bet you got some actual Bondo-Glass type of stuff, because the putty I was talking about DOES NOT have to be mixed... it's basically just red primer 'solids' suspended in some solvent (maybe like lacquer thinner) and you just apply it straight to the spirals, give it a little while to dry (maybe 15-30 minutes) and then sand it down. It works pretty well, but cleanup IS a little harder than it would be with a water-based solvent product. BUT it also dries faster, and I'm convinced it's more durable and it DEFINITELY fills spirals better than water based stuff like Elmers filler. I don't know if it's my technique or what, but I haven't had any luck at all filling tube spirals with Elmer's filler... they look as noticeable after I'm done as when I started, and I don't like having to do something 2-3 times or more to get the desired effect... :)

Lemme see if I can find a link to the spot putty I'm talking about... It's called "Dynatron Glazing and Spot Putty" and it's sold in a tube like toothpaste. I got mine at Advance Auto... I went in and went back to the body fillers, and found the tubes of putty next to the cans of Bondo... they had two sizes... a like 4 ounce tube for like $3.59, and a 1 pound tube for like $3.99... so I bought the MONDO HUGE tube since that should last me close to a lifetime for 40 cents more... (don't know if they were mismarked but that's their problem!) I'm guess it's primer solids in lacquer thinner, because it will seperate a little in the tube (helps to knead the tube a bit before opening it, and be sure it's opened over something to absorb any spills of the 'watery' thinner if it HAS seperated). The solvent in it is hot enough that it has wrinkled the paint/printing on the tube, and it wiped off in a few places where I cleaned up dribbles on the tube with a paper towel. I just opened the tube, and it smells sorta like model airplane glue (love that smell LOL:) but it doesn't require any hardener or anything like that, just 'smear it on' let it dry, sand it off, prime, sand, paint as normal.

Here's the pics I found... I just yahoo'd "dynatron glazing and spot putty"...

Hope this helps! OL JR :)

PS... know what you mean about the smell of Bondo... I was helping a bus driver buddy of mine work on his 56 Chevy (he's also got a CHERRY 57 Chevy, a sweet 58 Chevy with a 454 in it, and a showroom restored 53 Mercury Monterrey, and recently sold his 56 Ford) the other day and that stuff DOES stink... course I'm kinda used to stinky stuff with all the farm chemicals I've dealt with over the years... I did the dolly work and let him do the final bondo stuff...

[tbzep]

(Start of off topic comments): BTW, Jeff, I used Bondo Spot Putty (which you had recommended awhile back) to fill the spirals on this rocket. Oh, man, does that stuff STINK!

I love the smell of Bondo Spot Putty. I'd use it for cologne if I were ever to run out of Hoppe's #9. :D

[Evo666]

Generally 3/64" to 3/32" with a shape x-acto knife. Letting the knife do the work, sometimes takes 2 or 3 passes. Anything thicker then 1/8" cut on a Scroll or Band saw.
Really for most LPR and MPR models once you use a piece or two You'll never use Balsa again for fins.

Thanks a lot :cheers:

[MarkII]

Really for most LPR and MPR models once you use a piece or two You'll never use Balsa again for fins.I have used a fair amount of basswood. I still use balsa for LPR fins most of the time, though. Never have a problem with it. :D Usually aircraft plywood or basswood for MPR, but sometimes balsa even there, too. :dark:

MarkII

[MarkII]

I love the smell of Bondo Spot Putty. I'd use it for cologne if I were ever to run out of Hoppe's #9. :D"That gentleman has a certain air about him..." :y: :D
Parfums des xylene, toluene et MEK...

Hoppe's No. 9? Are you really that much of a bore? :rolleyes:
"Give that man his residue!"

MarkII

Rifle or musket?

[shrox]

Basswood is short for "bad-a** wood" I think it's great, especially it's toughness when used as a fin or wing.

[Boosterdude]

Basswood is short for "bad-a** wood" I think it's great, especially it's toughness when used as a fin or wing.

