Coffee Stains

A. G. Maisey · 17th June 2011, 09:49 AM

I'm no chemist Mr. Wizard, and in this matter I will bow to your superior knowledge if I happen to be incorrect, but my memory of the process for manufacture of gun cotton is that for the combination of cellulose and nitric acid to take place, the nitric acid needs to be free to combine, so it is mixed with sulphuric acid. If the nitric acid is in combination with the ethanol of the nitral, surely it is not free to combine with the cellulose of the cotton?

Is this correct , or am I way off track?

mrwizard · 17th June 2011, 11:11 AM

Hello Alan,

You are correct if you want to set up a controlled process to manufacture nitrocellulose (gun cotton) which is relatively stable.
Just combining cotton and nitric acid by itself, may lead to a highy unstable explosive material (xyloïdine).
see page 245 and following in T.L. Davis "The Chemistry of Powder and Explosives" http://www.scribd.com/fullscreen/559...w1m9v49ztfc2bu

If or if not that happens depends on many process parameters (e.g. temperature, concentration, luck). Ditching a cotton rag in nital and then letting it dry is in my opinion like tossing some dice. IMHO the rag should at least be extensively watered before it begins to dry.

Nital by itself is a dangerous substance:
http://www.ab.ust.hk/hseo/tips/ls/ls005.htm

Even some on first sight harmless substance like lineseed oil may become dangerous if the safety protocols are not followed: http://www.naturalhandyman.com/iip/i...uscombust.html

Best Regards,
Thilo

A. G. Maisey · 17th June 2011, 01:13 PM

Thanks for that Thilo.

I understand where you're coming from.

rasdan · 17th June 2011, 03:42 PM

G'day Alan and Thilo,

Thanks for the advice. I am not actually very keen in using specialised chemical solutions for my blade, for this is the only one I have. But application using cotton swab sounds harmless enough. Anyhow, the blade is still under restoration and wont be ready for staining anywhere soon. I'll check further on the safety part as Thilo mentioned. Again, thanks for the advice.

17th June 2011, 11:11 AM	#2
mrwizard Member Join Date: May 2010 Location: Dortmund, Germany Posts: 102	Hello Alan, You are correct if you want to set up a controlled process to manufacture nitrocellulose (gun cotton) which is relatively stable. Just combining cotton and nitric acid by itself, may lead to a highy unstable explosive material (xyloïdine). see page 245 and following in T.L. Davis "The Chemistry of Powder and Explosives" http://www.scribd.com/fullscreen/559...w1m9v49ztfc2bu If or if not that happens depends on many process parameters (e.g. temperature, concentration, luck). Ditching a cotton rag in nital and then letting it dry is in my opinion like tossing some dice. IMHO the rag should at least be extensively watered before it begins to dry. Nital by itself is a dangerous substance: http://www.ab.ust.hk/hseo/tips/ls/ls005.htm Even some on first sight harmless substance like lineseed oil may become dangerous if the safety protocols are not followed: http://www.naturalhandyman.com/iip/i...uscombust.html Best Regards, Thilo Last edited by mrwizard; 17th June 2011 at 11:27 AM. Reason: added reference

17th June 2011, 09:49 AM	#1
A. G. Maisey Member Join Date: May 2006 Posts: 7,015	I'm no chemist Mr. Wizard, and in this matter I will bow to your superior knowledge if I happen to be incorrect, but my memory of the process for manufacture of gun cotton is that for the combination of cellulose and nitric acid to take place, the nitric acid needs to be free to combine, so it is mixed with sulphuric acid. If the nitric acid is in combination with the ethanol of the nitral, surely it is not free to combine with the cellulose of the cotton? Is this correct , or am I way off track?

17th June 2011, 01:13 PM	#3
A. G. Maisey Member Join Date: May 2006 Posts: 7,015	Thanks for that Thilo. I understand where you're coming from.

17th June 2011, 03:42 PM	#4
rasdan Member Join Date: Dec 2004 Location: Kuala Lumpur Posts: 369	G'day Alan and Thilo, Thanks for the advice. I am not actually very keen in using specialised chemical solutions for my blade, for this is the only one I have. But application using cotton swab sounds harmless enough. Anyhow, the blade is still under restoration and wont be ready for staining anywhere soon. I'll check further on the safety part as Thilo mentioned. Again, thanks for the advice.