Collodion Decanting Rig

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A collodion decanting rig facilitates removing collodion from a bottle without removing the sediment which settles to the bottom as the collodion clears.

In my seven months practicing wet plate collodion photography, I’ve continually struggled with a way to remove the collodion from the bottle I prepare it in without including any of the sediment which settles to the bottom as it clears. Of course, it’s critical that none of this sediment ends up in the collodion you plan on using on your plates, because it causes all sorts of contamination issues with your images and chemistry.

In my initial research, I found suggestions for making a traditional chemistry decanting rig using glass tubes and a rubber stopper, but there were no clear explanations on how to do so or how to use it. Plus, the only images I could find of them were grainy sketches from 1800’s manuals.

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My attempt at using a plastic turkey baster to decant collodion resulted in the collodion causing the plastic to shatter, which was actually kind of cool!

Shying away from bending glass tubes over a torch I didn’t own, I tried a first round of decanting using a couple of turkey basters. This failed miserably, as the collodion actually caused the plastic turkey baster to shatter (which, I must say, was kinda cool). This week, I finally bit the bullet and purchased all the stuff I needed to build my own proper decanting rig, which I’ll share with you here along with links.

A quick note on how this works: The heart of the operation is a two-hole stopper that goes tightly in the neck of your collodion bottle, and through the stopper, two glass tubes are passed through. One, which is bent at an angle, is placed down into the collodion inside the bottle. The other tube, which I kept straight, is placed just slightly through the stopper so that it is inside the air space within the bottle.

3_collodion_061014The final decanting rig inserted into my collodion preparation bottle. The straight tube is blown into, causing the pressure inside the bottle to rise. The clean collodion (without the sediment at the bottom) is sucked up through the bent tube into a second container for collection.

When you blow through this straight tube, the pressure inside the bottle is raised, forcing the collodion up through the other tube and into a second bottle for collection. Because the bottle you’re taking the collodion from remains perfectly level, the sediment which has settled to the bottom stays there. The perfectly clean collodion above it gets sucked out, and stays perfectly clean. Brilliantly simple!

The first thing you’ll need is a two-hole rubber stopper that will fit the opening of the bottle you made your collodion in. Since I’m using a 1 liter Boston bottle, I need a #1 two-hole stopper. If you’re not sure what size stopper to purchase, you can check this size chart.

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My #1 two-hole stopper, which I had to modify slightly by drilling out the holes to accommodate the 5mm glass tubes.

The next thing you need are two 5mm glass tubes, long enough to get all the way down to the bottom of your bottle plus about 4 inches. I recommend getting a few extras, as they’re very fragile (I accidentally snapped the first one I pulled out of the box just checking it out).

The #1 two-hole stopper that I purchased had holes that were 4mm in diameter (which were actually closer to 3mm). Since I couldn’t find a stopper in the #1 size with 5mm holes to accommodate the glass tubes, I took a Dremel tool and very carefully drilled out the 4mm holes a bit. You have to be very careful not to drill out the holes too much, or else the vacuum seal needed to decant the collodion won’t be possible (remember, things have to be snug).

The most tricky part of all of this is bending the glass tube which gets inserted into the collodion. This bend facilitates the clean collodion being easily transferred into a second bottle.

5_collodion_061014Two 5mm glass tubes are needed for the rig. One straight, and one with a bend which is created by heating it over a torch.

Here’s a YouTube video about working with bending glass tubes, which was my only training on this part! You’ll need a propane torch or a bunsen burner to do this. I tried using an alcohol lamp as well as a gas stove burner, and they’re not hot enough. You need a torch.

Bending the glass was actually pretty effortless, as I successfully completed a bend on my first try. Decanting the collodion was equally simple. I only had to blow into the tube just slightly to get the collodion going into the second bottle, which I held in my hand at the end of the bent tube.

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A detail view of the assembled rig at the neck of the bottle.

As you stop blowing into the tube, the collodion fumes will rush out of it and into your mouth if you’re not quick about getting away from it, and let me tell you, ether fumes taste pretty bad! I recommend continuing to blow as you take your mouth off the tube to avoid this.

When it was all said and done, I ended up with two 250mL bottles of perfectly clear collodion ready to use in the field!

Posted in Experimental, Photography, Tips And Tricks, Wet Plate Collodion by Guy Rhodes on June 11th, 2014.

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