Hi guys. I've been making efforts to get this 2 1/2 car garage and my tools and equipment squared away so I can once again do some good work on my projects. Still a ways to go. I'm gettin' there. As with most of you, one of my priorities is to have a good compressed air system. And as most of you know, part of a good compressed air system is having a method of removing the water so we don't ruin our paint jobs, air tools, and clog the sandblaster. And once you realize that COOLING the air is the first step... in fact, the main step... in getting the air to release its water, then you know we have to find a way to do that. We've discussed various methods. One way is to run the air through long lengths of pipe attached to the shop wall. Copper tubing works even better, because of its ability to dissipate heat quickly. Some of you have done a great job using this method. Some guys have talked about using a long coil of copper tubing hanging from the ceiling. I've done that. It cools the air well and allows the condensation to run down down down the coil of tubing to a purge valve. Or that same copper tubing installed inside a refrigerator. Others simply purchase a manufactured compressed air cooler built for the job. The option that I've always thought could work well, is to install the copper tubing inside a large container filled with cold water. We've discussed this option, too. Seems simple enough. Easy enough to imagine. But have any of you guys ever seen one that somebody built? I hadn't. I searched here and elsewhere on the internet. Again, some discussion about it... but I couldn't find any pictures. I had to do something. I'd been sandblasting in hot humid weather. Unclogging the sandblaster more than I was sandblasting. I know this stuff, but I thought I could muddle through, simply by opening the purge valve on the compressor tank often enough. Nope. I had enough of that... LOL. Temporarily stopped sandblasting to deal with the situation. I built myself a cooler. Just finished it a couple days ago. Figured I'd share my invention. This is pretty simple stuff, and any of you guys could do this without my help. But for any of you who might want to build one of these, maybe I can save you a little time and effort and headaches. I was going to post this on one of the "Homemade Tools" threads, but I felt it would just be lost. So here it is. First thing... we need a big container. Had this steel 55 gallon drum. Might as well use it. It was in better shape than a lot of old barrels I've seen, but it was still rusted a bit thin around the bottom and there were a couple of small holes. I soaked it in a citric acid bath for a few days and then sandblasted it. No more rust. Yes, ironically... I had to unclog the sandblaster a number of times to sandblast the barrel to build a cooler so the sandblaster won't clog. I figured out my design, cut the holes needed, sealed and strengthened the barrel with thickened epoxy type fiberglass resin and painted it inside and out with epoxy elastomer pool paint. Figured the pool paint is waterproof, durable, and blue is a good color to indicate water... and cold. Enough with the barrel restoration already. When I first started designing this thing, I soon realized that in order to have the copper tubing run mostly the full height of the barrel, I needed the compressed air inlet to be as high as possible, and the exit to be as low as possible. The down leg and purge valve need to be even lower... ending up below the bottom of the barrel. We need to raise the barrel. We need a platform. Put some wheels on it so it can be rolled around. Just a simple square wooden frame made with 2x8s. Plywood top and bottom. You can see. Left the bottom open so I could paint it inside and to keep it from becoming a mouse house. Added some corner pieces on top to secure the barrel. Gotta have four main holes. Air in, air out. And water in, water out. I've got my air from the compressor coming in on the back side near the top. Copper tubing coils down to the air out fitting on the front of the barrel near the bottom. Both water in and water out are on the back. Water in is near the bottom. It's also the drain. And I put another one near the top, mostly to act as a water level limiter and to release trapped air from the barrel as it's being filled with water. You can see that I started inserting some rubber grommets in the holes I had cut, and inserted short nipples through the grommets. Then a couple of big flat metal washers and a coupler or an elbow or two, and we have water tight fittings to attach the rest of our plumbing to. The back of the thing. Water valves in and out. The bottom one has an adapter to attach the hose. A short whip hose connects the compressor to the barrel and the copper tubing. The air exits near the bottom on the front of the barrel. Added a down leg with a purge valve. Adapted a short length of 2 1/2" pipe for more water holding capacity. And then of course, the vertical length going up up and away... away from the water. I cut a piece of 2X to make the standoff block to secure the upper portion of the vertical pipe to the barrel. A plumbing clamp, some long screws, little rubber washers, steel washers, nuts... Where the "magic" happens. A 50' length of coiled 1/2" dia copper tubing. Lay the whole coil in the bottom of the barrel. Stretch the coil upward and attach it to the upper fitting. The copper tubing is easily formed. Simply uncoil to expand the diameter of the coils until they are against the sides of the barrel and bend and finesse the tubing until the coils are spaced evenly and gradually going downhill. I fine-tuned the height and separation of each coil with some wire on two sides, suspended from the hardware near the top of the barrel. Wrapped it around each coil only once to allow for easy adjustment. Holds it well enough. Once I got everything where I thought it should be, I twisted the bottom coil around one more time for length adjustment and positioning and attached it to the outlet. 