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Uneven Finish When Airbrushing

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  • Member since
    November, 2017
Uneven Finish When Airbrushing
Posted by High Wycombe on Thursday, November 02, 2017 7:27 AM

I've been airbrushing for many years with an Aztec and switched over to a Badger 150 over the past 2 years.  Still getting a hang with it - but recently noticed that when I apply the paint, I get an uneven sheen, as in some flat, some gloss, some in between.  In the end it will all level out when I apply Future for the decals, Future again to seal, then dull it out - BUT - I don't like the uneven initial application, especially so when previous applications have gone on smooth with no uneven sheen. 

Settings:  I used to spray at 15-20 PSI, but recently had issues with clogging at the tip which would spit out chunks of paint and mar the surface with dots of paint.  Now spray at 10-15 PSI with very thinned paint.  No spitting of paint - but that uneven sheen noted above.

Thanks for whatever help in out there.

  • Member since
    November, 2009
  • From: Twin Cities of Minnesota
Posted by Don Stauffer on Thursday, November 02, 2017 8:28 AM

Is it just the sheen that is uneven, or is the color varying too?  I take it you are spraying gloss.  One problem with a double action brush is that the airflow when no paint is flowing will speed up drying, reducing the glossiness of gloss paints.  You need to keep this in mind when planning the pattern for the application of the piece you are painting.

Also, I find lighting critical to getting an even sheen. I have a positionable lamp at my workbench (for airbrushing I spray at my bench, not my spray booth), and always position the lamp, and tilt the surface I am spraying, so I can see the reflection of the light in the paint surface.

Don Stauffer in Minnesota

  • Member since
    August, 2013
Posted by Jay Jay on Thursday, November 02, 2017 8:30 AM

I have found that adding a little  retarder and  flow improver to my thinner for acrylics really helps solve this problem of the uneven sheen. I make my own acrylic thinner btw.  here's the formula;

2/3 water

1/3 90% iso alcohol

1ml Flow Improver

1ml Fluid retarder

the FI and FR i got from Michael's. not cheap but lasts a long time.

 

 

 

 

 

 I'm finally retired. Now time I got, money I don't.

  • Member since
    November, 2017
Posted by High Wycombe on Thursday, November 02, 2017 8:53 AM

Thanks for the speedy response.  No real color differentation - just that blend of sheen.  It has happened with Testors Enamel (Flat) and with Tamiya's Semi-Gloss black - both different paints completely but that same kind of sheen difference.  Perhaps it is a product of using the FINE Tip/Needle with the Badger versus the MEDIUM Tip?  My only problem with going beyond the FINE Tip was the camo scheme - as I needed that type of tip with the paint job I had (camo scheme for Monogram's old F-111 kit). 

Last but not least - seems like the paint is coming out a bit fuzzy - I get coverage - thinned right - but it's too much of a spray effect versus that nice concentrated focus of paint.

 

  • Member since
    November, 2017
Posted by High Wycombe on Thursday, November 02, 2017 8:55 AM

Thanks - I understand that retarders/flow improver are only for acrylics?  I never have used them but willing to give them a go if it will help with my latest sheen challenge.

 

  • Member since
    November, 2008
  • From: Florida
Posted by plasticjunkie on Thursday, November 02, 2017 9:11 AM

I'm a Testors enamel and Tamiya paint user so before I throw some ideas out to you........what kind of thinner are you using on with both brand paints? 

 

  • Member since
    November, 2017
Posted by High Wycombe on Thursday, November 02, 2017 10:23 AM
Tamiya thinner for Tamiya paints - and Testors Thinner for their enamel brand - nothing else.
  • Member since
    November, 2008
  • From: Florida
Posted by plasticjunkie on Thursday, November 02, 2017 10:55 AM

High Wycombe
Tamiya thinner for Tamiya paints - and Testors Thinner for their enamel brand - nothing else.
 

That is good you use the manufacturer's thinners, one less issue to deal with.

It could be your paint to thinner ratio or even the distance you spray from.

Air brushes also perform different between brands so experimentation is key here till you find the balance.

I notice that slightly more thinned flat paint will spray on smoother and glossy ones go on like glass. 

