Airbrush help needed

[Monty Python]

Been using a H&S infinity CP-R for the last couple of years with no problems. Stripped it down today to clean it and when reassembled I’m now getting blow back. Have tried different things but still no good. 
Anybody out there had a similar experience and if so, what cured it.

TIA

[bmwh548]

As in air in the color cup or paint in the trigger area?

[Monty Python]

32 minutes ago, bmwh548 said:

As in air in the color cup or paint in the trigger area?

air in the cup causing the paint to bubble up

[bmwh548]

What thinner did you use for cleaning? The rubber seal on the nozzle cap is solvent resistant, but it still swells up a bit from lacquer thinner so it might not sit properly. If that's the case it won't push down on the nozzle enough for the PTFE ring to seal against the body and air might seep through.

I would take the front end apart, soak the nozzle, clean it using an interdental brush or similar; soak the nozzle cap (without the rubber O-ring on it), clean that with a brush too and let them air dry. Put it all together and try it again.

Do you have a new PTFE seal for the nozzle? Maybe the one on the nozzle is worn and it can't provide a proper seal anymore. Or maybe the rubber O-ring is worn and the nozzle cap sits too low restricting the air.

To be honest I think that whenever I had some air bubbling it was due to the nozzle cap not being tightened enough (don't over do it though, I never use tools for it, just my fingers).

[Monty Python]

27 minutes ago, bmwh548 said:

What thinner did you use for cleaning? The rubber seal on the nozzle cap is solvent resistant, but it still swells up a bit from lacquer thinner so it might not sit properly. If that's the case it won't push down on the nozzle enough for the PTFE ring to seal against the body and air might seep through.

I would take the front end apart, soak the nozzle, clean it using an interdental brush or similar; soak the nozzle cap (without the rubber O-ring on it), clean that with a brush too and let them air dry. Put it all together and try it again.

Do you have a new PTFE seal for the nozzle? Maybe the one on the nozzle is worn and it can't provide a proper seal anymore. Or maybe the rubber O-ring is worn and the nozzle cap sits too low restricting the air.

To be honest I think that whenever I had some air bubbling it was due to the nozzle cap not being tightened enough (don't over do it though, I never use tools for it, just my fingers).

thanks for the advice, will try it over the weekend

 

[RobL]

1 hour ago, Monty Python said:

air in the cup causing the paint to bubble up

 

You have a blockage of some sort forward of the air cup, or, as bmwh548 stated, the front end isn't quite on tight enough.

[Black Knight]

have you tried sealing the threads with some beeswax?

[Retired Bob]

17 hours ago, Monty Python said:

Anybody out there had a similar experience and if so, what cured it.

I had the same problem with an Iawata Neo a/b, I could not see anything wrong but even with just thinner in the cup all I got was bubbles.  I had a look online for help, a video was great for cleaning tips and said the problem causing the bubble blow back was a split in the nozzle, I replaced the nozzle as instructed and end of problem.  I cannot see any split or damage to the old nozzle, and it has been cleaned and retried, but I just get bubbles.  I also have the same H&S airbrush as you, the seals do not like cellulose/universal cleaner, the seals swell to double size and have to be replaced.

Hope this is helpful.

[bmwh548]

There's only one "rubber" seal on the H&S (from the trigger forward) and it almost never comes into contact with thinner when you clean it. And it goes back to the original size and "elasticity" pretty fast. All the other seals are PTFE. The nozzle seal, paint cup seal, needle seal and trigger seal are all PTFE.

I've been cleaning mine with cheap lacquer thinner for years now and I have yet to replace rubber seals on it.