Is it overheating?

[Stebos]

I think I'm hitting an overheating problem in the compressor. It starts up maybe 20 - 30 mins into spraying. It's a single tank with piston.

Symptoms are: much quieter running while keeping the tank topped up, though AB use drains the tank so it's not actually doing very much. The case is very hot to the touch.

It doesn't seem to help much letting it cool for a while, I can't do much if I'm hitting this problem after 30 mins.

Does something need oiling? It's still quite new so I didn't think it would need a tune up so soon.

[edit]

It's an oil free one so nothing to change there. I don't see any air filters or anything clogging it up.

Edited May 30, 2009 by Stebos

[Mike]

Steve - it would be useful if you could tell us what make & model of compressor it is. Some compressors use oil, some don't. Usually, the ones that use oil suggest you change the oil after the first few hours of use... I guess to remove any metal particles as the newness wears off.

[Stebos]

It's one of these: http://www.made-in-china.com/showroom/real...sor-AS186-.html

I couldn't afford anything better at the time, especially as airbrushing was a dark art and I wasn't sure if I was sticking with it. There's no oil drain or anything I can spot like that.

[AnonymousA667]

Steve, I've got one like that and yes it gets bladdy hot (untouchable) and quite noisy when it's been working for a while. My rationale is that if it expires then it was almost cheap as chips as compressors go and you have an option to replace with another cheap as chips jobby or go with a badged product that ought to last for very long time. Somebody did mention once that they stripped down a similar compressor, tightened everything up and found that it ran much quieter. It's an oil-less compressor BTW.

peebeep

[Mike]

There you go... like a lot of things from China, they don't seem to be able to tighten anything past finger tight. It's the same with airsoft guns... first thing you do when you get it is strip it down & rebuild it tighter.

[Stebos]

Definitely something funny going on, even after 10 mins (and the casing not to hot) it's letting the air bleed out rather than replacing it. It sometimes runs when I'm not spraying either (no leak that I can find).

I have this absurd idea in my head of adding a second cheapy and just swapping between the two with each colour change

[Mike]

I have this absurd idea in my head of adding a second cheapy and just swapping between the two with each colour change

That's quite literally "buy cheap, buy twice"!

If you're going to lay out money, I wouldn't spend more getting the same item you already have problem with.

[AnonymousA667]

Definitely something funny going on, even after 10 mins (and the casing not to hot) it's letting the air bleed out rather than replacing it. It sometimes runs when I'm not spraying either (no leak that I can find).

Mine does that as well. You need to tighten up the casing and any joints/unions as they develop imperceptible leaks. The end plates seem to be particularly prone to air leaks.

peebeep

[Mike]

Mine does that as well. You need to tighten up the casing and any joints/unions as they develop imperceptible leaks. The end plates seem to be particularly prone to air leaks.

peebeep

Maybe add some PTFE tape to the joints? I noticed that my old Badger converter needed a bit of PTFE tape round the union thread, or it leaked like a sieve. Funnily enough, the Infinity's hose is so tight that I can come back to the workshop 24 hours later, and there's still a little pressure left in the tank from the previous session.

[Stebos]

I'll struggle on with it as it still works, I just need to pay close attention for losing pressure.

What do you think would be a good future upgrade?

[AnonymousA667]

Maybe add some PTFE tape to the joints?

Never a bad idea. When I get a round tuit I will dismantle mine, re-build and do exactly that.

peebeep

[Stebos]

Thanks for the replies by the way.

I think I'll save up for the Harder & Steenbeck 16A from Little-Cars, it seems to have everything I'm looking for and isn't a well out there price.

[Mike]

Never a bad idea. When I get a round tuit I will dismantle mine, re-build and do exactly that.

peebeep

You could do a "How To" for all the other users out there

[Stebos]

I've been investigating this some more. Any compressor tech heads know anything?

It's not overheating as I'm getting the following problem from a few days cold start:

I've ran it with the side cover off to see how the piston arm is running.

