Problems with Iwata Eclipse SBS

[Chewbacca]

Apologies if this has come up before but having done a search for Eclipse SBS, only 2 posts came up and one of those was by me in Maritime!

 

I've had this airbrush for about 6/7 years and for the most part its been fine and has been my go to airbrush for general paintwork.  I've also got an AR-Revolution that I use for fine work and very small areas; that's the one that usually gives me problems with blocking.

 

Yesterday though, having used the Revolution to put a gloss black Alclad base coat on one part to be finished in aluminium, I turned to the Eclipse to spray white all over a 1/48 scratchbuilt H Class survey vessel flight deck and quarterdeck.  No matter what type or mix of paint I tried or what pressure (I usually spray at 15 psi but yesterday I was varying between 5 and 50 in an attempt to get it to work), all I could get at best was a spattering of paint as I lifted off the lever.  I fully strip cleaned it at least 3 times and each time it would spray water or thinners with no problem at 15 psi, but as soon as I switched the side cup to one loaded with paint, nothing.  If I put the thinners cup back on it produced a perfect spray pattern, so my logic was that the paint mix was too thick.

 

I tried with Humbrol acrylic, Humbrol enamel, Tamiya acrylic, Vallejo acrylic and Vallejo Model AIr and all were the same.  The acrylics were thinned with water (which I have used for years with no problem) , the enamel with white spirit (again, the thinners that I have used with enamel for years).  I tried thinning the paint right down to the point that when it did come out it just looked like water, yet I tried the standard mix in the Revolution and it sprayed without  a problem to the extent that in the end, I abandoned the Eclipse and did the first coat of white with the smaller airbrush.  That would suggest to me that the paint mix was okay, but the smaller spray pattern has left it looking streaky so I'm keen to get the bigger airbrush on it today for the final top coat.

 

On the first occasion that I stripped it, the nozzle was blocked but subsequent cleans showed wet paint in there that I could clear simply by blowing through.

 

Anyone else experienced this and have any ideas?

[little-cars]

Have you visually checked the inside of the nozzle for any paint gells moving around and blocking the nozzle ?

 

Paul 

[Chewbacca]

Hi Paul,

 

Yes, as far as I could with a magnifying glass.  It appears to be clear but I wonder how small any debris would have to be to cause a problem.  I did buy a set of airbrush cleaning brushes a few years ago but I had to tidy away my bench for 6 months while we had the builders in at the end of last year and they, along with a whole raft of other stuff, haven't re-materialised.  I obviously stashed them somewhere very safe!

[Ray_W]

Apologies, I am confused is the problem the Eclipse spattering at the end of the spray? If so what happens when you depress for air, pull back for paint, push forward to stop paint and do not release the air. Still spattering?

 

Ray 

[Chewbacca]

Hi Ray,

 

Not quite.  I depress the lever and pull back.  No paint come out.  I then release the lever and I get a spattering of paint as it closes.  I must confess I haven't tried closing the paint lever but leaving the air supply open so I'll give that a try tonight when I'm next out there (I managed to get the quarterdeck mostly complete yesterday using the Revolution though it was a slow and painful process - see results here (#173):

 

 

 

[Ray_W]

1 hour ago, Chewbacca said:

Not quite.  I depress the lever and pull back.  No paint come out. 

Sounds like another problem like the air cap is not sealing against its shoulder or on its threads and letting in a small amount of air. I am assuming the paint channel from the side cap is free judging by your cleaning.

 

I use a HP-CS I think the assembly is the same with the exception of the side paint cup.

 

 

I've removed the air cap to show the construction. Note the mixing occurs in the very end of the air cap.

 

It is mandatory that there is a good seal of the air cap to the body of the airbrush against that O-ring seal or on the thread depending on the Iwata design. I can duplicate your problem by loosening the air cap slightly. Loosen too far and you get bubbles in the paint cup. Tighten it up a bit for no bubbles and you still do not have an adequate seal and you depress the paint trigger for no effect and then get a short sharp blast of paint. 

 

I would say inspect the condition of this seal. The condition of the O-ring and threads and ensure mating surface are clean and locked up.  Important: Excessive force is not needed. For me hand tight is sufficient. Some Iwata airbrushes use a thread seal compound. If you remove the air cap you might crack that seal and need to replace this seal.

 

While you have it apart check the inside end of the air cap where the mixing occurs and ensure this is clean. There is not much that needs cleaning with an Iwata airbrush.

 

As a general comment, I've had my Iwata HP-CS for 15 years and in that time sprayed gallons of all types of paint - enamels, lacquers, aqueous acrylics you name it. Used all types of thinners/cleaning agents. Always what is appropriate for the paint in use. I've also used at times diluted ammonia (Windex), acetone, 95% ethanol, pure cellulose thinners and Mr Tool Cleaner (regularly) and never replaced anything and never had to break down for a clean. Never had to use a mechanical cleaner like a brush. Still the original needle and o-rings.

 

I never run the airbrush dry and never leave paint in it for extended periods of time. I've found paints settles quickly in the needle and into it's orifice so no more than 30 minutes dwell time. I clean the needle with each colour change and at the end of a session. I will leave some thinner in the airbrush between spraying jobs on the same day before the end of day clean.  Always run with a water trap off the compressor and a second mini one on the airbrush. Brilliantly easy to clean and trouble free.

 

I have no affiliation with Iwata, just love my airbrushes.

 

Ray

[Chewbacca]

Thanks Ray, that's really helpful 👍.  Unfortunately I had an early evening commitment after work last night that overran so didn't get a chance to try either this or your earlier suggestion and I won't get any time tonight either but will have a good look at that seal tomorrow. 

 

When I took the air cap off it was really tight - way more than finger tight - so it may have been damaged and with me only tightening finger tight probably would certainly suggest that I'm not getting a seal.  On one occasion on Saturday when I was trying to get it to work, I did notice bubbles of paint appearing from that area so that proves at least at that point it wasn't sealing.

[Ray_W]

11 minutes ago, Chewbacca said:

When I took the air cap off it was really tight - way more than finger tight -

Do you recall, did it have an o-ring or use their thread seal or both? 

[Chewbacca]

Pretty certain it has both

[Ray_W]

1 hour ago, Chewbacca said:

Pretty certain it has both

Should seal sufficiently on the O-ring. Check its condition, no splits or scratches. Everything clean. Tighten up. Use a little of the lube they supply on  O-ring. Very light smear. You can see in my HP-CS  there is nothing on the threads. My HP-B Plus has no O-ring and uses thread sealant.

[Chewbacca]

Well a quick update.  I took the O ring seal off and scrutiny under a magnifying glass didn't reveal any damage so I reseated it and replaced the aircap.  Gave it a quick test and it seemed to work fine with a Vallejo acrylic mixed 50:50 with water.  So thanks for everyone's input.  Hopefully that's cured it.