be careful with nitrocellulose

[r1dermon]

if you've synthesized nitrocellulose on your own, be careful with it, and here's why...

 

nitrocellulose has a shelf life. over time it degrades and seeps HNO3, which will ignite the material. i've warned people of this before (not on this forum, but on others).

 

here's why i bring this up:

 

the company i work for manufactures biopharma membranes with various materials. one particular membrane they manufacture is made of 100% nitrocellulose, which is created on site. we have a massive nitrogen tank with 2 huge coil condensers, and produce reagent grade 99.9%conc HNO3 on a daily basis...well, one particular roll of filter membrane (picture a roll of porous thin, plastic-like material) was left on a shelf, under a workstation since 2005...untouched, unmoved, unknown about.

 

on tuesday, at approximately 2:30pm that roll ignited, and exploded. luckily nobody was nearby. glass beakers, metal lab objects, and culture equipment were all thrown throughout the lab. approximately 1 million dollars worth of lab equipment was a total loss, and counting, the explosion triggered the massive sprinkler system which dumped 10's of thousands of gallons of water onto months worth of research projects. the office area was drenched, computers ruined, furnature ruined...etc...estimated damages are well in excess of 10 million when you include the lost R&D.

 

this is all because of a roll of fairly pure nitrocellulose material, which had been stored for 6 years. boom boom. be careful out there girls and boys.

[PersonGuyDude]

How tragic! I do keep this in mind when storing nitrocellulose. I don't store it in any special way, but I don't keep it for longer than a month or so.

[spitfire]

Store it wet. In that way in can even be send by mail in a safe way. What you need, dry it and use it in a short period of time. An easy but effective way of preventing this problem.

[Potassiumchlorate]

99.9% nitric acid for nitrocellulose? Nitrocellulose is one of the few organic nitrates that can be made with pretty "weak" nitric acid.

 

One should always boil homemade NC in a 5% bicarbonate solution for at least one hour. Both before and after it should be thoroughly washed in cold pure water for several minutes and tested with pH indicators.

[spitfire]

99.9% nitric acid for nitrocellulose? Nitrocellulose is one of the few organic nitrates that can be made with pretty "weak" nitric acid.

 

One should always boil homemade NC in a 5% bicarbonate solution for at least one hour. Both before and after it should be thoroughly washed in cold pure water for several minutes and tested with pH indicators.

 

That's theory for the first minutes. Maybe the solution is neutral or even basic, but deep in the fibers, it might not. I used those small balls of cotton available at every pharmasist once, and will never again. They are too tightly packed to control the reaction. First i had a runaway, then i wasn't able to neutralize all acid deep inside the cotton balls. Just for the sake of being safe, store it wet anyway. I've had a similar occasion like mentioned above... a small can filled with homemade NC was left alone for almost a year. Just a few months ago, i opened it up, and red fuming HNO3 clouds where my gift. I slightly burned my fingers to it, noticeable of the distinctive smell and ''rough feeling'' on my fingertips that comes with it. I always store it wet since. It is a small, simple precaution, but it keeps you safe. I know, in theory, the HNO3 acids can be neutralized but in practice it is often not done well enough. That's where the water comes in. BTW, is HNO3 hygroscopic? It would explain the build-up outside my can.

[Potassiumchlorate]

H₂SO₄ is hygroscopic. HNO₃ is not, to my knowledge.

 

But it's pretty well known that you should never store NC dry. +30% water is often recommended.

[spitfire]

H₂SO₄ is hygroscopic. HNO₃ is not, to my knowledge.

 

But it's pretty well known that you should never store NC dry. +30% water is often recommended.

 

My knowledge of HNO3 isn't sufficient for this matter, fact is i found my can ''moist'' with HNO3. Somehow it got between the pvc can and the soft plastic lid. If you ever fooled around with HNO3 and it touched your bare skin you'll know that smell and ''rough'' feeling like no other. Only very strong acids do that.

[Potassiumchlorate]

My knowledge of HNO3 isn't sufficient for this matter, fact is i found my can ''moist'' with HNO3. Somehow it got between the pvc can and the soft plastic lid. If you ever fooled around with HNO3 and it touched your bare skin you'll know that smell and ''rough'' feeling like no other. Only very strong acids do that.

 

I know what it smells and feels like, yes. Not a very pleasant experience.

 

PVC isn't done to keep HNO₃. Sooner or later it will leak out, if your NC isn't pure enough. Doesn't have to be hygroscopic for that.

 

But yes, always keep the NC moist.

[Mumbles]

Keeping NC wet does not prevent decomposition. There are certain stabilizers that can be added, as well as other certain treatments that can extend shelf life, but I'm not getting into practicalities outside of the HE section.

