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Author Topic: Balsa Wood availablity and pricing  (Read 1790 times)
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kaintuck
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« Reply #25 on: October 17, 2020, 03:30:04 PM »

Like spruce....SIG was my go-to balsa and spruce......then the Japanese bought all they could, according to my source...they made pianos parts out of it! So we all changed to basswood....1:1 builders still get spruce, but try finding it in the local store.....
Good ol days.....sad to say, but the world was a better place when there was only 3.5 billion people.....
Marc
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PB_guy
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« Reply #26 on: October 17, 2020, 05:08:56 PM »

If you live in the Northwest, the lumber yards occasionally have Spruce 2x4's that you can cut down to size. If you can't recognize spruce, you can usually ask one of the old hands. They know.
ian
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Mike Thomas
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« Reply #27 on: October 17, 2020, 08:33:25 PM »

Spruce is a staple material for luthiers, and is readily available from specialist tonewood suppliers. If you have a guitar maker locally, professional or amateur, they are likely to have plenty of offcuts of high quality quarter sawn spruce perfectly suited to our purposes.
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lincoln
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« Reply #28 on: October 17, 2020, 09:21:10 PM »

Spruce comes in different flavors with significantly different properties, though I guess after dealing with balsa, we're used to that. You can build models with spruce, but the design will have to be a little different. Definitely smaller sizes, so buckling would become more of an issue.

We can build perfectly adequate models with foam, but then it wouldn't be stick and tissue modelling anymore. The genetic engineers should hurry up and create balsa equivalents that we can grow in our back yards in temperate climates. I wonder what ship breakers do with the balsa insulation from old LNG tankers?

Someone should invent a way to pultrude carbon fiber dispersed  in foam.


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tom arnold
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« Reply #29 on: October 18, 2020, 12:15:06 AM »

Actually, there is a great semi-solution. Years ago when we went through this same drill of scarce balsa, as an experiment, I went to foam dinner plates as a source of sheet balsa. It worked beautifully. You could draw on the foam with ballpoint pen, cut it with a scissors or exacto-knife, and glue it with either foam-friendly CYA or ordinary white glue (or wood glue). It worked for fuselage formers and wing ribs equally well. For stringers I used the only balsa found which was the rock hard stuff as thin as 1/32. I'd slice stringers 1/16 to 1/8 wide of the 1/32 sheet and, of course, 1/16 square from the 1/16 sheets. Notching was easy as for the thin stringers you just clipped a spot on the edge with a scissors, and pressed the stringer in. For the 1/16 square stringers a V-shaped notch was clipped, dabbed with a spot of glue and pressed in. It was easy to  sand scallops between the stringers with a moto-tool and sanding drum.

A nice characteristic of the foam bulkheads is that they would not shatter in a crash but would fold. Repairs to a bulkhead consisted of flattening it out again and gluing a strip of 1/16 square across the fold line to keep it flat. The stuff was not perfect as you had to roughen the flat side with fine sandpaper if you wanted to glue anything to it. It had a hard finish from the manufacturing process that repelled glue otherwise. The raw cuts on the edge had no problem holding a glue joint. Because the foam has no grain you design the formers a little different in that you cannot count on the sheet being strong in one direction and weak in another.

The foam is very close in weight to sheet balsa.....so close that I really did not notice in the final aircraft weight. My experimental subject was a 24" span Typhoon complete with the fat scale airfoil and it flew as well as the balsa planes that came before it. I never pursued it further as the Typhoon construction was prohibited by the FAC rules and I could only fly it for fun. It still hangs in the my shop and I dust it off for occasional fun flights.
« Last Edit: October 18, 2020, 12:25:22 AM by tom arnold » Logged
p40qmilj
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« Reply #30 on: October 18, 2020, 08:33:51 AM »

 Grin  hear hear! i keep a good supply of foam diner plates to use as balsa substitutes because of the closeness in weight and their ease in cutting.  white glue is good enough but for major joints a foam glue is necessary.

jim
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Viperkite
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« Reply #31 on: October 18, 2020, 01:05:47 PM »

During WW2 and soon after obeechi was known as balsa substitute. I assume there is no shortage of that.
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TheLurker
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« Reply #32 on: October 18, 2020, 02:17:17 PM »

On the basis of density, light obeche might make a passable subsitute for v. hard balsa having an average density slightly more than that of the heaviest balsa so could be made to work for large(r) outdoor models but I don't think it'd be all that hot for indoor models.  Some density values culled from teh intarwebs...

From https://modelshop.co.uk/Shop/Item/Obeche-sheet-100-915mm/ITM6803

"Trypolochiton scleroxylon (obeche tree) a soft wood with a low gross density of, on average, 350 kg/m³.
The lightest hardwood in general use."

