I am very, very new at this…I have recently finished my first model and now ready to paint my second. I noticed right away that very little paint was coming out, even at max psi and the needle pulled back all the way. FYI, I am talking about an Eclipse HP-CS on a SmartJet compressor, using Tamiya acrylics slightly thinned.
I normally clean the airbrush quite thoroughly, with thinner first, then water, then a mixture of thinner and windex and then water again. So instinctively disassembled the airbrush and gave everything a good clean. I have even tried replacing the 0.35mm nozzle + needle with a 0.50mm needle + nozzle (brand new) but still no paint! There is a lot of air but no paint. I even tried it with plain water, still no spray. Just air.
Maybe I did not assemble the trigger correctly after taking the airbrush apart, it was my first time doing that. Or maybe one of the parts isn’t doing its job, I don’t know. I also can’t figure out just how much of the needle should be protruding from the front of the airbrish body before you put the nozzle on it. Can someone help me out here? I would really like to finish this model, and also because admittedly, I am in love with my Iwata! I want it back!
First thing to do is, without anything in the cup, look down the front (into the needle) and pull the trigger back. Make sure the needle is pulling back with the trigger. If not, you forgot to tighten the rear needle locking nut and the trigger assembly is just sliding over the needle.
If the needle is moving and you still get no paint, there’s a jam in either the feed neck, the cap or the nozzle. The nozzle is easy to clog and a real PITA to clean. Soak it in windex over night (soak the entire front assembly while you’re at it - nozzle cap, needle cap and head cap).
Looked down the airbrush (into the needle), everything appears ok. Needle moves with the trigger. Once again: how far into the nozzle should the needle tip be? Should the tip be jutting out the nozzle end?
No visible clogs in the cup or feed neck. The nozzle may be clogged since I cannot see any light looking down the wider end into the narrow end. Front assembly is now soaking in windex, as suggested.
However, as I mentioned earlier, I switched this needle + nozzle with a brand new out-of-the-box needle + nozzle and there was still no paint. It just doesn’t make sense.
With the front end assembled, push the needle in as far as it will go. It’ll stick out about 1/16" past the nozzle cap. If it’s not all the way forward, you’ll end up leaking paint, instead of blowing it.
As suggested, you could try a simple backflush. Charge the brush and put some water into the cup. Place your finger against the cap and push/pull the trigger (as if trying to paint). If everything is working, you’lll get bubbling in the cup. At least you’ll know the air and paint are mixing.
Check that the Nozzle cap is correctly seated and tight (but dont’ over-tighten)
Check that the air cap is correctly seated and “finger-tight”
When you look at the front of the nozzle cap (after assembly) you should see the tip of the nozzle protruding (with the needle protruding, in turn, from the nozzle tip), with a slight clearance around it for airflow.
While looking at it from this point-of-view, pull the trigger back and watch the motion of the needle.
If you only see a very small movement of the needle (ie. if the needle does not pull all the way back inside the nozzle), the needle guide cylinder may not be screwed sufficiently into the rear of the body. If this is so, loosen the needle lock nut and pull the needle back about a centimetre or so. Turn the needle guide cylinder clockwise to screw it further into the body. Re-seat the needle, tighten the needle lock nut and test again.
Ok now I am reasonably sure that my 0.35mm nozzle is clogged. I switched it with the new 0.50mm nozzle and needle and it sprayed fine.
So now, problem #2: how do I unclog the nozzle? I did soak it in windex overnight but there is no visible improvement. It still won’t spray. Do they make wires thin enough to go through it? The funny thing is that I took out the nozzle and put it against the tiny hole that the air comes out of, and I could swear I saw some residual windex spray out but when I tried to spray again with the nozzle assembled, there is no paint again!
Yes, I tried with plain water too and even water does not spray so it is not a case of the paint being not thin enough, as I thought it might.
If you have some light electrical wire handy, you might try stripping a length of it and using a single strand of the conductor to poke (gently) into the nozzle. I’ve done this with my 0.35mm Sparmax nozzle. When you do this, resist the urge to ream it out.
Another thing you might try is soaking the nozzle in lacquer thinner. It should rip any paint out of there pretty quickly.
If you have been wiping out your paint cup with a rag, tissue or paper towel, you may have an accumulation of fibres in there.
I’m a bit slack, I should do this too, but when you backflush (by blocking the nozzle and forcing air back into the paint path), after it bubbles up in the cup, pour it out, don’t spray it through
What you want is the metal needle to clean the internals of the nozzle. True, this thing is not made for the brand and make of your airbrush, but I am sure it will be far less hazardous to the nozzle than just about any improvised tool you otherwise might be tempted to try.
Now, I am confused. In your first post, air came through, but no paint. If air comes through, the nozzle will not be completely clogged. You changed to the 0.5 mm nozzle/needle then and no difference. Now the 0.5 mm nozzle/needle works fine. What changed?
Backflush works wonders unclogging nozzle in most cases. If it did not work for you, the clog must be really sturborn. Dried acrylic could be very sturborn and scrapping it off is the most effective way of cleaning. But I still don’t understand how you would see bubbles when backflushing if the nozzle is clogged?
The Eclipse nozzle is relatively cheap in the US. Hope that it is the same in Pakistan. Why not try a new 0.35 mm nozzle? Use water only at first. If it does not work, replace the needle too. How much you paid for the 0.5 mm nozzle/needle? The 0.35 mm ones were priced the same. Good luck, you present us a real mystery.
p.s. If the CS is less than a year old, send it back for repair under warranty. It is free unless they found the airbrush damaged by misuse.