Inexpensive air driers?

[Notch1988]

Originally Posted by theastronaut

Here it is guys. Its a dorm fridge with a 5 gallon bucket of water inside, and 20 feet of copper tubing coiled inside of the bucket of water. The cold water cools the air line so that the water vapor can condense and be caught by the water trap on the outside of the fridge. I've got it connected with quick disconects so I can move it if I need to. Works great! I haven't had any problems with contamination since I started using it.

The only question I have is... why the bucket of water? Technically, the water inside the fridge will never be as cold as the air inside the fridge. Why not just leave the coil of copper open to the air inside the fridge? Seems less efficient having to cool the air and then the air has to cool the water. I'm no engineer or anything so if I'm missing something please explain...

[theastronaut]

Originally Posted by Notch1988

The only question I have is... why the bucket of water? Technically, the water inside the fridge will never be as cold as the air inside the fridge. Why not just leave the coil of copper open to the air inside the fridge? Seems less efficient having to cool the air and then the air has to cool the water. I'm no engineer or anything so if I'm missing something please explain...

Water can transfer/absorb heat about 24 times faster than air can. Even if the water isn't as cold as the air, it still transfers heat out of the copper lines faster than air would. The best scenario (it's not possible though) would be to completely fill the fridge with water, so that the water could be cooled directly by the fridge.

I'm big into high performance aircooled VW's and many guys running turbo's (350-400+ hp) are welding water jackets around the cylinder head fins to help cool the heads off better than air alone could. The air cooled heads are fine for normal driving and low loads, but the air can't absorb the heat from the heads well enough to keep them from overheating when making big hp over an extended amount of time.

It's the same principle where aluminum cylinder heads are able to run more compression without detonation vs using cast iron cylinder heads; the aluminum transfers heat away from the chambers more readily so the chamber surface doesn't get hot enought to cause detonation.

[El Campo]

Prob a dumb question but does the temperature of your air affect the paint that you are spraying?
Posted via Mobile Device

[theastronaut]

Originally Posted by El Campo

Prob a dumb question but does the temperature of your air affect the paint that you are spraying?
Posted via Mobile Device

The air coming out of the drier will be cold, but after traveling through your air line (in my case about 30 feet) it has time to warm back up some. The first five or so feet of the line coming out of the drier stays cool enough that water will condense on the outside of the line, but after that it's warmer to the touch. I haven't measured the temps to see how cool it is at the drier vs at the end of the air hose though.

[RanchFlyer]

Comercially available driers use a 2 pass cooling system. This keeps the down stream pipe from sweating. Imagine astronaut wrapping his incoming airline with the outgoing line. Doing so prechills the incoming air, warms the discharge, and does so with free energy.
Posted via Mobile Device

[El Campo]

Dragging this one back up. Been looking at copper pipe to build one of these and it's outta sight! Its over 70 dollars for just the copper and fittings. What I was wondering is this: if I have 100 feet of rubber hose can I put all of that in a bucket packed with water and ice and make a temporary cooler? I will build a permanent one like this someday soon but need to paint a frame pronto. I know that rubber is a very good insulator and would not move the heat out of air nearly as well but was thinking that since the ice water would drop temperature lower and would have way more length that it would do the same thing just not nearly as efficiently. Any thoughts? Or am I full of hot air? I have the Devilbiss QC3 that I am going to be using ultimately after my 40 micron filter which will go after the cooler.
Posted via Mobile Device

[theastronaut]

Originally Posted by El Campo

Dragging this one back up. Been looking at copper pipe to build one of these and it's outta sight! Its over 70 dollars for just the copper and fittings. What I was wondering is this: if I have 100 feet of rubber hose can I put all of that in a bucket packed with water and ice and make a temporary cooler? I will build a permanent one like this someday soon but need to paint a frame pronto. I know that rubber is a very good insulator and would not move the heat out of air nearly as well but was thinking that since the ice water would drop temperature lower and would have way more length that it would do the same thing just not nearly as efficiently. Any thoughts? Or am I full of hot air? I have the Devilbiss QC3 that I am going to be using ultimately after my 40 micron filter which will go after the cooler.
Posted via Mobile Device

El Campo, check into aluminum tubing. It's way cheaper, transfers heat really good, and is flexible enough to be coiled up. We built ours before copper went sky high. Rubber insulates too well and I doubt there'd be enough thermal transfer to cool the air enough.

[El Campo]

How about aluminum fuel line? Can get 30 feet of 1/2 inch from Speedway for 23 bucks. You think that would work? Is 30 feet long enough?
Posted via Mobile Device

[theastronaut]

That would be great, there's only 20' of tubing in mine.
Posted via Mobile Device

[NONHOG]

Maybe the coffee is not working real good but based off what I'm reading and what I'm having going on with my air. I'm confused.
My set up is not done so its just rubber hose coming out of a filter and its really spitting the water. I'm o.k. with that for now because I have copper lines and water seperator waiting to be set up.
What I'm curious about is the air causing the tool to get super cold.
Will this be an issue after running the copper lines with drops and filters and water seperators?

