Rubber And Celluloid...storage Question

[Jennings]

Based on the fact that I heard the sulphur compounds in things like rubber sacs actually caused caesin and/or celluloid to discolour and even break down I have a couple of questions:

 

1) Is this the case and should I worry about it?

2) Is it wise then only to re-sac pens I want to write with, but store others without sacs?

3) Should hard rubber pens be stored in the same boxes/trays as celluloid and caesin pens?

 

Just want to make sure I'm doing the right thing!

[red52ripple]

The decay of rubber sacs can certainly cause discoloration in some casein and some celluloid patterns. I'm not so sure that it will cause either to fragment - that's down to variable humidity in casein and probably inadequate curing in celluloid.

 

Jade, Lapis Lazuli and some other colours can be badly affected by latex sacs. It is assumed (on what evidence I know not) that silicon sacs don't have any adverse effect. I think it probably is advisable to remove the sacs from pens that are to be permanently or long-term stored.

 

I've had celluloid, casein and hard rubber pens in the same box for years without adverse effects. However, the decay of hard rubber can discolour pens, as can be seen in the altered colour of some pen caps with hard rubber inner caps. If you wish to eliminate this risk, store them separately.

[Trebster]

[joke] I store all my pens and pen parts in honey.

 

Honey is a well-known preservative. Casein, Ebonite, it doesn't matter - pens I preserved in honey still look sweet!

 

I make sure I fill them with honey too, before I put them up. (Filling the Parker 61 with honey was daunting.) While start-up is very slow, I get a beautiful line that can shade from amber to buckwheat. Drying time is very poor and it is not waterproof at all. I'd post a scan but Ruby Sue licked off the results of my test. None of the kids have eaten since I won the auction on the demonstrator Montblanc Agatha Christie, which is being preserved in honey now. [/joke]

[JakobS]

+1 On using silcone sacs that will not out gas.

 

The biggest issue I have had with casein pens is variable humidity, they can be very sensitive to changes in humidity, and can form cracks quite readily if not kept at a constant humidity level. I am basing this on vintage ~1940's Burnham pens, with the cracking limited to, but encompassing most of their caps.

Edited January 9, 2013 by JakobS

[ihimlen]

However, the decay of hard rubber can discolour pens, as can be seen in the altered colour of some pen caps with hard rubber inner caps. If you wish to eliminate this risk, store them separately.

 

 

This is actually due to the fact that in many pen models (e.g. early Wahl pens) there were rubber (i.e. soft rubber, not hard rubber) seals to the top of the inner cap, as well as rubber washers glued to the inner cap lip where the nib went in. This was to create a seal between the nib section and the inner cap in order prevent the pens from leaking and it were those rubber seals that decomposed and caused discolouration. So storing hard rubber and celluloid pens shouldn't be an issue.

When it comes to celluloid decomposition, that's a different issue altogether; but as long as the pens are not stored sealed and with no ventilation (e.g. in a plastic bag in a safe), they should be fine. Finally, for pens that tend to discolour, it is always a good idea to use silicone or plastic sacs as these do not cause darkening. Storing pens with plastic sacs shouldn't therefore be a problem.

 

i.

Edited January 9, 2013 by ihimlen

[Jennings]

Thanks for the replies folks...the honey joke made me chuckle :ltcapd:

 

So it looks like I don't have to worry too much then. Currently I store my pens in a a few old wooden Victorian/early 20th century boxes I've lined with felt. None are exactly air tight, so I think they're OK then. I do have a desktop temp and humidity gauge (also vintage, interestingly!) which tells me both are fairly constant, so again I htink that's a good thing then.

 

I do have a couple of old Parkers (one's jade green, although the cap is less darkened than the barrel, presumably due to the original sac's decay) that I've re-sac'd but not used. Perhaps I should unsac these then. Or should I put up with the risk of further darkening as just natural age?

 

My Burnams don't seem to have any issues at the mo, nor my Conways, so I'll keep an eye on them but I'm largely happy that they're safe. I often use the Conways at work, and they seem fairly robust in that environment.

[red52ripple]

This is actually due to the fact that in many pen models (e.g. early Wahl pens) there were rubber (i.e. soft rubber, not hard rubber) seals to the top of the inner cap, as well as rubber washers glued to the inner cap lip where the nib went in. This was to create a seal between the nib section and the inner cap in order prevent the pens from leaking and it were those rubber seals that decomposed and caused discolouration.

