Air Compressor Lube: Synthetic vs. Organic???

[john hobdeclipe]

I just bought a new air compressor. The instruction sheet recommends synthetic compressor lube for 100% duty cycle. The duty cycle is reduced to 60% when using petroleum lube.

Then they have a list of compatible and non-compatible stuff that can be in the downstream piping system. Among the non-compatible items are:

neoprene
natural rubber
a whole bunch of other common plastics and rubber compounds
and POLYCARBONATE!

Aren't the bowls on nearly all air line water separators and lubricators made of polycarbonate??

And since there is always a little bit of the oil mixed in with the air, will this stuff eat up my car tires from the inside out?

Thanks.

[Black_Moons]

I thought the bowls where usally made of acetel?

[Willy]

And since there is always a little bit of the oil mixed in with the air, will this stuff eat up my car tires from the inside out?

Perhaps after several lifetimes.

The amount of residual oil in the air stream is so minute that it is, or at least should be, inconsequential.
If it isn't you have serious compressor problems.
Besides, your car is eating them at a much faster rate from the outside in.

[Duffy]

Some of this stuff is a COMPLETE CROCK! Are you likely to EVER run your compressor on a 100% duty cycle, or even 60%? Very few percent would likely be closer to reality. Where would there ever be bearing temperatures or pressures that would cause the breakdown of petroleum lubricant?

[Boucher]

Use the synthetic oil. It will save you in repairs and down time if you run your compressor hard. It doesn't form carbon type ash like the older oils. This means fewer valve problems and less repairs. Not all synthetics are good so get some recommendations.

[wierdscience]

X's 2 for saving the valves which is probably where the duty cycle comes in.And yes 100% duty cycle is possible on an AC when sandblasting or using high volume requirement tools like sanders.

[Clevelander]

I'd be tempted...

I'd break it in on regular oil (to allow the rings to seat more easily) and then switch over to the synthetic. In particular if your compressor is in the garage it will really help with cold weather start up (you won't pop breakers) and it will also help reduce friction (hence wear, and keep the temperature of the compressor head lower). It's cold flow characteristics will also help with start up lubrication.

One thing you'll want to check is whether the manufacturer recommends a detergent or non detergent oil. In the past it has typically been non detergent but it seems that for some brands that is changing.

As for the oil coming out of the compressor...if you put in a moisture trap or air dryer that should solve that concern (however unless your compressor is worn out that shouldn't be an issue really).

[Paul Alciatore]

.....

And since there is always a little bit of the oil mixed in with the air, will this stuff eat up my car tires from the inside out?

Thanks.

Ever look at the shop floor at your mechanic or even in your garage or driveway. Probably hundreds of times the dose of oil that the tires will ever get in the air used for inflation. Heck, asphalt is oil based and we make our roads from it. And the hoses used to inflate the tires are rubber. I suspect that the tire makers have long ago learned to control this source of possible deterioration.

Add a filter jar to the line and clean it out occasionally.

[john hobdeclipe]

Well, I've decided to go with the synthetic lube and take my chances that I don't have anything it will destroy.

There will be times when I need the full output and 100% duty cycle. I occasionaly do some sand blasting and need to do more, and it will be nice to be able to use a couple of the sanding devices that I have and that the old compressor just couldn't handle.

Thanks, all, for the comments.

[CCWKen]

Well, aren't you even going to fill us in on the specs of your new compressor? I mean will if take up space in the shop or in your glove box?

[oldtiffie]

A decent plasma cutter can sure be classified as a high air demand machine if you are really using the plasma.

[macona]

Transparent filter bowls are made from acrylic. Polycarb breaks down when in contact with oils very fast and becomes a brittle mess. Natural rubber and neoprene (latex) breaks down as well. Thats why silicone lubes are used to put on diving suits.

In general, oils and plastics often do not get along. Its just a matter of time before it breaks down.

Tires are not natural rubber. They are vulcanized rubber which changes a lot of the properties. Even at that they still don't like oil, but the minuscule amount that comes down your air line won't make a difference. You will wear the tires out faster than the oil will effect them.

[john hobdeclipe]

Well, aren't you even going to fill us in on the specs of your new compressor? I mean will if take up space in the shop or in your glove box?

It's taking up a corner of the shop. It's a garden variety Ingersoll Rand 60 gallon, vertical tank.

It replaces a 20 gal wheeled unit, Campbell Hausfeld, that I bought 24 years ago and ran the crap out of until it finally showed a pinhole leak in the tank. Yeah, I kept it drained but that didn't stop it from rusting out. Funny thing, the hose that came with it is still there, in great condition with no sign of deterioration over all these years.

The new compressor will be hard wired, bolted down, and eventually I'll run a piping loop around the shop, with appropriate drip legs, etc. When I get ready to do that, I'll start a thread about what kind of pipe / tubing to use, and see if I can generate any interest.

I remember several years ago seeing some new filters, lubricators, and moisture separators that had a safety warning against cleaning the polycarbonate bowls with solvents. Thus my concern that perhaps mine are also polycarbonate.

Just as an additional safety measure, I think that I'll try to find an appropriate excess flow valve and plumb it in close to the tank, mainly as protection against cut or burst hoses.