Needle packing and paint

I've found that paint inevitably gets around the needle packing, especially if you pull the needle out towards the rear each time to clean it. I pull the needle out from the front, and it helps. Every once in a while I stick a micro brush through the packing and clean that area, but its not necessary each cleaning. when you re-install the packing, just screw it in alittle at a time, sliding the needle through until there is a bit of resistance. You may have to tighten the packing up from time to time.

Unless some paint has inadvertently dripped into the trigger area, It sounds like the needle seal may need tightened slightly, It's not unusual for a minimal amount of paint to find it's way past the seal, but not that much. When the seal is correctly tightened, there should be a noticeable increase in tension as the needle is refitted & passes through the seal. 

Thinking about it, it might be that the needle packing wasn't tighten enough because lately when I put the needle or when I took it out I didn't feel any resistance at all. And when I remove the needle or take it out I like to rotate it a bit so it's easier to pass it thought. And that might have untightened the needle packing. Because at other times the needle felt quite hard to pass though.

That what I think happened, and that would make sense but I'm no expert so I can just guess.

Anyway thanks for your help and I'll try to replace it correctly.

I re-use this thread because my problem isn't solve. today I painted again with the same blue paint and when I removed the needle to wipe it it was full of paint again. I took pictures this time so you can see, I had since last time re-tightened the needle packing but maybe not enough...

Here you can see paint in the rear of the cup:

keveuh

I'm still seeking a solution or at least a reason for this problem: I cannot believe it's the paint since I had used it before without this problem, needle packing missplaced/damaged ? How to know ? Not enough lube in the needle packing ? 

Please let me know if you have any idea what's going on.

I doubt that it's the paint, just coincidence as the Revolution CR has a solvent resistant PTFE seal.

The needle seal / packing is complete, but it's hard to say if it's damaged or not. I'm assuming that the seal has been thoroughly cleaned, but see that some paint residue has been left on the front face of the seal - is the seal cracked or split near these paint markings?

The needle seal screws against a flat face inside the airbrush body & when it's screwed in properly the only way that paint can get back past it is through the gap (if any) between the needle & the seal, so I'm still thinking that the seal is possibly still not being tightened enough. The PTFE seal mushrooms when the screw is tightened & if it's tightened enough it will spread to a point where the seal is too small for the needle to fit through - so a bit of adjustment should get you to the "sweet spot" (try not to get to the point where the seal is too tight, as the seal isn't that flexible & may not return to it's previous shape).

I'm figuring that you are using the CR's standard 0.5mm needle? I ask as the 0.3mm set up requires that the CR's standard needle seal be tightened to compensate for the differing needle body diameter's or that an 0.3mm needle seal be fitted;

CR's 0.5mm seal (7251);

AR/BR's 0.3mm seal (1257);

 The seal should be sufficiently tight to seal on the needle without lube being required to complete the seal.

Clearly, the seal is leaking.  Either you didn't tighten it enough, or it is damaged.  It could have internal scratches if you have ever drawn dried paint through it.  There is a passage between the seal and the cup where paint can collect.  It might be a good idea to swab this out once in a while.

Don

I have gently rubbed the needle against the needle packing to check if those marks were just dred paint or scratches and they seem to be scratches. These were already there when I first removed the needle packing when the problem happened the first time. So  I guess I have somehow damaged the needle packing, maybe with those airbrush brushes:

www.hiroboy.com/.../product_info.php

Weird thing is that  after I had this problem the first time I sprayed some Alclad primer and Tamiya acrylics and I didn't have any leaks, so maybe it depends on the thickness of the paint ? Or it is mostly a tighthening problem then. I have replaced the needle packing now and I'll try putting some food color in the cup. if that leaks it will be easy to clean.

Thanks for your help.

keveuh

so maybe it depends on the thickness of the paint ?

No, even with water there should only be a minimal amount getting past the seal, like said before it's perfectly normal for some paint to get dragged back through the seal when the needle is removed, but it should be minimal - more like pigment that is on/in the surface of the needle body rather than actual paint/fluid.

