CM-SB not spraying well-what should I do?

[Melbee]

OK Folks, here's a quick update. I got my airbrush back from Iwata today, they changed the needle and did tests apparently.

So like a happy bunny I fired it up to find it doing exactly the same as it did before I sent it!! They didn't fix it at all! I don't understand how their technicians would think it was spraying good?

Anyway, I took off the 0.18mm Head Unit and New Needle and then put in my spare 0.2mm Head Unit and Needle and did another test spray. Then compared the two and you will see from the photo's that they look pritty much like the pictures I posted before I sent the airbrush to Iwata.

I don't think you need to be an expert to see the difference between the two tests.

I've sent them an email asking them to send me a Replacement 0.18mm Head Unit and the problem should be solved and it is a shame they did not replace it before they sent it back to me. I have no idea how they will respond but I've sent the photo's and I will see. If they don't I have wasted a lot of money (I can't afford) on a Faulty product. I just hope they do the right thing.

 

[AndreZA]

That sucks so bad. But one thing you can't use the same mixture in two different size setups. I reduce my paint more if I use my .15 Infinity. Hope you get sorted, again.

 

[Immortal Concepts]

Try reducing more first, anything under .2mm requires further reduction. When airbrush companies test airbrushes they just use ink. Quick, easy to clean, no reduction needed. Problem is though ink behaves differently since doesn't have larger pigments. I've had airbrushes that won't spray paint reduced 300% but will spray ink no problem. Also have you checked the needle packing? If one is not adjusted properly I've seen it do a similar skipping pattern as well. Can cause a vortex inside the head and pulse air delivery from either being too tight or too loose and needle isn't actually seating.

 

[Melbee]

That sucks so bad. But one thing you can't use the same mixture in two different size setups. I reduce my paint more if I use my .15 Infinity. Hope you get sorted, again.

Hi AndreZA, OK, I've just tried the 0.18mm again with 1:3:3 ratio of Com-Art 60% Gray:Com-Art Medium:Bottled Water and it does make an improved difference but it still is grainy and unreliable. I have a feeling I won't know if this Head is good or not until I have a new 0.18mm Head Unit to test it against.

To be honest, when I put the 0.2mm Olympos Head Unit in the CM-SB body it's brilliant!! And it puts this 0.18mm Head Unit to shame. I just keep thinking if I didn't have the Olympos Micron to use I would have been up Sh*t Creek without a paddle with this CM-SB.
I'll do more tests tomorrow because I'm tired and fedup now.

Try reducing more first, anything under .2mm requires further reduction. When airbrush companies test airbrushes they just use ink. Quick, easy to clean, no reduction needed. Problem is though ink behaves differently since doesn't have larger pigments. I've had airbrushes that won't spray paint reduced 300% but will spray ink no problem. Also have you checked the needle packing? If one is not adjusted properly I've seen it do a similar skipping pattern as well. Can cause a vortex inside the head and pulse air delivery from either being too tight or too loose and needle isn't actually seating.

Well, I have to say Immortal that I do have trouble with the Packing screw. I have to tighten it because otherwise it just spins around loose and I know it's too tight. The only thing I can think of is to put some PTFE tape round the threads, would that work? Is there something else that would stop it being too loose? I feel I got a real duffer here!

Good to know about Iwata using Ink in tests, that does explain why they might think it sprayed ok. My main complaint is that the spray pattern is too grainy and unreliable, it is better now I've reduced it more but the problems are still there, just less. I'd never want to airbrush with paint this thin anyway.

Thanks guys,
Cheers Mel

 

[AndreZA]

Unless I want coverage quickly, I mix at least 1:6 with water and then a drop or two of medium. And that is with about 10-15 psi.

 

[Immortal Concepts]

I've heard of people making their own packing but I wouldn't recommend it. Check the threads on it and in the body. If you go too tight you can actually strip them out. It's really not supposed to be tight. Tighten to snug then a 1/4 turn. I've gotten a micron before brand new that had the threads stripped out from whoever assembled it. Took me forever to figure it out.
Even if the packing is bad, ink tests usually pass because it doesn't affect it since they spray make a squiggly line then dump it out. If you continued to spray then it may leak into the body. People who buy a mojo know all about this. Mike tests with ink as well and sends you the test peice. Fill er up with paint and it won't spray. Adjust the packing and it starts spraying. I can't really explain why this is but I know from experience.

