Acrylics for airbrush's!

[Erfolg]

I am finding it a little difficult to spray my model, using airbrushes and spray brushes as used for models. That is when using acrylic paint rather than enamel.

 

I have used flattening agent in the past, which allowed a thicker paint consistency, than using water which I have been presently trying to use.

 

I have read that you can use Isopropyl as a thinners with acrylic paint. It also suggested that a retarder is needed to prevent the paint drying as it is atomized.

 

Has any one any practical experience and advice on thinning Acrylic paint.

 

I am using B&Q emulsion at present, which seems less suitable than Crown tester pots. I have also used Revell acrylic. With much the same difficulties.

 

I have no trouble F&W sprayable acrylics (artist materials), which may become my standard product for the future. Though I must make a trip to Manchester to buy it.

 

Any experiences welcome, including problems.

[Braddock, VC]

Is B&Q emulsion acrylic? I thought it was latex based and therefore almost impossible to use with either a gravity or syphon modelling airbrush as the nozzle is so small.

True acrylics come in various formats almost all will be suitable for spraying though some of the more dense colours used for pallet knives have too much pigment in them and need thinning drastically.

For best results I understand that paint for model sized airbrushes needs to be thinned to the viscosity of milk. This enables a whole new ball game over whether or not it's full cream, semi-skimmed or skimmed milk. It's one of those areas where you need to practice to perfect both your technique and the material being used.

Latex paints can be successfully sprayed; it needs to be thinned as above and water is the least expensive medium it also needs a touch up spray gun which has a significantly larger nozzle than model spray guns.

Success is also dependant on the pressure used to spray with, for continued success this needs to be as stable as possible as wide variations in pressure will provide different consistencies of the medium being sprayed.

I'm no expert and the results of my spraying leave much to be desired though I don't use acrylic as it's not fuel proof and sometimes doesn't take kindly to a covering of fuel proving lacquer.

I used enamels and clear varnish to fuel proof or solarlac products. Modelling paints are expensive in the amounts we buy and some are not the safest of materials to be used so you need to research and then practice.

What I will say with certainty is that an airbrush compressor will be difficult to use, simply because it's usually intended to spray airfix kits etc for which, in experienced hands, it can be satisfactory.

Cheap materials for practice are printer inks which already have a suitable consistency though a limited range of colours but they are excellent for practising technique provided you spray onto a suitable medium.

HTH.

[Erfolg]

Hi John

 

I have tried to establish what is in B&Q emulsion. To date I have not been successful.

 

However investigating Acrylics, I came across this Wikipedia reference which suggests, although some emulsions are described as "Latex", there is no latex or rubber product in them.

 

I think you have a point with respect to the consistency of household emulsion paints. I had noted that although substantially thinner than artists paints such as Winsor & Newton, Daler tube paints, they do not thin as as well, nor spray anywhere near as well. I had put the difference down to pigment milling. I now suspect it is also the binder and filler etc., that differs.

 

It is surprising to me that Revell acrylic doe not thin well with water.

 

It suggests to me that a acrylic specific thinner is necessary. As I have stated earlier, acrylic flattening agent thins the paint well for spraying. But specific thinner may be better still.

 

I take your point with respect to modelling paints, they are expensive, given the amount needed. The Acrylic does not go as far as enamel paints. F&W paints (artist ink/acrylic dependent on supplier web site) is not to bad on price. Although not ideal for models , because of the hues, requiring a lot of mixing.

 

I have no problem with my compressor, I have it set at 20 psi, which has been fine for all media, that was until now. The output is adequate, the comprssor charging the tank, about every 5 minutes or so.

 

[Erfolg]

The Link did not work.

[Erfolg]

I have found this, may provide ideas, is windowlene the same stuff he mentions, I wonder?

[Braddock, VC]

FWIW I use 35 - 40 psi with my airbrushes with 0.35 and 0.5 nozzles, one's a cheapo from machine mart and the other an iwata though, frustratingly, I have better results with the former. Perhaps it's because I do the bulk spraying with cheapo and the finer ( well it is to my mind ) with the other!!!!!

Incidentally the link really opened my eyes to paint chemistry I have to be honest and admit that I'd never considered it before.

I'd tried spraying "emulsion" with my touch up spraygun with reasonable results but on my walls as opposed to modelling stuff and the milk consistency worked for me. IIRC I used more than 50% water in the final thinned paint though it was three or 4 years ago when I did it. 

Edited By John Gibbs on 31/12/2011 22:20:57

[Erfolg]

I think a contribution from a chemist would be useful, in at least pointing at possible directions of interest.

 

Looking at the video of alternative household substances to thin acrylics, it struck me that all seemed to be products where the reduction of surface tension could be beneficial. Typically window cleaning products.

 

I was not sure that other products such as washing up liquid would work. They typically contain chemical groups referred to as Surfactants. I do not know how they work, I assume that they preferentially like to bond with fats. But then again I have noticed that they also reduce surface tension, or appear to. Are they, or can both characteristics be one in the same thing?

 

I did look at the myriad of household products my wife uses. Most seem to have vinegar which (seems to be the latest wonder ingredient in all cleaning products) in them. So no joy there.

 

I then thought of Windscreen Washing Fluid. The one I have just says it contains 5% Anionic surfactants in it. I have reasoned that the car screen cleaning system will contain various plastics, metals and paints (mainly the body work). From the perspective of both the manufacturer and vehicle owner, these fluids must not damage any part of the car. On that basis I am guessing my airbrushes should be safe, particularly if well cleaned after use.

 

I have tried it as a thinner,it seems to work, by mixing (50/50), giving a homogenous dispersal of the constituents to the naked eye. I have brushed the resultant dilution onto some card with a small brush, which also seems to work.

 

I will try the airbrush tomorrow, hopefully.

 

Has any one any comments?

 

With respect to air pressures, I was taught that 20 psi, was about the upper limit. At that pressure a 6" standoff would provide a  good local coverage. Reduce the pressure and you need to come nearer, but get softer coverage.I am not saying that your pressures are wrong, merely different. It would be good to hear from others at what pressures they typically spray (airbrush) with.

Edited By Erfolg on 01/01/2012 16:58:43

[Erfolg]

I have tried the "windscreen cleaner" through my siphon suction annular airbrush. The difference in the viscosity was very apparent, the flow in the bottle being obvious.

 

The spray pattern was still not quite as consistent as is easily achievable with enamel solvent paint. I turned up the pressure as suggested to 40 psi. This works very well, in giving a very good pattern, little overspray and good coverage. The nozzle is pretty much opened to max.

 

I am not sure, how it will work with my proper airbrushes, as the nozzle is fixed at about 0.2mm.

 

I am not convinced that the Revell acrylic is very good, not much, if any better than B&Q paint, when thinned with water.

 

I did find that flattening agent does improve the viscosity, without over thinning. I will go to Fred Aldus and buy some Acrylic flow improver, designed for Acylic. I will probably buy the cheapest brand be Daler, Rownay, N&W, Liquitex etc or preferentially an Universal Flow improver.

 

At the back of my mind I know that plastic kit builders seem to have no issues with Acrylic, I guess, because of the low quantities of paint used, that they are not aware of the high cost of Revell flow improver etc.