I agree 100%, plus the tight grain makes finishing a snap. It's heavy than balsa, but requires a lot less filling to hide the grain. So, by the time you seal, fill, prime balsa fins the weight difference between balsa, and bass might not be all that significant.

[MarkII]

Oh, I like and use basswood, too. But I also use balsa quite frequently as well. It all depends upon what I am building. I mostly use C-grain balsa, which is the heaviest, densest kind, yet I have never had a set of sealed, finished and painted balsa fins that weighed anywhere near as much as an equivalent set of unfinished basswood fins. Also, I simply can't imagine building a boost glider out of basswood. Basswood has plenty of virtues, but I have absolutely no problem using balsa for fins in most cases, up to a certain size and power level. And I never have any trouble getting a glass-smooth finish on them.

MarkII

[Trident]

A bit off-topic but how do you cut basswood? Use exacto knife? or do i need something more heavier? I'm still a newbie BAR

I'm partial to using my small hobby bandsaw with 1/16 to 1/8" blade to cut out basswood fins a bit oversized, then sanding them down to the pattern lines with a small disc sander. Obviously this works best for fins with straight edges, but curved edges could be handled with a Dremel tool with sanding drum attachment.

I would highly discourage anyone from trying this with a large bandsaw, perhaps with the exception of fairly large fins. In general they are just too powerful to have your fingers so close to the blade. I have resawn 6" oak with my large bandsaw, so it is best reserved for heavy duty cutting.

For sanding the basswood fins to size, I use a small Dremel 5" disc sander (also has a 1" vertical belt, which is ideal for sanding all kinds of wooden model rocket parts) -- again, hobby-grade, and not sized for large woodworking tasks.

I used to stack fins, and pin them together for sanding, but with a small disc sander, it is easy to hold them tightly in a stack by hand, and sand all fins at once. I also find that this method goes so fast, I can do them individually if stacking is an issue.

[MarkII]

A bit off-topic but how do you cut basswood? Use exacto knife? or do i need something more heavier? I'm still a newbie BARX-Acto knife up to 1/8" thick, and utility knife for anything thicker. I can't get precise enough cuts with a saw. Basswood cuts pretty easily.

MarkII

[luke strawwalker]

I love the smell of Bondo Spot Putty. I'd use it for cologne if I were ever to run out of Hoppe's #9. :D

hehehe... it ain't about what WE GUYS like, it's about what the CHICKS like... :)

On a related note, I have to laugh at those AXE body sprays commercials... the ones where the hot chicks mob the guys wearing AXE products... my wife turns her nose up and says, "that stuff smells like (edit) ... half the boys in school wear it and it STINKS!!-- they go for the advertising."

LOL:) Later! OL JR :)

[Peartree]

hehehe... it ain't about what WE GUYS like, it's about what the CHICKS like... :)

On a related note, I have to laugh at those AXE body sprays commercials... the ones where the hot chicks mob the guys wearing AXE products... my wife turns her nose up and says, "that stuff smells like (edit) ... half the boys in school wear it and it STINKS!!-- they go for the advertising."

LOL:) Later! OL JR :)

A couple of our teachers put it this way, "Sixth grade boys reek of B.O., Seventh grade boys reek of cologne. After that, they start to get things figured out."

[bob jablonski]

We use light ply in the SS Barracuda's fins. Strong, fairly light and no need to reinforce with paper and no wood grain issues.
Mr. Bob
Starlight Dude

[Boosterdude]

We use light ply in the SS Barracuda's fins. Strong, fairly light and no need to reinforce with paper and no wood grain issues.
Mr. Bob
Starlight Dude

What's the thickness of the light ply that you use?

[MarkII]

We use light ply in the SS Barracuda's fins. Strong, fairly light and no need to reinforce with paper and no wood grain issues.
Mr. Bob
Starlight DudeCan't find that at Michael's, which is where I buy nearly all of my fin stock.

