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I've seen some vendors' websites (can't remember which) that say that the plastic scale material of modern Dovos would be celluloid. Does any of you have further information whether Dovo/TI still use celluloid, or is it some other plastic?
And if it is indeed celluloid, is it susceptible to cell rot?
Apparently, at least the Bismarcks have celluloid scales.Quote:
Originally Posted by ursus
Time will tell.Quote:
Originally Posted by ursus
All celluloid is prone to rot and distortion. However, with proper care, a celluloid set of scales should last decades. That said, I had a nice fountain pen in celluloid (a new one) that had warped pretty badly from poorly aged celluloid...so you just never know. Celluloid is about as 'organic' as you can get in a plastic and unfortunately doesn't have the longevity as many of the newer 'super plastics'.
My understanding is that most modern Dovos are scaled in celluloid. I discovered this after noticing that the scales on my Bismarck and Best were showing signs of "melting" after being dipped in isopropyl alcohol for 30' to sterilize them. Alcohol damages celluloid. I checked some websites, one of which stated many Dovo scales are celluloid.Quote:
Originally Posted by ursus
Cant you tell by smell?
Plastic scales dont smell of anything whereas celluloid has a strong distinctive scent? My Bismarck has a really strong smell and it hasnt faded with time. My microtome has black plastic scales and doesnt smell at all.
Its hard to describe, but its a bit like the smell you get from a new pack of camera film. Its not unpleasant at all, but you can definately tell theres an aroma there...!
Yes. You can check (sometimes) if something is made of celluloid by rubbing your thumb on it vigorously until it gets warm and then take a smell. If it has a sweet camphor type smell, it's celluloid. Other methods require more heat, ie. touching them to a hot stove, to get that smell.
One word of warning to those considering this...celluloid burns different than other plastic and is a more, uh violent, kind of burn. About a decade ago, the Montegrappa fountain pen company was curing some yellow celluloid when a spark touched off a fire that burned down their factory.
There is not much molded out of celluloid these days. If the modern scales are indeed made out of celluloid I would not worry about cell rot. Most of the breakdown came from early forms of celluloid (cellulose nitrate). The formulation has been improved since the early days of a simple cellulose nitrate, camphor (plus a little more, color, bulking, additional plasticizers) mix.
Charlie
Thanks for the input, guys. I guess they still do use celluloid then.
If I understand correctly, celluloid can smell of faintly/strongly of camphor without being infected with cell rot?
So I was cleaning the inside of a dissassembled old set of Boker scales by rubbing with extra fine steel wool and I noticed a fairly strong smell similar to vicks vapo rub. Is this the "camphor smell" you were referring to (I assumed these were celluloid scales) ?
Sounds like you have celluloid scales there friend. :)
People usually describe the smell as vinegar.
thebigspendur,
The acidic, vinegary smell is from traces of nitric acid, either from the original manufacture of the celluloid, or from its break down.
Have fun !
Best regards
Russ
Cellulose acetate breaks down to give a vinegar smell (sometimes also a bit like ammonia) - it was once called the "vinegar syndrome." It may also stretch, shrink and flex and exude the plasticiser, leaving an oily deposit, as well as triggering a chemical reaction in nearby articles made of cellulose acetate.
Cellulose nitrate is worse: the breakdown products are strongly acidic: this causes metals to rust and as it is a strong oxidising agent it can also cause spontaneous combustion (early formulations). To counter this, camphor was added - hence the camphor smell.
Two types of celluloid - two different smells!
Who knows how many more varieties there are?
Regards,
Neil