63 years old, hanging upside down inside a 55-gallon drum, wrestling with plumbing... LOL. I hurt pretty good the next day. The couple of extra turns of black pipe at the top are just so I could center everything instead of having it hanging off to one side. I think it gives it a little extra Rube Goldberg look. Added a water separator, regulator and an old oil-filled 200 lb gauge I had. Put the lid and ring on that I blasted and painted and tightened it down with some new hardware. Quick disconnect, add the hose... And Robert's your mother's brother. I've been using it... sandblasting again for a couple days. Seems to be working great. I'm of course getting water when I purge the compressor tank... which I do very often. After a number of cycles, I'm blowing water out the purge valve on the barrel... as to be expected. But nothing after that. So far, NONE even in the separator at the top of the unit. There's another water separator at the sandblaster and I have a mini separator at the end of the hose to boot. But there's zero indication of any moisture there. And no clogging of the sandblaster. Eventually, I'll attach more pipe and plumbing to my shop wall along with its own separator, regulator, additional connections, etc. Just to make double triple sure for painting. But I feel pretty confident that this cooler in standalone mode is actually enough. And that's it. Now... we all know that whenever designing and building something custom... a one-off... "Bob's your uncle" doesn't come easily. I was a draftsman for 25 years. I drew machine tools... before computers. I never ever saw one single design that didn't require some changes. Some of our drawings were 30 feet long. Our erasers were basically drill motors. I think some of you guys need to be easier on yourselves when you start feeling dumb because you have to make unforeseen changes part way through your builds. It cannot be avoided LOL. Anyway... it was the same with this thing. So I'll share the little particulars about building it. In other words, where I messed up... what I might have done differently... things I might still change. A few stray thoughts. I sure could have saved myself some work and time by using a newer barrel. But we had this one. And I was practicing the finishing process... the same process I'm going to use to finish the inside of the swimming pool... the thing I'm sandblasting. You might be able to get away without using a steel barrel. But a plastic container might not be strong enough to support everything. Even a trash can could maybe work. Or even just a tub filled with water in a pinch. But you really need the height. The coiled tubing should be stretched enough to allow the condensation to flow downward and not collect in a low area of the tubing. And you need room for a purge valve down low. You could set the tub up on a platform to allow room for a purge valve. Depends on how far you want to go. I wanted to make something that would work perfectly every time for a long time. You can fill the barrel with cold water intermittently, or you can let the water flow slowly to maintain temperature. The hot air in the copper tubing will eventually warm the water. But with such a large volume of water, it seems to be staying cold for a long time. I thought about adding a temperature gauge so I could check the temp at a glance. Probably overkill LOL. Just a touch with my hand on the outside of the barrel tells me how cold it is. There is fairly heavy condensation forming on the outside of the barrel. Not really a problem, but I might add a drip pan between the platform and the barrel. The coiled copper tubing is held fairly securely by the upper connection, the lower connection and the wire I added. But it's not perfect. I may likely replace the wire with small plumbing clamps attached to the wall of the barrel. That would allow perfect positioning of each coil of the tubing with no low spots. And it would stay there. I guess I'll be buying some more little rubber washers. I had no water leaks at all. Rubber grommets at the fittings going through the barrel. Just little rubber washers on both sides of the barrel wall for the screws attaching the wooden stand-off block. In fact, I don't think rubber grommets are necessary. Rubber washers seem good enough, and they're way easier than using the grommets. It was a pain getting the holes just the right size for the grommets, so that the nipples would be snug without being so tight that I couldn't put them in. If I did it again, I'd just use some big fat rubber washers. Finding rubber washers the correct size is a challenge, too. I just used what the local hardware store had that would fit (the grommets) and it worked out. If you've ever worked with plumbing, you know the tapered pipe threads can be tightened... then tightened more. But if you get too tight, you won't be able to turn it again far