Patching cracked trays?

Steve Goldstein · Sep 14, 2020

Has anyone ever successfully patched a cracked plastic developing tray?

I just got some 20x24 Cesco trays at a very good price. One of them has a crack about 4” (100mm) long where the bottom curves to the sidewall. These trays are a softer plastic than most others I have. Would something like Gorilla tape or FlexSeal do the job? My concerns would be chemical resistance and strength.

Donald Qualls · Sep 14, 2020

Epoxy should be inert to photographic chemicals, but you'd have to drill a hole at the end of the crack to be able to flex the tray enough to work the adhesive into the crack. As long as the tray material isn't polyethylene or nylon (both "immune" to epoxy), that's what I'd recommend.

AgX · Sep 14, 2020

If it is gluable the then attach a non-flexing patch at the underside. The slit still existing at the upperside could be closed by melting with a heated tool of apt shape, but this would be something for an experienxed tinkerer.

In contrast to cracked processor tempering bath (repeatedly inquired for) at a tray you want nathy not smoot protruding. A bead of silicone rubber already might be disturbing.

Donald Qualls · Sep 14, 2020

Slow-setting epoxy ("2 ton" or 120 minute type) will self-level after you work the glue into the crack; put a strip of duct tape on the outside, fill the hole you drilled at the end of the crack with the epoxy (just barely above level), and leave it sit, inside up, overnight at room temperature. The epoxy will come out smooth enough not to scratch; if you're careful, you might be unable to even feel the repair on the inside.

AgX · Sep 14, 2020

Donald Qualls said:
Epoxy should be inert to photographic chemicals, but you'd have to drill a hole at the end of the crack to be able to flex the tray enough to work the adhesive into the crack. As long as the tray material isn't polyethylene or nylon (both "immune" to epoxy), that's what I'd recommend.

Without a non-flexible patch glueing a crack in a sheet is asking for trouble, especially with trays. With a strong patch attached you will not need end-holes.

Donald Qualls · Sep 14, 2020

AgX said:
Without a non-flexible patch glueing a crack in a sheet is asking for trouble, especially with trays. With a strong patch attached you will not need end-holes.

You'll still need to flex the tray to get the epoxy inside the crack, hence my advice to drill a small hole.

AgX · Sep 14, 2020

Donald Qualls said:
Slow-setting epoxy ("2 ton" or 120 minute type) will self-level after you work the glue into the crack; put a strip of duct tape on the outside, fill the hole you drilled at the end of the crack with the epoxy (just barely above level), and leave it sit, inside up, overnight at room temperature. The epoxy will come out smooth enough not to scratch; if you're careful, you might be unable to even feel the repair on the inside.

If you want the epoxy to close the slit at the upper side nicely you might bevel the upper edges as a very fist step. To get at nice surface (not really needed here) quite some experience is needed.
However, if necessary the typical tray materials allow grinding and polishing.

Donald Qualls · Sep 14, 2020

OP already stated this tray is softer material than is common -- hence my concern that it might be polyethylene or nylon instead of the polypropylene or ABS (or hard rubber) often seen depending on the age of the tray.

AgX · Sep 14, 2020

Softer can just mean thiner. But yes, there are critical materials, and that is why I referred to "gluable" materials. But even PE or PP could be patched by means of common hot-melt as glue. But then a hairdryer is necessary to keep the patch material long enough on temperature. And I am not sure of the longevity. With tiny cracks in PE/PP I had better result with welding in itself.

In case of PE/PP I would rather try clear adhesive tape. On both sides. Some got a high tack. You cannot tear them off after a few days with leaving traces of glue. Being clear one would see air getting under it.
But tossing it would not be a bad idea either...

MattKing · Sep 14, 2020

Could you glue in a plastic liner?

AgX · Sep 14, 2020

What do you mean by this?
My recommendation is to glue something strong as a wide strip of ABS, hard-PVC or Aluminiun at the underside with apt glue (solvent based or epoxy)

A "liner" to my understanding would mean a cover layer over the complete upper-side of the tray. I assume that would mean more hassle and cost than a new tray.
The best way to do say would be vacuum-forming with the old tray as form. Needs some apparatus. But once you tackled that you could make trays in series...

David A. Goldfarb · Sep 14, 2020

I'd use epoxy, but would keep an eye out for some Columbia stainless steel trays, which can be had for relatively cheap these days. Enamel is also good, if you can find them in good condition.

MattKing · Sep 14, 2020

MattKing said:
Could you glue in a plastic liner?

