Maximum Safe Dry Heat Temp With Celluloid?

[Paul80]

Hi all

A quick question I hope

When using dry heat to soften shellac or thread sealant on a pen made from celluloid, whats the maximum safe temperature that can be used.

Thanks for any help with this

Paul

[GlenV]

Hi Paul I don't use a thermometer so my answer may not be what you're asking, but I test against my upper lip as I heat if gets too hot to hold for a second or two that is my testing. If you overheat celluloid you also begin to smell it noticeably.. Metal parts near the celluloid may get quite a bit hotter so use some caution, say the clutch ring on a 51 for example.

[GlenV]

By the way rosin based thread sealant does not require as much heat, although I maintain the heat longer to soften that, say on a vac fill pen..

Edited March 16, 2019 by GlenV

[siamackz]

Some things I keep in mind:

1. I keep testing against the insides of my fingers

2. I do not use section pliers as I feel its easy to put too much pressure

3. Once I feel movement I am very careful to keep hearing and the twist just a little at a time. The moment there is resistance I heat again, and so on...

[surprise123]

If you stick your finger in the heat and don't feel pain, you are in the green. Treat all celluloid like they're made of explosives... because they actually are. I personally alternate between a hairdryer and a halogen lightbulb (NEVER EVER LET THE CELLULOID TOUCH THE BULB). The halogen bulb helps with concentrated heat, like heating a section, and the hairdryer is for everything else. Rotate the pen as you go to prevent overheating of one side.

 

I once had a Parker 51 clip bushing with a piece of celluloid (the jewel broke off). I held it with tongs and tried burning off the celluloid. As soon as the flame from the lighter licked the bottom of the bushing, the tiny bit of celluloid went POP and shot the bushing away from the tongs like a firecracker. I knew celluloid was flammable, but I didn't know it went BANG when exposed to a flame. Lesson here? Don't EVER use an open flame on celluloid if you don't want to cause it to explode in your face.

 

Makes me wonder, would cellullid be banned on planes?

[Inkysloth]

Makes me wonder, would cellullid be banned on planes?

I suspect if celluloid nitrate was still commonly used it would be a restricted material, but by virtue of it being not in the wider public consciousness its slipped under the radar.

[Tweel]

I knew celluloid was flammable, but I didn't know it went BANG when exposed to a flame.

 

As far as I know, celluloid isn't ordinarily nitrated enough to explode, but maybe sometimes when it ages just wrong this can happen. I once had a sheet of cellophane explode. It had been wrapped around a box that had sat in a sun-baked store window for some number of years (it was a pretty venerable old hardware store; the print on the box was badly faded and the cellophane ambered). I accidentally dropped the box at home and the cellophane went off with a huge bang -- my ears were ringing and there wasn't a trace left of the cellophane.

 

But ordinarily, I think it just burns (pretty fiercely).

Edited March 17, 2019 by Tweel

[surprise123]

 

As far as I know, celluloid isn't ordinarily nitrated enough to explode, but maybe sometimes when it ages just wrong this can happen. I once had a sheet of cellophane explode. It had been wrapped around a box that had sat in a sun-baked store window for some number of years (it was a pretty venerable old hardware store; the print on the box was badly faded and the cellophane ambered). I accidentally dropped the box at home and the cellophane went off with a huge bang -- my ears were ringing and there wasn't a trace left of the cellophane.

 

But ordinarily, I think it just burns (pretty fiercely).

I knew of the potency of celluloid, but I never knew cellophane could do something like that. All I knew about cellophane was that it goes "crinkle crinkle".

 

Celluloid reacts unpredictably in many other cases as well. I was heating up a Duofold section once, and a crack appeared all the way down the barrel. Shortly after, the barrel, now by itself, had broken down into four pieces. I set those on fire, just for fun, since the pieces were badly dicolored and wouldn't even be good for mini rod stock.

[Ron Z]

I am pleased to see that the concept of "seeing with your fingers" is firmly taking root!

 

The answer to the OP's question is, "It depends on the pen." Granted, the usual number quoted for celluloid is 135F or so, but it does vary from pen to pen and the thickness of the material, and you usually go higher than that. I use far less heat to open a Vacumatic or plunger fill Balance than I do a Triumph nib pen. You are safest to stick to the rule that if you can hold it for a few seconds, you're OK. Check the temperature frequently, and gradually ramp up. Sometimes though, you have to get the material quite warm. To get a Triumph nib out, the section has to get up to around 160F to soften the thread sealant to safely remove the nib unit.

 

re. section pliers. To clarify - I don't use section pliers on the barrel either, but you must use them on the section. A rubber grippy pad made out of the rubber mesh stuff for drawer liners though is an excellent way to grip the barrel.

 

re. a heat source.

 

I would not suggest a halogen lamp as the heat source. The thought makes what little hair I have left stand on end.

 

I have a Steinel digital control heat gun that I never use. The gun measures the temperature at the outlet, and the temperature rolls off very quickly as you move away from that point, which means that if you set the gun for 140 or so for celluloid, by the time the air reaches the pen, it won't be anywhere near hot enough. Higher, focused heat for short periods is better than broad, lower temperature. Again, check the temperature frequently.

 

All of the professional pen mechanics I know use the small embossing heat guns, a couple of inches away from the opening. We use it because it has a focused outlet about 1/2" in diameter. You can take a digital meat thermometer and measure the temperature at different levels to see how much and how quickly the temperature changes as you move away from the opening.