Combustion of binding inside of case

[krishna]

In Winnipeg ,over the 8 years I had my Insrument Repair shop there , I had two instruments come in for repair that had combusted inside their cases. In both cases, between 7 and 10 inches of plastic binding,(both in the same spot, front, lower bout were tone and volume pot go on an electric) was burned,and the finish around the burn had bubbled away about one half inch on both side and front,,,... Neither of the cases had been opened in many years. On one of them, the crushed velvet inside the case had actually melted into the guitar #finish ,and had to be cut off before the guitar could be removed. It was a Gibson electric from the 50s if I remember correctly. The other one (He blamed / freaked out on one of his kids) the inside of the case, all around were the buning had taken place, was charred and blackened. Both owners smelled chemicals burning (smoke residue) when the cases were finally opened. #neither of them had been moved in many years...both were in #master bedroom closets...Has anyone else had experience with this? #.....Kerry....I know it has to do with off-gassing of the plastics...

[Chris Baird]

Nitro-based plastics become unstable with age. Heck they are somewhat unstable to start with. I've heard of pickgaurds going up in flames the same way.

[Michael Lewis]

Some batches of celluloid seem to be less stable than others, and deteriorate more quickly. One fellow brought in a Super 400 with the pick guard crumbling, all the metal parts were corroded, and the inside of the case lid over the pick guard was devoid of upholstry fuzz. He thought it had been in a flood but couldn't remember when it possibly could have happened. It looked pretty awful but there was no water damage. The problem is that the guitar had been in the closed case for at least 12 years, and any outgassing stayed right there. As celluloid breaks down it emits nitric acid fumes, this is what does the damage.

Celluloid is cellulose dissolved in nitric acid and camphor is added as a plasticizer, otherwise it will become brittle. That is why you smell camphor as you scrape celluloid bindings. I think that if the instruments are aired out frequently they should survive much longer.

[Luthier Vandross]

I did a rosette in celluloid today, and it was proud nearly a 16th of the top when I finished (was scrap) and I didn't feel like *not* using the thickness sander.. so I put on my face shield, and welding gloves, and let her rip. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/mad.gif

Thanks for that technical info Michael, interesting about the camphor, I have always wondered. That would also explain the dryness/peeling of the skin on my right thumb, and index finger from using old Fender xtra heavy picks... hmm.. gross. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/laugh.gif

Just to stay on mandolin topic for sure, that rosette was made from scrap F5 bindings..

(m)

[Rob Grant]

After spending a multitude of hours struggling with some too-well seasoned New Guinea ebony binding material and an f-4, I HAD decided to try celluloid next time to ease the pain of the razor cuts and burned finger tips. After listening to you blokes, I think I'll stick with the wood!<g>

[Steven Stone]

Nitro pickguard breakdown is very common, but only gets to the point of combustion in extreme cases where the guitars are in unopened cases for many years. Perhaps that's why I usually see it on high-end archtops as opposed to lower-priced models.

The high end instruments are often purchased by collectors or non-players who put them away and don't open them periodically. If you open a case as little as once a month the nitro damage won't occur. The nitro pickgaurds may still break down, but their gasses wont damage other parts of the instrument and case.

[Bandersnatch Reverb]

The thing with celluloid... is that moisture really speeds up its deterioration. So does heat.

Celluloid - old movie film stock... would spontaniously combust, but more often it would just crumble. "Kodak Safety Film" is still marked on Kodak Acetate and Polyester (Estar) base films.

Nitrocellulose is made by nitrating cellulose (duh), a process which involves whats called red fuming nitric acid, plus some strong suphuric acid. Red fuming H2SO4 is pretty potent stuff, and indeed does fume red in all but very dry atmospheres. The sulphuric acid is to absorb the water from the reaction. Speaking of which, you need a water bath to control the heat of the reaction or you get a big boom. The most common cellulose to nitrate is cotton. I think the heat of the reaction must be kept close to 180 degrees, which is at first endothermic, then becomes exothermic once it gets going. Not much sulphuric acid is added to the nitric acid... less than ten percent... more like 5 percent.

Nitrated cellulose, looks just like regular cellulose. To make it into a plastic colloid form, its dissolved in an ether and alcohol mixture. Again mostly ether, and the alcohol will absorb any mosture present. It is at this point the camphor is added so that the nitrocellulose becomes celluloid and remains plyable and workable once the ether and alcohol are evaporated off. Dyes are added at this point too. You can get tortoise and other mixes by rolling, pressing and extruding different batches of colloidial celluloid into one finished item.

I'm not sure if nitric acid is given off when it reverts. It may be acetic acid, or perhaps a combination of some leftover nitric, and sulphuric (and maybe acetic) acids, all of which will corrode copper, steel, and nickel finishes like no tomorrow.

BTW, dont try nitration at home, chances are you'll really get hurt bad.

