Max Dry Heat Temp with Celluloid

[Paul-H]

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

[Jon Szanto]

I don't know if I'll ever find it, but a couple years ago on FPN there was a thread discussing this with input from Ron zorn and David Nishimura. My memory was that up to about 130 degress F was safe. Don't heat a pen based on my memory, though. Spending a little bit in the Repair forum over there should turn up the original source.

[Chrissy]

I did a Google search for "heat temp and celluloid" and although it's probably not the thread Jon referred to this FPN thread came up

[Jon Szanto]

I did a Google search for "heat temp and celluloid" and although it's probably not the thread Jon referred to this FPN thread came up

That may have been the thread, or there may be something similar, but that thread certainly contains the pertinant information. Thanks.

[azkid]

That's a great thread. Thanks. My limited experience is in using a hot air rework station which has digital temp control but it puts out heat starting at 110°C which is too hot I guess. So I have to keep it far from the pen.

I suppose a small, colder, hot air gun would be better. I also have a large heat gun but it is unwieldy and not digitally controlled.

I tried to be patient so that a low temp applied evenly would slowly conduct from outside to the joint inside. I was afraid I would overheat the outside too quickly and damage it before the joint ever got warm enough.

I was able to practice on an old beat up Arnold and disassemble and reassemble twice.

I was also able to soften the celluloid around the lever just enough to reshape it back after it had bowed out over the years. Now the lever doesn't wobble around and it looks and works much better. That technique is a work in progress but looks promising at least.

[Chrissy]

That's a great thread. Thanks. My limited experience is in using a hot air rework station which has digital temp control but it puts out heat starting at 110°C which is too hot I guess. So I have to keep it far from the pen.

I suppose a small, colder, hot air gun would be better. I also have a large heat gun but it is unwieldy and not digitally controlled.

I tried to be patient so that a low temp applied evenly would slowly conduct from outside to the joint inside. I was afraid I would overheat the outside too quickly and damage it before the joint ever got warm enough.

I was able to practice on an old beat up Arnold and disassemble and reassemble twice.

I was also able to soften the celluloid around the lever just enough to reshape it back after it had bowed out over the years. Now the lever doesn't wobble around and it looks and works much better. That technique is a work in progress but looks promising at least.

Indeed it does sound very promising. Well done you.

[Robert]

I have a sort of related, maybe oddball, question: has anyone tried using a sous vide device to heat pens? I have one of these devices that I use occasionally for cooking (works great on steaks!). For anyone unfamiliar with the sous vide method, the "subject" - be it a steak or pen - is enclosed in a plastic baggie; air in baggie is purged; baggie is then submerged in a container of water; sous vide device does its thing.

I can set my sous vide device for a specific temperature, and it gradually heats the water to, and maintains, that temperature for whatever period of time I program. Possible advantage of heating celluloid via sous vide: heat is applied gradually allowing one to test results at lower temp before graduating to a higher one.

Just a thought . . .

[Jon Szanto]

I have a sort of related, maybe oddball, question: has anyone tried using a sous vide device to heat pens? I have one of these devices that I use occasionally for cooking (works great on steaks!). For anyone unfamiliar with the sous vide method, the "subject" - be it a steak or pen - is enclosed in a plastic baggie; air in baggie is purged; baggie is then submerged in a container of water; sous vide device does its thing.

I can set my sous vide device for a specific temperature, and it gradually heats the water to, and maintains, that temperature for whatever period of time I program. Possible advantage of heating celluloid via sous vide: heat is applied gradually allowing one to test results at lower temp before graduating to a higher one.

Just a thought . . .

As Ron Zorn noted in the thread mentioned above: the point/purpose is NOT to heat the entire pen, only a small portion that needs the heat applied. Warming the entire pen that way, to a temperature that might loosen the shellac/section, could lead to problems elsewhere in the pen. Just my extrapolation on this...

[penwash]

I can set my sous vide device for a specific temperature, and it gradually heats the water to, and maintains, that temperature for whatever period of time I program. Possible advantage of heating celluloid via sous vide: heat is applied gradually allowing one to test results at lower temp before graduating to a higher one.

