Type of plastic used for old chisel handles?

[Will Krautkramer]

Hi,
Im just getting in to woodworking and over the last few months I've purchased quite a few old chisels at garage sales and auctions. A few had plastic handles that were badly cracked where the the handle meets the chisel, the chisels themselves appeared to be of decent quality so I tried to heat the handle on one with a torch to loosen it up so I could rehandle it. Much to my surprise it near instantly burst into flames :eek: like a log soaked in gas or kerosene! I quickly dunked it in a bucket of water to extinguish the flames and proceeded to cut the handle off with an old hand saw. The cut plastic smelled like pine/tree resin. The ones I've dehandled already were marked Gensco on the handle with the blade marked Eskilstuna Steel, Gensco, made in Sweden. I have ~30 more gensco's and a few others that handles appear to be of the same plastic. Most have good handles but now I have concerns about how safe it is to have these around if they start on fire that easily. I haven't run across a plastic like this before. Any one out there have an idea what kind of plastic was used on these old handles?

I've attatched a picture of some of the chisels and a small piece of the plastic handle (tictac size) burning.

Thanks,
Will

[Johnny Kleso]

I have worked many types of plastic and even worked at a place wen young called Chemplast that the owner invented the way to glue teflon to other materials and I dont have even a guess.. I google and see what I get :)

[Bart Leetch]

If your going to re-handle them a little at a time in the mean time don't try starting them on fire & you should be fine. Trying to fire them off I suspect isn't normal & is the reason we've not hear of this problem before.

[Johnny Kleso]

I found it, cellulose acetate plastic .......

You could use Nylon as I think its a better plastic just will not have the true look of a handle..

Info from
http://www.alhandles.com/pages/handles-colors.htm

[Jim Koepke]

Why not make new handles of wood?

jim

[Will Krautkramer]

I wasn't really planning on rehandling the ones in good condition. This stuff really lights up and i don't think it would be easy to put out if the bulk of the handle got going. I think I could light a handle on fire just using a match. My main concern is that I keep most of my tools in the main part of my garage were there is often grinding or sanding sparks flying. I try not to keep anything too flamable in there.

[Will Krautkramer]

I have some large uhmw polyethylene pieces I could turn down for handles but I was planning on making the new ones out of some apricot and maple I have.

[Lucas Bittick]

I found it, cellulose acetate plastic .......

I had to look it up...

Interesting-- the plastic is derived from wood and has been in production over 100 years!

More here: http://www.azom.com/Details.asp?ArticleID=1461

[philip marcou]

"Type of plastic used for chisel handles"...
Most are plastic or nylon of some sort , with the exception of the Marples orangeand red type -this is a BUTYRATE compound -I think certain Stanley models also use it. Beware of the possibility of toxic gas if you must burn them. They can all be cut with a hack saw or bandsaw. Butyrate handles aren't stronger than 4 pound hammer either.
Making replacement handles is instructive and enjoyable.

[Dave Anderson NH]

Both Johnny Kleso and Philip Marcou are actually correct. Celluose Acetate and Butyrate have been used as handles for chisels. There is a third, which actually is both of the above. Celluose Acetate Butyrate is a common and relatively inexpensive plastic and the major producer for many years was Eastman Chemical (Kodak) in Kingsport TN who marketed their resin under the trade name Tennite. In the plastics world its commonly refered to as CAB. Confusion comes from the fact that the names Celluose Acetate and Butyrate were often used interchangeably, particularly by marketing people.

Addy Protocol: I spent 6 years selling plastics.

[Bill Houghton]

Stanley used to market the successor to its Everlast chisel, which used a black plastic handle with a metal cap and stud arrangement that touched the tang of the chisel, by pointing out proudly that the chisel handle was "slow burning." I'd wondered about that for years, since I'd had little experience with combustion of chisel handles; perhaps I don't work quickly enough.

Of course, they could have been contrasting it to cellulose nitrate, which did burn easily - but one of the catalogs I used to get, 25 years ago, continued to promote this virtue, long after spontaneously combusting plastic was an old issue.

[Will Krautkramer]

Thanks for the info.

I did some reading on cellulose nitrate based plastics and I think that is what the handle in question is made out of. (http://yarchive.net/explosives/nitrocellulose.html), The camphpor could explain the tree resin smell?
I'm not sure if all the gensco chisels have the same type of handle as there appears to be several variations of manufacture used to make them. I tried lighting a marble size piece of it on fire today with a match and it burst right into flames. For comparison I tried this with a few pieces of plastic from a newer screwdriver that was damaged and from one of those plastic faced hammers, these melted a bit but did not start on fire.

[David Martino]

Is butyrate the almost indestructible clear plastic used in modern (recent) chisels?

Cellulose nitrate was one of the original clear 'plastics' used as a base for film stock. Unfortunately it proved to be highly flammable over time, especially in hot conditions and if a lot was stored together. When you hear about an old film library burning, or concerns with flammable film stock, it's often this stuff. Stored dense enough in hot dry conditions, it can self-ignite. I think it was mostly phased out for film use by the 1920s-30s. Don't know about other industrial/commercial uses?

The replacement - often marked 'Safety Film' in the negative in the early days - was cellulose acetate. It didn't self-ignite or corrode in the same way, but eventually other problems with longevity developed. It was later replaced, at least in better quality films, with polyester (or proprietary Dupont tradename 'Mylar'). Clear, inert, flexible, and resistant to most chemicals, it will outlast all of us if properly cared for.

Now of course we don't use anything for camera film! (Well, a few companies still make a bit.)

If your chisel handles really are cellulose nitrate, they might be dangerous to store in closed conditions - it gives off gases as it breaks down, which build up in a box or drawer and accelerate the process. Supposed to give off a distinctive acrid smell when it decomposes, and turn brown, brittle, eventually to dust - the more broken down, the more unstable it becomes. All this is for film stock - I don't know about a use like a tool handle (or even if they ever used it for that)? But your match tests suggest caution... how many of these did you say you have? You might keep them in an area that gets regular air exchange and not all jumbled together until you figure out what you have...

[David Keller NC]

By the way - another word for nitrated cellulose is "gun cotton". In other words, an explosive. An explosion is unlikely in a solid form, but it does explain the rapid and easy combustion. Many of the various forms of early plastics like bakelite and permaloid are quite flammable, but I wouldn't think the danger is any greater than having a few cans of solvents like laquer thinner around in the shop.