Compressor problems

Start putting down a pass and the air supply slows after a few seconds. Release the trigger for a few seconds and pressure comes up again and the slowing air supply repeats. Doesn't completely stop and there's just enough air to atomise a small amount of spray. Feels like you're running low on air or the compressor isn't keeping up.

I took the cap of the cup - no difference.
Tried a new moisture filter on the gun - no difference
Tried another gun - no difference
so compressor is dodgy?

What do you reckon the problem is?

Check the nut behind the trigger. They have a habit of coming loose, allowing air to escape when trigger is depressed.

Two guns doing the same thing kinda points to the compressor as the problem I would have thought.

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Originally Posted by old_picker

Two guns doing the same thing kinda points to the compressor as the problem I would have thought.

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..... or both guns have been maintained the same way and have the same issue??

Have you tried another air hose? Could be that the air hose is de-laminating. There could be debris in the line. Mud and leaf cutter wasps are a real PIA around my place, love outboard motor tell tales, wood lathe head & tail stock knockout holes, garden hose fittings, etc. Take the female fitting off or place a male fitting (without hose or accessory) into the female and blow the line through.

Also clean out/substitute your pressure regulator and any inline fittings. There may be a tiny bit of something which when there is air flow, is pushed such that it blocks the flow, then when flow stops, there is no more air pressure holding it in place so it drops back down, removing the blockage. I hope I explained that well enough.

Can you tell us about the compressor I.e. does it have a tank & what pressure is in the tank? Does the compressor motor cycle on/off as pressure changes in the tank?

It tank pressure is ok, then likely a restriction in the flow as others have suggested.

I noticed when I disconnected the airline from the compressor a good deal of water blew out. I drained the tank and there was way more condensation than usual I'll blow the line out 1st thing this morning.

I generally drain the tank fruday night but may have missed one last week

in the light of a new morning I find a rupture in the air line. Compressor running too much to keep up I guess building up a lot of water in the tank and air line. The spray area is away from where I've been working so not keeping an eye on it. I tend to disconnect the line at the compressor when I walk away as it is a bit leaky at the front end but not yesterday all day up to 11pm last nite.

Air line is probably 5 years old at least and not top of the range when new - First 8 or so feet looking pretty ratty I guess its has perished and split along the line for maybe 30mm. No wonder the compressor was not liking it.
Compressor seems to be delivering a steady air flow this morning after draining out the water in both tank and line

Off to bunnings to pick up some new nittos for both ends and a new air line -

Take care to use good quality airhose such as "Total Tru Blue" made in Australia to AS2554 rated to 250PSI. Lots of cheaper imports do not handle our wide variations in climate and swell and embrittle etc. I would also suggest using HVLP type guns as in my experience I am able to readily apply crosslinking coatings on furniture using only 35PSI . Although I have a large high capacity compressor when using HVLP application my smaller direct drive unit works just as well even with a 10M air hose.
Cheers,
Paintman

While you are purchasing air fittings get a Air Regulator & Water Trap for the air hose as well. If you are using a long hose to the spray booth / area place it in-line at the work area and use a short hose from it to the gun, otherwise just place it on the compressor outlet.

Placing an Air Regulator & Water Trap close to the gun allows you to see the "real" pressure that you are using = tank outlet pressure minus airline losses.

Thanks for the tip on the air reg. I use a water trap at the guns and bought new ones. Also bought new Nitto connector for each of the three guns. I was using aluminium anodised Ryco but I found them leaky. I guess I'll find out if Nitto is any better.

Often thought of having a reg/gauge at the gun but not yet gone for that. Usually I get enough pressure as the jobs are small. I can get a pass done on all sides in a minute or two. Definitely something to give a bit more thought to.