Need new outlet pipe for compressor

Hi. Now I have another problem with a compressor! The outlet pipe - the pipe which carries the air from the compressor head to the cylinder - has been damaged by yours truly. Its an L shaped copper pipe about 340mm long with flared ends, and retaining nuts at either end. Basically, the flared end is starting to separate from the copper tube with little cracks appearing, made worse by me twisting it. I need to replace it. I assume these are all different on each type of machine. I don't have flaring tools or pipe bending gear or much experience with metalwork or engineering so although I suspect it isn't hard for most people to make one I'm not in a position to do so.

How is this repaired ? Are there generic parts ? Is there a quick and dirty solution for this ?

cheers
Arron

First a dumb question. Is is simply a bent and flared pipe, or does it have a spiral form wrapped around it to function as a heat exchanger to cool the air between the head and tank?

One possible fix that should be within your capabilities would be to obtain olive style pipe to threaded fittings for both ends that will mate with the male compression fittings at the head and tank, either directly or via couplers. Then trim the pipes to eliminate the faulty flares and adjust pipe length to take the extra fittings into account. Debur the trimmed ends, slide the olive fitting nuts into place, then fit the copper olive, mate up to the rest of the fitting and connect and tighten, The copper olive will deform around the pipe and between the fitting and nut to form a seal. If you need to use couplers, you will probably need a jointing compound to seal the threads there.

Quote:

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Originally Posted by malb

First a dumb question. Is is simply a bent and flared pipe, or does it have a spiral form wrapped around it to function as a heat exchanger to cool the air between the head and tank?

One possible fix that should be within your capabilities would be to obtain olive style pipe to threaded fittings for both ends that will mate with the male compression fittings at the head and tank, either directly or via couplers. Then trim the pipes to eliminate the faulty flares and adjust pipe length to take the extra fittings into account. Debur the trimmed ends, slide the olive fitting nuts into place, then fit the copper olive, mate up to the rest of the fitting and connect and tighten, The copper olive will deform around the pipe and between the fitting and nut to form a seal. If you need to use couplers, you will probably need a jointing compound to seal the threads there.

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Yep, its just a simple pipe with flared ends. Only one flared end is damaged - its has a small split just where the flaring starts - i guess I wrenched it too hard.

Anyway, your idea for a fix sounds like a good one. I cant see any reason why it wont work. Sort of like a kenko nut solution.

Cheers and thanks
Arron

Any other advice still welcome.

My mate had to replace this pipe and from memory it was hard to find and exe so if you find them or get them made up get 2x as it was a design flaw in his compressor as it kept breaking. I will ask where he got one.

Just noticed the pipe is not copper. Looks like some sort of alu alloy.
Arron

put 2 male air fittings at each end (nitto, ryco whatever you like) and put a airhose with female fittings between them.

replace the alloy tube with a short air hose.

will work fine.

Quote:

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Originally Posted by _fly_

put 2 male air fittings at each end (nitto, ryco whatever you like) and put a airhose with female fittings between them.

replace the alloy tube with a short air hose.

will work fine.

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I like this idea very much, but am concerned the heat from the head may cause issues?
maybe use a high temp hose like ortac available from irrigation shops or maybe ring a hydraulic hose mob and ask how much and if they think it will work.

Quote:

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Originally Posted by _fly_

put 2 male air fittings at each end (nitto, ryco whatever you like) and put a airhose with female fittings between them.

replace the alloy tube with a short air hose.

will work fine.

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That sounds like an interesting alternative. I'll pursue this idea if the copper olive idea doesnt work. The pipe gets fairly hot - too hot to touch - is the air hose Ok with that ?

Thanks
Arron

Hi Arron,

Something to try is to undo the nut and put two wraps of thin electrical solder around the pipe above the flare then do the nut up on it and see if that seals it.

Cheers,
Geoff.

My original idea of an olive fitting may not work if the tube is not a standard size copper, due to sizing tolerances and availability of fittings to match.

The line is normally a high thermal conductivity metal to achieve as much cooling as possible before the air reaches the tank, as cooling the air reduces the absorbed moisture in the air, and tank accumulation and transfer to tools etc. My 3HP twin comp has fairly large fittings and the pipe is about 16mm ID, going to 10mm air hose would be a definite restriction even with barb fittings to couple the hose into the existing metal fittings. Going via Nitto or similar fittings with their smaller bores etc would be a nightmare to my mind, and heat dissipation would be much lower, giving rise to more moisture transfer.

I had to rework the inlet side of my comp when it was almost new as I broke the spigot of the plastic air filter housing loading the unit into the car for a job. I established that the inlet port was bored and threaded a standard water pipe thread and was able to repair the filter with off the shelf Bunnings plumbing fittings. I subsequently had to rebuild the compressor unit due to lack of oil (crankcase sight glass bubble fitting appears to be ali but was a nasty leaky plastic that let the oil out). During the rebuild, the outlet port on the head was observed to be the same as the inlet (from memory 1/2in water pipe). Based on that, I would be tempted to go with a replacement annealed copper and the olive fittings suggested originally.

OK, I've fixed this :U - and now I'm just putting the resolution here for future reference.

The olive idea was a good one but didn't really fit, so not knowing whether the idea of using a piece of hose was a good one or not, I shortened the pipe by cutting away the old flare and the cracked bit, bought a flaring tool and applied a new flare, rebent the pipe a bit so it still fitted, and it works.

cheers, and thanks for all the suggestions.
Arron

That grey stuff looks to be Chinese replica "Aluminium". Sometimes they have a heat dissipating coil spring from the head for a few inches.

The cheap compressors do a good enough job, but they thrash and the vibes wreck the pipe in no time at all. If you give it a good thrashing for a day or two, continuously, it gets so hot it'll steam like an old greased up Ford engine.

The solution is to take the connector from the head and the nut from the tank end, take them both down to an Auto Store (I used Auto-pro) and buy:

- the appropriate brass end fittings with a 1/4" or 3/8" OD barbed nipple ends (they will match them up for you)
- 4 of those screw driver tightenable 11-15mm bands/clamps (two for each end)
- a 1M length of high temperature high pressure 1/4" or 3/8" ID hose. Its black and they sell it off rolls by the metre. (they hid mine behind the counter. Its the Good Stuff, not the cheap rubber crap at the front of store, but the reinforced stuff). Its apparently used for brake master cylinders and negative crank vents etc. Its everything-proof.

Think all up it cost me $25 for all the parts. Fit the fittings, cut the hose to length, put two clamps on the hose at each end and away you go.

I know this as I give my compressor an absolute pizzling. I paint with the spray gun all day (furniture with house paint!) and the poor compressor absolutely does not cop a rest. Its all as hot as buggery at the end and steaming like a boiling pot roast. :D Change the oil too.... also, get an inline water/oil filter off ebay, they are cheap enough.

Hope this helps. :D