Anyone ever seen crosstrees formed in nitrocellulose?

[Sparkysparks]

I'm wondering what time period kits and suppliers used this stuff.

[wefalck]

What do you mean by 'forming in nitrocellulose' ?

 

Nitrocellulose is chemically alterated cellulose and its initial state is a kind of viscous liquid. You can use this for different purposes:

 

- you can push it through thin nozzles and spin the resulting fibres into a thread - the first man-made thread

- you can cast into films - celluloid, as used for cinematographic material or packaging, or artificial ivory (billard balls used to made from it)

- you can dissolve it in solvents to make paints, varnishes, wood fillers and the likes

 

So, perhaps you can explain a bit better, what you mean ?

[Sparkysparks]

OK. What I want to say was celluloid tortoise shell. My brain doesn't kick in at times. Chronic Fatigue. So forgive the incorrect description.   

[wefalck]

Ahh, I understand. Interesting question. There are various interesting man-made materials that have interesting properties and workabilities for model-building, but they are difficult to come by these days. We mainly use styrene, ABS and acrylic glass in model building, but builders of 'historic' ships seem to frown on them. They have become common, because they are cheap to produce.

 

However, with a bit of searching you can find the more 'historic' materials as well. I am using bakelite paper (from around 0.2 mm to perhaps 10 mm thickness) a lot. It is brittle, but otherwise machines and sands well.

 

Celluloid is more difficult to find. Because of its high flammability it has been replaced by other plastics. Indeed, various consumer goods, such as combs, boxes, knife and nail-file handles, fashion jewellery, buttons, frames for glasses, etc. etc., used to be made from coloured celluloid. It was also widely used to make toys, such as dolls.

 

However, your question prompted me to search a bit on ebay, and I discovered that one can find actually a lot of celluloid, tortoise shell and other, among products for making guitars, for knife-handles, and still for jewellery-making too. One would need to verify that it is really celluloid and not some other plastic to make look-alike.

 

Thanks to your question, I may discovered some interesting sources of material

 

I tend to use a lot man-made materials for my miniature models, as the grain in wood tends to be too promient, even when using boxwood, or the anisotropy of wood is inconvenient.

Edited April 18, 2020 by wefalck

[Sparkysparks]

I'm glad you now have a new material to play with. I shy away from zinc, pot metal, styrene and Celluloid after seeing how poorly they age. I agree with the wood grain problem. If it's the wood you want to show then who cares, but it can look pretty bad when paint is layed down. Having been on a few and worked on one, the worst I saw were white oak pieces trying to unravel. Even sandpaper will yield to the grain after time, temp and humidity changes take their turns. 

[Dr PR]

Wefalck,

 

You forgot to mention one other use for nitrocellulose. It is also called guncotton, and the highly nitrated version is a powder charge used to propel projectiles from guns. It burns extremely rapidly, what is sometimes called a low order or Class B explosive, but it doesn't explode like TNT. The low nitrated version that was used for commercial products is not considered an explosive but it still burns rapidly.

 

So if you do work with nitrocellulose treat it gently. Just don't heat it too much. It has a flash point (temperature where it vaporizes to produce a flammable gas) at 4.4C (39.9F) and ignites at 170C (338F). That is lower than the ignition temperature of paper. And it is toxic so don't breathe the fumes.

[wefalck]

I focused on the constructive uses of nitrocellulose, not on the destructive ones

 

The low flash point was one of the reasons, why celluloid was replaced by other, mineral oil-based plastics, although it has interesting mechanical properties. Celluloid can be milled or turned much better than the common plastics (except acrylic glass) we come across as modellers. The high flammability resulted in more than one cinema being burned down. Film-archives are battling with the problem and have to store the films under special conditions.

 

Off-topic: my late father was a chemist and had a book on explosives, their manufacturing and testing. There is a lab-experiment described in it for making gun-cotton for demonstration purposes. When I was a teenager, I tried to replicate this, but I guess I was lucky that the cotton-wool I had was not real cotton, but some sythetic fibre. I shudder, when I think, how me and a friend did this without proper lab and protective equipment ... this was at time, when you could walk into a drug-store in Germany and buy all sorts of chemicals for which you would be arrested as suspect terrorist, if you tried. I also made black powder, but its quality turned out to be rather poor. Today this kind of 'technical' drug-store doesn't even exist anymore and you would get the chemicals only, if you can proof that you are a professional.

[thibaultron]

The other problem with the nitrocellulose, is that it deteriates over time. The movie storage mentioned above has the added problem that the film disolves into a gel over time, a quit flamable one. I learned this from a film collector about 40 years ago, who described the condition of some of the films he had bought, and the care he needed to use, whenever he opened a "new" old film he had purchased, for the first time.

[thibaultron]

AS a note; Do not buy tortoise shell, if you live in the USA. It is illegal to import.

[wefalck]

Auf course, in most countries around the world, with a few sad exceptions, the trade in endangered species or products made from them is prohibited. I think you can bring into the country for personal use such items, when you can show that they are antiques and that you, say, inherited them - thinking, for instance of combs, boxes, frames for glasses, etc.

 

The said degradation does not seem to affect too much coloured and 'filled' items of celluloid. We have in our family dolls  and some household items made almost a hundred years ago and they are still in good order.