Assortment of questions re. using an airbrush to paint plastic models

[Housesparrow]

1) Can I expect to have the option to buy needles for most/all sizes for any popular airbrush model?

2) If I want to paint plastic models, size 30-40 cm in length, is there a preferred needle size for that if the model is a lengthy ship hull?

3) Is there a preferred needle size for applying a base coat to a plastic model of about 30-40 cm in length?

4) What air pressure is recommended for when spraying on a mist of paint, presumably so that the paint goes on wet in wet?

5) I am thinking of buying a cheaper compressor commonly named "AS-196, is this one more noisy due to it having two pistons (as opposed to the model only having one)?

http://www.amazon.co.uk/Airbrush-Compressor-AS196-Cylinder-Switch/dp/B0036SZ80U

6) When painting models with an airbrush and finishing with a coat, matte, semi-gloss or gloss, should the first layer of paint over the base coat ideally be gloss or matte paint?

7) If say a plastic ship hull has been sanded and a little scratched and not ending up being 100% smooth, does applying a base coat help to make the surface smoother?

8) If airbrushing a layer of color over a base coat, how long must this paint dry before proceeding, if being enamel paint?

9) If airbrushing a layer of color over a base coat, how long must this paint dry before proceeding, if being acrylic paint?

10) Will it get messy if you put on many coats, of any combination of base coat, paint and finish? What is the best method for applying all these things?

11) When using a decent ultrasonic cleaning device for cleaning the airbrush, can the liquid be reused?

12) Can bottles of acrylic paint be idle on the shelf for a year, without getting weird? (I bought some stuff, but don't airbrush yet, so I'm wondering if the stuff is going bad over time.)

Edited October 4, 2015 by Housesparrow

[Jetblast]

I'm no expert, but from what I do with my limited experience (compared to some around here);

1) Depends on what brand & model you go with, some easy, some difficult, some impossible. Airbrushes with a drop-in nozzle design (like H&S or Iwata Eclipse) are the easiest to swap.

2) 0.4mm +

3) 0.4mm +

4) Approx. 20psi

5) Twin piston compressors typically have a higher quoted noise rating than their direct single piston counterpart, but twins generally have a deeper & less intrusive tone that of the comparative single in the real world.

6) I generally coat with consideration to what's happening next, such as a gloss coat before decals.

7) Depends on the severity of the scratching & filling ability of the paint. Using regular hobby paint over a scratched surface will give little improvement, but using a primer or basecoat specifically designed for this type of work (like Mr Surfacer) will help significantly. It's a double edged sword though as the better the filling ability, the easier it will be to "loose" detail on the kit.

8) A long time... I don't use them very much & am no expert, but wouldn't go back within 24-48 hours

9) Very variable, but a couple of hours plus as a guideline - it all depends on the paint, thinning, depth of coat & ambient conditions.

10) Too many coats will start to obliterate surface detail, so you really want to get the job done with the minimum number of coats.

11) Yes, but it's generally water with a small amount of detergent that's used, so it's no big deal to dump it.

12) As long as the lids are airtight it shouldn't be an issue

[little-cars]

HI,

Some answers;

1) Can I expect to have the option to buy needles for most/all sizes for any popular airbrush model?

Depends on the brush, Cheap chinese, depends if/how they are supported. A brand such as Iwata have different needle/nozzle sizes, but the sizes available depend on the brush. Harder & Steenbeck have four sizes for their Evolution and Infinity range, 0.15, 0.2, 0.4, 0.6mm And different paint cups

2) If I want to paint plastic models, size 30-40 cm in length, is there a preferred needle size for that if the model is a lengthy ship hull?

For area work you would go for a high flow wide area nozzle, 0.4 or 0.5mm. But some people prefer to build the area up using a smaller nozzle such as a 0.2/0.3mm.

3) Is there a preferred needle size for applying a base coat to a plastic model of about 30-40 cm in length?

Same as above.

4) What air pressure is recommended for when spraying on a mist of paint, presumably so that the paint goes on wet in wet?

The normal answer is about 20psi, but I know people that happily use 5psi and 40psi. It depends on the paint type, mix, brush etc...

5) I am thinking of buying a cheaper compressor commonly named "AS-196, is this one more noisy due to it having two pistons (as opposed to the model only having one)?

http://www.amazon.co...h/dp/B0036SZ80U

The compressor is the power source for your airbrush, so as long as it will produce the pressures you want for the time you are going to be spraying that is all you need to get started. Acceptable noise levels vary from person to person, and from compressor to compressor. If at all possible try the compressor before you buy it to get an idea of noise levels and with tank compressors how long it takes to fill/re-fill the tank.

6) When painting models with an airbrush and finishing with a coat, matte, semi-gloss or gloss, should the first layer of paint over the base coat ideally be gloss or matte paint?

If you are changing the surface finish after applying the coloured paint I can't see what difference the initial paint finish makes. If in doubt, try a sample of your colour combinations on a plastic cup/bottle to get an idea of how it looks before trying it on a model.

7) If say a plastic ship hull has been sanded and a little scratched and not ending up being 100% smooth, does applying a base coat help to make the surface smoother?

Depends on the scratches, surface primer fillers will help, but it can be a trade off between thickness of coat and loss of detail.

8) If airbrushing a layer of color over a base coat, how long must this paint dry before proceeding, if being enamel paint?

9) If airbrushing a layer of color over a base coat, how long must this paint dry before proceeding, if being acrylic paint?

Paint drying times vary from paint to paint depending on temperature, paint thckness etc.. Enamels are a lot longer drying than acrylics, best to test the combination of paint, thinners, flow enhancer etc. that you use before trying it on a model. Paint manufacturers instructions should give you a guide.

10) Will it get messy if you put on many coats, of any combination of base coat, paint and finish? What is the best method for applying all these things?

As with primer coats, the thicker the coats the more likely you are to loose surface detail.

11) When using a decent ultrasonic cleaning device for cleaning the airbrush, can the liquid be reused?

If you are using a specific ultrasonic cleaning fluid, refer to the instructions. But I normally use water and change it when it get get cloudy or paint particles in it.

12) Can bottles of acrylic paint be idle on the shelf for a year, without getting weird? (I bought some stuff, but don't airbrush yet, so I'm wondering if the stuff is going bad over time.)

No problem as long as the lids are done up properly.

Just noticed Jetblast has posted on this, hopefully our answers will be along the same lines.

Paul

[Housesparrow]

Thanks a bunch!