Air Piping and After Cooler, My Version

[MrSurly]

I got a deal (Craigslist of course) on some stainless tubing, so I set about building the piping system for the shop with it. In order to keep costs down I decided to weld the tubing rather than spend a ton on compression fittings.
Of course, I didn't know HOW to do this, but the welding machine I have says 'no problem!" right there in the manual...it claims we can do this.
So I set about teaching myself to TIG weld, primarily schooled on youtube.

It took a bit and held a few surprises, setbacks, but I eventually got it all done.
The only component missing is a ball valve that I will add in the vertical riser.

The shop is a 30 X 40 X 14 post frame that I built last year. it is spray foamed as you'll see and otherwise unfinished inside.
The compressor is an 80gal SpeedAire 5HP 1725 RPM rated 17 CFM.
The install is to support my car restoration plan including the occasional sand blasting, blast cabinet, air tools, painting. Quick connect drops and fittings in six places, with one of them specifically piped for higher flow for a sandblast pot and a half-inch QC.
I'm adding a cooler between the pump and tank (after cooler) fashioned from a repurposed hydraulic oil cooler.
Just under the cooler, there's the (relocated) check valve and a drip leg which will get an auto dump valve, with another on the tank drain.
The cooler and the associated piping at the compressor is 3/4 ID copper and 1" ID copper, brazed. From there, the piping is 1" OD 0.083 wall 316L SS and goes vertical to 13'. The tubing is fairly heavy wall but not heavy enough to be threaded. Every connection is either TIG welded to another tube or to a threaded fitting to allow connection to another.
It then runs as a trunk line along the West wall 40' dropping 12" in the process.
At this low end there is a tee, dropping to a drip leg to drain the trunk, and a riser that crosses over to the next bay, dropping to a cross with QCs inside and outside the wall.
Along the trunk line, there are three topside ports, 180 degree turns down to two drops and the third runs up and over the shop, dropping down along one lift post and also over to the East side workbench area.
It is my intent that the aftercooler will be able to knock most of the water out
and into the dripleg before it gets a chance to get carried up to the trunk line. The tall vertical should help drop some out (back to the first drip leg).
The trunk line is set up to drop any water to the drip leg at the South end of its run. Hopefully none of the topside ports will get any water, but every QC drop has a drain just to be sure.
The copper piping at the compressor is not pretty, but every effort was made to drop moisture into the drip leg and not into the tank or line. I relocated the check from the tank and installed it before the drip leg, before the tee.
The main reason I went this way (rather than just connecting to the port on the other side of the compressor) is to make the connection at this 3/4 port rather than the provided 1/2" on the other side.
Pictures to follow... they are on my phone; I'll upload them today






More pics coming....





























At this point the piping is operational; the temp difference top and bottom of the cooler is huge. I'll have to get a good thermometer to check it but suffice it to say that its huge.
Remaining detail: I am going to cut in a ball valve in the riser from the compressor tee; I'm going to replace all the pipe straps with proper clips; I will fabricate a bracket to clamp the drop to the two-post lift and a bracket to provide support to hold the cooler.

EDIT FOR NEW READERS OF THIS THREAD: All of this copper piping just below the after cooler was tossed out because it was too ugly, too cramped (and I just didn’t like it). I replaced it with a new all-stainless redesign. This starts about post #40

 

[Bretny]

No pics?

 

[MrSurly]

No pics?

added a few

 

[Musicinabottle]

What was this thread about again? ...............

 

[930dreamer]

Are you going to get enough air flow with it so close to the wall?

 

[LXCam]

Holy **** that was a ton of welding and fit up. Nice job!

 

[mike93lx]

Hard line from the comp to the distribution? You should have something flexible in there

 

[MrSurly]

Are you going to get enough air flow with it so close to the wall?

I do wish I had mounted the compressor a bit further away from the wall but I didn't think far enough ahead. I can, if it seem necessary, either drill new anchors to move it OR, I can trim the wall foam insulation back a bit.

At this point it seems pretty effective as is at lowering the temp.

 

[dfiler2]

I'm impressed, nice job!

 

[MrSurly]

Hard line from the comp to the distribution? You should have something flexible in there

I've given that some thought and may add a hose later. the way it's piped now, the riser is supported vertically at the top but not anchored otherwise and can 'float' laterally so the horizontal is safe. The vertical axis could give me an issue down the road.

 

[larry4406]

Where did you source that heat exchanger?

 

[MrSurly]

Where did you source that heat exchanger?

There's a thread here.
From an old broken down bobcat:

 

[MrSurly]

Where did you source that heat exchanger?

