Air Brushing finish

[georgeT]

Hopefully someone can tell me what the problem is? l am using Humbrol paint mixed with white spirit, but the finish is a very,very flat and dusty finish, so l tried mixing the paint with Lighter fluid, yet still the same result, l have never had a problem before, even tried Railmatch paint, still with the same dreadful finish, l have done lot's of airbrushing in the past, but never with the result's l am getting now, it was a good ten year's ago, and l seem to have forgotten everything l used to do ? HELP please................

[Lady_Ava_Hay]

Are you sure that the Humbrol paint is the old style enamel? Modern paints are mostly acrylic. The reason is that the thinners has become very difficult to both transport and sell under the current regulatory requirement.

 

You might also find that the white spirit is a very different mix to the one you used to use but it does sound like you are spraying acrylic mixed with white spirit.

 

To test the paint, try mixing it with water.

[georgeT]

Hi David, Thanks for the reply, l tried spraying acrylic paint once, because l thought it would be safe indoor's, never again, it was awful, very much like the finish l have now, l have checked the humbrol tin-let's and they say enamel, something's gone wrong somewhere along the line............

[JeremyC]

In my experience over-thinning enamels with white spirit gives you get a very flat finish, I usually work on a 2-1 paint/white spirit mix, which seems OK. I find Railmatch particularly prone to this problem.

 

Jeremy

[BigAndy]

Hi George,

 

Without being patronising, as you have airbrushed before, are you holding th brush to far away from the subject surface?

 

It's just that with some very quick drying white spirit, as soon as the mix leaves the front of the brush, the thinners is starting to evaporate on it's way to the surface of the model.

If you are holding the brush to far away, all that's hitting the surface, is paint that is also starting to cure in the atmosphere - which results in a very flat and dusty finish, as you describe.

 

From my own experiences, I mix the paints with just enough white spirit ( TBH I find B+Q's own quick drying white spirit good ) to get it through the brush. As the mixture traverses the gap between the end of the brush and the surface of the model, most of the white spirit should have evaporated - but with enough left, so that when it hits the subject surface, any spirit left in the paint flattens it to the surface and then evaporates, creating a nice smooth finish.

 

I hope that kind of makes sense and to be truthful, different makes of paint, like Humbrol, Precision or Railmatch will all have differnet properties and the various colours, will also have different mixing and drying properties, so depending on whose paint you are using and how much you thin your paint down, has a direct knock on effect to how far you hold your brush away from the surface of the model.

 

Also, one other thing to consider - are you using a compressor or aerosol?

If you're using a compressor, ensure that you are not blowing the paint mixture out at to high a rate of PSI, as that can also have the effects that you describe.

 

It's a bit of a mindfield getting it right, but stick with it and I'm sure you will win through.

 

Hope this helps

 

Andy

[georgeT]

Thank's David,Jeremy and Andy, something to think about ?, The paint's l'm using are a bit old, l can't remember if thinned them down in the tin's? Normally l use the side cup to mix/thin the paint, then if there is any left l pour it back in the tin, l think l will bin it in future....