Air Compressor aftercooler Info thread

I’m going to condense some of the information I came across while researching this and searching for all the fittings. I don’t know about most of you, but I’m constantly amazed and frustrated by how much a person needs to learn while undertaking a hobby such as ours.

Why do we want this? Compressed air come out of the the pump HOT and when it cools, water condenses. We basically have three choices on where to cool the air.

  1. Before the tank (aftercooler)
  2. In the tank (just wait for it?)
  3. On the way to the tool (large run of copper pipe turns with drip legs.

You can drop some money on a refrigerated air dryer and just be done, probably the best overall bet. But I think most of us are engineering some other way to cool our air.

Is the aftercooler worth it? I think so. My 135 PSI 60 gal 5 hp Ingersoll Rand runs for 45 seconds to go from 100 PSI to 135 PSI. With everything starting at ambient temperature, I collect almost a teaspoon of water. That’s water not going in my tank and I’m happy about it.

Once everything heats up, it doesn’t collect as much water, cause it’s not cooling obviously. So a fan is needed on the cooler for extended run time. Initially I got a 240v dc concertgoer to wire right to the compressor so the fan came on automatically and shut off with the pump. But now I’m planning on having my fan manually controlled so it will run after the compressor shuts off so there’s a greater chance my next cycle will start with an ambient temp cooler and not one that’s still warm from the previous cycle. Plus keep it cooler on extended runs.

First, my saga. Skip to the parts list if you so desire.

I really did not want to learn about fittings and tubing and all that crap. I wanted to put an after cooler on my compressor by following a set of instructions. Yeah, no.

I don’t think any two different model/brand compressors are going to be the same when it comes to the pump outlet and tank inlet, but aside from that the rest is pretty straight forward. Most of the compressors we are using are 60 gal and up and have 3/8 ID (1/2 OD) Tubing from pump to tank so that’s what this is based on. If your tubing is smaller these fittings are not right for you!

My IR 60 gal had a very short run of copper tubing with double flares at each end. The pump outlet had a 3/8 male fitting to a 1/2 female inverted flare fitting. I probably could have taken that adaptor out but the tank input at the check valve had the same female inverted flare so I wanted to find the right adaptor anyway to avoid messing with the check valve and safety relief on the brand new unit. It also appears that you could single flare some tube and just be done with it, @sr71xJet just flared his on the same double flare that I have and hasn’t had any issues. But I was paranoid and had to get the fitting.

The first step is identifying your pump output and tank inlet locations. On some compressors these are easily visible, like my IR 60 gal. Others they are hidden beneath a fascia, like my Husky 30 gal.

Once you know where the outlet and inlet are, take off the fittings and determine what you need to hook right to the pump and tank. As long as you can get it to 1/2 flare threads the rest of this will work for you.



This appears to be the most commonly used cooler. Construction seems excellent, lots of passes through the cooler. This is what I used as well. Be careful tightening the fittings onto it. I heard a slight creak when I was finishing up. Looks like you can twist hard enough to break off the connections so hold the fixed end of the coolers fitting when tightening.

Tubing for the runs in between. Type L tubing is a little thicker. May not be necessary. 10 feet was plenty.



This was what I needed for my specific compressor. It had the double flared 1/2 tubing. I found it at Pirtek. They have several locations. I can’t link to the item, but it showed on my invoice as PS-08-08 ADAPTOR SAE INV FLARE X JIC. This fir the tank outlet and pump inlet and connected directly to my 1/2 flare fittings for the tubing I bought.


To go with the flare nuts, use any 45 degree flaring tool.

(The flare nuts and flaring tool can but substituted with 1/2 compression fittings. I chose to flare because it had a lower profile and looked a bit cleaner. I don’t have any knowledge on compression fittings. If someone wants to add a parts list post it up.


I’m going to add some of these elbows to clean up the connections at the cooler. The tubing does not want to make sharp bends without kinking, unless you have the proper bender. I do not.


These are the fittings you want to adapt the 8AN on the above cooler to the 3/8 NPT you will need. This will let you add your water separator right onto the swivel fitting.

@timtiminy is running 1/2 flare rod nuts right off the 8AN Fittings and reports no issues with it. Specs show 8AN is 37 degrees vs 45 degree flare fittings. Visual inspection of the fit up looks correct as well. Looks like either will work.


This is what you need to come off your water separator back to tubing to go to the tank.|PIP|Internal||emailafriend|207176505?cm_mmc=ecc--THD_EMAIL_A_FRIEND--V1_M1_CA-_-VIEW_ITEM


This is what you need to come off the tubing into the cooler from the pump.


Get one with 3/8 inputs to minimize the use of adaptors. This is just an example of one, there are tons out there to choose from.