enough to get your fittings pointed in the right direction. Although I found that I was able to turn the whole assembly, which helped a couple of times. You want to tighten against the rubber grommet or washer, but not too awful tight. So you have to make a determination ahead of time as far as the length of your nipples, (LOL) your stack of washers and the guesstimated thread engagement to get everything just right. On the other hand, I'll bet one of you has a better idea. Feel free to share it. Like I said, I had no water leaks. But I definitely had air leaks. I usually use tape on my threads. But it's a little hard to handle sometimes, and I thought pipe compound would be easier when dealing with so many fittings. I used enough without being too sloppy... but I had leaks. Especially the larger threaded pieces... the pipe dope couldn't seal it. Tape fixed it. It's fun taking stuff apart after it's all painted and assembled LOL. I'm probably forgetting a few things. I'll add them if I think of anything more. Later! - Rick
@Rickybop Thanx for posting this. Nice job! I recently did something similar. My version is much simpler as I was just experimenting with the concept. I simply ran the outlet from my compressor through the copper tube and then to the tank. Here are the particulars: 50' of 3/4" refrigeration coiled copper. 50 gallon plastic barrel Compression fittings (same as compressor original equipment) Straightened the ends of the coil to run vertically to the fittings on the pump and tank. No drains etc. Results: I had a severe condensation problem in my air lines. When using my small die grinder I would get water coming out the exhaust, particularly in the summer. Since installing the condenser, I have absolutely no detectable moister in the lines. I still get water in the tank but it seems to be less than before. One thing I have noticed is that it takes a bit longer to refill the air tank after draining it all the way down. I believe this is due to the air being pumped into the tank being cooler so it takes more to reach the shut off pressure. I want to refine this system over the winter and one of the things I'm considering is running the air from the first stage through the cooler and then to the second stage of the compressor. I'd like some opinions from some guys that know more about thermodynamics than me about doing this. At this point I see no reason to cool the water in the barrel, but this might change with the addition of a second coil.
Thanks for posting, gentlemen. Hey, @GearheadsQCE. Thanks for sharing your setup. You're not too far from me. A few thoughts... Regardless of the configuration of the system, it's imperative to have blow off valves at every low spot... where water collects. It really helps to have at least one run of pipe or tubing that goes up above the rest of the system just before the hose connection. Two or three runs is even better. The collected water down low has a difficult time following the air upward. The coiled copper tubing in cold water works great. But the tubing doesn't really have to be submerged in water. It does a pretty good job even if it's just hung from the ceiling. And that makes installation and connecting to the rest of the system much much easier. You mentioned maybe shifting the copper tubing to between the two cylinders. There's good reason to have cooling apparatus almost anywhere in the system. Manufacturers often include a coiled tubing with cooling fins between the cylinders. It certainly helps to keep the second cylinder at a lower temperature, considering that it's being fed hot air by the first cylinder. I haven't seen cooling systems between the pump and the tank, but there's no reason it wouldn't be beneficial. I do believe the main focus of cooling should be after the compressor, though. The tank itself does a pretty good job of naturally collecting a large portion of water from the air that's already beginning to cool. And that relieves some of the work that would otherwise have to be done downstream. Good luck with your system. Let me know if maybe I can help.
Dang Brother Flea - looks like you could also kick out some mighty fine kickapoo joy juice 2 - good too - glad to see ya making progress Take care and stay safe Sent from my iPhone using H.A.M.B.
Brother Mikey. Been wondering how you're doing. Been working all summer on your coupe, huh? Good to hear from you. I did notice a couple guys in hats driving by here real slow in a two-door 57 Chevy 210 with no front bumper.
Looks pretty cool, hey and from the looks of it you might just be able to put a good hot fire under it when not in use and a thumper top and start making some "Rickybop's Shine" HRP
Thanks, guys. I like how you put the word "simple" in quotation marks, Pete. LOL Not until just now when I read your post LOL. I had thought about rust, but I don't think I considered the mismatch of metals. But that's why we talk about this stuff. So, let's see... where's the galvanizing? Oh yeah... most of my Plumbing is black pipe, but of course I didn't have everything I needed and I ended up getting a handful of elbows and couplers from the local hardware, and those are galvanized. Question... What's gonna corrode? The inside of my non galvanized pipe and fittings? There's Teflon tape on the threads, but there's still metal-to-metal contact. And the water carries the galvanic corrosion anyway, right? Thanks. Let me tell the story, I can tell it all...