MarkII

[MarkII]

A couple of our teachers put it this way, "Sixth grade boys reek of B.O., Seventh grade boys reek of cologne. After that, they start to get things figured out."I keep wondering when I am going to start developing that "old person smell." :y:

MarkII

[artapplewhite]

I use 3/32" and 1/8" basswood in all my kits including monocopters (http://artapplewhite.com/monocopters.html). The properties of basswood (http://forestry.about.com/od/hardwoods/tp/American_Basswood.htm) such as grain and strength are more consistent than balsa. This is important to me because I buy it in quantity from wholesalers so I'm not able to select individual pieces as I would if I were buying from a hobby shop.

Basswood is a "greener" product than balsa because it's renewable, and it's grown in the USA in tree farms, so no rain forests are destroyed in the process.
http://www.artapplewhite.com/logo.gif (http://www.artapplewhite.com)

[bob jablonski]

What's the thickness of the light ply that you use?
It is 1/8" thick. We get it from our balsa dude. (they don't sell retail).
Mr. Bob
Starlight dude

[Boosterdude]

I use 3/32" and 1/8" basswood in all my kits including monocopters (http://artapplewhite.com/monocopters.html). The properties of basswood (http://forestry.about.com/od/hardwoods/tp/American_Basswood.htm) such as grain and strength are more consistent than balsa. This is important to me because I buy it in quantity from wholesalers so I'm not able to select individual pieces as I would if I were buying from a hobby shop.

Basswood is a "greener" product than balsa because it's renewable, and it's grown in the USA in tree farms, so no rain forests are destroyed in the process.
http://www.artapplewhite.com/logo.gif (http://www.artapplewhite.com)

Never thought of it this way, but a good point. Basswood is great to work with and overall a much better choice for fin material.

[Scode68]

I wound up getting 1/16" Bass wood for the Harpoon I'm building.

http://www.spacemodeling.org/JimZ/dom0184.htm

Got as far as cutting the fins which cut no problem with an X-Acto knife.

I'm in luck since the Ace Hardware carries both in different thicknesses.

[MarkII]

Harvesting balsa does not involve destruction of rain forests. Balsa trees do not grow in stands, but rather grow singly in scattered places in the forest. Because of this, they cannot be harvested through industrial logging methods. Clearcutting an area where they grow will yield very few balsa trees, thus it is not economically feasible to obtain them that way.

Balsa trees grow very rapidly, reaching maturity in just a few years. The rapid growth is the reason for the very light density of the wood. The seeds of the balsa tree are air-dispersed and the seedlings sprout like dandelions. Balsa trees are short-lived; soon after they reach maturity, they begin to die, rotting from the inside out.

Harvesting balsa does not reduce the forest canopy, and due to their haphazard and widely dispersed distribution, constructing a large logging infrastructure within the forest to obtain them is not feasible. Most balsa is obtained in Ecuador, on the western coast of South America. Individual balsa trees are harvested by Ecuadorans working individually or in small teams, cut down by hand, and then dragged down to a nearby river or stream by donkey and then floated down to a collection point. This is a textbook example of sustainable low-impact wood harvesting that preserves the health of the forest.

http://www.mat.uc.pt/~pedro/ncientificos/artigos/techbal.html (http://www.mat.uc.pt/%7Epedro/ncientificos/artigos/techbal.html)
http://www.britannica.com/EBchecked/topic/50863/balsa
http://en.wikipedia.org/wiki/Ochroma_pyramidale

MarkII

[Micromeister]

Marks got some good points there LOL!
In Costa Rica Balsa trees grow at Weed like rates, several "balsa tree farms" supply lots of the ballast wood used in the holds of large cargo vessels and some of it also ends up as hobby wood. I have a Friend who's father's mission in Costa Rica has balsa trees on the property and every so often I'll get a package of balsa logs to keep me in nosecone material LOL!! it's sometime very interesting to see the varience in density within the same log.
It's my understanding most folks in the balsa growning countries consider it a nuisance tree as it growns so fast but has a very short life span.

All that said: I still prefer Basswood for all the reasons we've already discussed, it's just a better choice for fins. I also REALLY Like the fact it's grown right here in the good Ole USA.

[shrox]

Isn't most commercial wood farmed now? I know there are exceptions, like the giant redwwods in northern California, and other woods from other places.

