Air compressor water filter

You can't compress the water vapor in the air because it's near enough to its triple point that it will condense instead, giving you 100% humidity at the tank's temperature plus liquid water. If the tank is too small to cool the hot air from the pump the warmer air can hold more water.

When a regulator drops the pressure the volume increases and the relative humidity (at ambient temperature) drops, since unlike the air the water vapor wasn't compressed. However the cooling from expansion may condense water droplets.

The water filter at the tool catches any liquid water that condensed or was blown into the line, if the line stays connected to the tank. IMHO if you normally disconnect the hose it may dry out and a trap at the tank could be adequate.

I've been considering a cheap, high maintenance DIY drier consisting of a coil cooled by ice, a separator and drain, a large pipe filled with Calcium Chloride and a filter.

jsw

I thought that you shouldn't weld to a pressure vessal.

Mike - others have explained, let me add a few things

1. the little compressor will not put out enough air for a full sized paint gun - be sure that whatever you choose uses less air than the compressor puts out - you can run an air brush or a small touch up gun.

1. you need to let the air cool a bit before the filter - a coil of 1/2 inch copper tubing will cool it if the tank doesn't. Larger compressors have a length of tubing with fins on it between the compressor head and the tank - if you add some fins to the tubing on yours that will help a lot.

2. Harbor Freight (and thus presumably Canadian Tire) carry a combo unit that has a coalescing filter, a regulator and an oiler for about US, on sale from time to time for about US. If you employ this and put three outlets on it - one after the filter (for full pressure), one after the regulator (for spray gun) and one after the oiler (for air tools), you will have a proper unit for your little pump.

1. do not use a hose that has been attached to the oiler for painting, ever ever ever. To avoid this, I have hoses permanently attached to my air tools, I connect them to the oiler, never use an extension.

For a conventional plumbed air system, with a large air tank and an oil-crankcase air pump, there is the risk of water or oil vapor reaching the air tool or paint gun nozzle.

Conventional air systems are plumbed with pipe sloping back to the air tank (hotter air from the tank cools in the long lengths of pipe), to minimize the likelyhood of water laying in the piping, and instead of any accumulation of water, it would drain back to the tank, where it would be drained off at regular intervals.

For the conventional air system, there is always a possibility of a small amount of vapor reaching the tool/paint gun. The accessory that effectively removes vapor from the air by trapping it in a bowl (to be drained regularly), was commonly referred to as a water/oil separator. I've done lots of painting with only a water/oil separator (trap), without any problems from moisture or oil affecting the paint.

Many small portable air compressors don't have oil crankcases, but they will likely still have water vapor in the compressed air. A length of air hose laying on a cool concrete floor is similar to the pipe in a conventional air system, in that the hotter air will cool in the hose. A water/oil separator near the tool/paint gun will trap vapor, but won't effectively stop a sudden blast of accumulated water, if that should occur.

Someone here added a transmission line cooler with muffin fans to cool the air between the pump and the air compressor receiver:

It=92s larger than your air compressor, but might be food for thought if you upgrade yours in the future.

ooohhhh! Nice idea! Or once could use a heater core from something like a Ford Van..they are rectangular and could hold 2 muffin fans one above the other.

Gunner

"A conservative who doesn't believe? in God simply doesn't pray; a godless liberal wants no one to pray. A conservative who doesn't like guns doesn't buy one; a liberal gun-hater wants to disarm us all. A gay conservative has sex his own way; a gay liberal requires us all to watch and accept his perversion and have it taught to children. A conservative who is offended by a radio show changes the station; an offended liberal wants it banned, prosecuted and persecuted." Bobby XD9

Thank you and all the others.

Looks like "suck it and see" (or in this case blow it and see) policy is in order. OTOH I wondered about this gizmo:

which could be conveniently placed between the tool and the line.

BTW the compressor is oil-less. The tool oiling is achieved by droping oil into the tool inlet. I assume that there is no blow back of this oil to contaminate the line? Considering the frequency with which I will be using the brad nailer I am reluctant to go with anything more elaborate.

As far as "painting" is concerned, airbrush is about the size of it.

Technically you're probably right, but practically I don't think that it's a big concern in this case. I worry more about corrosion eating the bottom of the tank. That probably also voids the certification of the tank, but few amateurs have the means to measure wall thickness on these things. Good ultrasonic thickness gauges are a bit pricey.

Somewhere in my spare parts I have a new stainless steel core about the size of a heater core. It has a mount for a pair of fans, and was made to cool an industrial laser. I picked it up for $5 about 15 years ago. :)

When my central air system was replaced, I kept the old A coil. Still haven't found the round "TUIT" to check them out and hook them up. Gerry :-)} London, Canada

A crude solar heater?