Airbrush problems.

General Modelling discusion that doesn't fit into any of the other sections
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Augustus
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Airbrush problems.

Post by Augustus »

I only have 1 airbrush, the Neo .35, which served me well on my first 2 models, and then came the 35(t) which was giving me loads of jip already but that's a different matter?

I laid down the primer, Vallejo black, and that went well. As it was very thick, when I finished, I gave it a good strip down and clean.

When I started the base coat I thought the air pressure was low and it continued to get lower the more I sprayed. This resulted in horrible orange peel all over the model, however I'm more worried about the airbrush.

I cleaned it again and it was still blowing very low. I tried to localise the problem.

I blows fine without the needle cap and nozzle cap on. So with just the needle sticking out and the hole below it it blows good and strong. Then when I add the nozzle cap (with or without the needle cap) and do it up tight the pressure drops. As I loosen the nozzle cap the pressure builds up again.

Im afraid I have no idea how these things work. Any ideas anyone?
chalkyw
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Re: Airbrush problems.

Post by chalkyw »

Not an expert but my Neo is performing ok.....bum seals maybe?
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digger303
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Re: Airbrush problems.

Post by digger303 »

Assuming all parts are clean( nozzle causes most problems). Just to be through I would soak the nozzle in either airbrush cleaner or lacquer. You might have the needle to far forward. Back the needle out a little add the nozzle then gently push the needle forward until it seats then back it off just a little then tighten the back clamping nut.
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Augustus
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Re: Airbrush problems.

Post by Augustus »

digger303 wrote:Assuming all parts are clean( nozzle causes most problems). Just to be through I would soak the nozzle in either airbrush cleaner or lacquer. You might have the needle to far forward. Back the needle out a little add the nozzle then gently push the needle forward until it seats then back it off just a little then tighten the back clamping nut.
Cheers digger, I'll give that a go in a bit and report back.
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Re: Airbrush problems.

Post by Augustus »

No luck there.

But while looking at it I noticed the the O-ring for the nozzle cap was in fact just a round mark where the O-ring had been! I tried Teflon tape, no good. I tried cranking the pressure up full bore, it was a bit better but loads of splatters. Then I noticed that on the screw in back part (unless it was the back part from the old el-cheapo Chinese clone I had found- in bits) has a black rubber ring around it. I took it off and tried it on the nozzle cap and it appears to be the same, or close enough, size. By this time I have cleaned the airbrush again and didn't want to dirty it and clean again. I tried it with just air though and there is a definite improvement.

Whether or not it is a cure though remains to be seen until I try the camo for the first time.

EDIT: I also noticed on cleaning it that there seemed to be a fair bit of paint on the needle, don't know what that has to do with it but it didn't happen before.
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digger303
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Re: Airbrush problems.

Post by digger303 »

try spraying some water first, before you dirty it. But sounds like you need some o rings.
I have found locally that if I go to the local bearing service ( light industrial area) you can often get all the o rings in Viton ( chemically resistant ) for a fraction of the price. I got 3 for $6 aud. You just need to take the old ones in so that they can measure them ( most likely will be 0.8 in cross section ) or take in the airbrush. I was told on my last visit that they may be able to even get the packing seal.

:th: :cheers2:

Yes the old paint causes a restriction and like a partially blocked nozzle will lead to splatters and restricted flow. But if you have paint on the needle then odds on it is also in the nozzle. :th:
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digger303
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Re: Airbrush problems.

Post by digger303 »

If the paint is wet or fresh then a new packing seal maybe needed as well if it has traveled a long up the needle past the position of the paint cup.
Have a look at your parts diagram that came with your airbrush for a better understanding. My explanations are not always clear.
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wookiee76
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Re: Airbrush problems.

Post by wookiee76 »

I get this on occasion with my neo and the problem can usually be traced to the needle cap ( larger of the two bits that screw on the front) gunk can build up around the hole the needle comes through. I run mine with no front seal with no problems whatsoever, just be sure not to overtighten the brass part.
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Re: Airbrush problems.

Post by Nev »

Always a good idea to push the needle out of the front when cleaning it to stop gunk being pulled back through. Have you seen Pauls airbrush cleaning tutorial on the YouTube site?
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Re: Airbrush problems.

Post by Jetblast »

If the nozzle isn't properly screwed in / seated, it's conical shape will protrude too far into the needle cap - this will reduce the annular gap between the two parts & restrict airflow.

That being said, don't over tighten the nozzle!!
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