As I mentioned before, the bathroom in our new place in Oxford is not a good place to dry negs - there's just too much dust no matter what I do. So I took matters in hand and built a home made negative dryer. It's worked a treat on the rolls I put through it this week - next to no dust and negs pretty much completely dry in 90 mins or so. Certainly good enough to get into the archive sheets and under a book to flatten them. Total cost was about £30, though it could probably be done for less. I'll stick pics of the setup at the end of the post.
I used a 2m length of 110mm waste pipe that I cut down to just under 180cm to make it more manageable. 3 L brackets and some offcuts of wood made some simple feet to exhaust the air. The film clips were hung from a piece of 4mm aluminium rod that I drilled some holes for about 15mm from the top of the tube. One change I'd make here is to swap the tube for some teflon rod as it's not scratched any films, but I'm paranoid it might. I'll probably wrap it in ptfe tape just for peace of mind.
The actual dryer bit is made from a 150mm square section inspection piece that fits over the pipe. I cut some ply to fit in the top section and cut a circular hole in the middle to work with a 12cm computer fan. I got the fan (a 12V model) from Maplin along with an air filter to prevent the fan sucking in dust and a suitable 1A 12V dc power supply. The insulation tape is just to seal any small gaps since I didn't seal everything with glue in this model in case I wanted to change something. I'd probably just seal it all with bathroom sealant in another version. In hindsight I'd get a multi voltage power supply and run the fan at 9V to slow it down a bit and avoid any possibility of water streaks (I had one small one, but it cleaned off ok) due to the air flow speed. As a compromise on this one, I've picked up some vacuum cleaner filters from a poundshop and I'll cut one to fit and mount it after the fan to slow the air down a bit - we're mainly looking to have a small positive pressure in the tube to prevent dust making its way in from the bottom along with enough of an air flow to keep fresh dry air moving over the film to dry it.
The main problem with it is loading the film - it's done from the top and while the 110mm pipe should allow a couple of rolls of 35mm or 120 to be done at once, you do need to be careful. If I had access to a table saw I'd cut a 1m section on a chord at 80% of the diameter (i.e. enough offset that the hanging rod is still nicely mounted across the pipe centreline) and hinge that. The pipe could then be sealed with masking tape or somesuch once the film is loaded.
Let me know if anyone builds one, I'd be interested to see any other improvements people think of. Oh, and if anyone does have access to 5 or 6mm teflon rod stock, then I'd really appreciate a 150mm length
Pictures:
Top part of pipe with square section and fan mounted. You can just make out the aluminium rod on the upper left of the black waste pipe (it's level with the top of the flash reflection in the door)
Top view of fan unit showing mounted air filter
View from bottom of fan unit showing fan and simple ply mount