Sac Durability

[pieemme]

About two and half years ago I bought an ink sack for a repair that I eventually didn’t make. When I intended to use it yesterday I opened the plastic bag and found it almost sticking to the polyethylene bag it had come with. As it looked rather rigid, I tried to pull it and it yielded like a piece of chewing gum. I have known these sacks not to last long, but their shortness of life came as a great surprise to me, as I was planning to keep a couple of sacks in store for resacking my vintage fountain pens. I wonder if their life is any longer in always filled fountain pen. My bike’s tubes have worked without replacements for no less than a decade and I also keep a spare tube ready for years without any problem. Are there any more durable sack# out there? My Parker 51 still fills after half a century of use.

[shalitha33]

i would probably go with https://www.vintagepens.com/catill_sacs_seals.shtml .

 

Note that I haven't actually used any of these myself, but I would trust that site to do what it say. Fairly sure these sacs will last for a while.

[pieemme]

Thanks. I'll give it a try. David Nakimura is sure a well known name. I had so far prefered a European (UK) supplier for shipping reasons.

[Tweel]

I have known these sacks not to last long, but their shortness of life came as a great surprise to me... My bike’s tubes have worked without replacements for no less than a decade and I also keep a spare tube ready for years without any problem.

 

As an aside, your bike's inner tubes are likely synthetic (butyl) rubber, whereas pen sacs are natural latex.

 

For sacs, besides retailers such as David Nishimura, you can also go straight to the source (the manufacturer): The Pen Sac Company.

[BaronWulfraed]

Being trapped in a "plastic" bag may not have helped either. Especially if the bag was out-gassing potential solvents.

 

The sacs I've ordered were shipped in brown paper envelopes (FPH mixed bags). None have gone gooey on me -- though some have done the opposite: gone the way of a stale French baguette. {I STILL haven't located my heat shrink gun to work on an Esterbrook SJ with crumbled sac}

[Ron Z]

Shelf life of new and unused sacs is quite long. Failure is usually related to use, and especially the ink used in a pen.

 

There were sacs made a decade or so ago and sold by an now passed Canadian supplier that were missing the "pixy dust" that kept the sacs from failing, though I doubt that there are any in circulation because they failed rather quickly. I've been buying sacs from the Pen Sac Co. in California since the early 90s, and haven't had any problems with them. - and I use a lot of sacs!

[pieemme]

I got mine from https://www.vintagepensacsandparts.com/, which, based on this experience, I wouldn't recommend. I made them aware of my issue, but got no particular reaction.

Edited September 29, 2020 by pieemme

[shalitha33]

hmm i have used their sacs before without any trouble. just checked all the pens i have these on and they all seems fine so far. a faulty batch may be ?

Edited September 29, 2020 by shalitha33

[praxim]

I got mine from https://www.vintagepensacsandparts.com/, which, based on this experience, I wouldn't recommend. I made them aware of my issue, but got no particular reaction.

Most of my sacs were from that supplier, and all are perfect, both those in working pens and the few remaining still stored dry in a small wooden box. I store practically nothing in plastic bags, Like BaronWulfraed, I suspect that may have contributed to the problem.

 

Based on my experience with sacs and other repair products, I recommend the supplier (The Pendragons), adding that comment to keep some balance in that part of the discussion.

 

eta: my sacs are up to four years old at this point, not exactly Ron's experience but it will do so far.

Edited September 29, 2020 by praxim

[pieemme]

Most of my sacs were from that supplier, and all are perfect, both those in working pens and the few remaining still stored dry in a small wooden box. I store practically nothing in plastic bags, Like BaronWulfraed, I suspect that may have contributed to the problem.

 

Based on my experience with sacs and other repair products, I recommend the supplier (The Pendragons), adding that comment to keep some balance in that part of the discussion.

 

 

 

 

 

 

 

Fair enough. However, my motto is: anyone can have a problem, but it is how they address the problem that makes the difference. My sack stayed in the bag it came with, in a dry drawer. i don't know if it would have lasted longer inside an unused pen or a filled one.

Edited September 30, 2020 by pieemme

[FredRydr]

Return them to the seller without waiting for him to ask so he can evaluate the problem for himself, and to motivate him to accommodate you (unless you already burned that bridge).

[EdgarK]

I buy my sacs preferably at The Pen Sac Company too. I think such a sac will last for at least 20 years no aggressive inks were used.

 

In the past there were some inks suspected to cause damage on the natural latex sacs such as (some) of the Noodler's inks:

https://www.fountainpennetwork.com/forum/topic/242452-what-liquefied-this-sac/

Edited October 19, 2020 by EdgarK

[eachan]

I have two pens that were re-sacced 14 years ago. They were used a little at the time then set aside. I decided last week that I would sell them, so I checked the sacs. One had gone hard, the other was still in perfect condition. I don't know what conclusions, if any, you can take from that. No aggressive inks were used. At that time I bought my sacs from a reseller; he had a pretty rapid turnover of sacs so I don't think they would have been old when I bought them. I buy direct from The Pen Sac Company now.

[pieemme]

Thanks for the tip: I will certainly give The Pen Sac Company a try.

[EdgarK]

I have two pens that were re-sacced 14 years ago. They were used a little at the time then set aside. I decided last week that I would sell them, so I checked the sacs. One had gone hard, the other was still in perfect condition. I don't know what conclusions, if any, you can take from that. No aggressive inks were used. At that time I bought my sacs from a reseller; he had a pretty rapid turnover of sacs so I don't think they would have been old when I bought them. I buy direct from The Pen Sac Company now.

So, they have been from the same seller, but do you remember if they had a different shape? Maybe they were from different manufacturers.

[eachan]

So, they have been from the same seller, but do you remember if they had a different shape? Maybe they were from different manufacturers.

 

They were different sizes. The Unique had an 18. The Dinkie would probably have been a 14. I think they were from the same source. They weren't a different shape.

[EdgarK]

Quite strange if they were from the same manufacturer since you said you didn't use any aggressive inks. A while ago I also received a pen which was restored about two years ago by someone - but the sac was already gone.

 

I wonder if nitrile would be a conceivable material for pen sacs because in many cases silicone is not due to its high gas permeability.