And from WIKI
"The density of dry balsa wood ranges from 40–340 kg/m3, with a typical density around 160 kg/m3.

My highlights

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Russ Lister
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« Reply #33 on: October 18, 2020, 02:29:40 PM »

I bought a £100 lot of depron over a decade ago .... I have been almost giving some of the remainder away. I'll have to hang on to it now .... just in case.
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Russ Lister
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« Reply #34 on: October 18, 2020, 02:40:08 PM »

.... built with some of that depron ... actually over 15 years now.
The depron version compared well in performance to the built up version ... there will always be alternatives.
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Jack Plane
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« Reply #35 on: October 18, 2020, 02:42:50 PM »


Not fake news I'm afraid. This was predicted last year and reported in the Financial Times.

All the major balsa producers in Papua New Guinea and Ecuador have been bought up by the Chinese to supply their wind turbine industry, the Chinese government have paid over the odds to secure the material exclusively for their own use for the foreseeable future, leaving nothing in surplus for the rest of us...

Slowly but surely the global economic domination by the dictatorship is creeping forward. Thank you China.


Wakey Wakey Western World!  This is spot on and entirely consistent with the way things have been going for quite some time and will continue to go, inexorably:  the Chinese economic model is utterly rapacious (think "Belt and Road") while also extremely oppressive (think "Urgar").  BUT the most serious issue at stake for everyone living on the thin crust of the Hot Pebble is the carbon problem - and the only good news coming out of this is that China at least recognises its own very considerable and very dirty role (as well as trying to corner the market in turbine blades for good measure).  Having said that 2060 is far, far too late - better to have a 20yr plan on this one rather than a 40yr one!

In the meantime, I best drop my plans for larger RC plan builds and stick to Peanut jobs!  Shocked
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Viperkite
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« Reply #36 on: October 18, 2020, 03:52:58 PM »

Yes, obeche isn't ideal, but I have used it for extra strength on some models and no one seems to be cornering the market just yet.
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TheLurker
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« Reply #37 on: October 18, 2020, 04:01:58 PM »

Quote from: Viperkite
....no one seems to be cornering the market just yet.
Now there's an idea.  If we have a quick whip-round as well as a shufti down the back of the sofa...  Smiley
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Russ Lister
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« Reply #38 on: October 18, 2020, 04:32:09 PM »

If I had to choose an alternative wood, I think I would possibly opt for cedar .... though it does take a bit of working. I have already used it for struts.
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Mike Thomas
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« Reply #39 on: October 18, 2020, 04:58:26 PM »

On the basis of density, light obeche might make a passable subsitute for v. hard balsa having an average density slightly more than that of the heaviest balsa so could be made to work for large(r) outdoor models but I don't think it'd be all that hot for indoor models.  Some density values culled from teh intarwebs...

From https://modelshop.co.uk/Shop/Item/Obeche-sheet-100-915mm/ITM6803

"Trypolochiton scleroxylon (obeche tree) a soft wood with a low gross density of, on average, 350 kg/m³.
The lightest hardwood in general use."

And from WIKI
"The density of dry balsa wood ranges from 40–340 kg/m3, with a typical density around 160 kg/m3.

My highlights




Western Red Cedar is also a good substitute for hard balsa with an average dry density of 370 kg/m3. Commonly used for Venetian blind slats, which are a useful and readily available source, depending on where you live. Many Australians will remember Max Starick. He used Western Red Cedar for longerons on more than one vintage rubber model, out of choice, when there was no shortage of balsa.

Russ, you got in just before me.  
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Russ Lister
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« Reply #40 on: October 18, 2020, 05:16:39 PM »

I'm glad to hear I'm not the only one, Mike  Smiley
Used for the struts on my DPC Triplane amongst others.
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Russ Lister
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« Reply #41 on: October 19, 2020, 08:00:39 AM »

I'm also good for blue foam for as much foam modelling as I can do!

This .... combined with Chris's (Squirrelnet) Simple Stampe in the current AeroModeller, has got me thinking of a 'less balsa' build.
How about a 'Less Balsa' cookup, Chris?! I would build your design.
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Squirrelnet
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« Reply #42 on: October 19, 2020, 01:13:49 PM »

Thanks Russ, glad you like it. Good idea , though not sure how popular it would be - there's a lot of balsa builders on here.