1. switch it on and it starts to fill the tank. The gauge rises to about 30psi then stops moving, however it's still running for a while longer (shouldn't the gauge still be rising?)

2. it auto switches off as it should.

3. after about 30 secs of AB use the trigger to top up the tank switches in. The motor is still cool to the touch at this point.

4. instead of filling the tank the motor runs... but the piston starts up much quieter than usual and runs slower... and gradually slows to a stop. At this point the motor still seems to be running - it's silent, but there's a humming vibration coming from the compressor and the piston arm is still moving, but in small jerking steps of maybe 2-3mm. This continues until the tank is empty, though sometimes the piston will cut back in at full speed.

5. If I drain the tank to empty and then switch it back on it works as normal, fills the tank and then the problem repeats.

I'm guessing the problem lies with the piston not running despite the motor working (and this is likely putting it at risk of burning out)

I'm also guessing that the problem is showing up as it is because with no air stored the piston can manage, but it's not got enough juice in it to pump beyond a certain pressure.

I am right in thinking the problem is either: a sticky piston (it seems smooth enough in motion when turning it manually) or the motor isn't providing enough power to turn it when it needs to.

Something is clearly stopping it from pumping, is is fixable? Or do I have a broke compressor?

[little-cars]

Everything is fixable, it's a case of are the parts available and is it cost effective.

It does sound like either the motor or the bearings, more likely the bearings.

Looks to me like you have three choices;

Pay for someone to look at it, if it's the bearings there are specialists you could take it to get these changed.

If it's something else it may cost more than the unit is worth.

Take it apart, investigate, clean and re-build it your self, this might clear the problem, or may not.

Use it as it is until it finally runs out of steam.

I suspect it's something simple, the unit may not be overheating, but the bearings inside may be.

[gcn]

if you have your heart set on a 2nd one I have one of these gathering dust in the garage, and I'm literally down the road from you.

It runs continuously now as the tank never seems to fill up, but saying that when it did stop it would only be a matter of seconds airbrushing before it kicked in anyway.

and yes it runs exceptionally hot but I haven't had it cut out from getting too hot.

It hasn't been switched on in 9 months but I can't see why it wouldn't still work

[k_k]

I've been investigating this some more. Any compressor tech heads know anything?

It's not overheating as I'm getting the following problem from a few days cold start:

I've ran it with the side cover off to see how the piston arm is running.

1. switch it on and it starts to fill the tank. The gauge rises to about 30psi then stops moving, however it's still running for a while longer (shouldn't the gauge still be rising?)

2. it auto switches off as it should.

3. after about 30 secs of AB use the trigger to top up the tank switches in. The motor is still cool to the touch at this point.

4. instead of filling the tank the motor runs... but the piston starts up much quieter than usual and runs slower... and gradually slows to a stop. At this point the motor still seems to be running - it's silent, but there's a humming vibration coming from the compressor and the piston arm is still moving, but in small jerking steps of maybe 2-3mm. This continues until the tank is empty, though sometimes the piston will cut back in at full speed.

5. If I drain the tank to empty and then switch it back on it works as normal, fills the tank and then the problem repeats.

I'm guessing the problem lies with the piston not running despite the motor working (and this is likely putting it at risk of burning out)

I'm also guessing that the problem is showing up as it is because with no air stored the piston can manage, but it's not got enough juice in it to pump beyond a certain pressure.

I am right in thinking the problem is either: a sticky piston (it seems smooth enough in motion when turning it manually) or the motor isn't providing enough power to turn it when it needs to.

Something is clearly stopping it from pumping, is is fixable? Or do I have a broke compressor?

From what little I know about compressor and your "investigation report" I would suspect that the no-return-valve between the compressor and the tank might be stuck.

Maybe when the compressor try to fill the tank, the valve is not letting air though so the piston is struggling, but when the tank is empty, the valve is open and it is easy to fill the tank with air.

