MOUTHPIECE SHUTOFF MODIFICATION FOR RGU REBREATHER

You can die from too much oxygen. You can die from too little oxygen. You can drown. Screw up and you are likely to die. When you enter the water, you are on your own, even if a buddy is nearby. You alone must make the decision that you are capable of using a rebreather, you are up to the dive, and that your equipment is up to the dive. Even extensive open circuit experience will not prepare you for the details inherent with staying alive underwater on a rebreather. If you have any concerns about your abilities, take a course or do not dive. If you are foolish enough to dive rebreathers, be aware that it is a case of Evolution in Action. It is an effective sorting out process that has created many unhappy widows, mothers, and children. I recommend against it. This project is described for your amusement only. It is not the intent of the author that you build one of these and go out and kill yourself. Worse yet, when I inquired about some fittings for the RGU unit from a good friend in Germany, he said, "Throw that damned thing as far away as you can." I still might take his good advice.



One of the problems with the RGU is that the mouthpiece does not have a shut off. Take it out of your mouth underwater and the loop is full of water. Not exactly what we want. I had used a garden hose cutoff on my pendulum rebreather and I thought, why not do the same for the RGU. Did I save money.....No, but this is probably the only project I have done in the last few years that came close to breaking even. The total time it took was less than two hours and half of that was looking for the hose cutoff on one of the lines of my irrigation system. Must remember to replace that before next summer. Parts were under just under $10. After I cut the two pieces down, it was molding epoxy while watching TV.

Here is the RGU mouthpiece that comes with the unit. It has no shutoff and a really big rubber mouthpiece. I guess since it does not have a cutoff, the top command did not want someone to drop it out of their mouth. Not much chance with this sucker. You may never get it out.
The first step was to find a garden hose cutoff. Mine actually came from the garden since it was closer than Lowes. I used a band saw and file to remove the rubber mouthpiece holder from the RGU mouthpiece. Then I cut the female end of the hose cutoff so it would fit reasonably well against the RGU mouthpiece. I stopped by Lowes and got some epoxy. The epoxy I use is found in the plumbing department.
Next I attached the shutoff to the mouthpiece with the epoxy. I did this in several stages. The first stage was to just attach the shutoff. Then I filled in the spaces and made it watertight.
A little black model paint and it looked like this. Had I really cared, I would have made the epoxy smoother by either sanding or spending more time molding.
Then I attached a brand new rubber mouthpiece from my local dive shop. At first I was a little concerned that the shutoff would add to the work of breathing, but to my delight, it didn't. The valve turns easily. I could grease it and make it turn better, but that was not necessary. If I was ever crazy enough to go in cold water needing gloves, I would build up a bigger knob on the shutoff with the some of the remaining epoxy.
See what a few minutes of boredom causes. The big knob really is easy to find and even easier to turn. Now for the really hard part......deciding what color to make the knob. Decisions...Decisions....

This was just one of the little steps in my development of one of my rebreather systems. Here I am testing it and it worked great. One more step for landkind. What fun, no bubbles, cannot hardly feel that it is there. Please note that I have painted the RGU shell yellow. It comes in either Macho black or camo OD (thats olive drab for you non military types.) Neither of those colors are acceptable for anything but for stealth operations where you are going to kill people. Not that there is anything wrong with killing certain people. I just gave up on the idea about the time I quit killing fish.

Doesn't the yellow look much more festive and fun for picking on fish and invertebrates. You should also note the matching strap, mask, and real Churchhill fins. Cool huh. The diver (moi) is also dressed in a black shirt, shorts, and sports a matching wristwatch. My wife has to approve all color combinations. Underwater photo by Ellen Pulaski, Chemical Engineer, French Maid, and wife of my ever suffering dive partner Tony.

Isn't it amazing how that little yellow box can keep you alive over one hour under water. Just what will they think of next.What a great world we live in.