There's a thread here.
From an old broken down bobcat:

 

[May Pop]

Nice job on the whole project. I like the way you teed up as Ive found thats the best for keeping the air dry. Was the stainless donated or bought cheap. Are the fitting a slip on?

Ron

 

[MrSurly]

The stainless popped up on CL for $1.00/foot. I had been pricing black iron and copper at way more. None of the fittings are slip-on. Actually none of the fittings are made for the purpose. Most were **** welds but the 1/2 ******* would actually fit inside the tubing with some persuasion. That made those easier to weld for sure.
Noteworthy: The tees and ******* etc for welding to this all had to be stainless of course. Much to my surprise, going to an industrial metal supplier locally, I was able to buy the SS fittings for *HALF* what Lowes was charging for *Galvanized*

 

[oilslick]

Bet you could weld a pop can to a screen door? Seriously nice fitting and welding.

 

[May Pop]

The big box store charge more than McMasterCarr charges for black fitting also.
McMasterCarr is X3 for SS fitting over black. You got a great deal on all the material.

 

[kbs2244]

That is very well done.

My only comment would be, as said, flex between the compressor and the piping, and a 45 vs 90 degree for the hose hook ups.
It just lessens the stress on the hose.

 

[pattenp]

I do wish I had mounted the compressor a bit further away from the wall but I didn't think far enough ahead. I can, if it seem necessary, either drill new anchors to move it OR, I can trim the wall foam insulation back a bit.

At this point it seems pretty effective as is at lowering the temp.

Too close to wall. Should be around 18" to 24" away from wall for good air circulation from air to cool compressor head. Read the install manual.

 

[MrSurly]

Too close to wall. Should be around 18" to 24" away from wall for good air circulation from air to cool compressor head. Read the install manual.

I actually looked that up, for grins. The manual calls for 12" not twice that but it actually only has about *half that. I may consider moving out a bit *IF* there proves to be an issue with cooling. It is truly much more likely that I will install a simple electric fan (pressure switched) adjacent to ensure adequate air.

 

[exranger06]

Keeping the compressor away from the walls is also necessary for servicing. Do you have enough room to change the belt where it is?

Off-topic: I thought it was against building code to have exposed spray foam insulation due to its fire resistance (or lack thereof). Do you plan to cover it up eventually? Ok I'm done criticizing now. The piping looks really good.

 

[MrSurly]

Keeping the compressor away from the walls is also necessary for servicing. Do you have enough room to change the belt where it is?

Yes, as a matter of fact, I noticed that the motor sheave needed to be moved to re-align the belt when I was taking measurements for the cooler. the cage assembly has just enough room for removal. This was the way I planned when installing, of course but in retrospect I wash I'd given it a few more inches.

Off-topic: I thought it was against building code to have exposed spray foam insulation due to its fire resistance (or lack thereof). Do you plan to cover it up eventually? Ok I'm done criticizing now. The piping looks really good.

The building passed city inspection with no issues. The inspector stated that if it were a *residence* that it would have to be covered by 1/2 Sheetrock or OSB. Because it's a detached garage, he said the covering is not mandated. I don't currently have a plan to cover it but I will likely drywall *some* of it just to create a fab shop area.

 

[MrSurly]

Following up just to complete the install. I did cut in a cut-oiff valve and also added a somewhat-easier-to-read gauge for my old eyes.

 

[larry4406]

I don't think your gauge is big enough. I thought everything in Texas was supposed to be big?

 

[Movover]

I don't think your gauge is big enough. I thought everything in Texas was supposed to be big?

I thought it was a large weight scale... geesh I can read it from Maine

 

[pcmeiners]

Pressure gauge looks blurry to me, needs to be bigger. Nice gauge. I have one half that size, I believed it was large, oh well.
Welding looks good.

 

[mda2000]

Welding looks amazing! How's your cooler doing at removing moisture?

 

[Firebrick43]

What ss rod are you using? Either to much heat,to large of rod, went over a bead a second time, or steel/309L? Normally 308 or my fav tigtectic 680 is bright and shiny with the rainbow colors.

Also way to much heat with the brazing. Oxy torch or tig? Carefull use of silcone bronze can look stack of dimes and silphos brazing shouldn't spread that far.

Nothing looks structurally deficient however.

 

[MrSurly]

Nothing looks structurally deficient however.

Well at least there’s that!

Also way to much heat with the brazing. Oxy torch or tig? Carefull use of silcone bronze can look stack of dimes and silphos brazing shouldn't spread that far.

Sil-phos (StaySilv 15); Oxy acet rig. Waaaayyy out of practice!

