Problem with AB'S

[JR]

Seems to have very low pressure, regardless what the gauge says. I even removed the bottom drain plug, no great woosh of air either.
When I spray the paint seems very under pressure, even when I turned up the setting to 40, no difference !
I've used both of the a b's and both seem to be the same just lacking in air.

Yet when I depress the value in the connector hose to the ab there is air there. All very strange, so .4 and .2 in each ab are effected.
Has any one any ideas please.

I've tried various mixes thinking it might be the thickness of the pain, I did manage to paint the Toon had to have several goes.

John.

 

[Archetype]

So the pressure is right and you’re getting air without the ab attached, but getting reduced air when using the ab?

Are you able to check the valve at the base of the trigger that lets the air in? Could be sticking or obstructed?

 

[JR]

So the pressure is right and you’re getting air without the ab attached, but getting reduced air when using the ab?

Are you able to check the valve at the base of the trigger that lets the air in? Could be sticking or obstructed?

Hi Chris, thanks for replying, yes that's right to your first question.
Very strange as using the mixed up needle on them it seemed fine, of course the paint did spray well !
In answer to your second question,
Yes I did think that, so stripped both down, nothing, If I push a very thin metal tube into the valve down through the ab from the trigger housing there is plenty of air, admittedly this opens its fully .

 

[Archetype]

Hmm....strange!

The paint mixture shouldn’t affect the air delivery, only the paint delivery.

If the issue is with the spraying pressure then I would inspect the paint line and check the needle is retracting as expected.

 

[JR]

Hmm....strange!

The paint mixture shouldn’t affect the air delivery, only the paint delivery.

If the issue is with the spraying pressure then I would inspect the paint line and check the needle is retracting as expected.

The needle is retracting perfectly Chris.
In the morning I'll strip both down again and post some photos.

 

[Archetype]

A mystery then!

Full strip down is wise. The only other thing I can think that it might be is the nozzles, but it’s odd that it’s on both.

The valve on the end of the hose is not faulty? The hose / valve connection is airtight?

 

[Tim Marlow]

I would check the air delivery from the hose again John. This sounds like a delivery tube blockage rather than an airbrush blockage. As Chris says, check the valve at the end of the hose is working as it should and you are getting a high volume of air delivered from the tube. You can get pressure without airflow.....The other thing that comes to mind (pretty off the wall, but worth checking) is that the line from the compressor to the brush has been fitted the right way around. I don’t think they are directional, but that might be a problem.

 

[Jim R]

Hi John
I don't know what compressor you have but if it is an AS186 or similar then it could be the valve in the head. Have a look at THIS video. I have serviced mine as it was not coming to pressure. In the head there is a brass flat valve thing held in place by a screw. If that valve becomes slightly bend upwards it will not seal. The solution is to remove the head (4 bolts) clean out the crap in the head - ensure things are clean. Undo the screw and reverse the brass strip, centering it over the hole under it. The video explains it quite well. My compressor is now running perfectly.
Jim

 

[JR]

Hi again, rather early to strip the compressor at this hr 0430 ! But will definitely try that tomorrow, plus Tim's suggestion.
Chris , Tim and Jim , thank you.
Going to have a concerted effort later , starting with the compressed, yes Jim it is a 186, , 4 years old .That video is most helpful, now where that Allen key
More later !

 

[Deleted member 7181]

I'm a bit late to the party but if both brushes are affected the same way then its pretty much got to be something upwind.

It could possibly be a restriction in the hose, regulator or quick release, but compressor seems by far the most likely.

As suggested, maybe it's producing enough air to build up a decent static pressure, which is how it can register on the gauge when not in use, but hasn't got the puff to keep up demand in use (dynamic pressure).

I stripped my 186 down not long after getting it and it's a fairly simple process so definitely worth a go.

 

[JR]

I'm a bit late to the party but if both brushes are affected the same way then its pretty much got to be something upwind.

It could possibly be a restriction in the hose, regulator or quick release, but compressor seems by far the most likely.

As suggested, maybe it's producing enough air to build up a decent static pressure, which is how it can register on the gauge when not in use, but hasn't got the puff to keep up demand in use (dynamic pressure).

I stripped my 186 down not long after getting it and it's a fairly simple process so definitely worth a go.

Morning Andy, was hoping last night that you might appear .So glad you have joined in.
Think you are on the right track, if both AB' s are sharing similar problems,it must be the source of the air.
Once I've been lucky enough to have toast and coffee I shall hurl my self from bed, as I've just been given first warning the coffee and toast may be off !

 

[Tim Marlow]

Be methodical John. Start at the source and work outwards, testing airflow as you go. The bit where you don’t get airflow is the problem......

 

[JR]

Be methodical John. Start at the source and work outwards, testing airflow as you go. The bit where you don’t get airflow is the problem......

Morning Tim
Checked the hose from the compressor to ab ok
Took compressor head off.






No dirt , that plate In photo above I turned over.

Now reassembled andg this time no pressure at all .
When trying to undo the head bolts again one has refused to move, the socket head part is so soft .
Result going to cut my time and just look for a new one .
Can't undo the screw, even with grips or
Pliers.
Thanks for all the ideas and help every one .

John .

 

[Tim Marlow]

Are you getting air though? If so, you may have a leaking joint. Use an old one inch brush and some soapy water to look for leaks....to do this, dip the brush in the water and paint it over the suspected joints....fresh bubbles will mean leaks!

 

[JR]

Are you getting air though? If so, you may have a leaking joint. Use an old one inch brush and some soapy water to look for leaks....to do this, dip the brush in the water and paint it over the suspected joints....fresh bubbles will mean leaks!

Tim, there is nothing ! Dead as the Parrot.

 

[Tim Marlow]

Hasn’t just blown a fuse has it?

 

[MikeC]

Not sitting on the hose are you???

 

[MikeC]

Morning Tim
Checked the hose from the compressor to ab ok
Took compressor head off. View attachment 371820

View attachment 371821

View attachment 371823
View attachment 371822

No dirt , that plate In photo above I turned over.

Now reassembled andg this time no pressure at all .
When trying to undo the head bolts again one has refused to move, the socket head part is so soft .
Result going to cut my time and just look for a new one .
Can't undo the screw, even with grips or
Pliers.
Thanks for all the ideas and help every one .

John .

John,
Have you checked the preassure valve itself, there could be some gunk in there. If it is the valve give me a shout on the blower.
Mike

 

[JR]

Hasn’t just blown a fuse has it?

No Tim, power is there. just no pumping .

John,
Have you checked the preassure valve itself, there could be some gunk in there. If it is the valve give me a shout on the blower.
Mike

I cleaned out the bottom release valve, just a little damp in the trap, and no I wasn't sitting on it, but when I trip over the lead it nearly ended up in the garden !
John.

 

[Deleted member 7181]

No dirt , that plate In photo above I turned over.

Now reassembled andg this time no pressure at all .

Have I got the wrong end of the stick John? Seem like you are saying you turned the black plate over?

If you refitted it upside down then that's probably why there's no pressure at as the diaphragm valves will now be working the wrong way.