How to agitate 'old' GAF tanks

[Max Power]

Last year I bought my darkroom kit from a chap who was no longer interested. There were two GAF developing tanks in the lot. They date, at the least, from the early 1970s. They are small and black, only about a centimeter 'higher' than a 120 reel, and the top twists and locks on without being water tight.

A couple of days ago I decided to 'test' the reels with a short length of 120 and found that they wind on much more easily than my Paterson reels, so I have decided to give them a test. There is, however, one problem; they are not leakproof and when I turn them upside down for the 'Ilford' method, all of the fluid leaks out the sides!

So, what is the recommended technique for agitiating these tanks? How does one ensure proper circulation of chemistry without losing some off of the top and getting irregular development?

Cheers,
Kent

 

[John Koehrer]

I believe they should have a thermometer that fits in the center hole. When inserted, the thermomter is then rotated to provide the agitation.
If this is too rapid it causes a build up of density on the edges..

 

[Konical]

Good Evening, Kent,

Shaggy is correct. The only way to agitate is to twirl the reel. I briefly used one of these tanks back in the 1960's but quickly "graduated" to Pattersons which can be inverted. Before long, I went to stainless steel. It was one of those trial and error matters that having APUG around at the time would probably have prevented.

Konical

 

[BradS]

Ah yes. The old GAF tanks -- I remember them fondly. They were very easy to load and did indeed come with a thermometer / agitator. Once the agitator got lost (they always do) you are left with the slide it back and forth method or the twirl it method. These both work fine for 35mm but, I suspect that you'll slop liquids when doing 120...Guess you have to try it. I too eventually switched to Paterson.