Milairjunkie

keveuh

so maybe it depends on the thickness of the paint ?

No, even with water there should only be a minimal amount getting past the seal, like said before it's perfectly normal for some paint to get dragged back through the seal when the needle is removed, but it should be minimal - more like pigment that is on/in the surface of the needle body rather than actual paint/fluid.

Yes, exactly what I had until these 2 times with that blue paint, I'll have to give it another try anyway to find the problem.

I've done some testing today. I have put food color in the cup and I tried with the needle packing tighten in 2 different ways. One way lightly tighten and more strongly tighten. When lightly tighten I had leaks on the needle packing, and when strongly tighten I didn't.

It feels like I have to tighten the needle packing quite a lot to prevent leaking and I'm sure I've seen that the needle packing shouldn't be tightened a lot. So I think it may be damaged and therefore I must tight it a lot to prevent leaks.

That's why I thnk I'm gonna buy a new one and at the same time take an extra nozzle and maybe needle too.

while you are spending all that money get some iwata super lube. minimal amounts on all moving parts, needle, trigger,  threads, needle packing and air valve improve the feel of the thing massively.

Actually I already had some Iwata super lube but I only put some on the needle packing, I'm not even sure if I use properly, I'm afraid to get that in the paint somehow.

Anyway, I recieved my new needle packing, I placed it inside the airbrush, I tighted it a little. What felt enough at least, put some food color and checked the needle packing, there as again some paint on the thread of it. So now I have replaced it again and tightened it a little more and I really feel some resistance whan placing/removing the needle. Therefore my question:

What if I tight the needle packing too much ? Will I damage it ? And how should I know when it's tight enough so paint doesn't leak but not too tight to damage it ?

Anybody with an Iwata can share their experience ? I guess most of the Iwata airbrushes have a similar needle packing.

The needle packing is a little on the firm side, so if it's overtightened it will spread / mushroom it won't readily return to it's previous shape, possibly leaving the needle a bit on the tight side.

I would fit the seal until you feel some resistance & then check, if it's too loose tighten it a bit more & check again & so on. A quarter of a turn at a time between checking will be more than enough.

If you over-tighten the seal you will have difficulty getting the needle in & out of the airbrush - if this happens, remove the seal & work it back & forth over the needle body a few times until it starts to loosen off & then re-fit it to the airbrush - when you re-fit it only do so until you meet resistance (any further tightening will spread the seal again).

Big thanks for the answer because my "damaged" needle packing seems to have this "mushroom" effect, meaning that when I put the needle through it I feel a lot of resistance and even when I try this with the needle packing out of the airbrush, while the new one doesn't "stop" the needle at all when I try to fit it in.

Anyway I've painted a little part with Tamiya acrylics black, and I didn't have any problem so I guess the needle packing sits well inside the airbrush. It feels like a bit of resistance when I place the needle but not that much. The needle tends to get "stuck" though when I try to remove it, Maybe the tip of the needle gets stuck on the nozzle. Luckily for me I also bought an extra nozzle just in case.

And the reason why I so ask about this is because the next big paint job is to clear a car body, and if the clear leaks I won't see it, therefore I want to be sure that the needle packing sits well and doesn't let any paint or liquid through.

Sorry if this is a little off topic, but if I buy a Badger how should I check for this problem, or will I not need to?

Which Badger are you thinking of buying?  Most of them are non-adjustable.  If you feel a little drag when you install or remove the needle, chances are the bearing is OK.

Don

Don Wheeler

Which Badger are you thinking of buying?  Most of them are non-adjustable.  If you feel a little drag when you install or remove the needle, chances are the bearing is OK.

Don

The Krome has an adjustable needle seal.  The shaft diameter of the needles is the same.  I believe the Krome comes with both sizes.

Don

If you buy a Badger, they wil warrant the entire airbrus including needle packing for life. Better than Iwata.