Sciencemadness Discussion Board

Strong smell of acid in commercial nitrocellulose?

Scalebar - 18-5-2016 at 09:52

I get through a fair bit of flash cotton and paper and I buy it in rather than make my own ( I do dabble but the commercial stuff is cheaper and better). Just opened a pack of paper from my usual supplier and it's got a nose flinching aroma of acid.
Is this usual ( I've never noticed before)? Has it not been washed fully or is it trying to break down ?

I've given it a good soak - I don't trust it so I'll dry it out sheet by sheet as I need it. It's not burning as fast as usual either but since I mainly use it to put a little extra distance between me and what's going to go safely bang that's not really a concern - it's mainly for show.

Smells more like HCl than nitric to me - could be relevant, could be hayfever

PHILOU Zrealone - 18-5-2016 at 10:29

Quote: Originally posted by Scalebar  
I get through a fair bit of flash cotton and paper and I buy it in rather than make my own ( I do dabble but the commercial stuff is cheaper and better). Just opened a pack of paper from my usual supplier and it's got a nose flinching aroma of acid.
Is this usual ( I've never noticed before)? Has it not been washed fully or is it trying to break down ?

I've given it a good soak - I don't trust it so I'll dry it out sheet by sheet as I need it. It's not burning as fast as usual either but since I mainly use it to put a little extra distance between me and what's going to go safely bang that's not really a concern - it's mainly for show.

Smells more like HCl than nitric to me - could be relevant, could be hayfever

Maybe test with litmus paper to confirm acidity or ask the seller or manufacturer for MSDS or ask the question if the smell is normal.

I doubt acid would be any good to NC.

For safety of ignition and distance use: a fuse or a blue laser

Scalebar - 18-5-2016 at 13:09

Cheers, from the safey point of view I set off nothing that I wouldn't do on the palm of my hand - except flash powder which is a slow match job so fuses aren't a major issue for the nc - it just adds to the drama. If the wool came in smelling of acid, it'd be off the demo.

As a laser worker I'd be worried about using one for ignition - what class does it take to light nc?

PHILOU Zrealone - 19-5-2016 at 11:20

Quote: Originally posted by Scalebar  
Cheers, from the safey point of view I set off nothing that I wouldn't do on the palm of my hand - except flash powder which is a slow match job so fuses aren't a major issue for the nc - it just adds to the drama. If the wool came in smelling of acid, it'd be off the demo.

As a laser worker I'd be worried about using one for ignition - what class does it take to light nc?

I think the blue laser 5 W will do the job!
Of course if you are a magician (playing with pyro compositions in your hands), this is another story.

Scalebar - 19-5-2016 at 12:48

Quote: Originally posted by PHILOU Zrealone  

I think the blue laser 5 W will do the job!
Of course if you are a magician (playing with pyro compositions in your hands), this is another story.


5W? Not my idea of fun - I use lasers every day at work, I wouldn't want to contemplate the consequences of demoing such a hefty beam with no interlocking and I already have one eye strike myself.

I'm not a magician but I do science outreach, I prefer keeping things down a safe distance of about a meter for the public - if I can't hold it in my hand I get a bit edgy ( though I do use sodium metal and flash which I don't hold).

EDIT(woelen): Fixed layout of message.

[Edited on 20-5-16 by woelen]

PHILOU Zrealone - 19-5-2016 at 15:03

Quote: Originally posted by Scalebar  
Quote: Originally posted by PHILOU Zrealone  

I think the blue laser 5 W will do the job!
Of course if you are a magician (playing with pyro compositions in your hands), this is another story.


5W? Not my idea of fun - I use lasers every day at work, I wouldn't want to contemplate the consequences of demoing such a hefty beam with no interlocking and I already have one eye strike myself.

I'm not a magician but I do science outreach, I prefer keeping things down a safe distance of about a meter for the public - if I can't hold it in my hand I get a bit edgy ( though I do use sodium metal and flash which I don't hold).

I have made explosives demos at Free University of Brussels during the science day...subject was then "Order and Chaos" so I could'nt resist presenting powders and explosives...only 5 meters safety perimeter for audience (safety nadar fences), everything outside.

-Silver Flash (NaClO3-S-C-Al)
-Golden Flash (NaClO3-S-C-Fe)
-Thermite (Fe2O3-Al)
-Black powder
-KClO3 black powder
-KClO3 coloured flares
-Silver acetylide nitrato complex (SANC/SADS)(detonating stuff)
-Boosted KClO3 black powder (with dust of SADS)
All chlorate based pyro comp with CaCO3 dust as acid stabilisator for S (sulfur).

Even if the quantities where small (max two soup spoons (+/- 50g for the safe mixes in paper cones and about 50 mg for the detonating stuff)...I woudn't hold any of those into my hand.
Also for all I had 30 cm plastic drinking straw fuses (KClO3/C/S/CaCO3) that lasted at least 10 seconds (very effective for ignition) and lighted via a piezo gas welding pistol.
Then I went a few steps close to the fence and the public.

[Edited on 19-5-2016 by PHILOU Zrealone]

Bert - 19-5-2016 at 15:35

Destroy the smelly batch. Not worth taking any chances.

If you can smell it, it is getting ready to destroy itself anyhow.

Scalebar - 19-5-2016 at 22:12

I may have caused confusion there - the only demo I'd do in my hand is nitrocellulose in low quantities. For flash I use a flashpot and limit it to 3g - it's plenty for a good foof! mini mushroom cloud and flash of light. basic flash nix - Al, K nitrate mixed straight before use - nitrates easy to get hold of, low toxicity and the mix lights well.