HELP - Airbrush problem

What air pressure are you using?  You need at least 25 psi to keep a VL from spattering.  That thick needle just doesn't atomize well at low pressures.  HTH.

E

Persephones_Dream wrote:

MikeV wrote: What are you thinning it with? You shouldn't be having those results at all.   I am wondering if the aircap is leaking and causing this. Have you tried putting a narrow piece of Teflon tape on the threads of the head and then put the head on and tighten it? Not too tight now as it is brass. Mike, I'm thinning with Model Master thinner. Hmmm.....no, I haven't tried teflon tape on the threads of the head.....  Thanks!  Lemme try that! -Ro

It's worth a try as Paasche VLs are notorious for that problem.  

MikeV wrote:

What are you thinning it with? You shouldn't be having those results at all.   I am wondering if the aircap is leaking and causing this. Have you tried putting a narrow piece of Teflon tape on the threads of the head and then put the head on and tighten it? Not too tight now as it is brass.

Mike,

I'm thinning with Model Master thinner.

Hmmm.....no, I haven't tried teflon tape on the threads of the head.....  Thanks!  Lemme try that!

-Ro

What are you thinning it with?

You shouldn't be having those results at all.  

I am wondering if the aircap is leaking and causing this.

Have you tried putting a narrow piece of Teflon tape on the threads of the head and then put the head on and tighten it? Not too tight now as it is brass.

MikeV wrote:

Ro, Are you straining your paint through a piece of pantyhose material or similar? I was curious if you had lumps that are causing this. Have you tried other paints? What kind of compressor are you using and are you using a water/oil seperator on it?

Mike,

No, I am not straining my paint.  It certainly doesn't look lumpy at all, especially when thinned to nearly 4:1.  Very watery and even/smooth. 

So far, all I've used (and all I have) are Model Master paints.  I've tried a bunch of different colors though.

The compressor is an Iwata Silver Jet and yes, there are water/oil traps on the line.

-Ro

Ro,

Are you straining your paint through a piece of pantyhose material or similar?

I was curious if you had lumps that are causing this.

Have you tried other paints?

What kind of compressor are you using and are you using a water/oil seperator on it?  

Your problem exceeds my experience.  It seems as though you've eliminated all the obvious variables that I would play with if I were experiencing that problem i.e. different paints, different thinning ratios, different air pressures, different painting distances.  I've never used a Paasch VL, but I do own a Paasche H which should theoretically have worse atomization than he VL, so other than than sympathizing with your plight, I have no ideas.  Keep fiddling, and good luck.

Andy

ABARNE wrote:

Persephones_Dream wrote: The black line at the top of the pictue is approximately 1 inch Do you mean one inch long?  When I click on the your photo, it expands so that that line is an inch long on my monitor.  If so and I am therefore looking at your sample at life size, zero magnification, you definitely have a serious atomization problem there.     Persephones_Dream wrote: I've thinned the paint up to almost 4:1 and have tried with no thinner at all... By 4:1, do you mean four parts thinner to one part paint?  If so, that should have covered the thinning angle.  If you mean four parts paint to on part thinner, try using more thinner.  I certainly have experienced a similar effect before when I did not thin the paint enough.  How does it feel when you run your fingers over it?  If it feels gritty like fine sandpaper, I would definitel add more thinner.    Persephones_Dream wrote: I've tried air pressures from about 8 psi to 40 psi. When you vary the air pressure, do you feel it coming out the tip as well?  Lousy atomization could occur from paint that's too thick or it could come from too low an air pressure.  Now I usually spray at aboy 15 PSI, maybe a bit less for close-in camo or a bit more for further out base coating.  My compressor can't even get to 40 PSI, but I can notice a huge diffenece in painting between 10 and 25 PSI.  So I am wondering if there is something messed up in the trigger air valve or maybe some sort of clog in an air passage that is preventing the 40 PSI from your regulator from ever reaching the tip.  Maybe your AB body is messed up somewhere, so that all it is getting is 8 PSI at the tip. Andy

Andy,

Thanks for the reply.  To answer your questions....

Yes, I tried to scale the photo so it would appear as life size, zero mag.  If it is not, the black line in the pic is scaled to the photo regardless.

Yes. Thinners up to 4:1 ratios with the paint. 

The weird thing is, when the paint is dry on all these samples, it feels fine. No grit.  Nice and smooth.  This doesn't seem to change much when it comes to thinner ratios. I posted some pics in the aircraft forum of a finished Bf-109 Tropical.  Take a look.  The paint is fine on the aircraft other than the lack of thin, smooth lines (but in this case, it sort of works for the model anyway).

Yes, I can definitely feel a difference in air pressure from the tip when I vary it on the compressor.  I can hear the difference, too.  So it doesn't seem to be that, at least as far as I can tell.

Hmmm???

-Ro

Persephones_Dream wrote:

The black line at the top of the pictue is approximately 1 inch

Do you mean one inch long?  When I click on the your photo, it expands so that that line is an inch long on my monitor.  If so and I am therefore looking at your sample at life size, zero magnification, you definitely have a serious atomization problem there.   

Persephones_Dream wrote:

I've thinned the paint up to almost 4:1 and have tried with no thinner at all...

By 4:1, do you mean four parts thinner to one part paint?  If so, that should have covered the thinning angle.  If you mean four parts paint to on part thinner, try using more thinner.  I certainly have experienced a similar effect before when I did not thin the paint enough.  How does it feel when you run your fingers over it?  If it feels gritty like fine sandpaper, I would definitel add more thinner.  

Persephones_Dream wrote:

I've tried air pressures from about 8 psi to 40 psi.

When you vary the air pressure, do you feel it coming out the tip as well?  Lousy atomization could occur from paint that's too thick or it could come from too low an air pressure.  Now I usually spray at aboy 15 PSI, maybe a bit less for close-in camo or a bit more for further out base coating.  My compressor can't even get to 40 PSI, but I can notice a huge diffenece in painting between 10 and 25 PSI.  So I am wondering if there is something messed up in the trigger air valve or maybe some sort of clog in an air passage that is preventing the 40 PSI from your regulator from ever reaching the tip.  Maybe your AB body is messed up somewhere, so that all it is getting is 8 PSI at the tip.

Andy