Joined: 3:26 PM - Apr 27, 2015

6:00 AM - Aug 09, 2018 #71

DocsMachine wrote: That's pretty much what I figured it was, Allen, and thank you again but I think I'm going to pass.
Not a problem, I just thought I would offer.

On a related note, if you (or any of the others here) have any use for some pneumatic vacuum generators, I have a few dozen of them sitting around as well.
90psi input gets you ~28 in/Hg vacuum, though it is not frugal with the air flow required.

I have lots of leftover fittings and pieces from salvaged equipment traded in with my employer.
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Joined: 12:00 AM - Jan 01, 1970

6:25 AM - Aug 09, 2018 #72

Earlier today, I cracked open the big air dryer to see what kind of shape it was in. The filter (the little part at the very bottom) was pretty well gooped with oil, but the inside of the housing had very minimal corrosion and should clean up easily.

The upper-left unit is a sort of physical water trap- air comes in the side, but the outlet pipe extends all the way up inside, nearly to the top. The incoming air hits the pipe, water collects at the bottom, and air goes through the top of the pipe and down to the filter.

The drain valve is a cheap little brass quarter-turn unit, that I'll probably replace with a stainless one with a good teflon seal.

The main thing I was curious about was the desiccant chamber. The end caps came off reasonably easily, and I was able to pour out the media with little difficulty.



The two immediate discoveries were one, whatever this stuff is, it's not silica gel.



They're pellets roughly the size of the beads from a beanbag chair, but made of something like ceramic. They're hard, opaque, and seem vaguely porous.

And two, apparently at some point this thing had enough moisture in it that the inside of the housing started to rust.



There was a considerable amount of rust-dust in with the pellets, and said rust didn't come from the input air, as the filter was lily-white inside and out, save for the oil which was turning a faint yellow.

So what likely happened was whoever had this thing last never changed the desiccant, or didn't change it often enough, and it got saturated, with the moisture starting to rust the container.

I got out a flashlight and a digital inspection camera (Milwaukee M-Spector, very handy, and has been worth every penny on multiple occasions) and looked around the inside. There's some pitting of course, but nothing terribly heavy- and the walls of this thing appear close to 3/16" thick.

So I misted some Ospho in there to 'cure' the rust (it converts the iron oxide over to iron phosphate, which is inert) and swished it around. By the time I get ready to use this thing again, it'll be thoroughly dry.

I was thinking, however, of swapping the existing filter chamber for the new one I just bought:



It's a bigger filter for one thing, but mainly has a pressure regulator built in. I plan to knock the operating pressure down to 90 psi rather than the straight-from-the-tank 120 or so I've been using, which should help my overall air consumption a bit.

That'd also reduce the strain on the desiccant tank a bit, which probably isn't necessary, but certainly couldn't hurt.

Getting back to the rest of the system, I had a chance to notch the back of my pegboard frame and get it, my guns and the tools back up in place.



It's pretty close to the arrangement I had before, but neatened up a little. I also got rid of a couple of things that no longer needed to be hung up- like the VM-68 valve tool, which when I took it down likely hadn't been off that peg in five years. 😁

The top of the bench itself is still a mess, as is the little shelf below the pegboard, but I'll get those sorted shortly.

I also put  the shelf back up that holds my 5C collet closers, which I had to take down to run the lathe-side air line drop:



That, too, needed a notch on the back to clear the hose, but it's all happy now.

And finally, I found a chunk of 1/2" plywood in the scrap pile that was already painted white, and I was able to trim it down to fit in the space under the bench.



At some point I'd broken the original outlet plate, so I picked up another one. I'd forgotten that I'd set the outlet boxes a bit high, and had to trim the old cover plates- I only did that some 18 years ago, my memory must be going 😁 - so I picked up a new one, ran it through the belt sander for a couple seconds, and voila`!



And that'll be about what it'll look like, save for the compressed air QD sticking out somewhere.



I keep thinking I should do something with the rest of the space, but it's kind of oddly shaped for drawers, I don't have anything tall and thin I need to store in there, it's too narrow for a trash can, etc.

