# Balsa vs. Papered Balsa vs. Basswood

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##### Well-Known Member
Probably an age-old debate but I am really surprised that more people do not use basswood plywood given the cost / challenge of finding balsa.

Has anyone done a weight comparison of 2mm balsa vs. papered 2mm balsa vs. 1.5mm basswood plywood vs. 2mm basswood? I bet that basswood is negligibly heavier than papered balsa (especially if you compare to the thinner basswood that is similar strength to thicker balsa - basswood might even win out on weight here). I am not going for any altitude records or anything so maybe I am not appreciating the impact of small differences in weight.

Basswood is so much more durable, you do not need to worry about direction of grain as much, can make more complex fin shapes that will not snap, can make massive fins/wings out of a single piece of basswood, etc... On the negative side, basswood is definitely harder to cut (I forget how easy it is to cut balsa till I get back to a kit). Also, I am by no means great at finishing / painting, but it seems that the tighter grain of the basswood with a bit of sanding makes it really similar to papered fins for finishing (especially if you are using a filler-primer as a first coat).

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##### Well-Known Member
I think part of the difference in perspective is different goals and different size rockets - I should have clarified I am doing LPR with relatively small rockets (BT80 is largest I have done but mostly doing BT60 and smaller).

Also for me cost is a big factor and getting a 200x300x2mm sheet of basswood for around \$.75 is nice. Also I should note that my basswood is some type of plywood (3 layers) - is that always the way it is?
What you're describing is lite-ply. Plywood with layers that are about 1/32" The top veneers can be anything so basswood is an option but normally its birch.

Solid basswood in sheets has a look of dense balsa with little to no grain. Except where extreme mass control is a concern like gliders, you can swap balsa with solid basswood and notice no difference

##### Well-Known Member
What you're describing is lite-ply. Plywood with layers that are about 1/32" The top veneers can be anything so basswood is an option but normally its birch.

Solid basswood in sheets has a look of dense balsa with little to no grain. Except where extreme mass control is a concern like gliders, you can swap balsa with solid basswood and notice no difference
Thanks for clarifying - I assumed that "basswood" was always a plywood since this was what I had received when I ordered basswood online from a couple of vendors (1.5mm and 2mm versions) and it seemed like all the "basswood" on amazon was a plywood ...

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#### BEC

##### Well-Known Member
I have never done papered fins, so I can't address the weight or strength of them. But here is a little data about relative weights:

These three sheets are each 2 1/8 x 7 5/8 inches. The basswood and balsa sheets are 3/32 inch thick. The plywood one (bottom in the picture, never mind it also says bass on it) is 2mm thick. The balsa sheet (middle) weighs 0.23 ounce. The basswood sheet (top) weights 0.39 ounce and the poplar ply sheet (bottom) weighs 0.37 ounce. The balsa is about 16 lb/cu. ft. density, so fairly dense balsa (at least from a model builder's perspective).

(edit: deleted redundant copy of picture)

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##### Well-Known Member
I have never done papered fins, so I can't address the weight or strength of them. But here is a little data about relative weights:

These three sheets are each 2 1/8 x 7 5/8 inches. The basswood and balsa sheets are 3/32 inch thick. The plywood one (bottom in the picture, never mind it also says bass on it) is 2mm thick. The balsa sheet (middle) weighs 0.23 ounce. The basswood sheet (top) weights 0.39 ounce and the poplar ply sheet (bottom) weighs 0.37 ounce. The balsa is about 16 lb/cu. ft. density, so fairly dense balsa (at least from a model builder's perspective).

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This is really great information -- thank you so much for weighing / sharing. Never would have guessed that someone had exactly comparable fin-sheets on hand to compare like that...

#### BEC

##### Well-Known Member
I was working with James Cramton at Rocketry Works on those Alpha fins (both the original shape and the current one) and got the sheets to verify them. So it just sort of happened that I had such directly comparable bits to hand.

