Final Unicolor Unidrum Gasket Repair
I've come to two great solutions for repairing a leaking gasket on a Unidrum, read on if you're interested at all..
I've had a leaky Unidrum for a while and have tried more than a few simple repairs. Curuxa gave me a great tip that essentially consisted of cutting out a new plastic gasket from a large coffee-can lid then using vaseline on top of the gasket. This worked great, I only had a few drips and dribbles along the way. I only needed to apply the vaseline every other time I'd develop film or so.. Not too bad at all.
Essentially, I pulled the top plastic gasket out and then removed the rubber seal from the lid (carefully!). I had to cut the seal and pull it up that way..
I then applied a thin (thin!) layer of silicone sealant/adhesive where the rubber seal goes and placed the ring back on. I pressed it down slightly and wiped the excess silicone away. It still looks a bit messy when I did this.. Attach the lid and let sit for 24 hours while the silicone cures.. The next day, cut the gasket out from the coffee lid using the original gasket as a guide.
Smear some vaseline on both sides of the gasket before you place it back in.. Works great! Still dribbles a little (a few drops after 5 minutes generally, getting steadier after that.. still nowhere as bad as it was originally).
I then read a post by dmax, (http://www.apug.org/forums/540260-post8.html)
involving a sheet of neoprene foam (black coolfoam from michaels arts and crafts, $1 will make 6 gaskets)
I cut out a square of material, smashed it with a hammer to make it a bit thinner.. cut a ring out using the gasket as a guide (not even worrying to cut out the ridges or little fingers) and siliconed in on top of the rubber ring/seal. I then place the lid back on the tube and let it sit for 24 hours again. The next day I removed the lid and smeared a small bit of vaseline onto the foam. The tank seals very tightly (but not too tight) The vaseline makes it go on and off a bit more easily.
After half an hour there is not a single drop. I observed this by placing the Uniroller on top of a large sheet of paper. No drops at all.
I'm not sure if removing the rubber seal underneath and silicone sealing it back in is necessary. It certainly is/can be messy. Cutting the rings out of both neoprene and coffee-can lids are simple but the neoprene is WAY EASY with a sharp x-acto knife.
Sorry for the length of this but I thought that it may help someone else with a leaky drum.
Oh, and definitely hammer the sheet material before cutting the ring.. Hammering the ring will flatten the ring outward, thus making the ring not fit)
Good to know that my recommended repair worked well for you. In my original posting, I had neglected to mention that I usually coat the neoprene ring with a bit of candle wax or paraffin to make the lid slip onto the tube a bit easier. I might try using vaseline on a couple of my unicolor lids to see if it might work better for me.