[spitfire]

Keeping NC wet does not prevent decomposition. There are certain stabilizers that can be added, as well as other certain treatments that can extend shelf life, but I'm not getting into practicalities outside of the HE section.

 

Just for the record: i am talking about NC for laquer and flash cotton for practical jokes... not HE. Won't burn my fingers on that.

[Potassiumchlorate]

NC with a high nitrogen content seems to be better in prime and for ignition when used as a binder but, like I said, it's a nasty process making it.

[50AE]

I have some homemade NC that was stored diluted in acetone. One year and a half until now. No acid smell for now, the acetone has much evaporated though. It has hardened a bit.

That doesn't mean I don't believe in NC decomposition, just sharing my results.

[anapogeetoofar]

Is there a particular reason why nobody uses smokeless powder for their NC lacquer? I have been using it forever, am I doing something I shouldn't?

[50AE]

Availability is an issue. Not everyone can freely buy smokeless powder.

[Potassiumchlorate]

It's not like America everywhere, alas. Like someone said on the UKPS forum: In many countries in Europe it feels like you need a gun license just to enter a gun store.

[anapogeetoofar]

I'm well aware of that, I was referring more to people who DO have access to it, but don't seem to use it. Either I am mistaken, or there is a safety issue I am not aware of.

[NightHawkInLight]

I'm well aware of that, I was referring more to people who DO have access to it, but don't seem to use it. Either I am mistaken, or there is a safety issue I am not aware of.

 

Quite a few people do use it.

[PersonGuyDude]

I used those small balls of cotton available at every pharmasist once, and will never again. They are too tightly packed to control the reaction. First i had a runaway, then i wasn't able to neutralize all acid deep inside the cotton balls.

 

What do you use now? I've been trying to find an alternative to pulling an endless amount of cotton balls apart...

 

I didn't even know you could use NC for HE, I prefer quick primes and big handheld fireballs

[NightHawkInLight]

What do you use now? I've been trying to find an alternative to pulling an endless amount of cotton balls apart...

 

I didn't even know you could use NC for HE, I prefer quick primes and big handheld fireballs

 

Cotton balls are easy to use if you know how. The trick is finding what direction they're rolled in and unrolling them before reacting. Takes about five seconds per cotton ball and makes the NC you end up with nice and fluffy right off the bat. Before I knew how to unroll them it took a long time both to nitrate, as well as pull the cotton balls apart afterward to make useful NC. Now it's a very simple process.

[spitfire]

What do you use now? I've been trying to find an alternative to pulling an endless amount of cotton balls apart...

 

I didn't even know you could use NC for HE, I prefer quick primes and big handheld fireballs

 

Now days i use cotton ''loafs'' also sold in every pharmacist . They come in a plastic bag, and the cotton loafs are roughly 4'' x 3''. They are more ''fluffy'' then the balls, so the process takes less time and is better to control. Make sure you get the ones without any skin wax/ odor/ smelly-stuff mixed in. Only 100% clean cotton.

[r1dermon]

Yes 99.9% conc. We make pharmaceudical grade micro-porous filtration devices. One membrane material is (as mumbles described) "treated"nitrocellulose material. The roll of membrane in question was due for QC (quality control)...sent to a lab untreated to test for impurities...it took years, but it finally decomposed to the point of ignition. We have a massive tank of n2o on the property with two huge condenser coils. I will snap a photo some time.

[anapogeetoofar]

What sort of application does a nitrocellulose filtration membrane find? It obviously fills some niche, I'm curious as to what it is. Seems an odd material choice in this age of high tech polymers and foamed metals.

 

 

Anyways; another way to produce NC, if you are so inclined, is nitration of sawdust. More efficient. But that is sort of a topic in its own right. Off to the chemistry forum!

[Richtee]

Quite a few people do use it.

All I ever used. Have a nephew in service, and he brings home "blank" rounds from war games. Great stuff. Not that I use it any more of course.

[kleberrios]

I had these two experiences. Once Half kg of dry NC caught fire in a drawer but not detonated.

 

In another 300 grams dry but also caught fire and burned down the shack where I worked, was one of those runs runs!

 

This all happened in my mother's house. Today I have 4kg of NC but I'm always moistening it with alcohol 99% for non-drying,

 

Edited December 12, 2011 by kleberrios

[50AE]

Just another warning for homemade NC. Today I decided to clean up all my chemicals and put them into the basement. I opened up the plastic container to see and smell a cloud of brown NO2. This NC was dissolved months ago, but the acetone has dried. I burnt it. Just another reminder that it's not wise to store homemade unstabilized NC and mixtures. Imagine what could it do to chlorate based comps.