[sunburst]

Bandersnatch Reverb,

Since you seem to know about the chemistry of celluloid binding, why does the binding often crack into little squares when an old instrument (mandolin, for example) is refinished with nitrocellulose lacquer?

[Bandersnatch Reverb]

Sunburst.. I have no idea. It might just have to do with stress, maybe like "checking" on a nitrocellulose laquer finish.

Jacob! Nice story! Totally unrealistic, but nice none the less. I dunno... there are lots of nitro stories. I've made and played with nitrated paper (I cant remember why we nitrated the filter papers, but I DO remember they were neat to play with). If you held a match to one, it simply vanished. No bang, little ash, terrible acrid biting smell, and no real "flame" either. There was the old story of the students who nitrated their hankies... and put them in with the laundry. They looked like regular cotton until the laundress tried to press them with her iron, in which case they vanished without a trace. Take that same guncotton and put it in a closed container and you've got a low explosive, or very rapidly burning propellent. The action of straight guncotton is far to rapid for most arms propellent. I think they mix the colloided nitrocellulose with chalk and graphite.. and control its shape with extrusion.. to get actual arms propellant. There are numerous processes I'm sure. The boom from making nitrated cotton is from the nitric acid itself. Somebody help me here... its from the trapped moisture being released as the temperture meets a certain point and you get a rapid release of engergy at that point. Thats one reason for the sulphuric acid in the reaction. Guys its been something like 30 years since my last chemistry class... so dont take any of this to the bank!

[Luthier Vandross]

You walk in a bank around here with something like that, they call the cops.

;)

M

[Darryl Wolfe]

Having made hundreds of pickguards, I have a very nice supply of various tortoise nitro plastics. #They vary considerably in age. #What I find interesting is how some of them react to each other while in storage. #Some seem to cause others to deteriorate while others do not. #With that said, I believe that various lining materials on cases, finish materials and generally most anything that may come in contact with the guard (including it's own binding) can possibly lead to accelerated deterioration.

I had a thirties A-50 long ago. #The guard was in nice condition until I took it off and layed it inside the case. #Within a month it was in crumbs

[TommyK]

Everybody,
I'm glad Bandersnatch Reverb #is on our side... I hope.
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wow.gif

[TommyK]

Help out a guy that got through Chemistry with a "C-".
This thread was begun with the word 'combustion'. Is the celluloid really combusting? Is it spontaneous combustion like that of wet hay in a barn? Should I open my Japanese built Epi, with bone colored binding, monthly to make sure my house doesn't burn down? Are my "Super 8s" a ticking time bomb? Or is this just a chemical reaction whose (sp?) result resembles charring?
http://www.mandolincafe.net/iB_html/non-cgi/emoticons/rock.gif

[krishna]

Tommy, I have'nt heard of anthing other than the instrument being damaged. And it IS spontaineous combustion.

[s1m0n]

Nitrated cellulose, looks just like regular cellulose. To make it into a plastic colloid form, its dissolved in an ether and alcohol mixture

Does this mean that it's a really bad idea to try and learn french polish on an old (forties) beat up mando with what looks like plastic bindings?

[Bandersnatch Reverb]

S1m0n I dont think its a bad idea.

Nitrocellulose/celluloid can spontaniously combust. It can also crumble to dust without combusting.

Try burning a celluloid pick... oh man... just light one up, on a cookie sheet please

Then shave one into little pieces like coarse sanding debris... and do it again

It'll make ye think twice about that stuff... that is certain.

[danb]

Another interesting datapoint- a Style O a friend of mine recently purchased has slight 'guard deterioration, and otherwise inexplicable finish wear around the guard in a case that is in nearly perfect shape. Looks like it was stored shut for many years?

[John Ely]

Bandersnatch's explanation of how to make celluloid also tells you why it is not commonly made any more. The process is just too dangerous, and the chemicals are just too nasty. It was one of the very first plastics ever made, if not the first. It was originally used a replacement for ivory - in billiard balls, for example, and then for tortoise shell. Table tennis balls are celluloid, and the good ones still are celluloid.

[Dale Ludewig]

Does this mean that celluloid flatpicks that I carry in a little case in my pocket could suddenly ignite and, well, you know?

[MANDOLINMYSTER]

My momma was right, the world can be a dangerous place http://www.mandolincafe.net/iB_html/non-cgi/emoticons/cool.gif

[mikeomando]

I've known some women who would occaisionally act like celluloid.

[TommyK]

"...It was one of the very first plastics ever made, if not the first...."
Believe it or not, Leonardo DaVinci invented a substance we call 'plastic.' He made some artistic items, but that's as far as it went.
Click Here (http://dsc.discovery.com/news/briefs/20040202/leonardo.html) to read about it.

[krishna]

Dale, Not unless you ,,,1; seal them in something airtight 2 ; Keep them undisturbed in your pants pocket about (I'd say) 15 years......Kerry...So unless you have a ziplock handy, and REALLY bad personal hygean (?).....