Air Compressor aftercooler Info thread

I host it on youtube and then post a link.

sorry for delay. i had previously posted it elsewhere on here i though. anyway here you go!


I read through a lot of the comments. You guys are very smart. Great info. I wouldn’t want to try to alter my compressor in any way. I was looking at some of the expensive ones that have the silent technology and auto drains. [EMAX 80 Gal. 5 HP 3-Cylinder 1-Phase Silent Air 175 PSI Electric Air Compressor with Isolator Pads and Auto Drain

But as far as the copper vertical U drops with drains at the bottom. It seems to me that the surface area of the copper cools the compressed air. But would a second tank have a lot of surface area also? And they have a drain already built in. The second tank might be quick easy and maybe cheaper? All my time is going into turning a dirt floor carport into a concrete slab CNC plasma shop.

The refrigerated air dryer too.

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A second tank would help drop your air temp. I can’t tell you which would work best. I have after coolers post tank with a fan to drop the temp to around room temp before it goes in my refrigerated dryer. They have spec on input temps. I didnt like the cost of copper pipe nor did I have the wall space.

Keep in mind anything you do to dry air will restrict flow. I have dry air tanks I pull from without restrictions that are after my air drying equipment. You may want to consider a bead cell dryer and filter as the last stage.


I was moderately successful, primarily relying on my auto drain of the tank.

Your second tank will have the advantages to your set-up:

  1. You will get some added temperature drop.
  2. Another auto drain will take more water out of the system.
  3. The extra storage of compressed air will help with better volume on the short run but only until the compressor kicks in. Then you will see that your compressor will run twice the time to get up to full pressure. That could be a disadvantage (increased temperature in the system).

I am not sure if you are saying “I plan to use the refrigerated dryer” or if you are saying “I also plan to wait on the refrigerated dryer.”

I would say, follow your plan but prepare for a backup plan if you see moisture causing issues with your situation.


here is a video of my system…


You are 10000% correct on the ore tank. It made my pump go out on my I.R. comprrasor.

Got a new Quincy, amd will be running post tank with the cooler now

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I was looking at an EMAX today as well, the 10HP 80 gallon in particular. I’m definitely looking seriously at that compressor, 38CFM@100PSI is more than enough air even for my sandblasting and it’s rated for 70,000 hours with the silent air system (50,000 without it). Not cheap but it would probably be the last compressor I would ever have to buy.

Back to the aftercooling…
I think the air cooler I had mounted to the front of the pulley housing on mine will have to be moved. My head temps went up 30-40 degrees (air temps after cooler were still less than 100 though) and yesterday my compressor blew the head gasket. I’ve had this compressor for 17 years and put MANY hours on it so it could just be age but it’s a bit of a coincidence for my tastes. I can’t fault the compressor, it’s been a real trooper through the years. Ordered the new head gasket today and I’ll install in and put the compressor back in service.


Just beware 10HP motors on single phase can be short lived, depending on use. I have a friend that has one and has replaced the motor several times over the years. This is in a body shop and gets a fair amount of use. I have the 7.5 HP made by Eaton and it will run a blast cabinet fine, will even cycle but not very often.

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Did you have a cooler between the pump head and the tank?

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Yes, airflow went from head to cooler to water separator to tank. @Knick the EMAX has a killer warranty, but I will look into the reliability of the 10HP motors before dropping that kind of money on a compressor.


The extra pressure on the pump is the reason I removed mine. I have a two stage compressor rated at about 24 cfm 7.5 hp. The first pump lasted about 25 years. I had a bearing go down while I was out of town I had forgotten to turn in off


I think this thread might be heading towards at least one anecdotal conclusion: aftercooler between pump and tank has the potential to create backpressure, increased run-time, & heat buildup in excess of what exists without said intercooler, and possibly outside the planned range for which the compressor was engineered.

But I’m not gonna be the one to say it and be labelled :supervillain:


I don’t think pressure was a factor at all, it’s an air compressor making pressure is it’s sole purpose in life. Mounting it directly in front of the compressor so the pulley fan is moving air through the heat sinks on the head after it has traveled through the heat dissipating fins of a 300 degree cooler on the other hand “may” be responsible for a 30ish degree increase in head temps that “may” be responsible for a blown head gasket on a 17 year old heavily used air compressor. It could also just be the moons of Sagitarius are misaligned with the dawn of Aquarius…

A after cooler between the pump and tank will increase the back pressure on the head. I installed one on my compressor it nearly doubled the cycle time. Honestly in my opinion with the tests I did on mine a after cooler is better off post tank.


is the head and deck surface flat? you might want to double check that

I’ll clean them up and run a straight edge over them, but honestly whatever condition they are in the new head gasket is going on and it’s getting bolted back together. It didn’t look warped to me at first glance, but I didn’t take a particularly close look beyond the blown gasket.

I had a two stage given to me with a blown headgasket. Surfaces appeared flat to me. I went through 3 or 4. Tried flattening surfaces. Tried coppercoat. They just kept blowing out. Finally gave up and put a cheap v twin cylinder on it from harbor freight and never looked back. 160 bucks for 17.3 cfm at 90 psi and 145 max operating pressure. Been using it several years and been rock solid.


I’m using the same pump. Has worked well for me.


Been real busy the past week but I did replace the head gasket about a week ago, running like a champ and substantially quieter. Still looking to get a second compressor, this one only runs 11.5CFM@90 and I have my eye on a Quincy QT54 that puts out 15.2@175. That would give me more than 25CFM which should be enough to keep up with the blast cabinet.