Project Film Dryer — Ver. 2.0

Published on 22 July 2019


It may not look like much, but the above shows version 2 of my film dryer. Since most of the materials are the same as the prototype, please see here for information on what is needed. In version 2, I have changed the design in several ways:

  1. I have inverted the airflow. In the prototype the fan would push air into the dryer, but in the new design air is pulled by the fan through the dryer.

  2. The stick on which the reels hang is made of metal.

  3. The stick no longer rests against the bottom of the dryer, but hangs suspended on a horizontal bar under the fan.

  4. I have found a new filter.

For this new design the following additional things are needed:

  • A metal rod of suitable length and diameter

  • Metal wire or nails of suitable size

  • Kitchen fan air filter

  • A ring, rubber band or metal wire to hold the filter in place

  • Metal mesh

The additional tools needed for version 2 are:

  • A metal saw

  • A drill with metal drill bits

  • Something to hold the metal rod firmly while drilling (I used a small vise)

The Airflow

Fig. 1 — The fan with cushions (click for large)

The fan remains the same Eluting 120mm USB-powered fan I used before and the crown-like tube which houses the fan is the same PVC pipe connector as earlier. But I flipped the fan around to change the airflow direction. This circumvents the problem of forcing the fan push air through a filter placed very near the fan itself, which would require a stronger fan. I imagine that inverting the airflow causes the air to move more gently inside the dryer.

To ensure that the fan’s efficiency isn’t being lost through the gaps under the fan’s corners I have put pieces of one of the filters I bought. Recall in the previous design I used duct tape to cover those holes but that does not work in this design if I want a removable fan.

A solution would be to use an ever longer tube and attach the bar (see below) to the tube rather than the crown in which the fan is seated. I might change that in the future since I have more of the tube. But as it is now these cushions cover the holes enough to prevent air from being sucked in there. And yet another solution would have been to cut the crown better in the first place :D

The Stick

For the stick I chose a 1 metre long brass rod, ca 5 millimetre in diameter. There is no particular reason I picked brass except that it was only metal rod I could find that was thin enough to fit through the hole in the core of my reels.

I also tried with a 5 millimetre wooden stick first and while that worked I had doubts about the longevity of the design.

I cut the brass rod to a length that is almost the height of the tube, from the bottom mesh to the underside of the fan. For this I used an simple metal saw.

I used a 3mm metal drill bit (and a power drill, of course) to make the holes. The right-most hole in fig. 2 (top) is 1-1,5cm from the end of the stick and is used for hanging the stick on the horizontal bar (see below).

Fig. 2 — The Stick, with hole (click for large)

My original idea was to re-use the 2 millimetre nails I had used for the prototype, but my 2 millimetre metal drill broke when I drilled the second hole (oh well) so I had to use the 3 millimetre drill.

This turned out to be a good thing because the plated copper wire I now use for “reel stoppers” is more sturdy and less fiddly to put into the holes than the nails.

As you can see in fig. 2 (bottom), I just cut suitable lengths of the copper wire and bent the pieces 90 degrees.

The other holes are also 3mm in diameter and spaced such that I can dry five 35mm reels at the same time (since I have a five-reel tank). As fig. 3 shows, the stick fits two 120 reels and one 35mm reel which is another combination I sometimes develop.

Fig. 3 — The Stick, loaded (click for large)

The Bar

Fig. 4 shows how the stick hangs on the 3mm bar, which is also made from the same plated copper wire I have used for the reel stoppers.

This is probably not a long-term solution for the bar because the wire is a little bit too soft and bends slightly due to the weight of the stick and the reels. But it is good enough for now.

Fig. 4 — The Stick, hanging (click for large)

The Filter

I looked at several filters and tried this one intended for Dyson vacuum cleaners and this filter cloth which filters out 50% of ePM10 but both were too thick to work with the fan I have.

One of the always friendly chaps over at suggested to use a filter for a cooking hood so I bought that (fig. 5). I’m happy to say it works like a charm. It’s easy for the fan to pull air through it. Even on the lowest speed I can feel that air is sucked in from the bottom at a sufficient rate.

The filter is pressed against the bottom of the tube by a ring I cannibalised from the Dyson filter (fig. 6). There are other ways to hold it in place, such as using metal wire or the always-useful duct tape. Speaking of which, I use duct tape to hold the yellow ring in place (not shown in fig. 6) which works well enough.

Fig. 5 — Filter and mesh (click for large)

Fig. 6 — Filter and retaining ring (click for large)

In use

This is the most important thing, of course. I am pleased to say that it works really well and will dry a set of reels in around 30 minutes.

One thing I need to decide on is how it should be used. There are a few options, for instance affixing a hook or something to the tube so that it can easily be hung while running, or to build a little stand. It quickly becomes tedious to hand-hold it for a half-hour :D

As for the results, click on fig. 7 to see the full 2700x4000px scan on Flickr. This scan has not been processed in any way. There are a few spots but it is truly a night and day difference compared to my past results. Night and Day.

Summing up

I hope this little guide may be of use to other photographers who are struggling with dust and crud on their films. Nothing beats having clean chemicals and doing the last wash in distilled water with a bit of wetting agent, but it doesn’t end there, at least it did not for me.

If you have any questions or suggestions feel free to contact me. I’d be very interested to see what designs you come up with.

Fig. 7 — Sample scan (click for large on Flickr)

Fig. 7 — Sample scan (click for large on Flickr)