This weekend has been the start of a venture into the unknown for me - my first efforts at airbrushing. I have been practising on scraps mostly. After much deliberation and saving, a couple of weeks ago I invested in an Iwata TR-2 brush with a pistol grip and an Iwata Smart Jet compressor. This set-up is very compact and perfect for my small work area. I have also bought a vent system, which is essentially a portable fan unit, with a filter about the size of an A3 sheet of paper which exhausts, through a flexible duct, out of the window. It can be stowed under the desk when not in use.
To get started with the airbrushing kit and become familiar with the feel of spraying paint through the TR, I started with spraying some well diluted gouache paint on to paper. I was very pleased with how intuitive it was and the degree of control that could be achieved by varying paint flow and distance from the paper to create fine lines (around 1mm) through to an impressive, almost spray-gun fan at distance with full paint flow. There is much more control, perhaps, than the trigger set up suggests. The first depression brings the air on tap and then you can feel more resistance in the trigger, which tells you that the paint will start coming on line with further depression. It really is excellent
The compressor is quiet when it runs (sounds a bit like a fridge when it turns on) and then doesn't run much of the time - switching on just to top up the air pressure.
Having cleaned the brush out with some water, it was time to try spraying some acrylics. The first thing I wanted to try was Vallejo's Surface Primer on brass and nickel silver. I tried the black Surface Primer first, neat, and sprayed at about 20-25 psi and it came out of the brush and on to a piece of scrap brass a treat, giving smooth and comprehensive coverage in just a few passes. Cleaning was very easy with Iwata Medea's airbrush cleaner, sprayed through a couple of times into a special cleaning jar (which captures the spray).
So far so good. That is until, having let the primer dry overnight, I managed to peel it off in almost one complete piece having lightly scratched the surface with my fingernail
Not encouraging! Looking at people's experiences on the internet did not make me feel much better either
Then I realised I had not run the metal through the cleaning regime recommended in all the railway modelling press - I went down the all purpose cleaner, neat, and an acid cleaner after that route. So I tried that regime on two new scrap pieces of brass and sprayed them with primer, grey this time:
You can see on the above piece of brass (a Collett style cab for the 517, going spare from the sprues!) where the black primer has been scratched away easily.
I also had a gentle spray over one side of a chassis which I had started and then replaced during the build (wrong gauge spacers were used when I started
):
I let the primer cure and, holding my breath, subjected the sprayed items to the scratch test... It's rock hard!!
It really is resilient stuff! For a water based, acrylic primer, it is very surprising how well it works! And it seems to me that the difference is all down to following the cleaning regime and then making sure to handle the parts subsequently with latex gloves. Even more surprising has been that it has not given me any trouble at all in clogging the brush or drying too quickly through the air. It is clearly well engineered paint, in my view
On to the 517 itself, then! Time has been running out with all the practising, so the only thing I had time to do was to mask and then prime the wheels:
Thin tape for the tyre treads and the flanges. The sides of the tyres have been protected with Maskol, a sort of liquid latex solution that can be brushed on and then rubbed off when painting is completed. Maskol also for the crankpins. The wheels were then primed, together with the balance weights, which will be stuck on after painting (they are off for the moment to make sure I have easy access to all the spokes for painting):
Next paint to be applied to these will be the Indian Red equivalent paint I have found. Chassis next to be primed before an application of black (and crimson for the inner frames around the motion). Then the body after that. That will be next weekend now
Lessons learnt from this weekend:
1) I am not going to scrimp on the cleaning regime for brass and nickel silver. Relatively speaking it does not take that long but it makes the world of difference in terms of paint adhesion.
2) So far, I have been very pleased indeed with the acrylics. I had been a bit sceptical, especially after "peelgate", about their ability to do the job instead of enamels. No concerns at all now. That said, I will have to be more careful with the paints (rather than the primers, which are designed to be applied neat from the airbrush). There are loads of useful tips for spraying acrylics in the military modelling press which I am hoping will help (using drying retarder, appropriate thinners etc). I have every hope of using acrylics all the way through.
3) The vent system (an A300 - SD) is worth its weight in gold. I have not had any overspray dust on any surfaces, no smell at all and no paint residues coming out of my nose (not unknown with airbrushes in an unventilated environment, even using water-based paints). And it is pretty quiet - Test Match Special still audible at normal listening volume
4) Equally useful is the cleaning station (basically a covered jar with a filter and a hole into which you can insert the airbrush and spray cleaners). No smell and no overspray. The resulting sprayed cleaner and paint residue can then just be tipped into a sink and the jar rinsed with water.
5) In terms of applying the primers, I have found it useful to spray the first bit of paint on to a piece of newspaper, each time the brush pot is filled, before aiming at the object for painting. It has helped me get a feel as to how the paint is coming out at any time before applying it.
Can't wait to carry on!
A
) and using the cut out for the spring in the peg I put pressure on the wire either side of the nob and hold it at the desired angle and then warm the nob as above,
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