Oh well, I can always add something later. 😁

Doc.
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Joined: 6:53 PM - Jun 13, 2016

2:38 PM - Aug 09, 2018 #73

Hey_Allen wrote: On a related note, if you (or any of the others here) have any use for some pneumatic vacuum generators, I have a few dozen of them sitting around as well.
90psi input gets you ~28 in/Hg vacuum, though it is not frugal with the air flow required.

I have lots of leftover fittings and pieces from salvaged equipment traded in with my employer.
Hey_Allen, Check your PMs
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Joined: 7:01 AM - Sep 16, 2014

7:01 PM - Aug 09, 2018 #74

If the inside of a _PRESSURE_VESSEL_ is severely rusted, you really should do (or have done) a Hydro on it. 

Cleaning it out with Oxpho and then tumbling it with ceramic media inside to knock the crumbs loose would be prudent, but then you pressure test the darn thing before putting it back in service.  Yes, it's small - but if it blows an end-shell off it'll still launch nicely, and I wouldn't want to be standing there...  If nothing else, you'll have to go change into clean shorts.  

If the desiccant media looks compromised it probably is - it's cheap, change it.  Buy enough to have two changes - Regenerate and inspect it, then bottle it back up for later.

I'd love to find the Molecular Sieve Filter media for doing Oxygen Concentrators (good enough for a cutting torch) and Nitrogen Generators (good enough for tire filling and paint-can inerting) - it should be cheap and easy to roll your own, and the control & purge valves should be off the shelf stuff too, but they hide it behind Handwavium for some reason. ("These are not the components you're looking for...") They want several grand for even the smallest packaged N2 Generator systems. 

Theoretically you can do both with one, but practically they would cross contaminate during the purge cycle.
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Joined: 11:09 AM - Nov 17, 2014

7:15 PM - Aug 09, 2018 #75

That filler looks weird...  
It sounds like LECA (ceramic balls used in soil improvement, and also as the filler in cinderblocks...) except it's usually brown, not white....     
It's good at absorbing water, but good enough to work in that filter?  
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Joined: 1:31 PM - Oct 15, 2015

11:50 PM - Aug 09, 2018 #76

ok doc, we need a complete picture of your markers wall
2003 BIOHAZARD ELECTRO COCKER
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Joined: 12:00 AM - Jan 01, 1970

6:31 AM - Aug 11, 2018 #77

BruceBergman wrote:If the inside of a _PRESSURE_VESSEL_ is severely rusted, you really should do (or have done) a Hydro on it. 

Cleaning it out with Oxpho and then tumbling it with ceramic media inside to knock the crumbs loose would be prudent, but then you pressure test the darn thing before putting it back in service.
-The vessel has no hydrotest data on it. Absent that data- IE, a factory specification, or specs the hydrotester can look up, any such test would be meaningless beyond "hey, it didn't blow up when we put 1-1/2 times what we blindly assumed was it's working pressure into it!" 😁

However, we do have other options. Out of curiosity I got out my ultrasonic tester and first checked the side of my Campbell-Hausfeld compressor tank, high enough that even if it, too, was rusty (it's not) the wall thickness would not be affected by it.


The result, a .125" wall tank- right at 1/8" exactly. And that tank was in fact hydrotested at the factory, and has hydro data.



So now we check the bottom of the dryer, where presumably the rust would be at it's worst:



Looks like that's either lost 0.002", which is entirely possible seeing how much debris I got out. But, this is also a far smaller tank- given the surface area, the relative wall thickness is technically greater- and one presumes there's a wider margin of safety than two thousandths of an inch.😋

Admittedly I didn't "scan" the entire bottom of the tank looking for the thinnest point, but as noted earlier, I inspected the inside carefully both by eye and flashlight, and using a digital inspection camera.  Pitting is mild and shallow, with no obvious "craters".

And, out of curiosity, I checked the side of a 20-ounce CO2 tank:



Keeping in mind that's aluminum, not steel, it's also rated to 1,800 psi, as opposed to the compressed air system's likely rating of 150 to 200 psi. And it's only 20 thou thicker.

