Airbrush sprays intermittently

[Tromance]

Hello all.
I am very new to airbrushing, and have purchased - against the advice of some, it must be said - a cheap Chinese airbrush, as it's the only thing I can get hold of here in the Middle East, at least for now. That said, it feels sturdy enough. Here is a pic.

The problem I'm having is that the paint spray is intermittent. It's dual action, so I press the trigger, pull back, and all is good for a few seconds, but then the paint supply stops. I release the trigger, then bring it in again, and it works again. I suspect something somewhere is blocking it, but my knowledge isn't sufficient to know for sure.

As far as I can tell there are no burrs on the needle, or anything that looks out of place to the naked eye. Could anyone recommend things to check?

Here is a pic of the airbrush disassembled as far as it will go. The last piece of the nozzle doesn't unscrew - at least, I haven't been able to budge it.

Many thanks.

 

[Elm City Hobbies]

Sounds like the paint might not be quite thin enough, or you don't have enough air pressure and it is causing the intermittent spraying.

 

[Tromance]

Sounds like the paint might not be quite thin enough, or you don't have enough air pressure and it is causing the intermittent spraying.

Thanks for the advice. I'm spraying at about 20PSI. I thought the paint might be too thick, so I tried spraying just water, which seems to be OK. So I added four drops of Aqua Color to a pretty much full cup, and it messed up again.
I've had other advice suggest a deep clean of all the components in case there's some sort of manufacturing gunk still on it all.
The lesson appears to be not to buy cheap knock-offs, but I'm still keen to see if I can get as much out of it as possible before upgrading.

 

[pxpxpx]

My guess is also the paint being too thick. Start with 70/30 thinner to paint and see if it sprays properly and then add some more paint until it starts acting up.

Apart from thinning your paint, try cleaning the nozzle with some laquer thinner (or other strong solvent). Just don't lose it, it's real tiny and easy to lose (ask me how I know ). Screw it back carefully.

Do you have any other brands to try out? My Iwata Neo absolutely refuses to spray some colours (Vallejo Metallics mostly) that my H&S Infinity with the smallest nozzle sprays without a hitch. Perhaps your airbrush just doesn't like your current brand?

 

[Tromance]

Thanks for the advice. Have cleaned everything as well as I can without brushes and the like - soaked the small bits in cleaner and then twizzled where possible with the end of a piece of kitchen roll. Rubbed down the needle with cleaner too.

Then I started with a cup full of water and added Revell Aqua Color one drop at a time, mixing it in the cup with an old paint brush. It's definitely better than it was, but it still starts spitting a bit and cutting out the paint supply far earlier than I'd expect it to. I've been told that the paint should be the consistency of milk - it's a lot runnier than that. I was spraying light coats on a piece of paper and it was soaking through it.

Argh. I wish I knew whether it was still just me doing something wrong or the fact that it's a dodgy copy brush. I guess the only solution is to get a proper brush and see if it still happens.

Sadly I don't have another - I haven't been able to find anywhere that sells anything other than the type I've got out here. I'll be visiting the States at the end of the month, so might try and pick up a better one.

 

[TiM]

I am only speculating here, however it sounds like...

there may be a film of dried paint inside the nozzle which once you soften it a bit with fresh paint flow and air is coming loose and partially blocking the passage past the needle... sort of like a heart valve.

Not being sat there.. are you sure the front won't unscrew further, it might mean getting careful with a pair of pliers to separate and really clean inside the nozzle itself.

note, I might be completely wrong ;D

 

[Quaralane]

Tim might be onto something here

 

[Tromance]

Thanks chaps. A good soaking in airbrush cleaner has improved things somewhat, although I've still not hit on a good balance of thinner v paint. Either I'm basically spraying water or I'm gooping up the airbrush. Got some airbrush cleaning brushes on the way so hopefully that will help things further.