View Full Version : File for glue, paint, Etc., that works

03-01-2006, 11:46 PM
Mending plastic tanks that leak may have been mastered by someone. A glue that stands up to chemicals would be a "gift"; patching sinks or Jobo processors likewise.

03-02-2006, 12:33 PM
Looking for a glue or a file?

03-02-2006, 02:48 PM
There's one glue that will stand up to anything you're likely to put in a developing tank: epoxy. A good slow-setting variety (the 20 minute type is the fastest I'd recommend), with a minimum of fillers (anything that mixes 1:1 has a bunch of filler in the catalyst tube) will be stronger than the plastic and stand up to anything short of strong lye solution (Rodinal concentrate probably wouldn't touch it, and that's the strongest stuff we deal with on a routine basis, AFAIK).

The trick is whether the tank plastic is compatible with epoxy. If the tank is polystyrene or ABS, it would probably be preferred to solvent weld it, but epoxy will work. If it's polyethyelene, when it breaks it's trash (but polyethylene is pretty impervious to anything like a crack; it'll tear, but not shatter). ISTM most tanks are polystyrene or ABS, so epoxy is likely the best route. Worth noting that JB Weld is not only strong and chemically pretty inert, but it's opaque...

However: a cracked plastic tank is a sign that it's time for a new tank, because it'll crack again somewhere else shortly after you seal up the existing crack. And if the leak isn't due to a crack, you probably can't stop it short of redesigning the tank. I'd suggest, instead of trying to fix a plastic tank, you consider buying one of the very inexpensive apron-type tanks sold at Freestyle. They're only $5 (including apron) for the 35 mm size, and $7 (likewise) for the 120 size; they also sell extra aprons, though I don't know if the 120 tank is tall enough to take two 35 mm aprons...

03-02-2006, 04:16 PM
As an example of what JB Weld can withstand, I made a "temporary" repair to my car's radiator with JB Weld. It was still working when I replaced the radiator three years later.

I agree with IM, repairing plastic is usually an exercise in futility. It sounds obvious, but plastic tends to break at its weakest point. Then you try to replace the weak plastic with even weaker glue. If you can build up the area with epoxy it might work, or might not. One of the problems is getting epoxy to adhere to the plastic. If you try it, sand the area first to roughen it a bit, then wipe it with denatured alcohol and don't touch it with your fingers before gluing.

JB Weld might be a good choice for a sink, but one wonders why it failed to begin with. It probably needs to be reinforced.