This is the one I bought for my off road rig but repurposed it. Any 12V fan of similar design should work.

120/240 to 12V DC ADAPTOR

You can wire this right to your compressor so your 12V fan only comes on when the compressor runs.


I just bent and drilled some flat bar and used zip ties for now. Looks like 8-32 or 6-32 machine screws would work for holding it still without risking melting. For mounting the fan, well I’m not there yet but will update when I do.

I think that’s it. Post up questions or make suggestions and I’ll add them. There’s got to be people out there that need to see this all spelled out to make sense of it. I know I did.


Very nice write-up and reference for all the parts. You’ll save someone a ton of time if they want to go this route. I’m a garage hack so I rely on removing the water just before it hits the plasma or other tool (like the blast cabinet or powdercoat gun). I do have an automatic tank drain though so it doesn’t collect for long periods in the tank. That’s working for me but I probably have spent as much on inline dryers as I would have on a proper tubing or cooler setup :smiley: I just did it $40 or $50 at a time with each tool puchase.

Thanks for the great write-up and parts list. Been looking a this for a while.

I’ve seen where folks have just mounted the after-cooler on the outside of the compressor fan. I was going to try that with mine. Might as well take advantage of the air movement.


That looks great. I also saw the use of the factory fan and wanted to do that at first. But I had already bolted my comp into the corner and accessing it would have been a pain.
The 12v fan May move a bit more air and you can keep it on after the cycle to bring the temperature back down a bit more.

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Good write up.

Great write up but really…

Not knocking your setup but the poormans air cooler works fantastic and is always running. Sometimes simpler is better.


After experimenting with the after cooler for a bit I totally see the value in your style of setup as well. I think once you run the compressor hard enough and the after-cooler can’t keep up, the next line of defense would be what you have.

I really wanted to avoid having a big run of pipe on my walls. I think time and effort wise they may be close to equal. We will see how all this shakes out long term.

I’m thinking of doing something similar to this. My workshop is built on a block foundation with a crawlspace that is a pretty constant 56 degrees year round. It’s only about 5 feet tall in the area under the CF, but, if I go from 1/2" air supply and use 1" copper on the verticals I think I get an effective length of 20 feet for each vertical. If I do this, however, I’ll need some sort of auto drain and I haven’t figured out how to do this inexpensively.

I certainly don’t want to go down there to open the drains! I’ve got spiders down there that growl at me!

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I think Harbor Freight has an inexpensive one that is typically used for the tank but could be plumbed into your crawlspace drain. It gets triggered by the on/off cycle of the compressor and opens for a few seconds. Worth checking out.

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I didn’t find it. Do you have a link?

Doesn’t look like they carry it anymore (stock # 68244 according to pics I found on line) but HD has a relatively inexpensive one.


I did find one on Northern Tool, but too expensive if I need a drain per vertical. I’m now looking at some low cost 1/4" solenoid valves and I’ll control them from the area above (where my CF and associated HW & electronics are located). I already have a 12V supply for the ‘auto filler’, so I can use that to drain the dryer.
This all still in the conceptual stage (AKA, I’m trying to think how I’ll pay for it), but it looks feasible and effective.

Brown fox this is what I am getting on my system after letting the compressor run and cycle for 45 minutes with the fan set to come on and off with the activation of the compressor.

image image image image image image

The ambient temperature here today is 82F

As you can see as the air moves through the after cooler with the fan, it gets cooler and cooler at each stage. You definitely have to have a fan of some sort in order for it to be productive at all.

“Dang, i just realized thats a 190deg difference from output of compressor to going back into the tank. The water separator is also pulling out a lot of water which otherwise would be going into the tank”.

Sorry for pictures being sideways. The forum is doing this.


Wow, what a great perspective, showing the temperature gradient. I’ll bet it would REALLY interesting with one of those Infrared cameras!
Thanks for posting!

I actually have one on a drone i fly for a company. When I get back from Guam, ill see what i can do to take a few snapshots of it.

Oh yeah I know I need the fan. Just thought it would be best to have it be able to run all the time vs only with the pump. Those temp readings are great though! Looks like only having it with the pump on is more than enough.

well, will see when summer really gets here and the heat. That will be the real test. Right!

I got to say that it is great having this forum. Everyone is helping everyone and Langmuir is learning what to do to make their product that much better…and i believe that someone here is going to come up with an idea to make this table at least a 4 X 8 size.


Just wired up my DC converter to the motor and zip tied the fan in place. Ran a cycle and works like a charm. Definitely makes a difference and only running when the pump is on should be plenty. Will be nice not to have to hear another fan or have to keep flipping switches.

That 240v DC converter is a sweet solution.


Great. Good to hear