Compressor advice

[Deleted]

Need to by a compressor and just need to know what the difference is between "normal" and "oil free" (and before you all jump in and say one has no oil in it) is one better than the other? I am looking at Machine Marts Airmaster Tiger 8/250 24 litre and Clarke Ranger 7/240 24 litre and their "oil free" equivalents. Plus the Clarke is about £12 more expensive but looks identical.

[barlowworks]

If you are thinking of using your compressor for spray painting you want an oil free one. The other kind have oil suspended in the air which can contaminate the paint. You could always fit an oil trap, I just went the oil less route

Mike

[92220]

As Mike says, buy an oil free compressor. An oil trap will work but it needs constant cleaning otherwise it gets gunged up with oil residue and stops cleaning the air. Another tip if you are going to use it for spray painting......buy a small pressure regulator/filter/water trap.....about 25mm diameter transparent bowl. Connect it to the compressor outlet with at least 6 feet of reinforced polythene hose. You can coil it up beside the compressor or behind it to hide it. You will ask why the 6 feet of hose. All compressors start to generate water vapour as they warm up with use. That water vapour will eventually condense out in your spray gum/airbrush hose, and will come out as fine droplets which will spoil the paint finish. The idea of the 6 feet of hose is so that the water vapour has somewhere to condense before it reaches the spray gun/airbrush. The pressure regulator/water trap will then separate the water vapour out of the compressed air. You need a small 25mm diameter regulator/water trap as it removes the water by spinning the air inside the bowl and centrifuging it out. Any larger and it won't spin it fast enough to filter out the water vapour, due to the small flow of air that an airbrush uses.

Bob.

[atgordon]

Oil-less compressors use teflon seals to ensure moving parts move without seizing. Oil sump compressors use oil splash in the sump of the compressor to lubricate the crank and the underside of the piston (just like a car ... so I'm really intrigued as to the posters who state that oil flows into the compressed air with oil sump compressors), which also ensures that moving parts don't seize. Neither compressor puts oil into the compressed air unless they are in dire straits of servicing. They both put moisture into the compressed air, which is a significant when spraying.

When using any rotating air tools (i.e. not paint tools), it is recommended that the tools be fed via an oil feed system that sits between the feed pipe spur and the tool coupling (air driven motor tools need lubricant since they almost always receive only moist air as a result of the decompression-related condensation as a function of the energy conversion process).

Oil sump compressors are quieter and longer lasting than oil-free, and when used with large reservoirs, they will work for a long time. My 150 PSI 10 CFM 80 gallon tank unit has had one 2 cyl compressor replaced once in 10 years. My manifolded system has a high point spur (moisture runs down hill) that feeds into a triple oil filter/water trap/drier system that is then used for paint spraying. The filters are changed every time we spray.

[Tony K]

The cheaper ones squeel louder than the love-making round the back of Spalding Corn Exchange on a Saturday night in the sixties and, if you use them a lot, the thrill lasts about as long.

We talked before here

Discussions have centred on oil free but, for me, that was a secondary consideration. Belt-driven should be much quieter and, nothing beats an old one in a dog kennel outside - as in previous comparison

[chester]

But how about the compressors?