 

That's as may be, but it's not what I was talking about. I was talking about celluloid discolouration due to the presence of hard rubber inner caps.

[Vintagepens]

I wouldn't worry too much about mixing pens of different materials, but if you want to get very precise and be very careful, note that faded hard rubber when exposed to moisture will give off dilute sulfuric acid. So keep your hard rubber pens dry, especially if they are faded. This isn't much of an issue at all with unfaded hard rubber, which is why you don't usually see much effect on adjoining celluloid parts from hard rubber sections and inner caps, which don't get much light exposure.

 

The risk of discoloration to celluloid and other permeable plastics from latex sacs is much greater, and it is indeed a good idea to leave any pen that isn't a user unsacked. The risk is greatest in pens that are tightly sealed, leaving no opportunity for trapped vapors to escape -- button-fillers, for example (store them with their blind caps off, if you want to let them breathe).

 

Finally, I have to point out that according to my testing, all of the sacs sold as silicone to date, with one recent exception, are not in fact silicone, but PVC (vinyl) instead. Real silicone sacs are indeed the best answer to preserving celluloid color, as the material contains no sulfur or other harmful compounds. PVC sacs, unfortunately, are not so benign. It's not that they will immediately destroy your pens, but there is a real and proven risk of the plasticizer migrating into plastics the PVC is sitting against. This can leave deep scars in the other plastic (celluloid is known to be particularly vulnerable), and can also end up turning the other plastic into a jellylike mass. I've seen this happen in decades-old pen parts, and there's an article on vinyl and nitrocellulose finishes on musical instruments here.

 

The recent exception is the real silicone sacs that Mark Hoover and I are now producing through American Art Plastics, and now being sold through that website, vintagepens.com, and on eBay under vintagepens.

 

I'm just finishing a video showing how to identify real silicone sacs -- will post a link as soon as it is done.

 

all best

 

David

[Vintagepens]

PS Regarding discoloration of celluloid pens by their inner caps, it is rather difficult to determine what is causing the discoloration in most cases. Is it the hard rubber emitting sulfur? Or is it that the sulfur vapors given off by the deteriorating sac get pushed out through the nib and feed, only to get trapped between the cap and inner cap? And what about sulfur getting washed out of an aging sac in the ink, which then gets trapped in the same place?

 

I'm inclined to think that these processes are much more to blame for discoloration than contact with the inner cap alone. Absolutely pristine, never-filled celluloid pens with inner caps of hard rubber normally have perfect color, even when the material is discoloration-prone.

 

best

 

David

[red52ripple]

While I take on board all that you say, David, and I don't disagree that all these factors play into cap discoloration, I remain unconvinced that the instability of HR inner caps isn't also a factor. After all, I don't see this type of colour change to anything like the same degree when scrap celluloid is used for an inner cap, as in some Watermans, among others.

[Vintagepens]

That is certainly a good point.

One thing that must be kept in mind, though, is that celluloid stability generally improved over time. Many of the earlier celluloids discolored a lot more easily than later celluloids. For that matter, quality of HR was (and is) highly variable, so we are dealing with a high degree of speculation regardless.

[vondauster]

Interesting thread, and especially the idea, new to me, that all sacs sold as silicone aren't necessarily genuine. However, there is one point that might be relevant to the original post.

 

Yes, storing pens - especially some shades of celluloid - without sacs can retard further discoloration. But, taking a vintage pen, especially one with a good functional sac, and removing the sac for storage runs significant risk of damaging the pen if not done expertly. This is especially true of some brands and models, like the W/E Skyline series. Therefore, I leave all sacs in if working, and would send the pen to someone who has replaced thousands of sacs and has developed the "touch" to do so more safely than I ever could.

 

Will

 

(who has no pens worth thousands of dollars in mint condition in his collection)

[Vintagepens]

Here's the link I promised to the video:

 

Definitely a valid point about the risk involved in opening up a pen. Assuming the pen has a working sac, however, that risk should be minimal (assuming proper training and technique) since the pen has already been successfully opened relatively recently.

[Jennings]

Thanks to everyone for all the opinions and technical information. Based on the above, and since I service and resac most of my pens, I might reappraise my parker and burnham buttons. They seem most likely to discolour, and least likely to get regular use. Do many folks use silicon sacs in all but their hard rubber pens? I don't notice much discolouring in any of my conways, so I'm happy they can take a rubber sac

[Montblanc owner and lover]

i'll try to put them in honey too lol