Cheap, easy to make, wetplate dip tank

Cheap, easy to make, wetplate dip tank

So one of the handy thing you need for wetplate work is a silver nitrate dip tank. A lot of people seem to be using the tanks available from several commercial providers. While I’m sure they offer very professional, good quality products, they seem to be a bit pricey to me for what’s basically a flat rectangular plastic tank. For a holder that fits 4×5 you can easily spend somewhere around 80 dollars. So this lead me in search of a cheaper DIY option…

So now my design, it costs about $5 for the 4×5 variant (less than the dipper alone for some commercial options…) and is about an hour of work to make. Here are two pics of my 9×12 cm (also fits 4×5″) and  13x18cm (also fits 5×7″) finished results.

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Materials needed

  • A flat water bottle (your choice of size) from your favorite chinese supplier – $4.50 for the A6 – They change prices all the time maybe you can even find a better deal… Yes that is a flat rectangular water proof tank for under $5 yes, yes, yes, it costs less than buying the plastic and cutting and gluing it yourself… they even sell different sizes like real plate holders… the one I ordered disappeared but just search for “memobottle” or “paper bottle” on and things seem to come up from lots of sellers. Just don’t pick the first one usually you can find exactly the same item for up to 30% cheaper if you look around a bit or search for synonyms.
  • Wood screws, I used 4 4x40mm screws and 8 3x20mm screws  but anything you have works – $0.5?
  • A largish piece of plastic (I used the lid from a bucket of tile adhesive but again just be creative) – $0.0
  • Some scrap pieces of wood – $0.0
  • A long flexible piece of plastic or cardboard with a straight edge

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Tools needed

  • Standard DIY stuff, tape measure, screwdriver, saw, …
  • A hacksaw or something else which cuts plastic
  • A heat source. I used a heat gun, but candles, spirit lamps (for the sanderacsters), lighters, … would probably also work.
  • A clamp or vise or something
  • Permanent marker

If you don’t have these tools your neighbour, friend, flatmate probably has…

To build the tank:

  • Using the flexible piece of plastic/cardboard and marker mark the cutting around the perimeter of the bottle. Having a clear guide makes it a lot easier to cut straight using the hacksaw.
  • Carefully clamp down the bottle this makes cutting a lot easier than hand holding it.
  • Using the hacksaw carefully cut the top of the bottle along the marked line. This is probably the most finicky bits of the build. Just take your time…
  • File/sand down the cut edge.

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That’s the tank bit done now the holder:

  • – Find a relatively heavy large (say 10 x 15 cm) piece of wood. You want this to be heavy to ensure the center of gravity is low enough to prevent the tank from tipping over easily. After building it I did a few bump tests with the tank filled (with regular water). With my piece I almost had to kick the tank for it to actually tip over. Make sure it is heavy enough so anything up to a gentle bump should not tip over the tank with your precious silver.
  • Use the long screws (4×40) so affix two vertical pieces of wood to the base. The screws go through the base from the underside into the vertical pieces. So they are invisible when the holder is standing upright.
  • Use the short screws to affix two horizontal pieces of wood to the vertical bits (see the photo of the finished think at the beginning of the article).

That’s the holder bit done now the paddle:

  • Cut a piece of plastic from the large piece. In my case I used the edge of the lid as a Grip for the paddle. Make sure the plastic is thick enough of the paddle will be too floppy.
  • Clamp down the bottom bit of the paddle between two thin pieces of wood. The thickness of the wood controls the thickness of the paddle grip.
  • Heat up the plastic using your heat source and carefully bend it around the wood “mold”
  • Cool down, unclamp, and admire your paddle
  • Cut two trapezoid bits of plastic from the back side of the paddle. This makes smaller plates easier to remove from the paddle as you can grab them by the edges.
  • Drill holes in the bottom of the paddle to reduce turbulence in the silver bath (I didn’t bother but the commercial ones have this ‘feature’ …)

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Finishing touches:

  • Insert the paddle along with the thickest,largest plate you plan to use (3mm glass in my case) in the tank.
  • Fill with water until the level is well below the edge of the tank
  • Remove paddle and plate. Mark the water level as “MAX”. This avoids overflowing the tank when you fill it to far with silver when inserting the plate. Note that for aluminium plates there is less volume displaced so you may need to mark several “MAX” levels.

If you want to travel with your tank filled you should make a lid (I didn’t do this, bottles still seem safer somehow). How to do this has been explained before just check the following video (the action is at 3:40 as embedded in the link).


  • Carefully wash everything to remove cuttings, factory chemistry, … these bottles are meant for drinking water so hopefully they should be reasonably clean from the factory. I let mine sit for a few hours with distilled water in it, just in case…
  • Insert funnel and fill with silver nitrate until the marked “MAX” level
  • Dip away!
  • When done you’ll notice it quite nicely pours from the the tank. I was most worried about this but the fluid doesn’t run down along the edge of the tank but pours nicely into the funnel. Not sure how you can influence this behavior maybe by careful filing of the edge. Or more/less sanding of the edges so the water “sticks” more to the edge?

Standard plate sizes – bottle sizes:

  • A6 bottle
    • 9×12 cm (what I use)
    • 4×5 untested but it’s big enough in theory.
  • A5 bottle
    • 13×18 cm (what I use)
    • 5×7 inch
  • A4 bottle
    • 18×24 cm (not sure what camera this is for but I’ve seen them offered online)
    • Sadly enough this just barely doesn’t fit 8×10 being only 7.7″ wide.

Finally, if this doesn’t seem your thing here are some pointers to other cheap-ass options and why they didn’t suit me at least:

  • Use a regular darkroom tray or something else like a baking tray. Silver nitrate will not attack most common plastics so any plastic container should generally be safe. (Note the salted collodion is generally not considered plastic safe, both the solvents and iodide in it may attack plastics.) While this is probably the cheapest option (especially if you have the tray already) there seem to be several disadvantages to it.
    • It takes up more working space than a vertical tank. Especially relevant if you work in a confined space like a darkbox or tent.
    • You need to switch the lights off while the plate is getting ready the tray.
    • Turbulence, lots of it, wit a tank it is easier to insert the plate in one hopefully laminar move.
    • It’s easy for dust and other debris to get into a tray, silver nitrate is expensive stuff so we want to care for it the best we can. No use being stingy on a tank if the silver in it is wasted which may well end up costing more than you saved. Furthermore, silver nitrate is toxic, aggressive stuff you ideally want it contained as much as possible.
  • Make your own tank from acrylics or glass. This seems to be the current state of the art in home-brew dip tank design (links here, here and here). However I hesitated to do it like this because.
    • I checked prices on acrylics and including having it cut, this still amounts to about 25 euro where I live, add a few euros to buy the necessary welding glue, … and it easily costs around 30 euros. Cutting it yourself may save a bit but you’ll need good equipment and a special blade to cut it perfectly straight for welding. Glass is probably cheaper than acrylic to source but plastic won’t break…
    • They are probably best if you want something bigger, say 8×10. I am still considering this for the 30 x 40 cm holder I need to hold full plates in my camera.
    • It seems tricky and a lot of work to glue everything properly at right angles ensuring waterproof seams (disclaimer: I never worked acrylics so maybe this could be easier than I think)