[thread drift] So, if anyone is looking for laser-cut fins for an Alpha that match the original shape as shown on the SP-25 fin template (and the subsequent die-cut fins), you can get them in 3/32 inch balsa or basswood or 2mm plywood from Rocketry Works. They also have the current shape (which has been the shape in Alpha kits once they began being laser cut in the early 2000s) in all three materials. [/thread drift]

#### boomtube-mk2

##### Well-Known Member
If balsa is getting in such short supply and thus more expensive, why don't the low power rocket kit producers look to replacing balsa with basswood?
Especially if the quality of the available balsa has gone into the crapper.

##### Well-Known Member
If balsa is getting in such short supply and thus more expensive, why don't the low power rocket kit producers look to replacing balsa with basswood?
Especially if the quality of the available balsa has gone into the crapper.
weight. Basswood is light but still almost 2 times heavier than balsa. (see post #20 for weights of similar sized sheets, 0.23oz vs 0.39oz)

It has been many years but there was a company called "Scale Kits" and they had a line of ~5 or 6 kits that were...imagine this...scale. I built their SA-2 Guideline. Lots of fins, a nosecone and a transition. Nosecone and transition in balsa but fins were basswood. That rocket wasn't stable and needed more noseweight. It could be that if the fins were balsa rather than basswood, it could have been stable in the stock config.

#### icyclops

##### Well-Known Member
But I would think that a balsa fin with two layers (either side) of styrene glued to it would be much heavier than basswood...
Nope…not at .10 or .20 thickness….about the same weight as some thick paper card stock…..basswood compared is weigh more (pun)

#### icyclops

##### Well-Known Member
Thanks for clarifying - I assumed that "basswood" was always a plywood since this was what I had received when I ordered basswood online from a couple of vendors (1.5mm and 2mm versions) and it seemed like all the "basswood" on amazon was a plywood ...

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I have found that many of the sellers on Amazon label the product wrong…they don’t really know the difference between Basswood and Balsa. Some of the Basswood is actual ply or birch ply, or you can find it in solid too in the thicker sizes…and true Balsa is very hard to find. You need to read the feedback as there is some balsa being properly sold, but you have to really search and you won’t find it in the long sheets like you used to at the hobby/craft stores…it will be in smaller sheets like 4x6 or 3 x 8.

##### Well-Known Member
It has been many years but there was a company called "Scale Kits" and they had a line of ~5 or 6 kits that were...imagine this...scale. I built their SA-2 Guideline. Lots of fins, a nosecone and a transition. Nosecone and transition in balsa but fins were basswood. That rocket wasn't stable and needed more noseweight. It could be that if the fins were balsa rather than basswood, it could have been stable in the stock config.
That is a great looking kit -- however, I bet that the sustainer would need nose weight regardless of fin material, those fins are pretty far up on the body...

#### prfesser

Nope…not at .10 or .20 thickness….about the same weight as some thick paper card stock…..basswood compared is weigh more (pun)
I think you mean 0.010" or 0.020". With 0.10" on each side the fin would be about a quarter inch thick or more.

#### boomtube-mk2

##### Well-Known Member
weight. Basswood is light but still almost 2 times heavier than balsa. (see post #20 for weights of similar sized sheets, 0.23oz vs 0.39oz)

It has been many years but there was a company called "Scale Kits" and they had a line of ~5 or 6 kits that were...imagine this...scale. I built their SA-2 Guideline. Lots of fins, a nosecone and a transition. Nosecone and transition in balsa but fins were basswood. That rocket wasn't stable and needed more noseweight. It could be that if the fins were balsa rather than basswood, it could have been stable in the stock config.

But by using Basswood, would you not then be able to use thinner stock than balsa?
Even back a few years I was getting some low power kits whose balsa fins were practically unusable unless they were papered and even then attempting to put an airfoil on the edges was a nightmare, the stuff didn't "Sand" it just fell apart, kind of like sanding burnt toast.