Overthinking this?

[El Campo]

Is that separator that you have a 40 micron do you know? I have a Milton 40 micron that I'm planning on using. Would be nice if I didn't have to put much burden on the QC3
Posted via Mobile Device

[theastronaut]

Originally Posted by NONHOG

Maybe the coffee is not working real good but based off what I'm reading and what I'm having going on with my air. I'm confused.
My set up is not done so its just rubber hose coming out of a filter and its really spitting the water. I'm o.k. with that for now because I have copper lines and water seperator waiting to be set up.
What I'm curious about is the air causing the tool to get super cold.
Will this be an issue after running the copper lines with drops and filters and water seperators?

Overthinking this?

Cold air tools are from the compressed air rapidly expanding when it's released. Gasses increase in temperature when compressed, and cool off when they expand when released.

It's the same thing that happens when a CO2 fire extinguisher is sprayed, the rapidly expanding gas cools off- enough to chill a 6 pack in just a few minutes. Fast forward the vid to 6:12 to get to the fire extiguisher part.

MythBusters s03 e06 'Cooling a Six-pack' part 1 ...

[theastronaut]

Originally Posted by El Campo

Is that separator that you have a 40 micron do you know? I have a Milton 40 micron that I'm planning on using. Would be nice if I didn't have to put much burden on the QC3
Posted via Mobile Device

It has a 5 micron filter.

[Notch1988]

Originally Posted by El Campo

How about aluminum fuel line? Can get 30 feet of 1/2 inch from Speedway for 23 bucks. You think that would work? Is 30 feet long enough?
Posted via Mobile Device

What's the pressure rating of the aluminum fuel line?

[El Campo]

From Speedway the stuff I found is 1/2 OD and is rated up to 225 PSI. More than I will ever put through it. I have a Mastercool flaring tool and I am going to put a 37 degree flare onto the line and then there is an adapter that goes from AN 8 to 1/2 NPT which is what both my 2 driers accept. Total cost is around 40 bucks. I'm going to just fill my bucket with ice and water for the painting of the frame until I can score a fridge. Then I will plumb it all in. I'll provide pictures when I am done
Posted via Mobile Device

[RanchFlyer]

El campo try to get it as close to 32 degrees coming out of the bucket for the best results. If you get it up and running and find the temp at discharge is not near 32 you could add some rock salt like making ice cream to the mix. If you get it much lower than 32 you can end up with ice blockage in the coil of tubing. Also notice austronaut's water seperator is at the bottom of the bucket. I will again applaud astronaut for his creativity.
Posted via Mobile Device

[El Campo]

RanchFlyer that is a good idea! I will do that. I was worried about ice blockage too. Will experiment around with it and let you all know what I find out. Does anyone know how large water droplets are? I know that vapor is very difficult to remove as it is essentially a gas but when it gets cooled and becomes droplets like we are doing we remove them. Will my 40 micron filter be small enough or do I need to get a finer filter?
Posted via Mobile Device

[RanchFlyer]

Water vapor is not removable by a common filter. The bucket will condense it into droplets which is removable. The cheapest thing is with a centrifugal device. I will bet you filter has a turbine looking defuser in it. The air/water combo hits that fan and the vortex caused sends the heavier water to the walls where it falls and is collected in the bottom. The actual filter element only catches debri. So to answer your question the element size is not important if condensate is what you are trying to remove. Double check your seperator for something that will induce spin and run with it. 95 percent that I have opened up all have a turbine looking blade in them so I bet your safe.
Posted via Mobile Device

[El Campo]

Just ordered my parts. Cost a total of 36 dollars from Summit Racing:
SUM G2512 (25 feet of 1/2 inch aluminum tubing)
AER-FBM3676 (pair of Aeroquip tube nuts for my AN fittings)
AER-FBM 3672 (pair of Aeroquip tube sleeves for AN fittings)
AER-FBM 2008 (need 2 of these adaptors, AN 8 to 1/2 NPT)

Obviously there would be other ways to do this but this is the easiest for me.

[MLB57]

I used a bendix ad9 drier for a truck air is supper dry and was only 175.00

[RanchFlyer]

El campo when you get this thing running start draining at 15 minute intervals. You can probably stretch that out as you get a better feel for it. You will likely be amazed at the amount of water coming out. For painting you may even leave the drain just barely hissing to make sure It stays drained.
Posted via Mobile Device

[jhrusk]

Hey guys,I thought I would post results I have had. I basically copied the one the astronaut has (thanks) and so far it has done a great job,I have a cheap $20 water seperator from sears on outlet side of the drier.I have about 30 to 40 feet of PVC between my compressor and the drier.I have had zero issues with moisture since,as a precaution I also use a motorguard filter if I use the spray gun or plasma but the rest of the time just the water seperator.I keep the temp in the drier about 34-36 degrees.