Airbrush paint and brush paint

[colinlp]

Hi

 

I am new to airbrushing and therefore have absolutely no experience at all with either equipment, technique or materials. I am reasonably proficient as a varnish sprayer of furniture but I appreciate airbrushing is probably very different and will practice until I feel comfortable enough to spray in anger. I have also bought a H&S Ultra airbrush as a starter based on reading the forum. So I'm guessing I won't be a million miles from the mark with that but paint I am 100% in the dark with:

 

I was thinking along the lines of something like Vallejo modelair as a starting point, I think I'm right in that it is ready for airbrushing straight out of the pot? Would that be a suitable paint for me or would I be better with paint that I need to thin myself? I will need to paint some part with a brush, would ready thinned paint be OK there or does it need to be thicker? Well that's probably point proved as to how clueless I am, I would appreciate any help with regards makes and paint types just as a starting point.

 

Just in case it's important, my first model is the Airfix Saturn V kit, so mostly black and white with some internal and external details, I will want to overspray the finished article with a matt varnish. On that subject, I have gallons of acrylic matt varnish that I use for spraying, would that be suitable?

 

Many thanks

[LotusArenco]

The problem with airbrushing (especially acrylics) is that quite often there are no hard and fast rules.

 

A lot of advice will be along the lines of ‘consistency of milk’ ‘60%/40% ratio’ ‘10-15psi’ etc. The best thing to do is just play around and practice, spraying on sheets of paper, yoghurt pots and bits of plastic. Use different psi settings and thinner ratios (if needed) to find what’s best for you. Just be aware that even with a retarder mixed in, hobby acrylics sometimes have a habit of drying on the needle tip.

 

Personally I find Vallejo modelair to be great straight from the pot, but some of their colours seem to be thinner/thicker than others and may require a bit of thinning down. No big deal, and it really is a minor inconvenience to plop in a drop of thinner. Vallejo modelair can also be used to brush paint. It’s not as thick as their modelcolor range, but you can squeeze out a drop and let it thicken up a little before brushing.

 

Everyone has their own favourite brands of paint, my suggestion to you before committing yourself to a particular brand, is to try out a couple of colours from different paint manufacturers and see which you prefer.

Have a shufti through this:

 

And have a good browse through this section of the forum, lots of great advice from the ne'er-do-wells that frequent Britmodeller!

 

Mart

[Kev The Modeller]

 

LotusArenco

 

Is spot on here,  there's no one setting that will work of all acrylic, even for anyone brand, as they differ across colours within any given brand.  I've found I need to adjust mixture and pressure to spray the same colour depending what effect I'm after, so if I'm spraying a base coat it would be 70/20% thinner, 17psi, 3 - 4 cm from the surface.  If I'm doing a camouflage pattern outline with the same colour it could be as much as 20/80% thinner, 7psi and 1cm from the surface depending how small or thin the outline is to be.

 

It's really all trail an error mate, just don't get disheartened and try as many combinations as you can until you find one that works for you and your airbrush.       

Edited December 27, 2017 by Kev The Modeller

[colinlp]

Thanks, most of that makes sense, so by playing around with the variable it sounds like you can get any paint to work well from the airbrush given enough testing. Also it would seem that for brushing thicker paint would be better.  One thing there that I'm not sure about is the retarder, I'm used to mixing and spraying anything from 10L to 100ml of lacquer so the process of adding a retarder to a couple of mls of paint is a mystery, it seems that maybe it would be easier to add a retarder to the thinners and use thicker paint that needs thinning? Is there a way of dealing with paint drying on the needle tip other than striping and cleaning?

[Kev The Modeller]

1 hour ago, colinlp said:

Thanks, most of that makes sense, so by playing around with the variable it sounds like you can get any paint to work well from the airbrush given enough testing. Also it would seem that for brushing thicker paint would be better.  One thing there that I'm not sure about is the retarder, I'm used to mixing and spraying anything from 10L to 100ml of lacquer so the process of adding a retarder to a couple of mls of paint is a mystery, it seems that maybe it would be easier to add a retarder to the thinners and use thicker paint that needs thinning? Is there a way of dealing with paint drying on the needle tip other than striping and cleaning?