Just a thought . . .

Robert, I am not familiar with the device that you described (I just eat steak, I'm not smart enough to cook them), but from your description, this device expose an open flame to the heated object. That would be a big no-no for a celluloid pen because celluloid is highly flammable.

Besides, as Jon mentioned above, you don't need (nor want) to heat the whole pen barrel, just the small section where shellac'ed parts are approximated to be (near the section if we're trying to take a section out).

[Deb]

I use a heat gun all the time and I don't have a thermometer. I have yet to set light to a pen with it. Even when shellac is used on a section ( a bad practice) it gives way long before the danger point. The trick is to continually rotate the pen so that the heat is not concentrated on one spot, and only apply the heat in short bursts. Though I usually have the pen apart in seconds, there are times when I have to set it aside and return to it later, perhaps several times. Patience and caution are always the watchwords.

Setting fire to celluloid intentionally gives an excellent display.

[Robert]

Penwash and Deb - I guess my description of the sous vide process wasn't clear enough. The item (be it steak, egg or pen part) is *not* exposed to an open flame. It is enclosed in a plastic bag, which is submersed into a water bath, which is heated gradually by a heating element to the desired temperature. More information on the process is to be found here: http://en.wikipedia.org/wiki/Sous-vide

The reason for my query: Last year I acquired a 1930's Onoto pen. The material is celluloid. It is a nice pen, but the clip on the cap isn't tight. I tried to twist off the finial in order the release the clip (for manual adjustment), but it would not budge - probably held in place by shellac. I wondered whether gentle heating to a specified temperature via the sous vide process might be a viable method of warming the cap assembly to the point where the finial would twist off without damage. To my highly unscientific mind, I thought it might be worth a try.

(As an aside, regarding steaks cooked in this manner, after the meat has reached the desired temperature, one does need to apply a "reverse sear" - - a minute or so per side on a hot skillet to achieve a nice, brown crusty exterior.) If you're curious, more details about the device itself can be found here: http://www.amazon.com/Anova-Culinary...s%2C169&sr=8-3

[Deb]

Hi Robert,
Even after studying the device as best I can - it's new to me - I don't really know. I would say, though, that the finial is unlikely to be attached by shellac. They generally screw in and can get bound by old dried ink. This is one of the few cases where I would recommend soaking. Not immersion, mind you - that can be bad for celluloid. Fix it upright in a water-tight container and pour some water into the cap. It may or may not begin to leak out right away. If not, leave it for an hour or two. In either case, after the water has drained away or been emptied out, apply heat and use section pliers. Repeat as necessary. You'll get the finial out, I assure you.

Edit to add: a hair dryer will be fine to supply the heat.

[Chrissy]

Many restaurateurs use the sous-vide cooking process now. It's been shown on TV in shows like Masterchef quite a lot. It's like soaking something in water without actually getting it wet at any point.

I think it would be a safe way of heating a cap in order to remove the finial without overheating the celluloid.

[FredRydr]

Google: eyeglass frame heater

[Ray-VIgo]

Work celluloid carefully by hand, a few inches away from the nose of the heat gun (if you're using an embossing or similar gun, 5-6 inches probably - that's what I've always used). Keep turning the piece and check temp by hand. If the piece is too hot to touch, it's too hot. If you can smell the celluloid, it's too hot. If the celluloid starts to feel soft, it's too hot. It should be warm to the touch, but not "really hot". Celluloid can combust suddenly and rather spectacularly. I've never roasted or damaged a celluloid pen using the method above. It has consistently been warm enough to melt any shellac or thread sealant inside.

Be persistent with the heat - keep working and rotating the piece in the warm air to let the heat penetrate into the threads or the joint. Don't try to rush the piece by going hotter - moderate and persistent is better.

I did once roast a celluloid barrel on a beater pen. It caught fire suddenly and with a fizzle, burned spectacularly. I threw it in my glass of drinking water to put it out. The reason it burned is that I was too close to the heat gun mouth (well inside of 5-6 inches, probably half that) and not paying enough attention because I was trying to watch TV at the same time. Lesson learned. Thankfully it was not one of my better pens.

[xewepi714]

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