Problem with brand new H&S?

[haga1981]

A warm hi to all. I have two questions about the packing screw which hopefully can be addressed.

1. Is it normal on a brand new H&S Evolution Silverline the packing screw to be problematic? I am asking because on my copy (just bought) even though the screw is completely tight the needle passes through it with minimal resistance. I have close to zero experience with airbrushes but still, the resistance is barely noticeable and i also found some light traces of paint on the trigger and air valve parts behind it. I checked the tightness of the packing screw with the respective screwdriver from H&S and indeed is maxed out. Can there be a problem with the PTFE seal?

2. Under what circumstances a perfectly set-up (resistance wise) packing screw, so adequately tight to do its job, the next day can feel completely loose? It has happened on various occasions and with various airbrushes so far. I spend some time to set it up just right and the next day is either too loose or (not so often) way too tight.

Thank you in advance.

 

[RK Ink and Focus]

I set up my needle bearing to just slip down the needle under its own weight. It is a fine line between too tight and just right and can be affected by needle lube, heat etc. some brushes such as thayer and chandler did not have an adjustable needle bearing so it could be that you are over thinking it as I do not need to adjust mine often.

Teflon can be a struggle to compress, I dont particularly like it as a needle bearing material. I have felt the same type of uncompressible resistance you are experiencing when fitting one in an old aerograph, I much prefer the feel of the old leather seals and orings. Once you have compressed the teflon it also does not have much rebound so will quickly become out of shape if over tightened.

If it is brand new and this is a consistent problem you are experiencing with this brush only there could be a defect in the teflon bearing, the bearing carrier nut or the brush body and I would suggest contacting the supplier and/or harder and Steenbeck for them to take it back for inspection and adjustment or replacement.

 

[RK Ink and Focus]

Any pictures of the parts and type of paint ingress will help others to help you more. This is hard to fault find without the brush in your hand.

If the teflon has been over tightened then it may need replacing due to its lack of rebound and it could have become distorted. It should have been tested and set up before it left the workshop, it may be that what you are experiencing is not an issue as such but if you are not happy with it and it is affecting you wanting to use the brush then I would contact H and S.

 

[erwin de pan]

What you describe is the opposite.
what is my experience with a new iwatta airbrush.
I found the resistance there too much.
And I just loosened the screw and tightened it a little bit after a few days of use.
You only need a little bit of resistance.
If I hold the airbrush with the tip down and release the needle with the tip for the gasket, it should stop before it hits the nozzle.

 

[yfen444]

You can buy additional needle packing PTFE rings from H&S accessories, there are 3 of them in one pack if I remember correctly and you need 2 to put in your needle packing screw.

My standard for the tightness of needle packing is that the friction is just enough to stop the falling of a needle from its weight.

 

[Airbrushkid]

I have a lot of Iwata's with PTFE rings, Microns, C's, BC's etc, that I used solvent base paint and 30 years of use never replaced one. You mention you bought it new. Was it sealed?

 

[DaveG]

Teflon is not a resilient material, so it does not have any rebound. If it was tight, it will stay tight until it wears, and that will not be overnight - it can only happen with friction. So, this makes me think that it may not be properly adjusted to begin with. I would suggest removing the internals to access the packing retaining screw, and remove it altogether. Inspect the screw and packing seal to make sure there is a little of the teflon seal protruding from the retaining screw. If there is no tefon at all protruding from the screw, it has already been over-tightened, and will more than likely need to be replaced. If you need to replace the packing, do so - then install the screw into place and tighten it only until you start to feel some resistance while turning the screw. Test the needle fit. You will want to feel a little resistance, but not so much as to feel "grabby" or tight. Adjust accordingly until you feel what you need to feel.

 

[haga1981]

Thank you for all replies. To address some comments...

Yes the Airbrush was received sealed and therefore completely new. The packing retaining screw was removed and @DaveG nailed it. The seal did not protrude AT ALL from the screw. Apparently it was originally over-tightened and therefore ruined...

I had no idea it should be like that (protruding part). Thanks again for this extremely helpful piece of Info.

In any case the Airbrush is already on its way back. I was not very satisfied with it anyway (0.2 needle too sensitive to damage, trigger too hard to push and too light to pull).