 I was thinking of doing another one as a Skywriting SE5A the basic design could easily be adapted to many other semi scale bipes without too much effort. It's just if they are white there's less 'colouring in'




PS I just tried to get some more balsa stock from Balsa Cabin but not they are not taking any new orders

From the Balsa Cabin site:-

DUE TO THE HIGH DEMAND OF ORDERS WE HAVE TEMPORARY PUT OUR BALSA SHEETS OUT OF STOCK WHILST WE TRY TO FULFIL THE ORDERS WE HAVE SO PLEASE BE PATIENT WITH US.
ONCE THESE ORDERS HAVE BEEN COMPLETED IF WE HAVE STOCK AVAILABLE WE WILL UPDATE THIS NOTICE AS WE CANNOT NOW GUARANTEE WE WILL HAVE STOCK.
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packardpursuit
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« Reply #43 on: October 19, 2020, 01:15:51 PM »

OK! I'm all for alternative materials, especially repurposed items.

However what do you guys do with foam plate ribs and tissue covering? How do you keep dope from attacking these ribs?  Alternative water based"dopes" have not , as of yet and IMHO, advanced enough for me, yet.
charlieman
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Russ Lister
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« Reply #44 on: October 19, 2020, 05:07:36 PM »

Chris,
Yes, there is nothing quite like balsa to me either  Smiley
Aeromodellers are a resourceful lot though and quite prepared to explore other materials.
If this does turn out to be a balsa 'drought', a spell of using alternative materials might save those valued stocks already in our possession?
I did word it as 'less balsa' used .... how could we ever contemplate a complete lack of balsa in a build?!
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lincoln
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« Reply #45 on: October 19, 2020, 11:11:44 PM »

I think paulownia is supposed to be a little lighter than obechi. In the past, it was used for rubber powered model airplane props. It's invasive in some places in the US, though it hasn't reached where I live yet. I think some is actually grown for export to Japan, where it's traditional.

I suppose someone could come up with a machine that makes hollowed out sticks, though they wouldn't be cheap. They could be as good as solid balsa sticks if the glue didn't weigh much. Maybe better.

Urethane foam could probably survive dope. Maybe in a few years we'll build all our models of Rohacell.

I've measured the stiffness of a reed that grew near our flying field. It was about as stiff as the same weight of 6 lb balsa. Of course you can't cut it up the same way you can balsa, because you'd lose the tubular shape. Might be good for stick fuselages.
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tom arnold
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« Reply #46 on: October 19, 2020, 11:33:55 PM »

I never had a problem with dopes or Krylon attacking foam dinner plate construction. The tissue is attached with dilute white glue to the balsa stringers and any solid foam areas,like around the nose are coated with a layer of regular strength white glue brushed on. Any water-based covering or sealant can also work like artist's gauche, or floor polish, or varnishes. The edges of the wing ribs are coated with a thick painting of white glue and let dry before covering. It does a good job of protecting from any dope/Krylon that is sprayed on the tissue. New stuff and new techniques.
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lincoln
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« Reply #47 on: October 20, 2020, 12:21:08 AM »

I've seen some all foam models from expert modellers that looked very good and flew very well, but it's a different game, and the models have a different feel. Foam like Highload 60 or Plazamate is probably best suited for metal or composite scale subjects, or perhaps aircraft whose outer surfaces were all plywood. If you go to the event reports at ffscale.co.uk, you can find pictures of what's possible, along with plenty of pictures of more conventional models.
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Skymon
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« Reply #48 on: October 20, 2020, 05:02:36 AM »

I think all the wind turbine usage will be for end grain so it will all be short lengths. Its funny although you say its made in Britain it is a Danish company making it, seems to be we cannot make anything any more, isnt that sad? One of the things I noticed is when there was a series on telly trying to "correct" the statement we dont make anything, all the companies that were concentrated on were hi tec digital companies!!

Hiya Mike
The parts are made here, designed here too, I know a couple of uys who work there. Went for an interview myself. Didn't get in but wasa little reticent to move to the IOW anyhow.
We're in a global world full of big corporations now. I work for an Indian owned company in Portsmouth, we make 150,000 car door mirrors a week. So there is manufacturing in the UK still. Just not much Sad.
Hi tech is still manufacturing, the whole 'consumerism' fad of the 20th Century is based on replacement rather than repair. We even build mobile phones in the UK, Wiley FOx, Bullit, Maxcom and Vertu.

Doesn't get us any nearer a good balsa supply though.
I think we all need to visit the LHS and check their stocks.

I'm an indoor flier, so I need my wood light !

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Pete Fardell
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« Reply #49 on: October 20, 2020, 05:53:00 AM »

I can easily get my head around coping without certain basics (Esaki tissue for instance) but building without balsa? I really don't relish it. Therefore, with all of the the above comments in mind, I've just ordered some more sheet from a place called Charge Electrical on eBay. I got a choice of thicknesses but no indication of quality, weight or grain, so goodness knows what it'll be like. My reasoning though is that my stocks were getting low and even bad balsa is better than no balsa. (And I've only spent about £12 so not too much of a risk.)
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