Improvising dip 'n' dunk for 120

So here's the deal: I'm loving life in my tiny Tokyo apartment, but undeveloped 120 film is once again piling up. Chemistry and other materials are easy enough to get, but doing two or even four rolls in a batch just isn't going to cut it, especially not with my current work schedule. What I would like to do is to improvise some kind of higher-volume system so I can catch up in an efficient way.

What I'm thinking is a series of sections of PVC pipe with end-caps, in some sort of framework to keep them upright. There would be four in total plus a fifth set up as a film washer. Imagine four in a row, in this order left-to-right: developer, H20, H20, fixer. The two water baths will be in lieu of stop bath, and the first water bath will also serve as the pre-soak.

I foresee making the tanks deep enough to accommodate either 6 or 8 reels of 120, all of them on a lifter rod for agitation and lifting the reels from one tank to the next.

All of this I can manage. I can lightproof my bathroom easily enough and materials are easy to get.

I'm used to doing everything in regular manual tanks, though, and where my experience runs out is with potential uneven development from whatever agitation pattern I'm able to manage just lifting the reels in the tank. I mostly shoot Tri-X and Acros 100, and mostly develop in HC-110.

Has anyone here built a setup like this? What do you think?

Thanks! These 80+ (and growing) rolls of undeveloped are giving me dirty looks.

Here the work of fellow member jamonadap:

https://www.youtube.com/watch?v=cvgAQ-t0mX4&feature=youtu.be

It's certainly feasible. Sounds like you don't intend to light-proof the tanks?
That would make things easier assuming you're comfortable with working in the dark.

What you've planned is not altogether different than processing large batches in deep tanks, those set ups could process 20 rolls with the reels placed into a "cage" which was lowered into the tank. Agitation is lifting the cage out, tipping it a bit to promote draining for a few seconds, then plunging it back in with another lift and tilt in the other direction. The idea is to randomize the patterns of the developer flow.
It's probably still illustrated in one of Kodaks tech sheets.

With that quantity of solution you'll probably want to use a replenishment scheme, Xtol would work well, as would lots of other developers.

Three inch black ABS plastic pipe should work for the tanks, and a long wire to string the reels and be able to lift them out . I would recommend acid stop instead of water, you're talking a lot of developer carry over and water may not work as good as you need. Check this out.
https://www.youtube.com/watch?v=6eKDWFqlIWM

Awesome. Looks like it's doable, and I'll probably opt for the acid stop. Hadn't thought about the amount of carryover, relative to working with small tanks.

bdial - no need to lightproof the tanks, as I can lightproof the room. I've spent enough time in the dark that I'm quite comfortable working that way.

Right now it's a matter of trying to get through a bunch of film with minimal investment in setup.

For developer, I thought about replenishment, but considering my living space, I'd rather not store large volumes of chemicals, perhaps with fixer as an exception. I use low dilutions of HC-110 anyway. Started with dilution G, but havesince moved to what I call dilution M (for Munson!) which is 1+100 from concentrate for ease of mixing. Does what I want and is still very economical.

I do not understand that issue of carry-over as hinted at above.

The amount of carry-over is even larger with closed tanks: the amount at the reel and film is the same but added by the amount at the tank wall and spindle.

And in dip&dunk processing the smaller amount of carry over even is diluted in a larger volume of processing bath.

water stop bath would be fine. I don't see the problem either.

It's a matter of displacement. In enclosed tanks developing many reels at once, you couldn't have enough water to rinse away the developer. The only way for that to be feasible is running water. The OP is looking to make deep tanks long enough to submerge many reels, not one or three. Acid stop would help guarantee consistency. To also speed things up, a neutral or alkaline fix to minimize time fixing and washing. If working in a blacked out room is not an issue, then maybe some deep large square or rectangle tanks that would allow reels to be placed side by side, and maybe enough room for a dozen reels stacked three or four high. Liquid volume levels would need to be deep enough to cover the stack initially, plus enough room for displacement when they are all in.

You really should reconsider XTol.

Assuming you need two litres for your developing "tube", you need two packages of XTol, one two litre container and six one litre containers. Mix up 5 litres from one package and put it into the two litre container. The other three litres goes into three of the one litre containers - that is your first batch of replenisher.

For each roll you develop, you need to replace 70ml of working solution with 70 ml of replenisher.

The first three one litre bottles will give you enough replenisher for 42 rolls. The next package of XTol (5 litres) will give you enough replenisher for 70 more rolls.

I'll look into XTol, but over the last 15 years I've standardized pretty much everything on HC-110 at high dilutions and like what I get with it, so I'll probably stick with it. I'll see what's easily available next time I'm at Yodobashi Camera, though. If I had the room, I'd be setting up a larger system, probably, and would definitely do replenishment. THat said, the bathroom in which I'll be doing this is one small corner of an 18 square meter apartment, so storage of equipment as well as chemistry is a real practical consideration for me.

In any case, when I get things rolling I will follow up here, including initial sketches and construction of things. I'll also write some posts about it on my blog (see "Photo Otaku" in my signature).