Mate thicker paint isn't the right way to go with most acrylics that said some of the lacquer based ones (Tamiya, Mr hobby Aquaus) are more tolerant but not always depending what and where (round/curved edge) my not, you want light coats. 

 

You've also got the types of thinner and they all behave differently, same with retarders.  You've just got to experiment, trawl UTube  and read the new book from Ammo Mig  https://www.scalemodelshop.co.uk/modelling-guide-how-to-paint-with-acrylics.html which I think is very useful.  From my experience if your'e going the Tamiya/Mr hobby (lacquer based acrylic) route use Mr Hobby leveling thinner it's amazing stuff, way better then X20a, for Ammo/AK/Vallejo (water based acrylic) thin with any good true acrylic thinner (their own branded or equivalent) retarders I find don't really much over what a good thinner mixed to the correct percentages for airbrushing.  Flow improves on the other hand do help just don't use too much or the colour dries silk and you still need thinner.  

 

I also find that all acrylics water or lacquer based need thinning even if they say they don't, that said if your using a 0.4 needle and above 20psi say priming or base coating you will probably get away with it.  As you can see it's all very, very variable and what works for me may not for you, but most should be a start line for you.  Read play/experiment and it will all come together for you, just not over night. 

 

              

[colinlp]

Thanks, I've been looking at youtube at Vallejo flow improver and that has uncovered all sorts of useful videos

[LotusArenco]

5 hours ago, colinlp said:

One thing there that I'm not sure about is the retarder

It’s trial and error, but you’ll be dealing in ‘drops’ of paint/thinner/retarder. 10 drops paint, 3 drops thinner, 1 drop retarder etc. Mix and match to taste. I’m lazy so do as you suggested and just squeeze some retarder into my thinner (Liquitex retarder and Vallejo thinner). I may be just wasting my time, but it seems to work for me.

Acrylic flow improvers/extenders/retarders are all pretty much of a muchness. As far as I remember they are all based on a glycerine/glycol/water solution (which is perhaps why some car windscreen washes can work well as a thinner). As Kev mentioned above, different paints often need different thinners. You’ll hear mentioned using IPA (Isopropyl alcohol, not the beer!) to thin acrylics. IPA will work great for an acrylic like Tamiya, but will turn some latex based acrylics into jelly goo. IPA will also speed up the drying time, not reduce it. I’ve not tried it, but ‘Ultimate Modelling Products’ do an ‘Ultimate’ thinner that works for most brands of paint.

 

5 hours ago, colinlp said:

other than striping and cleaning?

 

Pfft! No. Tip dry is easily fixed in seconds by using your fingers or a cotton bud to remove. Annoying, yes, but hardly a chore.

 

3 hours ago, Kev The Modeller said:

you want light coats. 

Yup, light coats. Perhaps not as thin as you’d airbrush, but certainly not too thick. Two or three thinner coats will give a much better finish (less brush marks) than one thick coat.

 

Confused yet?...

Just remember that ‘acrylic’ covers a wide range/type of paint, and doesn’t always equal ‘water based’. And that some will react differently to various thinners than others.

 

Play around, experiment and ‘have at it’. I’ve probably learned more from my cock-ups than anything.

 

Mart

[colinlp]

11 hours ago, LotusArenco said:

Confused yet?...

Just remember that ‘acrylic’ covers a wide range/type of paint, and doesn’t always equal ‘water based’. And that some will react differently to various thinners than others.

I think about as far as I've learned here is that Vallejo paints don't react well to thinners with IPA in them. I'm guessing then that some acrylics use some sort of mineral/organic thinner such as acetone or white sprit? If that's right, are there any compatibility issues with over coating one with another?

