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Thread: WELL??? How are they working!?

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  1. #1
    Join Date
    Oct 2000
    Location
    Chicago
    Posts
    5,947

    WELL??? How are they working!?

    All,

    We seem to be having very few problems in the scheme of things but I am not hearing from anyone using them. Please report if its working well for you or if your still waiting for hoses etc.

    Thanks,

    Tom

  2. #2
    I will report back as soon as I get my fill hose kit from Tunaman

  3. #3
    Timely question - mine has just totally seized. I ran it yesterday for about 12 hours to fill a SCUBA tank. It seems to fill at a rate of about 5-6 hours per 1000psi. Shut it off at about 2200psi when I went to bed.

    This morning I was planning to fill it the rest of the way, and when I flipped the switch, it blew the fuse.

    Took the connecting rod off to isolate the motor and the pistons, and it is definitely the pistons that are locked up. Can't move them at all in either direction.

    It got very warm while filling, and I am guessing that when it was shut off while hot, something fused or something. While it was running, I was replenishing the lube on the piston rods with white lithium as recommended.

    I will report back with more info once I get the pistons out to look at them.

    One other finding. After running for 12 hours or so, there was a surprising amount of water in the line connecting the compressor to the SCUBA tank. So much tat I got sprayed when I vented the line at the SCUBA yoke. I'm not at all worried about this, but people had asked about water condensation.

    Edit: I got it apart and the piston that has seized was the first, larger diameter stage.



    Below are the guts from the bad piston. The long black plastic sleeve on the right is what has become very tight on the piston rod. Like so tight I needed to use a large wrench and hammer to get it the rod out.

    Should I try drilling it a bit larger? Polishing the rod for less friction? Just lube the hell out of it and reassemble?



    Also, I have to say that this is a really amazing piece of design. Everything comes apart very nicely and easily, and it is so fun to see the mix of fabricated and hardware store parts in here.

    Tom, do you recommend running the unit with the cover on or off? I was running mine with it off, but I do appreciate the ducted airflow design using the motor to pull air across the pistons. It just doesn't seem like enough airflow to be any better than leaving it all open. The air exiting the motor is very warm. Too bad it doesn't move more air.

    Edit2: Fixed.

    The long black bushing in the piston photo was fitting SUPER tight on the rod. I think it's just a guide, and the o-rings do all the actual sealing, so I took a rat tail file to it and enlarged the inside of it so it would slide easily on the rod.

    Reassembled... and we're back!

    I would say that this thing could be rebuilt in an hour. Very clever design! I love it. I have heard that you should replace Swagelok bushings every time you reassemble them, and they are sensitive to torque, but these don't leak, so I'm happy.

    As for feedback - Tom, are these black bushings just to guide the plunger inside the piston assembly? If so, I wonder if there is a size slightly larger that slides more freely. I also worry that with a very tight fit, these will tend to wipe the grease off and make it difficult to add grease from the outside.

    Also, there was one small "defect" on mine - the hose going from the 2nd stage piston to the main airblock was almost closed on one end from how it was cut. There was just a tiny pinhole opening, and the rest was filled with the remains from cutting it on a saw of some sort. I drilled it out, but not all the way since it wanted to flare the end of the pipe out and I didn't want to ruin the seal.

    And one tip for those of you working on these who have read this far in this post - use a Sharpie or something to mark the position of the rods in the block with the setscrews, and the location of the collar that holds one end of the spring. That will make it much more likely to get it put back together and not in need of lots of adjustment. I think having the rods misaligned so that they are at the wrong depths relative to each other could seriously affect the performance of the compressor. And obviously the collar location affects the shutoff pressure, so that is very important.

    Edit3: Not totally fixed. It isn't filling past about 1.5k. I read a couple of threads here that indicate that this likely means a bad check valve on the 2nd stage. Pulled it apart and damn - trashed. It was super dirty with some sort of white crap (grease? crap from my compressor?) and the oring was split. Replaced it from the spare orings that came with the compressor and that one split. The plastic oring seat is damaged, which I assume is what's doing it. I might have installed the small plunger wrong so that it hits the check valve. I thought that it was flush with the back of the block with the set screws, but maybe I was wrong.

    'wose
    Last edited by Woodwose; 07-16-2010 at 07:58 PM.

  4. #4
    Join Date
    Sep 2004
    Posts
    1,142
    the only problem we had with ours so far is that sometimes the rocking arm (whatever you wanna call it) works its way up the screw and when it touches the screw head it gets enough traction to be able to turn off the compressor. simply tapping on the arm puts it back in place, and it can be turned on again.

    otherwise ours has been working pretty good.