If you are still interested in fixing this, I would try to clean the valve and see if it helps (or replace it with a new/working one).

Just a wild guess base on what you have de scripted so far.

-kk

[AdriaN (MLT)]

Hmm my compressor gets VERY hot. it always did. so its nothing bad right? it also vibrates alot.

My compressor doesnt have a 'tank'. is it good or bad?

Im scared to open it up to see how it works (no need to its still knew) and its oil free too.

My compressor is the type that pumps. stops at the selected psi. then when i use my AB it pumps up what is lost.

My compressor is of Fengda Japan, it is ALMOST EXACTLY like Stebos. just mine doesnt have that black tank!

Edited June 26, 2009 by AdriaN (MLT)

[little-cars]

Hmm my compressor gets VERY hot. it always did. so its nothing bad right? it also vibrates alot.

My compressor doesnt have a 'tank'. is it good or bad?

Im scared to open it up to see how it works (no need to its still knew) and its oil free too.

My compressor is the type that pumps. stops at the selected psi. then when i use my AB it pumps up what is lost.

My compressor is of Fengda Japan, it is ALMOST EXACTLY like Stebos. just mine doesnt have that black tank!

From my reserch Fengda is a Chinese airbrush compressor manufacturer,.

http://www.cnbida.com.cn/pro.php?cata=prod...-3&name=Air compressor&id=3

They produce cheap 'Iwata copy' compressors, (retailing for about £50) and unfortunately you only get what you pay for.

Yours sounds like it could be a diaphram compressor, they usually do get hot and vibrate a lot.

So it could be that there is nothing wrong with it.

Because they ar so cheap, it's not worth getting them professionally serviced once they go wrong, it's cheaper to buy a new unit.

Tank or no tank is not really the question, the important thing is does the compresssor product a constant stream of air or does it pulse.

If it pulses, the simples way to get rid of this is to add a tank.

Paul

little-cars

[tedtaylor]

All compressors get hot even the fridge motor type that Revell used to do, that is why they had a heat shield around them. and in the summer it just gets a little worse.

I think your non return valve might just be a bit sticky.

Ted

Edited June 27, 2009 by tedtaylor

[Stebos]

The non-return valve? Is that something I look into myself? At the moment it only works if I let it empty, which is a pain as it tend to putter out with little warning.

I'm saving up for an H&S16A from Paul at little-cars, now I'm happy with an airbrush I don't mind upgrading to a better quality comp. Until I get those funds though, I'll work with what I have.

[Stebos]

Am I right in thinking that the valve is in the small L-pipe between the tank and the water trap assembly? I took the assembly off and had a poke around, there was so much water in the tank it was sloshing! Drained it out and while the problem is still there it's not quite as bad as it was.

I hadn't realised the tank needed draining, I think it might have rusted up!

[Quin2]

All compressors generate heat - It's the Law! Actually it's a law of physics known as "Latent Heat of Vaporization" which basically states that when you compress a gas, you release heat and when you release a compressed gas, you release cold. Which is why a compressor gets hot and the propellant cans get cold.

[zero]

There you go... like a lot of things from China, they don't seem to be able to tighten anything past finger tight. It's the same with airsoft guns... first thing you do when you get it is strip it down & rebuild it tighter.

LOL this reminded me of the "Official" Atari ST fix, in the good old days of computers. Ie lift the computer 3 to 4 inches off the desk, and Drop!!! This reseated the chips in ths sockets as the assemblers small fingers could not push them fully in to the sockets properly!

Point was, it actually worked, LOL

Dave

Sorry

PS, just to quote the physics, compressing Gases produces Heat.

[AdriaN (MLT)]

Which is the proper way to emtpying the compressors of air and water??

when im done i switch off my compressor and press the water release spring which releases the stored air and the water that has been trapped. i repeat this about 3 times. good enough?? or shall i release the air through the AB? im really scared that the water inside it might rust it or something :/