What ss rod are you using? Either to much heat,to large of rod, went over a bead a second time, or steel/309L? Normally 308 or my fav tigtectic 680 is bright and shiny with the rainbow colors.

Now THIS is a subject I want to explore with someone who knows! If you read the thread, you see that I’m teaching myself, and my instructor is a *******.
I have been *trying* to get the rainbow colors...
watching videos, unable to figure out the exact issue(s).
The last few pics above were not double passes, they were not knowingly cooked though some others were, especially the 3/4 Tee. After a while I finally got in tight enough that I got a few narrow beads, had good puddle control, seemed as good as my best so far, but still turn gray.
If you are up for it I’d like to pick your brain on this.




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[MrSurly]

Here’s what I’m working with:


316 083 wall
316 1/16 rod
304 fittings
2% Thoriated tungsten
100% Argon
300A Lift TiG machine
No foot control

I don’t know if I’m using the wrong filler, too small a gas lens, too little gas flow...
I have a 5, 6 and a broken size 7 gas
Lens.
I have more and larger “gas lens” ordered in various sizes.

When I watch the you tubers who all create the rainbow beads I see a few differences in method but it doesn’t seem like any of them would be the obvious difference in color.

1. They all are using monster size gas lenses
2. They all are using back purge
3. They all have foot controls (and most have hi-freq start)
4. Positioners used on pipe stuff.

Any of these a glaring “cause” potentiallly?



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[camaro77]

I would tig this all up with prob .045 or 1/16 filler rod SS just pretty much need a rod with a higher # than the material so if you tube is say 304 I would use 308 or 316. def way to hot I would be prob about 70 amps and get a puddle going then pulse with my foot gray is not good need a nice rainbow. I use #7 cup with a gas lense for pretty much everything I do im cheap so I only flow 12 inches of argon when I weld all my stuff.

 

[dr_clyde]

I agree those welds are too hot. What amperage are you running? Remember that heat input is a function of amperage and travel speed, primarily. If you run high amperage, you need to move fast, and vice versa.

The "rainbow" on stainless welds is due to oxidation at specific temperatures. The gray color is too hot. If it crystallizes and makes what looks like sugar in the welds, that is excessively hot. This is mitigated primarily with heat input, but external shielding is also important.

Ideally the weld should be silver, no color at all. Some color is fine with most applications of SS, especially for air lines. It is pretty difficult to avoid oxides on the exterior of a weld without a purge box, trailing shield, or purge chamber. Most of the time there is not a problem with that.

I would personally run that with a #6 gas lens, 1/8" electrode, ( I prefer ceriated, but it doesn't really matter on DC), and I'd use a foot control if I had one. Amperage range between 75 and 125. Since you don't have a foot pedal, I'd set the machine to 90 to start and bump up or down depending on how it goes.

I like a 1/16" rod for general smaller work, since you're welding 316 you should technically be using 316 filler, but for a simple air line, any 300 series will work fine.

Here are some sample welds I did on some .065 wall sanitary tubing. I weld a lot of stainless. IIRC, these were welded at 34 or 35 amps, walking the cup.

These are on the verge of being too hot, but I'm also doing full penetration welds, and the inside is the important bit. The outsides get polished and passivated. These are purged before and during welding.

 

[dr_clyde]

I don’t know if I’m using the wrong filler, too small a gas lens, too little gas flow...
I have a 5, 6 and a broken size 7 gas
Lens.
I have more and larger “gas lens” ordered in various sizes.

When I watch the you tubers who all create the rainbow beads I see a few differences in method but it doesn’t seem like any of them would be the obvious difference in color.

1. They all are using monster size gas lenses
2. They all are using back purge
3. They all have foot controls (and most have hi-freq start)
4. Positioners used on pipe stuff.

Any of these a glaring “cause” potentiallly?

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None of these things make much difference in the hands of an inexperienced welder. Its all technique.

If I could recommend 2 tips for stainless tig, it would be to weld hot enough to move quickly, then move quickly. Then, keep a tight arc. The tighter your arc is, the more intense and focused it is on a smaller point.

Monster gas lenses do help with oxides, but you can get perfectly acceptable welds, even exceptional welds with common gas lenses and cups.

Back purge is required in some situations, where the inside or backside is required to be clean or fully fused. Not required to get nice looking fillet welds on a socket weld, at least on the outside. I purge most if not all thin stainless tube, because it aids in puddle control and penetration.

Foot controls are handy, but I usually do pipe welding without one. I like them for shop and bench work, but position welds are all lift arc with fixed amps.

