Air Compressor Advice Needed from Experience!

[Skep18]

So, I'm setting up my 60 gallon Craftsman Professional compressor. I am trying to make the driest air I can as I'm trying to get into paint. I saw a nice writeup on this forum which referenced a guy on YouTube called Chevahaulic. He demonstrates a setup using an old car A/C condenser coming straight off the compressor head, leading to a tank, going to the main compressor tank. Now, I plan on having other driers in my setup, post-tank, but my question is in regards to my condensation tank.

If I run compressor > condenser > Tee fitting connecting both a (drain tank collecting water via gravity) and (60 gallon air tank) obviously everything would be at operating pressure, which for my tank is 150 psi. I bought a Harbor Freight 5 gallon portable tank to put in place for my water catch can. I would drain it every other day or something, but my problem is its "technically" rated for 125 psi.

I want to throw out here, I am an engineer, and having gone to school, I know things are rated for a decent bit more than they can physically hold. Would it be unwise to hook this under-rated tank to my system knowing it is going to hold more pressure than it is rated for? Surely a welded tank can hold up to snuff... My main reservation might be if, over time, it rusts, since it is a drain tank, it might be a problem? But even then...

Any help people can provide is appreciated.

 

[Skep18]

I've thought about, as a safety thing, just going compressor > condenser > 60 gallon tank. And at the petcock of the tank, running extra drain lines to collect all the moisture, enough to where it won't sit in the tank. Any thoughts on this? This is probably the way I should go. This way, I could probably even drain this to outside my garage or something.

 

[HAP]

Regulate to that particular tank... otherwise, you or others will never feel/be safe around it in the back of your mind.

 

[1953mercury]

I wouldn't be to concerned by the 25# difference. Burst pressure is probably at least double that (250-300psi). Mike

 

[PT Doc]

Failure pressure could likely be many times over the rated. BUT why would you do this? It's a Chinese tank so it's not like you can call someone to check. You could buy one and have it tested to failure but that would be the only way I would fell safe.

Can't you find a small tank that is higher pressure?

 

[never enuf time]

Why do you have to be at 150 psi ? turn down to 125 psi good to go.

 

[pop pop]

its "technically" rated for 125 psi.

I want to throw out here, I am an engineer, and having gone to school,

And just what engineering school did you go to may I ask to not already know the answer to this question?

 

[Kevin C]

What matters is that the air going into your last dryer is as close to room temp as you can get it when you are running a spray gun. In most cases a 60 gallon tank and a compressor that is running intermittently will get you pretty close. 15 to 20 feet of metal pipe before your last filter should get you very close.

In my experience, after coolers are nice if your running air tools and sprayers at the same time and your compressor has to run a lot. Not as big issue an in a single person shop.

in either case, if you want to insure that you wont have a moisture problem you should consider some sort of dryer. I bought a used refrigerated dryer. A desiccant dryer is another option. Unless you cool the are you just compressed to below ambient ( or use a desiccant) its really hard to guarantee that you wont get moisture when painting.

At work we have inter coolers and after coolers on our compressors. That goes into 20 or so or iron pipe. We have auto drains, coalescing filters, drip legs... All the normal good stuff.

With the compressors running about 50% duty cycle, on humid days we still got water in the lines. Part of the problem was that the rooms the compressed air went to were cooler and the outdoor temp was 85°F.

That 15°F temp drop condensed a lot of water. The same thing happens at the tip of your gun, as the air expands it cools. My gut feel is wet air and a perfect paint job are not a good combo.

On dry days this may not be an issue, but if your painting on a warm humid day a standard ambient dew point system may be a problem.

I would recommend a desiccant or a refrigerated cooler for when you paint.

 

[Skep18]

Thanks for all the replies.

I wouldn't be to concerned by the 25# difference. Burst pressure is probably at least double that (250-300psi). Mike

This is what I was thinking and why I decided to ask. I know the rating has a safety factor of probably like 2 or 3, but I couldn't find the ASME or whatever, link to such. Also, as mentioned, these are made in China...

Regulate to that particular tank... otherwise, you or others will never feel/be safe around it in the back of your mind.

For this reason, I'll probably not do it. I can probably just use the tank for what its designed for during my autocross events. I bought a condenser from the junk yard today. I'll be running that between my compressor and the tank. I haven't decided yet whether I want to tun a tee between the after cooler and the tank or if I just want to let it all drain in the tank and build some sort of reservoir plumbed into the bottom tank drain so water won't sit in there.

What matters is that the air going into your last dryer is as close to room temp as you can get it when you are running a spray gun. In most cases a 60 gallon tank and a compressor that is running intermittently will get you pretty close. 15 to 20 feet of metal pipe before your last filter should get you very close.

In me experience, after coolers are nice if your running air tools and sprayers at the same time and your compressor has to run a lot. Not as big issue an in a single person shop.

in either case, if you want to insure that you wont have a moisture problem you should consider some sort of dryer. I bought a used refrigerated dryer. A desiccant dryer is another option. Unless you cool the are you just compressed to below ambient ( or use a desiccant) its really hard to guarantee that you wont get moisture when painting.

At work we have inter coolers and after coolers on our compressors. That goes into 20 or so or iron pipe. We have auto drains, coalescing filters, drip legs... All the normal good stuff.

With the compressors running about 50% duty cycle, on humid days we still got water in the lines. Part of the problem was that the rooms the compressed air went to were cooler and the outdoor temp was 85°F.

That 15°F temp drop condensed a lot of water. The same thing happens at the tip of your gun, as the air expands it cools. My gut feel is wet air and a perfect paint job are not a good combo.

On dry days this may not be an issue, but if your painting on a warm humid day a standard ambient dew point system may be a problem.

I wold recommend a desiccant or a refrigerated cooler for when you paint.

Also, I do have a desiccant and coalescing filter that will be down-stream from the main tank. Dry air shall be mine! Haha.

Thanks again!