AgX said:
What do you mean by this?

Heavy duty plastic sheeting.
And then use that tray for washing.

Donald Qualls · Sep 14, 2020

MattKing said:
Heavy duty plastic sheeting.
And then use that tray for washing.

If you're using it for washing, would it even matter if it has a crack?

Steve Goldstein · Sep 14, 2020

Donald Qualls said:
If you're using it for washing, would it even matter if it has a crack?

Good point. Right now I don't know what I'd be using these trays for, hence my desire for a patch. The crack is in the vertical sidewall, not at the smooth bend where the bottom joins the side.

I'd be nervous about any kind of patch that's more rigid than the plastic as it seems to me that would concentrate stress, so I'm more interested in tape.

I've been trying to figure out what material Cesco uses. I've sent an inquiry to Omega-Brandess, who are the Cescolite distributors these days. The McMaster-Carr site shows similar photographic trays made from polyethylene.

Yes, I could buy a new tray, but I'm not in a rush to lay out $89.13 for something I'd very rarely use.

Edit: Just found this: https://www.amazon.com/Gorilla-4612...794-9cd9552ac58d&tag=interesting_things_os-20 Hmmm.

MattKing · Sep 14, 2020

Donald Qualls said:
If you're using it for washing, would it even matter if it has a crack?

Well, the crack might widen without some sort of reinforcement or repair.
And I suggested using it for washing, because there isn't much worry about cleaning it between uses, or there being a chemical reaction between the lining material and the contents.

AnselMortensen · Sep 14, 2020

JB Weld was my first thought....

reddesert · Sep 14, 2020

Drill a small hole at each end of the crack before attempting a repair, to stop the crack propagating.

Donald Qualls · Sep 14, 2020

AnselMortensen said:
JB Weld was my first thought....

JB Weld is an epoxy. I wouldn't recommend it for this, though, because it's filled with aluminum powder (adds strength), and the aluminum nearest the surface might be prone to react with alkaline liquids. If you know someone who builds model airplanes, you might ask if you can have a teaspoon or so of microballoons (glass bubbles about 0.1 mm diameter) or fumed silica -- the latter by preference, as an inert strengthening agent, but less common than microballoons (volumizer, adds a small amount of strength). Otherwise, in this kind of application, a filled epoxy isn't really needed.

StepheKoontz · Sep 14, 2020

I've patched all kinds of things like this with flexible RTV silicone. I like the automotive "ultra copper" high temp orange. I've repaired everything from plumbing drains to garden wash buckets and watering cans. It seems immune to most chemicals and it's what I would try.

Andrew O'Neill · Sep 14, 2020

I've got a 16x20, flat-bottomed tray that is in crack hell. Thanks for the mending ideas, everyone!

Down Under · Sep 14, 2020

Some of us may be desperate for things to do during the Covid crisis, but to me this is a classic example of false economy, not to overlook wasted time and effort.

Old darkroom trays are basically worth nothing. Most are stained beyond being able to be properly cleaned.The cheaper ones may be contaminated by generations of photo chemistry and I for one don't care to risk any potential damage to my prints.

I see ancient Ilford and even Kodak trays in charity shops going for very little money. Nobody seems to want them.

The small ridged 1930s-1940s Kodak contact print trays are minor collectables. Even then, they often go for fifty cents each or a set of three for one dollar in the op shops.

If cost is so important a consideration to you, I suggest you do what many of the photo course students I've taught over the years have done, buy inexpensive cat litter trays from discount stores, use them for 12 months, then throw them out. Most definitely NOT recommended to let the house felines use them before you do to make or wash prints, maybe after, as concentrated fixer residue may well be lethal to cat bottoms...

Roger Thoms · Sep 14, 2020

Here are a couple links from my quick web searching because I was curious. One is to a GWJ Company who sells Cesco trays and states that the trays are made out of high density polyethylene. The other is to a Permabond website for a glue for high density polyethylene.

https://www.permabond.com/materials_bonded/bond-polyethylene-hdpe-ldpe/

https://www.gwjcompany.com/index.php?main_page=product_info&products_id=1029

Hopefully this is sending you in the right direction.

Roget

Steve Goldstein · Sep 14, 2020

Thank you Roger. Your Google-fu is strong.

MattKing · Sep 14, 2020

ozmoose said:
Old darkroom trays are basically worth nothing.

I would suggest that 20 x 24 trays may be an exception.
If not because of the cost of the trays, because of the cost of shipping the 20 x 24 trays.

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