View Full Version : Plastic trays: What adhesive for fixing cracks?

19-Oct-2012, 21:42
I actually have two questions:

1. Is it ok to use Araldite/epoxy resin for fixing cracks on plastic processing trays or is there something else that should be used? If it makes a difference, the chemicals I use are Ilford Multigrade developer, Ilfostop and Rapid Fixer.

2. Can just any plastic containers be used for processing (paper)? Are there any gotchas?

Thanks in advance.


19-Oct-2012, 21:55
Unless your trays are huge (i.e. expensive) I would buy a new one.

19-Oct-2012, 22:16
Thin, light-colored trays that have cracked are probably not worth fixing---they are most likely quite old and brittle in places that have not cracked (yet). Modern white trays are usually polypropylene, which is difficult to crack but difficult or impossible to repair except by welding. (I have a Cesco that I found on the street, clearly run over more than once by cars. It is now an unusual shape, but not cracked!)

However---if you have the older hard-rubber trays (thick, heavy, and dead black) they are repairable. There is an older thread either in this forum or on APUG dealing with cracked hard-rubber developing tanks, so there is some experience out there. I believe that epoxy was the material of choice.

19-Oct-2012, 22:40
Thanks for the advice, Jerold and Harold.

Are there plastic trays out there that are ok to use with these chemicals?

20-Oct-2012, 00:44
Fixing trays smaller than 50x70cm is hardly worth while.

Epoxy has little adhesion to flexible materials and is a poor choice unless you have to fix (DIY) fibre/epoxy or (ancient) bakelite trays. Most trays from the past three decades will be polystyrene, ABS or polypropylene. The former two can be chemically welded with suitable plastics cements, the latter (as well as HDPE food trays) can be welded with a heat gun and the matching plastics welding wire. Model making and plumbing supplies stores have the right materials and tools.

Ed Bray
20-Oct-2012, 03:44
Would marine silicon sealant not work as a stop gap? a small amount on both sides of the crack should stop any leakage.

Brian Ellis
20-Oct-2012, 05:06
The only "gotcha" I remember hearing about trays for processing paper is to not get something with a smooth bottom so that the paper doesn't stick to the bottom and be hard to get out with your fingers. I don't recall ever seeing a tray made for photography that had a smooth bottom, they always seem to have grooves or ridges of some sort. But I guess if you tried to adapt something made for another purpose (e.g. cooking) you might encounter one.

20-Oct-2012, 20:08
Thanks for the advice, everyone. Much appreciated.

20-Oct-2012, 21:05
You could process prints in almost anything from pyrex pans to plastic buckets. Need to be more careful with toners though.

John Olsen
20-Oct-2012, 22:11
Get a fiberglass repair kit at an auto store and apply a patch on the outside of the tray. I've done this with three of my 11x14 trays and they've lasted years that way (probably stronger than new).

21-Oct-2012, 19:29
Jerold: That's very interesting to hear. By prints I guess you mean paper, not print film? :) (Sorry i'm a bit new to darkroom stuff) I use the Ilford Multigrade Warmtone developer... would I be better off using plain Multigrade one instead?

John: Great idea. Fiberglass didn't cross my mind.

Thanks again...

Ian Gordon Bilson
21-Oct-2012, 22:40
I have had limited success in "welding",using an ordinary soldering iron,on thermo-plastics. Paterson brand trays.
Backed up with duct tape to reduce flexure/stress on the remelted area.

24-Oct-2012, 08:13
Epoxy-fiberglass works best. Silicon RTV doesn't work. You can get an epoxy fiberglass kit at Walmart or an auto-parts store. Be sure to rough up the surface with some coarse sandpaper before applying the patch.

Drew Wiley
24-Oct-2012, 09:22
Generally the better moulded (non-fiberglass) trays were made with non-gluable poly plastics like polyethylene. Only the cheap ones were ABS or styrene. Polys have to be
heat welded, but aren't prone to cracking anyway. Just rub some acetone onto the plastic.
If it hazes, it's gluable; if unaffected, it isn't.

24-Oct-2012, 18:10
Jerold: That's very interesting to hear. By prints I guess you mean paper, not print film? :) (Sorry i'm a bit new to darkroom stuff) I use the Ilford Multigrade Warmtone developer... would I be better off using plain Multigrade one instead?...

Thanks again...

I meant that you could process paper or film in any vessel. Trays are usually the most ergonomic. Huge prints can be rolled up and processed in wallpaper troughs for example. Plastic darkroom trays 12x16 inches and under are pretty inexpensive so I would not bother fixing a crack. Huge 30x40 trays would be worth salvaging because they are costly.

For processing film, you want to be careful there are no plastic burrs or other oddities that could scratch if you use cheap plastic storage bins or other non-photographic trays.

Ilford Warmtone developer is not a toner. My comment about toners is that some of them stain the plastic.

25-Oct-2012, 10:55
Proper trays are not expensive, and are even available used. Repairing one temporarily might be necessary, but not for the long term. It's just not worth it. Likewise, finding a substitute from another source generally doesn't save much, if any, money and involves other compromises with regards to size and shape. One good set of trays will last a lifetime. Just my opinion, of course, but this has always struck me as one of the false economies of photography. All of the money we spend on gear, film, paper and chemicals, and we want to save a couple of bucks on a print tray.

I don't recall ever seeing a tray made for photography that had a smooth bottom, they always seem to have grooves or ridges of some sort.

Cesco makes trays with smooth bottoms. I use them routinely. Of course, I use print tongs, and not fingers ... ;)


Drew Wiley
25-Oct-2012, 11:46
I use flat-bottomed trays for conserving fluid volume with expensive toners or dyes. I use
grooved bottom ones for ordinary black and white paper developing, and dimple-bottomed
ones for all film use. I also use dimples on the septum dividers on my archival print washers. For really big trays (over 30X40 nominal), I simply make them myself out of acrylic sheet. But I've been lucky to find big real 326 stainless trays cheap from old DT
labs going out of business. The dimpled little stainless ones were sold under the Cherry
brand of Japan, and I got them from a local importer. Haven't been able to locate any
others, but they are simply the best.

Keith Fleming
25-Oct-2012, 21:24
I have one thin white plastic tray with cracks in one corner. I sealed it on the outside with metal duct tape (the kind that has non-stick paper to peel off)--and it has worked well without leaking for several years. I put the tape on when the tray was dry, and rubbed it thoroughly to ensure good adhesion. I already had the tape, and realized it was at least worth a try. The only thing I've been careful about has been to make sure this particular tray is on the bottom when I nest the set of trays together.