I'm no plumber or metallurgist but from what I understand its the steel that reacts with the copper so copper shouldn't be connected directly to iron pipe whether it is black or galvanized. But I could be wrong and hopefully someone who knows more about this will chime in. In terms of what is the risk, if you have an iron air line connected to copper there is a risk of the iron portion of the line corroding and at some point failing. Or at least that's the way I understand it. Your set up looks excellent and it would be a shame to have issues down the road if there is a problem with mating iron to copper like you did. Again, hopefully I'm wrong.
"Are you worried about galvanitic corrosion from mixing copper with galvanized?" If money were no object it would be nice to have all copper and brass in the system, to cut down on nuisance rust stains, but it probably wouldn't work better. But then there'd be the danger of thieves spotting all that nice shiny copper and brass.
Your solution is similar to what I've been thinking. I did see an application of a used transmission cooler plumbed in between the air pump and the holding tank that looked interesting. The pulley on the pump passed air through the cooler and there was a water trap before the air passed not the tank.
Pretty cool Rick, well done. But how do you overcome the problem of waiting for the air to catch up with the blasting? For me, it was always 45-60 seconds of blasting, wait 3-5 minutes for the compressor to catch up. Have read a couple solutions to this problem, curious as to your solution.
I think I may have seen that one, @Fortunateson. I forgot to say that transmission coolers and the like seem to work good, too.
Hey, @BrerHair Main thing, the compressor has to be big enough. It has to be able to pump enough CFM. When sandblasting, you have to wait as you say, if you use anything less than a good-sized 2-stage compressor. The inner diameter of the various pipes, tubing and fittings affect flow to a point. A pressure pot type blaster utilizes compressed air more efficiently then a siphon type blasting gun. I'm almost embarrassed to say that I have to depend on this buzzy little thing for the time being... Because... I bought the used T30 Ingersoll Rand for a pretty good price, but had too much blowby... it was pressurizing the crankcase. Needs new rings and valves. I think the Pistons are okay even though a little discolored. So right now, I have to wait, too. How do I deal with it? By the time I run out of good pressure, I'm ready to get out of there, take a break, and let the room air out. Sometimes I find something else to do. But the best way for me to deal with it will be to fix my big compressor. Lots to do, lots to do. Kinda enjoying it, though.
Sandblasting is a balance between volume vs velocity. The job should dictate what's needed, but bigger isn't always better. If the compressor is big enough, you can go bigger with pressure, tip size and sand flow. But if the CFM is limited, lower air pressure, less sand flow and a smaller tip can sometimes help to use the air that's available more efficiently. Speaking of tips. Here's a tip. Take all precautions to avoid EVER filling your sandblaster with a bigger grit of blasting media than it can handle. It's difficult and time-consuming to get every grain of the big stuff out so you can replace it with the correct sized grit.
Would there be any disadvantage to putting the cooler before the compressor, so the compressor is sucking through the coil? You wouldn't have to worry about the coil being strong enough to take the pressure,and the air would be dried before it reached the compressor cylinders. Or is this a bad idea for some reason?
I don't think so as the compressing of the air is what releases the moisture though I'm not positive on this.
The warmer air is, the more moisture it can hold, so cooling it makes the moisture condense out. I don't think pressure has anything to do with it. but I could be wrong.
It's the lowering of the temperature that causes the air to naturally lose its ability to support suspended moisture. The colder the air, the dryer it will be. Just gotta stay above freezing so the water remains a liquid. A cooler before the compressor. A cooler anywhere in the system would probably be beneficial. But just the expansion of the air going into the receiver tank causes a natural cooling action. That's why we get so much water coming out of the purge valve at the tank. Might as well let that do its thing, then the cooler downstream doesn't have to work so hard and can easier take the air down to a nice low temperature. And then a T fitting with a down leg and a purge valve. And the upleg going up high for the next part of the system to connect to. Going high with the up leg makes it difficult for the water to follow the air. Doing that two or three times up and down up and down and the water will absolutely be left behind. If I was to install a second cooler anywhere before the tank, I would more likely put something between the first and second stage cylinders. The second stage cylinder gets pretty hot, working at higher pressures and being fed hot air from the first stage cylinder. Most compressors have a tube with fins connecting the two. But I think a little more cooling for the second stage couldn't hurt.
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