Need help with air supply for painting - garage setup

Yup, painfully aware of that. In your opinion do you think I need the cooling loop with the aftercooler?

Yes even more so than if you had a bigger compressor. Your compressor is going to be running more and working harder than a bigger one so the air will be more heated coming out. You need to have line length to let the air cool before it reaches the filters. You need water traps/ ball valves in the lines to drain off that water as it condenses.As important or more so than any filter.

Curious how do you know the temp will be only 10 degrees above ambient?
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Thanks for the feedback. I guess I have more to buy and do before I can start painting. I just need to figure out how to shoehorn 50' of copper pipe into my garage. I have very little wall space available. I'll probably end up hanging 2 x 25' coils from the ceiling in parallel with "T" joints to combine them.
...Curious how do you know the temp will be only 10 degrees above ambient?
I measured it with a laser thermometer when I built the aftercooler. I took multiple measurements at the outlet of the oil cooler, at the tank check valve, and at the tank area surrounding the check valve. I took the measurements after the compressor had run from full empty (!7 min), from 110 PSi to 135 PSI (3 min), and after it ran for about 20 min during blasting.

The temp at the oil cooler outlet remained fairly constant regardless of run time but the tank warmed up to ~20* above ambient after the compressor ran for 20 nin. The full-fill and refill temps were all ~10* under normal load conditions.

After rereading this thread, I can safely say your Compressor is the weak spot in your set up.

I started out with a horizontal tank compressor that couldn't satisfy the CFM requirements of the spray gun and tools I was using. It ran constantly when using my DA, which wouldn't run more than 5 minutes before I had to wait for the compressor to catch up. At the time I was using EVO spray guns that only needed minimal CFM to run but I was finding my spray pattern would change after a few passes on a panel.

It was then that I went online to auto painting websites looking for advice. Fortunately I found out about SPI Epoxy Primer during that time but I also began to understand the importance of having a compressor that puts out at least 20-30% more CFM than my gun requires. This prevents any changes in the spray pattern when the tank begins to empty and any pulsations when the compressor kicks on.

That is when I sold my old compressor and bought the one I am still using today. It cost just over $1000 but that was over a decade ago and I was really stressed to spend that much at the time. The difference was amazing and I am so glad I bit the bullet and spent the money, hence my tendency to immediately suggest a bigger compressor to anyone trying to get by with "just enough."

It sounds as though your are committed to giving the compressor you have a try and I understand that, however if you find yourself constantly struggling to get good results with your spray gun, it's probably the compressor and not the gun.

Just my $00.02 and worth everything you paid for it. :)
@ '68 Coronet R/T
I couldn't agree more with your assessment and I appreciate you taking the time to sum it up. I too learned too late (mostly on the SPI forum) that I bought the wrong compressor for my needs. My current project budget is quickly dwindling due to the air delivery equipment as well as the epoxy and fillers I still need to get. If I had the cash I would definitely upgrade to an 80 gal/5-7HP/2-stage compressor but alas, I'm stuck for the time being.

I spoke with Barry at length about my plans and the equipment at my disposal and he is of the opinion that it is doable albeit with some concessions to inconvenience. For now, I will only be spraying epoxy, poly, and 2k primer so I will give it a go with what I have. If I find that an upgrade is a must, I will figure out how to do it.