  • Member since
    March, 2013
Posted by patrick206 on Thursday, November 02, 2017 1:32 PM

The above points are good, especially about light. Whether painting real airplanes or models, light is your best friend.

For large area painting, it's essential to get enough paint flowing to cover with sufficient "wet" spray pattern, Then as you go from one pass to the next, you can see the pattern just seem to melt into the previous pass. Otherwise you will see the uneven texture as you describe.

As mentioned, the distance from the AB tip to the surface is critical. If too close you can just run the heck out of the paint, if too far the paint particles can partially dry on the way and you're left with a dotted layer.

I use mostly Tamiya acrylics, some MM enamels. With either one I thin as needed for the job, I know it may sound off base but in some cases with Tamiya I might well thin it 50/50. My most common psi is 15-20. I use strictly their X-20A, seldom use Flo-Aid or retarder.

It's also important to match the needle/nozzle set that is best suited for the job. For a 1:48th large model I might use the large size for the primer or single color base coat, medium size for more detailed painting, fine size for camo or confined small areas.

While you are painting, it's helpful to keep a supply of cotton buds, (Q-tips,) handy and some lacquer thinner, every few passes dip the bud in thinner and run it around the needle tip, to remove the buildup of dried paint that forms. When paint spitting occurs, that's the usual cause. It's called "dry tip," the air moving the paint out of the AB causes the paint to partially set up at the tip. Pretty much a universal problem, but easily dealt with.

As many would suggest, get in a supply of paint and some scrap plastic sheet, find a good light source, play around with thinning ratios, pressures, distance to the surface, etc. Then practice away, soon enough you'll find what works better, and what doesn't.

I hope you'll find this useful, and please let us know how you get on with your airbrushing.

Patrick

  • Member since
    November, 2017
Posted by High Wycombe on Thursday, November 02, 2017 2:27 PM
Thank you sir - and all above as well. This will help me immensely - and I actually use an old toothbrush to clean up the tip when painting - just dipping the brush in whatever medium thinner I'm using and gently going across the tip. Cheers! PS - I used to see the F-111's when we would head up to Heyford to do a "big shop" at the PX (in London - we had no such big PX or Navy Exchange - 1979-1982 timeframe). Those jets would be just inside the airfield fence, revving up to go - afterburners glowing and the red insides of the flaps showing so crystal clear. What a sight - hence - I had to build one, almost 40 years later. Good old Monogram - just can't shake my childhood favorite (affordable too!)
  • Member since
    July, 2013
Posted by steve5 on Thursday, November 02, 2017 3:36 PM

jay jay , I have seen that formula before , does it work on , valejo , mm , paint's , I ask because ,  tamiya is an alcohol based paint , and the others are water .

steve5

  • Member since
    November, 2008
  • From: Florida
Posted by plasticjunkie on Thursday, November 02, 2017 4:32 PM

steve5

jay jay , I have seen that formula before , does it work on , valejo , mm , paint's , I ask because ,  tamiya is an alcohol based paint , and the others are water .

steve5

 

Vallejo is a different animal and is best to use the Vallejo products with its paint to avoid ugly surprises.

I recently picked up some Vallejo Air to experiment and they are not as easy as enamels but seem to work out very well.

I don't use any retarder or flow improver with Tamiya, only their thinner. I have read that Gunze Self Leveling Thinner does wonders for the Tamiya paints specially the clear gloss.

  • Member since
    August, 2013
Posted by Jay Jay on Friday, November 03, 2017 9:37 AM

OOPS I didn't consider the brand of paint for the homemade thinner I suggested.  My bad.  I use the thinner on Tamiya and MM but not have tried the Velajo.

 

 

 

 

 

 I'm finally retired. Now time I got, money I don't.

  • Member since
    November, 2009
  • From: Twin Cities of Minnesota
Posted by Don Stauffer on Saturday, November 04, 2017 9:06 AM

For even more help on this subject, remember that there is an airbrushing forum.  Look down below in the tools, techniques and reference materials section.  Some really good airbrushing experts hang out on that forum.

Don Stauffer in Minnesota

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