 

[Russ Allen]

I think you definitely need to reduce more with the .18 setup. I love my SB, excellent brush, and another thing I do that seems to help quite a bit for me, when I reduce my paint, I let it set for 5 minutes after first mixing it, give the reducer time to break up the pigments, then mix thoroughly again before spraying. Looking at your picture, the .18 setup lines look like you either have too much pressure, or you are pulling back on the trigger too much. It does look grainy, but then again, that happens a lot if the reducer hasn't had time to break the pigments apart. With the packing, when you insert the needle, you should feel a SLIGHT resistance when going through it, if you feel a lot of resistance then you have it too tight. I know I preach on these three things a lot but they really come into play with fine details like what you need the microns for. #1 Trigger Control, you can have the perfect ratio but if you don't have good trigger control, it can be a pain. #2 Reduction, this is a big step when going from say a .3 nozzle to a .18 setup, you have to really play with your reduction to see what really dials it in best for you and #3 Air pressure. If I'm trying to get really fine details, I like to be around 12psi, even though I've gone down to 8psi before with illustration paints. You really need all three of these to work in unison to have what I call ones SWEET SPOT. I know exactly how frustrating it is but without really seeing the issue on video or being there to help its really tough, just a guessing game trying to figure out exactly whats causing your issue. I say start with your 1:3 reduction, spray 3 lines, then turn the air pressure down by 5psi, spray 3 more lines. Then make your reduction 1:6, spray 3 lines at your beginning air pressure, then lower it by 5 more psi and spray 3 more lines. Then try it at 1:9 reduction, spray 3 lines, then turn the air pressure down 5 psi and spray three more. Use this process to see if you can dial in a sweet spot that works for you, as it will be different for each of us depending on several variables. Best of luck to you my friend.

 

[Immortal Concepts]

I'm really leaning towards the packing imo. I don't know how different if at all the taper is on a .18 vs a .2, but if they aren't identical then the .2 may be seating perfectly and the .18 isnt. An improperly seated or bad packing will spray just like yours is, it wont atomize just right and act like the paint is too thick and produce splatter regardless how thick or thin paint is. How is the drag on the needle when you pull it out? If you have to really grip the needle to pull it out, then it's way too tight. I would loosen it a little and keep testing it to see if it changes. If it does change then you know it's the packing. If it doesn't, you have at least ruled out a variable. I'm just trying to think outside the box with all that's been messed with and no results. Like russ said, reduce more and try different air pressures. Each one of my airbrushes requires a different reduction to perform. Some are all .2mm and still require different psi and reductions. All in how the brush is made. I know years ago when I had a micron I found myself really really reducing my paint to get it to perform how I liked. if you go above 35 psi with a detail gun, a lot of them won't do squat. I rarely go over 27 psi unless it's a bottle feed. I would say my average sweet spot is around 15-20psi.

 

[Melbee]

Unless I want coverage quickly, I mix at least 1:6 with water and then a drop or two of medium. And that is with about 10-15 psi.

Ha Ha Ha!! Yes I know you like to airbrush water with a few pigments dropped in! As you are also a Com-Art user, is your paint grainy?
And why would the 0.2mm give a non-grainy pattern and the 0.18mm have a grainy pattern when it's the same paint?

 

[AndreZA]

It's not as smooth as E'tac but not so grainy as what you are experiencing.

 

[Melbee]

@Immortal Concepts I checked the threads on the packing screw and they look fine, I can't see inside the body though. However I have put plummers tape around the threads on the packing screw and changed the rubber packing o-ring for a teflon o-ring (I bought it when I bought the airbrush). The plummers tape definitely helps keep the packing screw from slipping around and I have adjusted the tension so it feels a slight resistance when I put in the needle. Generally it feels a lot better with the Teflon packing o-ring and it doesn't seem to be leaking paint like before.

@Russ Allen @AndreZA and @Immortal Concepts I've followed all your advice and re-tried my test with much more water in the reduction, different psi settings and with the packing screw adjusted. AND it is better!! I don't like it much but it's better. The paint is so light that my camera won't even focus to take a picture of it. Ha Ha Ha!! Anyway, thanks for your advice guys, I'm feeling better about the airbrush. Like I said I won't use it if I have to paint that light but at least I know that it is working better. I can still use the Olympos 0.2mm setup on it and I definitely like that. I've already started a new painting today using it which is why I'm so tired and my back is aching like hell!!

Thanks for all your help guys You've really cheered me up and added to my knowledge base
Time for feet up and a small Brandy and Lemonade me thinks

 

[Melbee]

Thanks for all the help and advice guys, you've helped me loads with this situation.

I've decided to give up trying with the 0.18mm for now because I don't like to reduce my paint that far so I'll stick with the 0.23mm setup. I'm just so glad my Olympos came with a spare 0.23mm Head Unit and that it fits the CM-SB because it is so much easier to use and sprays paint at the reduction I like. I can also use the same paint reduction in both my CM-SB and my Olympos and share the same 0.23mm parts. It makes life easier and I like easy!!

Also I think Immortal had it spot on with the Packing Screw because it works better since I put plummers tape around the threads, it's not loose anymore so I can make fine adjustments and it stays in place. So no more skipping and the needle isn't held too tight. I'll eventually order a new Packing Screw but there is no guarantee that it will work better than the one I've got so the tape will do for now.

You're all great and I really, really appreciate all the help I get.