does balsa harden with age?

[Phil 9]

I bought from ebay a hobby lobby telemaster 40 kit. I don't know the age of the kit but judging by the plan paper a and the typed instructions it must have been sitting about for a wile.

the balsa wood does seem hardened to me and some of the large balsa blocks feel very solid.

[onetenor]

I recently took the engine out of a Veron Velox and had to cut the cowling off It was like cutting pine so I would say yes .Balsa does harden with age

[Former Member]

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[bert baker]

I have been given a free flight plane a Avro 405, building commenced in 1947,, but never covered,

The wood has gone black, and hard it also won't accept glue any more.

[i12fly]

I have some balsa 3/8" thick that belonged to my father, 30 years old + ,whilst it is a bit carroty it is still quite usable and light weight and use it when I want some block.

However I have a sheet of 1/16" with the Keil Kraft label (how old?) which weighs 80g. I keep it as a souvenir, it reminds me of all the heavy KK kits I had as a boy. (Compared with my current stock of 1/16" which weighs 18g to28g)

I've also got an 8" length of balsa block that my father said was an offcut from Mosquito builds he got in WW2, it's darkened with dust but soft and looks usable. I keep it for sentimental value.

p.s. My balsa has always been kept in dry conditions and for 10years plus upstairs in the spare/ hobbies room

Edited By i12fly on 02/02/2018 23:16:45

[Former Member]

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[Don Fry]

I don't think it hardens with age, why should it. And it lasts well. I will have 30 year old stuff in my box, and I have no idea which is new, which is old.

But back in the day, kit quality control basically did not exist. If they wanted a nose block, and had nothing suitable, then something unsuitable went in the box. The industry then created aeromodellers who went flying despite what the industry supplied.

[David Davis]

Posted by Percy Verance on 02/02/2018 22:31:41:

...You'll love the Telemaster Phil. It's a superbly relaxing model to fly. I used to fly mine lying down..........

I'll drink to that! The Telemaster 40 was my favourite of the entire range which I used to import 10-15 years ago. Maybe it's one of the kits I sold, which the purchaser never started. Does it feature a picture of a young lady with a Senior Telemaster covered in transparent film on the box lid Phil? The model aeroplane that is, not the young lady!

Mine was electric powered and met its end when the wing bands let go one day. I still have the wing which fluttered down to earth unharmed. Must build another fuselage and tail for it one day. This is a picture of it before it's unfortunate demise.

[Former Member]

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[Phil 9]

[Phil 9]

[Phil 9]

A couple of photos of the box

[Peter Miller]

Yes, the wood tended to be much harder and heavier in the old days (50s and 60s) Who remembers cutting out those round formers with the notches for stringers in the old KK free fight scale kits with half a razor blade?

PICA kits are notoriously heavy. Sig kits tend to have very good wood.which is not excessively heavy.

What I do object to are vintage style kits with 1/4" sq. that is more like Elderberry pith which can be cut with a blunt thumbnail.

As for wood going hard with age. Well I know that Oak goes much harder over hundreds on years but we don't keep our balsa wood that long.

[Cuban8]

My Sig Zlin 526 was built from a kit that had been stored in a dry loft for 35-40 years by a club mate. the only wood that wasn't useable was the balsa sheet for the foam wing cores, the wood had gone very hard and would split very easily.

Luckily, the Americans would always leave the foam wing cores in their kits to be covered by the builder IIRC. Most Brit kits with pre-covered foam wings that spent a year or ten in a loft, usually wound up with the wood veneer pulling away, rendering the whole wing useless.

[Former Member]

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[Former Member]

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[David Davis]

Posted by Percy Verance on 03/02/2018 13:04:29:

Wow, that is an old box Phil. Looks like a Futaba M Series radio, so from 1975 (ish) onwards..........or is it an earlier Digimax? I can't quite tell from the pic.......

For what it's worth, I think it is an M Series. The Digimax transmitter was slightly smaller and more angular in apprearance. But still, I guess the photo could have been a few years old when they used it. Anyway, it's old!

Edited By Percy Verance on 03/02/2018 13:15:51

I agree. It's very old and not one which I sold. My labels had a coloured photograph on them.

It should fly well even if it's a little heavy. From what I remember, my T 40 weighed 6lbs with flaps a large 4S battery fitted. If that sounds heavy bear in mind that it has a wingspan of 73" so about 20% bigger than a Super 60 or modern ARTF trainer.

[Former Member]

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[Geoff S]

I don't think balsa so much hardens with age as tend to dry out and become brittle which may appear to be harder. The old Mew Gull kit (plan pack really) I've recently completed didn't have much balsa supplied but there were some bits (perhaps left in by the previous owner) that seemed a bit dried out. It wasn't as old as yours.

David: I always like to use 6 bands on wings then if one breaks things should still hold together. A young lad at the RR club a few years ago flew very well and very enthusiastically (perhaps because his dad provided the planes and did the repairs ) and he did s few violent bunts with a Lazy Bee and the bands gave up the unequal task of keeping the wings in place at around 50/60 feet. The wing fluttered gently down but the fuselage, or what was left of it had to be rescued from a tree. Hence my wing band overkill.

Geoff

[Erfolg]

I also was thinking about the difference in hardness of oak when new , compared to when it is old. I do realise that oak when used in construction is often green, not seasoned, as such. Naturally its properties change with drying out. Then I think of oak as seasoned for use by cabinet makers, typically the mouse man, pretty hard by then.

I am tending towards the properties will change slightly, although not massively, if the Balsa was properly kiln dried.

[Phil 9]

Thanks for all your comments so far. I think the wood may have been originally a bit heaver than I'm used to in newer kits and combined with that it may have dried out a little.it should be still useable I think

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[Don Fry]

My chainsaw goes through green oak like softwood.

After 12 months, you are cutting hardwood.

But, if you get some oak from ancient times, not much different.

My view, once a hardwood, and balsa is a hardwood, has lost its water content, it is seasoned, and changes are due to glues, insects, damp.

[Martin Dance 1]

I think you will find that the main difference between 'then' and 'now' is how it is sourced. Certainly in the 50's and 60's balsa trees were found in the rain forests of places like Ecuador by local native labour. Trees were felled and hauled to a suitable place for shipment. There was little idea just how old the trees were. A balsa tree reaches its commercial peak at about 7 years. Today balsa is plantation grown and therefore it is possible to harvest the crop at the optimum moment. Therefore there is a greater supply of prime timber today than in earlier times.

[Geoff S]

The exposed oak beams in our 150 ish year old cottage were secondhand when installed judging from the bits cut out that are superfluous, so I have no idea how old they are. I had to drill holes to knock in the pins for wiring staples the wood is so hard.

Of course balsa is a actually a hard wood.  I assume the reason the stuff we use is soft and light is that it's cut well before it matures.  The KonTiki raft Thor Heyerdal and his friends sailed from S America to the Pacific islands was made mostly from balsa logs which must have been quite different from model building quality.

Geoff

Edited By Geoff Sleath on 03/02/2018 21:21:51

[onetenor]

Maybe my cowl was so hard having been doped etc. It also split down the grain easily too. Heyerdahl's raft was made with green logs I think.