[Peartree]

Isn't most commercial wood farmed now? I know there are exceptions, like the giant redwoods in northern California, and other woods from other places.

Some, certainly not all. Many hardwoods are not particularly suitable for traditional "farming." Walnut trees are still immature at 50 years. I *have* heard of a man gradually planting his "back 40" with walnut trees in a farming operation, but it was with the expectation that it would be his grandchildren who would be harvesting them. Some other hardwoods grow even slower.

[MarkII]

Because of the way they grow, balsa trees traditionally were always gathered "in the wild." But apparently that has changed. Some balsa is now grown on plantations in Ecuador. Here is an excerpt from The Ranforest Alliance's "Sustainable Forestry Update" for Fall, 2009 (http://www.rainforest-alliance.org/forestry/sustainable-forestry-update/fall_09.html):

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Ecuador's Biggest Balsa Plantation Earns FSC Certification

There's good news in Ecuador's Los Ríos province -- so named because a number of rivers flow toward the Río Guayas and Pacific Coast -- where more than 19,000 acres (8,000 hectares) of balsa plantation (Ochroma pyramidale) have been certified in recognition of responsible management.
http://www.rainforest-alliance.org/clear.gif http://www.rainforest-alliance.org/forestry/sustainable-forestry-update/images/logs_0909.jpg http://www.rainforest-alliance.org/images/clear.gif Plantaciones de Balsa S.A. (PLANTABAL S.A.) is the first Ecuadorian forestry company to earn Forest Stewardship Council (http://www.fsc.org/) (FSC) certification, which was awarded by the Rainforest Alliance's SmartWood (http://www.rainforest-alliance.org/forestry.cfm?id=smartwood_program) program.
PLANTABAL S.A. is a leader in the industrial production and processing of balsa wood, which it exports to China, Europe and the United States for use in the construction of boats, wind turbines and other products.
"I'm certain this certification of PLANTABAL, Ecuador's largest balsa exporter, will serve as an example for other exporters and will motivate them to work toward certification," said Freddy Peña, regional manager of the Rainforest Alliance's SmartWood program. "I expect other balsa companies to enter the process." For more information contact Plantaciones de Balsa S.A. (PLANTABAL) (monika.merino@alcan.com).
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The linden tree (called the lime tree in Britain), which is the source of basswood, grows wild in mixed hardwood forests and it can also be cultivated on plantations.

http://en.wikipedia.org/wiki/Tilia
http://forestry.about.com/library/silvics/blsiltilam.htm

MarkII

[luke strawwalker]

Never thought of it this way, but a good point. Basswood is great to work with and overall a much better choice for fin material.

Meh... from what I've read, balsa isn't a "non-green" choice...

About the only things that grow faster than balsa is bamboo and kudzu...

Not against basswood, but for most things I like balsa just fine.

At one point, NASA was going to use balsa as insulation in their Saturn V rocket stages inside the hydrogen tanks... OL JR :)

[MarkII]

I also REALLY Like the fact it's grown right here in the good Ole USA.Very true. The linden tree requires a temperate climate, and it grows wild from the upper Midwest through the Northeastern US, in northern Europe and northern Asia. The balsa tree requires a moist tropical climate, i. e., it grows in tropical rainforests in Central and South America. I use plenty of both species of wood; they are both available in more than enough quantities to meet the needs of the hobby market. From a trade perspective, I don't think that there is a downside to the use of either one by hobbyists. There is a big worldwide demand for both types of wood, so whichever one that hobbyists prefer won't cause the overall market for either to rise or drop by all that much.

I have made good use of each type of wood in my rocket building so far, and I will continue to do so for the foreseeable future. In applications that require moderate strength and light weight, balsa is my choice. I have yet to see a boost glider made from basswood. In applications that require greater strength and where weight is not quite as critical, I often use basswood. For applications that require great stiffness and hardness but a thin profile, I most often use aircraft plywood. So far in my rocket building, nearly all of my fins have been constructed from wood. I have not had any real need yet to use any composites or other non-wood materials. So in order to answer the question, "balsa or basswood for fins?" I would say, "Yes." ;)

MarkII