[Kev The Modeller]

Vallejo, AK and Mig Ammo paints are true acrylics i.e. they are water based unlike Tamiya, Mr Hobby Aqueous. Which although water soluble are made of acrylic resins and contain a mild solvent hence their flammable sticker,  both their thinners/cleaners contain alcohol which is why they smell much more than Vallejo, AK and Ammo.

 

You can use IPA to clean/strip Vallejo, AK and Ammo it just smells but they don't really like it which is why they are good at stripping, if you use it as thinner it will break down their structure and can turn into a goo or dry out into small particles.  You can use water for both but it's not the best for thinning, although it's pretty good for cleaning of tools/brushes but not so good for your air brush, IPA is but it's a bit harsh and smells so stick with X20a/T110, 111 for Tamiya/ Mr Hobby and brand cleaner true acrylics or cleaners like UMP which will clean both.

 

It's a mine field but one that soon gets cleared as a rule for most acrylics  IPA/X20a/UMP will clean for thinning you need to separate to 2 and use the correct type of thinner, that said I believe UMP thinner works with both.              

[LotusArenco]

1 hour ago, colinlp said:

some acrylics use some sort of mineral/organic thinner such as acetone

Yup. Paints from Tamiya and Mr Hobby /Gunze Sangyo can be thinned with ‘lacquer’ thinners (cellulose base/acetone). Ironically, Tamiya paint isn’t too great when thinned with water! (Remember ‘acrylic’ doesn’t always equal ‘water based’). The ‘lacquer’ based/thinned paints can be considered ‘hot’ compared to the likes of Vallejo or Humbrol acrylic. Some paint ranges are intermixable with others, but I wouldn’t like to mix a lacquer based one with a non-lacquer one.

 

I’ve never had any problems with overspraying Tamiya with Vallejo or vise-versa. I’m currently building a model with four different paint manufacturers colours (Tamiya /Xtracrylix/Vallejo and Aeromaster).

 

As regards your Saturn V model, I’d be inclined to use something along the lines of a Tamiya or Halfords spray can for the majority just for the convenience.

 

Mart

 

edit: LOL I need to learn to type faster, Kev has already said what I've repeated.

Edited December 28, 2017 by LotusArenco

[colinlp]

Thank you both, helpful stuff, I had planned to use Halford's white for the bulk white of the Saturn, The airbrush will be used on things like engine bells and tops of fuel tanks.

 

I think for now I will play safe and stick to a paint that is water based, I've been using water based finished exclusively for my furniture for the last 27 years now and my chest has thanked me for it; I do use cellulose occasionally for guitars but the fumes from the gassing off after drying crucify me for days.

 

I take it that one make of water based acrylic thinner will be compatible for all makes of water based acrylic?

[LotusArenco]

3 hours ago, colinlp said:

I take it that one make of water based acrylic thinner will be compatible for all makes of water based acrylic?

I tend to use the own brand thinners for their own paints. I do keep meaning to get some of that UMP Universal stuff to try out.

 

Out of interest I just conducted a mini experiment using some Vallejo ModelAir paint with the various thinners that I use.

 

A tiny cocktail tips worth of paint stirred into each one.

Rather surprisingly Vallejo thinners had the worst results reacting with their own paint! Although as a disclaimer, I’d previously squeezed a bit of Winsor&Newton retarder into the Vallejo bottle. Not sure that would have affected it that much?

 

When thinning paint for airbrushing I normally just put a few drops of thinner into the colour cup followed by the paint. Cover the needle end and back flush the air to let the mix bubble up in the cup. I don’t usually have any problems thinning and spraying Vallejo using that method, and I can’t really explain the above results. Weird.

 

Then again, it was hardly scientific.

 

Mart

[colinlp]

Just an update on how I got on:

 

I bought some Vallejo Model air paints, thinners and flow improver, I had a good play around and ended up using one drop of flow improver to 5 - 10 drops of paint at about 20psi. It worked beautifully, a good fine even spray pattern and no build up on the tip at all. The actual spraying turned out pretty good, the weathering affect I tried somewhat less so but that's just down to practice. Thanks for all your help guys