Paterson System 4 developing tanks

[Flighter]

Has anyone found substitutes for the cap and the sealing ring?

I'm stumped with the caps but got some large o-rings as a substitute for the seals which seem to work reasonably well, just need to be careful they don't drop out of the lid in changing bag.

Frustratingly Freestyle have replacement lids at $2.99 for the Arista Classic, which looks identical to the Paterson, but the shipping from the States to the UK is $36 for 5 and I haven't found them anywhere else.

I did find some files for 3D printing both the caps and the sealing ring on the web - has anyone tried 3D printing for replacements?

 

[Peter B]

Paterson changed the design of their tanks many years ago, and this included getting rid of that seal/collar. I'd say your best bet would be to replace your tank with a new one and go for the Universal which comes with 2 reels. Ffordes have it at £24.99 plus about £5 postage. https://www.ffordes.com/p/PTP115/darkroom-equipment/universal-tank-with-two-reels

The postage stays the same up to £50, so maybe get some film or chemicals as well?

 

[StephenM]

I agree with Peter. I use the 20th Century reels for sheet film, which fit in a Super System Four tank but not in the older System Four tanks (slightly different centre column diameter). On sorting out my older tanks for passing on (via this forum) I found some of the grey plastic had become brittle and clearly needed replacing anyway.

 

[Mr Badger]

It seems a shame the seals aren't available anymore, as the original ones seem to shrink with age. I'm sure there would be a demand for a small production run if they could be 3D printed out of a suitable sealing material and sold at around the £5 mark. The rest of the tank seems to survive quite well, and it seems a shame to send it to landfill for the sake of a plastic seal. I note the suggestion of using a rubber/nitrile pipe 'O' sealing ring though.

 

[Flighter]

Thanks for the replies everyone. I suspect it's some sort of psychological flaw on my part that I would like to get all my tanks complete.

When lockdown inspired me to get back into film I dug out my old tank, last used in the 80s, which was complete although the sealing ring (grey) was brittle and cracked on washing. I managed to get an incomplete tank off Ebay which included a (flexible) sealing ring (white) and together with a couple of incomplete tanks acquired from a friend on a move around 2000 I now have five System 4 bodies of various sizes, 3 lids, 1 sealing ring and 1 cap.

As I have 1 sealing ring and 1 cap and I would struggle to use more than one tank at a time, I don't really have a problem, as I can always make up a complete tank of whatever size I need - it just bugs me that the other 4 tanks aren't complete.

The 3D files I saw on the web use TPU filament which DuckDuckGo tells me is thermoplastic polyeruthane and is used in 3D printing to create flexible parts as it has unique characteristics that make it elastic like rubber, yet durable like plastic. So it sounds like it might be suitable if a good sealing surface can be obtained.

 

[Cluster]

I've been trying out TPU on my 3D printer. It's nice stuff, very tough. Made a few lens caps in fetching translucent cherry red.
I imagine that it would make good seals/caps, maybe in black though....

 

[Flighter]

Thanks Dave, it’s good to have an actual user report on the properties of TPU.

 

[Cluster]

I can produce a pair in translucent red TPU for you to try..... if it works, we might share the cost of a reel of black TPU filament and produce enough to complete your set?

Unless anyone else here has a reel of suitable material?

 

[Flighter]

Hi Dave, that's most kind of you. I'll drop you a PM later today (once I'm clear of work).

 

[Cluster]

Parts printed off today. About 5hrs print time total (TPU prints only slowly on my machine).

Made from an extrusion of melted plastic tracks, 0.4mm wide in layers 0.2mm thick.

 

[Flighter]

Looking good! And looking forward to trying them out.

 

[Flighter]

Looking even better!

The proof of concept lid and sealing ring that Dave very kindly 3D printed for me (many thanks again) arrived today. Work commitments have precluded doing more than trial fitting them to one of my tanks, hopefully I will have time tomorrow to do a wet test.

 

[Flighter]

Three tanks now complete with seals and caps 3D printed in black TPU courtesy of Cluster