Solder guard material

It should not be shiny. Lacquer is dull unless it's buffed. I'm sure I got dust in my lungs from sanding old cars. What isn't toxic ?

Greg

--
Google "solder mask" 

John Fields

I don't think you will find that nitrocellulose is toxic, although there may be other toxins in the lacquer and, of course, any form of dust can be harmful.

The big danger is that cellulose nitrate (nitrocellulose) is potentially explosive. For many years now, in all applications except record mastering and some analysis laboratory processes, it has been replaced by cellulose acetate.

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~ Adrian Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

In the 19th, and early 20th centuries, men wore collars made out of the stuff (Celluloid). Picture the scene; man wearing celluloid collar leans over gas light jet, to light a cigar. POOF!

Photographers would occasionally use a celluloid collar when they ran out of flash powder.

AKA guncotton. Evil stuff. Naval guns used it as a propellant, before Cordite was invented.

Beware antique knives and forks. Cellulose nitrate was used as a substitute for ivory in handles (Trade name Xylonite). Piano keys, too. Now outlawed in just about every jurisdiction.

Early movies were made on nitrate stock. Now dangerously unstable. Projection box fires were common, once. Once burning, it's next to impossible to extinguish. Movie houses burned down.

Solder mask? FR4 wouldn't be FR, if they used cellulose nitrate ;-)

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

There were a couple of very telling phrases in a book about it [from memory]:

1) " There were attempts to use cellulose nitrate as a military explosive but it was soon replaced by more stable and predictable compounds such as nitro-glycerine." 2) "Fighting a cellulose nitrate fire is best left to the building's automatic extinguishing system, if this has survived the initial explosions intact. In any event, keep personnel as far away as possible until all the cellulose nitrate has burnt out, then tackle the resulting conventional fire."

I should add that a smouldering nitrate fire evolves copious quantities of carbon monoxide, cyanide and hydrogen - until the exothermic reaction reaches flash point...

--
~ Adrian Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

Never heard that before, but perhaps plausible given the process control of the day?

Well, all production hand guns do, too.

I'd hardly call it evil stuff. It burns, yes, but it's no nitroglycerin.

Cordite it would seem has been *long* out of use, with "triple base" types being preferred now.

The term is British; though largely similar formulations have been in use since their invention, I don't know that it was ever called Cordite in the US.

Ping-pong balls too, e.g.

Sounds like the guys are German, so I doubt those at least are really "outlawed in just about every jurisdiction".

Heh... with all the hubbub about plasticizers these days, one can only imagine what they'd think of that sort of stuff now... Who cares about plasticizers, my plasticware is giving me a headache! (Organic nitrates are notoriously strong vasodilators, hence, for example, pounding headaches after working near (let alone with) nitroglycerin and such.)

The difference is, the gun stuff has a high nitrate content, the ping-pong ball stuff has low nitrate content. It burns slowly. Probably not slowly enough to extinguish short of an intense frigid CO2 blast, but it will just about never explode.

Could be the old production stuff wasn't very well controlled, so the minimum nitrate content wasn't as low as would really be desired for safety. I don't know the intricacies of production like that.

Even the stuff they put in guns doesn't explode. Even when mixed with a rather considerable fraction of nitroglycerin (e.g., Bullseye Smokeless at up to 40%). Burns *very quickly*, ah, yep...

Offhand I don't know what the drop test of the latter is. It will detonate at some point... just about every exothermic mixture does, from the fairly inert but notable TNT, to innocuous thermite blends*. I wonder how it compares to the others (like TNT, pure high-nitro NC, low-nitro, and the old fashioned black powder).

*While I'm drifting off topic here, it's amusing how powerful some thermite mixtures actually are. You can take a torch to some copper wire, heat it until black, scrape off the oxide, then file some aluminum into the pile of oxide. Place the mixture on a heavy steel plate, and tap it with a hammer. But do cover your ears first! Somewhat larger, and better mixed, compositions are used in 'exploding targets' for target practice. Note the distinctive color of finely divided copper: I don't recall that traditional (iron) thermite is ever explosive (well, when dry.. moisture, that's cheating), but that might simply mean you aren't trying hard enough.

Tim

--
Seven Transistor Labs 
Electrical Engineering Consultation 
Website: http://seventransistorlabs.com

I figured Adrian would more likely have heard of Cordite, than the DuPont propellants from WWI era. Some Cordite was made in Canada.

Propellants shouldn't explode (detonate). If they did, your pistol slide would end up sticking out of the back of your neck, and you'd be short some fingers :-)

Deflagration versus detonation.

It was knife handles, and piano keys to which I was referring.

--
"Design is the reverse of analysis" 
                   (R.D. Middlebrook)

On Sun, 9 Feb 2014 10:40:28 +0000, snipped-for-privacy@poppyrecords.invalid.invalid (Adrian Tuddenham) Gave us:

Potentially?

Try *IS* explosive.

I agree, but it is still used relatively safely in the form of a thin lacquer film on metal. Master disc recordings are made by cutting the grooves into nitrate-coated blanks (which are called "Acetates" by the trade because of the bad reputation the word "nitrate" acquired ). The swarf from the cutting process is fairly dangerous, but the discs themselves take a lot of heating up before they begin to catch fire.

The real danger is in old 'direct recordings' which were made on similar material many years ago. The nitrate begins to undergo a chemical change which makes it more unstable. The first sign is of shrinkage, where occasional flashes of the silvery base material can be seen through splits at the bottom of the groove.

The next stage is 'mud cracking' as the shrinkage becomes worse; at this stage, some flakes begin to become detached from the underlying material and no longer have the benefit of the heat sinking effect of the bulk of the alloy disc. Records in this condition are still playable with a sapphire or diamond stylus, but should be drenched in water throughout the process.

The final stage is the formation of reddish-brown powder. This is a highly unstable contact-sensitive explosive - discs showing this effect are best left alone until the bomb squad arrives.

--
~ Adrian Tuddenham ~ 
(Remove the ".invalid"s and add ".co.uk" to reply) 
www.poppyrecords.co.uk

No it's not particularly toxic. I doubt they are using nitro still.

Check out "Bruce Ames Youtube" He was the #1 toxicologist in the US, and t he "Ames Test" is named after him. Now, at age 80, he says the programs scaring us about toxicity are all BS. He says his whole life work was invalid. Toxic substances don't cause cance r. The various toxic scares are all a lie, and mainly an excuse for bureauc ratic funding and chance to walk around with a stick up their ass. Check the U-toob.

and the "Ames Test" is named after him.

BS. He says his whole life work was invalid. Toxic substances don't cause cancer. The various toxic scares are all a lie, and mainly an excuse for bureaucratic funding and chance to walk around with a stick up their ass.

That turned out to be a rather interesting tip. As in Holy Shit, i have been missing the boat here.

Thranx

?-)