Positioners are for money making. They save so much time. But they aren't required by any means. Most in field pipework is done all by hand. They only break out the positoners and mechanized welding equipment if there is lots of welding to do and it will save an appreciable amount of time. I have a turntable positoner, and use it when appropriate, but rarely on pipework.

 

[MrSurly]

I would tig this all up with prob .045 or 1/16 filler rod SS just pretty much need a rod with a higher # than the material so if you tube is say 304 I would use 308 or 316. def way to hot I would be prob about 70 amps and get a puddle going then pulse with my foot gray is not good need a nice rainbow. I use #7 cup with a gas lense for pretty much everything I do im cheap so I only flow 12 inches of argon when I weld all my stuff.

The rod is 1/16 316ss
Machine is set on 60a for all of the welds that I’ve done on this. I don’t have a foot pedal, it’s a lift Tig with a little knob on the torch. The knob switches it on/off but I can’t tell that the knob’s range of rotation has any effect on the heat. (I’m not looking up at the box to see)
I tried at 90a at first and man I cooked some stuff! I’ve been guilty of using that busted cup as well, surely that’s not helping.


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[ez-duzit]

dc--pretty work.

 

[dr_clyde]

The rod is 1/16 316ss
Machine is set on 60a for all of the welds ghost I’ve done on this. I don’t have foot pedal, it’s a lift Tig with a little knob on the torch. The knob switches it on/off but I can’t tell that the knob’s range of rotation has any effect on the heat. (I’m not looking up at the box to see)
I tried at 90a at first and man I cooked some stuff! I’ve been guilty of using that busted cup as well, surely that’s not helping.


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If you're cooking it at 60 amps you're going too slow. Keep a tight arc, move faster. You may need to bump the amps up to allow the faster movement, but decrease the overall heat.

Its possible your torch has an amperage control on it, but it may be just a gas valve. Post a pic of your torch?

 

[dr_clyde]

I should point out that my welds while done at 35 amps, were done fairly slowly to allow the metal to melt all the way through.

If I was capable of moving faster and doing it in a controlled fashion, I.E. an orbital welder, that same joint would be done at 100 amps.

Amps + travel speed = heat input.

 

[MrSurly]

None of these things make much difference in the hands of an inexperienced welder. Its all technique.



If I could recommend 2 tips for stainless tig, it would be to weld hot enough to move quickly, then move quickly. Then, keep a tight arc. The tighter your arc is, the more intense and focused it is on a smaller point.



Monster gas lenses do help with oxides, but you can get perfectly acceptable welds, even exceptional welds with common gas lenses and cups.



Back purge is required in some situations, where the inside or backside is required to be clean or fully fused. Not required to get nice looking fillet welds on a socket weld, at least on the outside. I purge most if not all thin stainless tube, because it aids in puddle control and penetration.



Foot controls are handy, but I usually do pipe welding without one. I like them for shop and bench work, but position welds are all lift arc with fixed amps.



Positioners are for money making. They save so much time. But they aren't required by any means. Most in field pipework is done all by hand. They only break out the positoners and mechanized welding equipment if there is lots of welding to do and it will save an appreciable amount of time. I have a turntable positoner, and use it when appropriate, but rarely on pipework.

This is the kind of info I need. Those are beautiful welds! At first I watched all the videos and am blown away by some of you guys. This “Kanekid welding” guy is welding incredibly thin stainless (looks like a Thermos bottle) making rainbows that would put My Little Pony in the stable and the machines showing 90amps when he’s doing it!

I have another piece out there, much thicker stuff (.160”) and I need a **** weld. Because it’s thicker and fit tight, and I’m ‘cheating’ I practiced autogenous welding on it at 90a, rolling it on the table (my positioner).
At first I got rainbow

Then slowed just a little and went gray

So then I started experimenting on this piece trying a weave, circles to see if I could make a broader weld without filler just to learn. I learned right away that *this is how you overheat a weld zone!



This is helping, guys. I’m learning something. First I shouldn’t have started my training on thin stuff(!)
I think that I’m learning that running a little hotter (if I can nail the travel speed) I could do better... right?
Importantly, I found that it NOT because I have the wrong rod, the wrong gas, the wrong tungsten, the wrong machine.
What I’ve got IS capable and just waiting for me to catch up



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[MrSurly]

Its possible your torch has an amperage control on it, but it may be just a gas valve. Post a pic of your torch?

Pic
Has off and 1-10
I cannot discern any effect on the power, but someone familiar would, I’m sure.




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[MrSurly]

I like this thicker stuff!
These pieces are from different scrap stuff from work, repurposed pieces, much of it ugly... but all of it priced right!

The ugly will be turned off of the plug piece.

After cleanup