Warning: salt, corrosion and dirt up ahead:
Since I began diving about two years ago I’ve mostly rented gear whenever I needed it.
What I like about renting things is that you get to try different brands and models, and little by little start finding out what you like/don’t like/need/want/hate about certain gear. You also get some time to figure out how things work and what kind of preferences you have.
Diving equipment isn’t cheap, but taking time to shop around can get you a significantly cheaper set of gear.
A while ago I got hold of a second-hand Mares Dragonfly semi-wing jacket for €80.
Even though it seemed in good shape, I wasn’t sure how well the previous owner took care of it so I wanted to thoroughly clean it. And of course, in all honesty, just wanted to take it apart to see how it was made and how things work.
A service manual would have been nice, but I couldn’t find it for this jacket. I did find some exploded views in the “01 revision of the Mares service manual that’s floating around on the internet, but no guidelines. Well then… Off we go.
First I took a look at the dump valves on the right shoulder and the lower right side on the hip. They came off easily just by turning them counter-clockwise, as one would expect.
There’s just the outer plastic cap, a spring, a plastic piece that holds the rubber and the rubber seal that seals off the port. Pull the cord and the seal moves away a bit from the port. Overpressure inside the jacket puts enough force on the rubber from the inside to overcome the pressure from the spring and open until the pressure is below the threshold.
The rubbers are not glued onto the plastic caps, there’s just some kind of grease. I left that on, but cleaned the underside of the rubber seals from dust and patches of salty build-up. I didn’t take any pictures before the cleaning, only afterwards.
While they were open, I gave everything a rub, and got out the spray paint. Why not touch them up a bit again and make my jacket more recognizable?
Also replaced the dull black cord with some cord from my rock-climbing stash of cords.
This jacket has one big downside and that’s the weight. Close to 4 kg it’s really heavy when travelling by plane. I have been looking where I could lighten things without touching the main functionality of the jacket. I’ve tried replacing one of handles/weight on one of the dump cords with a ping-pong ball. My only concern is (ironically) the lack of weight. While it can fill up with water, it has no weight in itself so I’m not sure if it won’t float around too much while diving. We’ll see.
While, supposedly, you need a special tool to open the plastic ring that seals the airtrim thing on your left hip to the jacket (same for the valves itself) I opened up the console. An exploded view can be found in the Mares manual p. 102, drawing J83.
The console opens up after unscrewing the three screws on the outside. Mind you, these are machine screws without bolts. They’re just screwed into the plastic so treat them accordingly.
The system is a white plastic thing that comes off after unscrewing the two visible screws. There’s one big O-ring inside to seal it off. That’s all there is to it. The connector to the hose that feeds the two valves stays on the jacket, it has an O-ring and just slides into the white plastic. (pictures are after cleaning)
The connection to the low pressure feeding hose screws out of the plastic (14mm key), and so do the two buttons (both 17mm key). They both have another thread, so there’s no mistake possible while assembling them again. 
Inside the hole where the low pressure feeding hose connection goes into is a small plastic filter to keep contaminants out of the system. Make sure it stays in there. The inflate button assembly comes apart into its separate pieces, but for the dump button construction to come apart you need a 6mm and a 5mm key. The centre piston is in two parts, and must be unscrewed. The upper part comes out from the top, the lower one slides out to the bottom.
To me, the O-rings all seemed in good shape, so I didn’t search for replacements. If that would have been necessary I’d probably just would have taken the jacket to a shop for maintenance.
I cleaned everything with a lots love, warm water and some vinegar. I’m not sure if that’s the best way, but it’s the best one I found.
I gently tried to open the “special” bolt that needs special tools. An owner of a dive shop showed me this “special” tool and it seemed to just be a cup-like mould that slides over the bolt to get more grip on it. The thing didn’t move however and I really didn’t want to break anything. It would only need to come apart to satisfy my curiosity so it isn’t worth breaking it.
Everything was reassembled and put back on the vest. The plastic parts outside got a scrub and some layers of paint.
The jacket isn’t any better now, but at least I’ve seen the inside of the system, it got cleaned out and the visible parts got a cosmetic touch-up. I also cleaned and did some small changes to the manual inflator hose, but that’s for an other time.
Dieter Vansteenwegen (ON4DD) 