BTZS Tubes 5x7

[Carl Radford]

Hi Folks

looking for some plans to make BTZS type tubes for 5x7 film - can't seem to find ones pre-made. Anyone made any - shouldn't be too difficult if for someone as challenged as myself in the DIY dept?

Cheers, Carl

[Brian Ellis]

AFAIK the only tubes BTZS made were 4x5 and 8x10. I don't think they ever made 5x7 or if they did it was a really long time ago. They no longer make 8x10, only 4x5 today.

There are plans for 4x5 tubes in the back of Phil Davis' book Beyond the Zone System. It shouldn't be hard to scale up to 5x7 from there if you have access to that book.

[Michael Jones]

Carl:

The tubes were indeed made in 5x7. They were also made in 7x17 and 8x20. The tubes (and caps) can be made from plumbing pipe at a good home center or plumbing store. Phil's book has instructions for making them. The key is the proper schedule tubing so as to be light tight through the body. 5x7 tubes are approximately 1 15/16" inside diameter by 8" long and the caps are about 3 1/2" long. But if you want to take the easy route, I have a pair of 5x7 BTZS tubes and 4 caps I would part with. Email me if you are interested. Good luck.


Mike

[lee\c]

I have 3 tubes for 5x7 that look to be not home made. I bought them from an individual and not BTZS store.

lee\c

[Claude Sapp]

Real easy to make btzs tubes. Attached is a photo of one of my homemade 5x7 tubes. Each tube is made from the following pieces of 2" black ABS: 1 coupler; 2 end caps; one piece of tubing approx. 7.5" long; one piece of tubing approx. 2" long. You can cut the tubing with any handsaw, and use ABS cement to glue it up. Dimensions are not critical, but the big piece has to be long enough to insert the film fully, and the smaller piece has to be large enough to hold enough of the developer in the dilution you use. These homemade tubes work very well for 4x5 and 5x7 tubes, but in larger sizes not so well. I would advise you to make an extra cap assembly for each tube you make so that you have two developer caps for each tube.

[Carl Radford]

Thanks for the input folks, I will probably take Mike up on hhis offer and them use Claude's info and the tubes to try and fabricate a couple more.

All the best, Carl

[Carl Radford]

Another quick question! Have I read somewhere that you should use some sort of mesh between the film and tube to make the negs easier to insert and extract?

Cheers, Carl

[Claude Sapp]

Film does tend to stick to the inside of the tubes, and a piece of mesh will help remove the film, but I found the mesh was just another thing to fiddle with. Instead, I remove the film while the tube is immersed in a water stop bath. When the tube and film are underwater, the film slips right out quite easily.

[Mark McCarvill]

Fiberglass window screen mesh, available at most hardware stores, is what I use.

You just cut a piece a bit larger than the film size (e.g. 1/2 inch on all sides). You center the film in the mesh (emulsion side up) and gently roll the film inside this mesh so it will fit inside the tube. Practice a few times with some old scrap negatives until you can do it without scratching or bending the film.

The mesh protects the film from scratches during insertion / removal from the tube and gives you something to grip onto when removing the film from the tube. You'll see how important this is when you try removing a wet negative from a tube without mesh (try that too for comparison).

[Michael Jones]

I've used the BTZS tubes in sizes up to 8x20 and never had a problem removing film. You just pull gently from one corner and he film will break loose and then you pull it straight out. A piece of mesh is unnecessary and as was said "one more ting to fiddle with." Good luck.


Mike