I believe we can consider the used dryer to be fairly safe. 😁
Doc.
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Joined: 12:00 AM - Jan 01, 1970

6:36 AM - Aug 11, 2018 #78

Snowtroll wrote: That filler looks weird...  
It sounds like LECA (ceramic balls used in soil improvement, and also as the filler in cinderblocks...) except it's usually brown, not white....     
It's good at absorbing water, but good enough to work in that filter?  
-It's apparently called "activated alumina". Another variant of aluminum oxide, formed into very porous pellets. Apparently widely available and fairly cheap. Doesn't change color like silica gel, which is likely why this particular unit has an indicator window that does.

And, I'm given to understand, that once saturated, it doesn't necessarily need to be "baked" dry, unless you're in a hurry. If you have a low enough local humidity, you can simply leave it in an open container for a while- likely a week or three- and it dries out on it's own.

And apparently rather endlessly reusable as long as you don't get oil in it.

Doc.
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Joined: 12:00 AM - Jan 01, 1970

6:46 AM - Aug 11, 2018 #79

paintballsycho wrote:ok doc, we need a complete picture of your markers wall
-There's really not much to show. I've sold off all the really cool and fancy ones over the years...

One's a nearly-bone-stock Empire Sniper (only mod is an Inception trigger) the desert-camo Illustrator is an artifact of my very early playing days, originally owned by a local buddy who has since unfortunately gone off to that great playing field in the sky, the Angel is just a basic A1 I picked up cheap and incomplete, and had to fix- zero mods except for a custom made bolt- and the thing with the Flatline is an old basic Automag with an early Smart Parts red-and-gold splash kit.

I also have the TekAngel up at the top left, a basic parts-box 'Cocker, my well-modded but still kind of a junkpile Equalizer, an old Carbine, a custom Sheridan pump that I've had since about '97 and has never seen the field in that time, the barely-visible 007 is the "#1" marked ex-rental from the batch of Nelspots I picked up last year from a local late-80s era field, and the Splatty is just some random one I picked up over the years. 😁

There's a few hanging on the wall further down, but it's just an old Proto Rail, a parts-box Sniper, a basic VSC Phantom, an old Bushmaster and a couple other trinkets. Really nothing all that exciting.

Doc.
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Joined: 12:00 AM - Jan 01, 1970

7:14 AM - Aug 11, 2018 #80

Okay, now that the insert panel was made to fill in that little space under the workbench, I made a custom bulkhead fitting to attach to it, so I had a low-profile, yet easily accessible air connection right next to the main work area of my bench.



I had originally planned to add a drain valve to the underside of the bulkhead fitting (inside the panel) but due to the angle the air piping had to come out under the bench, and not wanting the hose to have a "bow" or low spot in the middle (where water could collect but not able to be drained) I had to have a bit of a rethink.

I made a trip to the local Homely Despot and bought some galvy pipe bits. If it works out, I'll likely replace it all with stainless, but I'll have to order that. This'll get me a "proof of concept". The pieces I bought fitted together about like so:



And attached to the back of the bulkhead fitting like this, so the tubing could have a nice gentle curve which would let water drain down to the valve. (Which is an old stainless quarter-turn which I had sitting around in my junk boxes for a while, and which I'd salvaged off a junk marker many years ago. Hey, packrat, y'know? 😋 )



Now, with everything hooked up, I could give it a test. The one end is still kind of dead-ended with the big ball valve, as that will head through the wall over to the new home for the compressor once I move it. But for the time being, with a male-male adapter like this...



I could feed air back in through one of the QD connections and pressurize the system that way.

The first try...



Resulted in this line blowing off at about 80 psi.



An easy fix, thankfully enough, because the subsequent three tries each blew off another line somewhere.😁

Apparently I wasn't tightening these badboys enough.

The fifth try didn't sink into the swamp finally held, pressurizing to, at the time, approximately 104 PSI.



I closed the valve in from the compressor, but left everything connected. I'll check it in the morning to see how much it's bled down, but already, two hours after that photo was taken, it's down to about 101. That's roughly equivalent to losing 36 PSI per day, meaning the compressor, which switches on at 80 psi and off at 120, would run slightly less than once a day.

That's not terrible, but currently, if I'm not using it, it runs less than once a week if left on its own. Probably more like less than once every two or three weeks, really.

Bumping that up to once a day would not be ideal- that would be a considerable increase in usage.

So depending on what it's like in the morning, I may have to get out the ladder and a bottle of Windex and go leak-hunting. 😁

Doc.
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