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Post by Terry on Mar 8, 2006 16:41:59 GMT -8
Just recently I became the owner of my first DW Mistral which I won on a bid at ebay. I had a few questions come to mind while I have been tearing it down, doing an inspection, cleaning & polishing and getting it ready for re-assembly & adjustment. Does anyone know of any chemical or procedure that can be used to clean the sintered filter that is located in the HP nozzle air inlet. I have several NOS filters in my "stash" but was wondering if there is any way that any of you have found to salvage and get further use out of used filters. I was also wondering what lubricating solutions any of you use, and on what parts when you are re-assembling these vintage regs. Any input would be greatly appreciated. Safe diving to all of you!
Terry Stevens
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Post by SeaRat on Mar 8, 2006 21:29:32 GMT -8
Terry,
First, it's better to replace the filters rather than try to reserrect them. They tend to get corroded over time, and clogged up. This will affect the performance of the Mistral, especially at low tank pressures and depth. These filters were meant to be replaced approximately yearly on new Mistrals and other regulators.
Concerning lubrication, you really don't need any except perhaps for the O-ring that is located inside the main housing, and seals the pin. The main thing I've done is to polish the metal-on-metal surfaces for the diaphragm and the levers to ensure that they slide easier (don't use an abrasive material though, as any scratches will make the surfaces have more friction).
There should already be a lot of materials here an working on the Mistral, so if I were you I'd do a search here, and in the "Vintage Instruction" area too (for threads on handling the clips).
Good luck,
John
For those wondering why I'm posting and not studying, I've been at it at a course for about 14 hours today, and needed a break. We're studying industrial hygiene, and I'm answering homework questions. My last one is "Which of the following is the correct formula for computing the standard deviation of a data set?"
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Post by Terry on Mar 9, 2006 18:19:06 GMT -8
Hi John:
Thanks for your reply to my questions. Your answers were just as I expected, and it sounds like we're following pretty much the same procedures when it comes to restoring these regs. In regards to the filters I was just wondering if anyone had yet found a way to salvage any of these. Thanks for your reply, and safe diving to you! Terry
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Post by Captain on Mar 9, 2006 18:46:47 GMT -8
A mild muratic acid solution will clean them but you would need to rig up a way to force it throught the filter and then neutralize it with baking soda and rinse in fresh water. Easier to just replace them.
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Post by JES on Mar 9, 2006 19:04:41 GMT -8
...For those wondering why I'm posting and not studying, I've been at it at a course for about 14 hours today, and needed a break. We're studying industrial hygiene, and I'm answering homework questions. My last one is "Which of the following is the correct formula for computing the standard deviation of a data set?" Sounds like after studying industrial hygiene for 14 hours, you've finally pegged your fun meter.  Keep up the hard work John. We're all pulling for you to ace this certification! |
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Post by duckbill on Mar 9, 2006 20:06:41 GMT -8
A mild muratic acid solution will clean them but you would need to rig up a way to force it throught the filter and then neutralize it with baking soda and rinse in fresh water. Easier to just replace them. Whatever you do, don't throw the old one away; Someday it will be very difficult to say, "Easier to just replace them"! |
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Creed
Pro Diver
Posts: 189
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Post by Creed on Mar 9, 2006 20:26:04 GMT -8
Whatever you do, don't throw the old one away; Someday it will be very difficult to say, "Easier to just replace them"! Except that new ones aren't that hard to have made, from what I understand. I may be wrong. |
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Post by SeaRat on Mar 9, 2006 20:42:26 GMT -8
Well, Terry, you can take a good look at the one you take out, and see how corroded it is. Then do clean it like Duckbill says, and test it in the water. When a filter begins plugging up, it becomes more efficient as a filter. The problem is that while the filtering is more efficient, the amount of resistence to air flow increases. But this is highly dependent on the air pressure behind it pushing air through the filter. The advise I gave you above is because these filters are still available, and the regulator will work optimally with a new one.
Having said that, and knowing that I recommend that others replace these filters, please also know that I haven't replace mine in years. I don't use them often, and there is no corrosion on them. I have seen no deterioration on mine. I would replace mine if I saw rust forming, if they had become distorted due to my poor efforts to remove and replace them, or if they were significantly damaged in some way. I will say that it is important if there is rust on them to replace them as the rust itself could cause a leak in the regulator if a piece becomes lodged under the seat; it could also damage the seat.
Jes, thanks for the kind words. Sometimes I need a break, and this provides it. I'm in Salt Lake City attending the University of Utah Rocky Mountain Center for Occupational & Environmental Health course, Comprehensive Review of Industrial Hygiene 2006. It is quite intensive, and I'm about to embark on my evening homework sessions for tomorrow in industrial ventilation. I'm learning all about static pressure, calculating ventilation rates, etc. That kinda plays into this post, as we also discussed all sorts of air filters and scrubbers in our "community exposure" session today. It used to be known as "air pollution," but times change and emphases change with them. The filter on the Mistral is a pretty vital part, although it is one of the few non-moving parts. One of the neat things about the Mistral is its ease of maintenance, with only 6 moving parts in the regulator (diaphragm, two levers, pin, seat and spring). This is why it was so popular with the Cousteau team; it was easy to keep going.
John
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Post by Broxton Carol on Mar 10, 2006 4:32:25 GMT -8
Im going to repeat myself again. Just use CLR for cleaning all your metal parts inside your regs. You can use it on the cans too, but never polish off the outside patina. You can throw your nozzles, and FILTER in this stuff, and it will come out as nice as new. I have used it on dozens of regs. Rebuilding a mistral is the most easy thing you can do. Set it the way the book says, and it will work great. Touch the back of the diaphragm with silicon grease where it contacts the finger. Now fix it, and go divin.  |
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Post by SeaRat on Mar 11, 2006 8:28:42 GMT -8
Do as Broxton Chuck says, then dive it.
Enjoy,
John
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