  5. #5
    15hours and itís going strong. I use a little lithium grease every tank I fill (2-3hours.)

    I wonder if the water problem is primarily filling bulk tanks. I havenít seen any water in my 68/45ís or in my water trap. Still havenít installed a desiccant/filter.

  6. #6
    Join Date
    Jun 2010
    Location
    In the Box shop
    Posts
    41
    Quote Originally Posted by PAINTHEY
    15hours and itís going strong. I use a little lithium grease every tank I fill (2-3hours.)
    Thats it. Use a little grease after EVERY fill. If you are going to run it for 12 hours, you need to grease it every 3hours. See TK's tech video on grease and a little dab will do ya.

  7. #7
    Join Date
    Jun 2010
    Location
    In the Box shop
    Posts
    41
    Quote Originally Posted by cockerpunk
    the only problem we had with ours so far is that sometimes the rocking arm (whatever you wanna call it) works its way up the screw and when it touches the screw head it gets enough traction to be able to turn off the compressor. simply tapping on the arm puts it back in place, and it can be turned on again.

    otherwise ours has been working pretty good.
    Well TK is working on giving everything a part name.

    Lets call it the shut off spring mount arm for now. I think that is what you are talking about. Correct? Unplug it and disconnect the spring from the collar. That arm should rock back and forth freely all day. See if it doesn't.

  8. #8
    I also had a good about of water buildup that shot out pretty forcefully when I opened the bleed valve. my cylinders (and the top fill nipple area) also got very hot after a few hours. the pulley on mine behind the aluminum block seems to have alot of lateral play (I'll try to make a video over the weekend so you can see if it's too much...) Only other thing is when I first ran it for a while, there was a good amount of very fine metal dust on the floor of the shoebox but with use that seems not to be happening any more.

  9. #9
    Join Date
    Dec 2000
    Location
    offshore
    Posts
    7,179
    Mine seems to be just fine. I have over 100 hrs on it now. No failures yet. Also got a little water vapor out of the bleed, but it is VERY humid here now. I know the ambient humidity will play a large part in how much water comes out. Doesn't seem to effect anything.
    Email me for low prices on ALL AGD Products and more. tunaman5@verizon.net
    Tunamart

  10. #10
    Join Date
    Aug 2006
    Location
    port st. lousey fl origin
    Posts
    2,828
    well i've got about 35 hours on mine , I only run it 4 or 5 hours at a time , I have had no problems & have done nothing to it , I did set up a fan to blow across the unit as it runs , I would have thought i'd get some condensate in my primary compressor but at this point have got only a few drops , none at my scuba yoke when bleeding

  11. #11
    I am also waiting on my proper fill kit from tunaman and will report my findings when it arrives. I have used just a simple whip to fill my Airforce tank a couple of times with no problems so far.

    Carl

  12. #12
    That tube was really stuck on there. To get it off I had to hammer on the rod with the tube backed by a huge crescent wrench in the vise. Seriously stuck.

    Now I am having 2nd stage check valve problems. It keeps splitting the orings. I am using the closest I could find from the local hardware store, so maybe they are a little bit off. But they fit well. I think the main problem is that the plastic piece that holds the oring is damaged.

    Can I purchase a new plastic o-ring carrier for the 2nd stage check valve, and a box of 100 orings (ok, maybe just a couple)? And maybe a replacement delrin tube for the 1st stage in case the one I had was off somehow?

    Also, what is the proper procedure for mounting the rods just right in the set screw block. I thought I had them right, but that is the only thing I can think of that would damage the check valve.

    Thanks,
    'wose

  13. #13

    Almost there

    I just got my hoses from Tuna. Headed out of town but plan on setting it up next week for its first run

    Swamp

  14. #14
    Join Date
    Oct 2000
    Location
    Chicago
    Posts
    5,947
    Woodwose,

    PM me your phone number and I will call you to get it worked out. We will replace your back check with a brass one. The orings are special Vitons. Hardware store ones will not work and will melt.

    Tom

  15. #15
    Join Date
    Jul 2008
    Location
    Minneapolis
    Posts
    115
    Had a sticking bleed valve - took all of 30 seconds to fix. dumping tank reg output back into the output sealed it right up. I had to spin the tank into the ASA I was using to get a good "pop" of air - but it seated right back up and works great.

    only problem so far - maybe 20 hours on it.

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