Having placed a new regulator on my compressor I needed to test it, so I'm using a technique called stippling, this involves the use of a clothes peg, and is very simple but effective for recreating stone or concrete. This entire piece is painted with Tamiya and Mr Colour paints, on a sheet of A4 paper.

(Pic 1) Having masked the edges of the paper to keep it in place, I put streaks of grey, at an angle across the paper then, taking half a clothes peg and using the curve against the nozzle I started the stippling.

(Pic 2-4) Firstly in applying the grey used for the base coat, then in black, and finally in white. Continuously testing the consistency on some scrap paper, (it easy for paint to build up under the peg and cause massive spats if your not vigilant), using a figure of 8 motion is best employed for this process. Also, altering the angle of the curve of the peg in relation to the airbrush nossle it affects the size of the paint spots - so you can, with practice, scale your concrete finish to suit!

(Pic 5) The end result is quite effective, normally I'd be painting this on a much bigger canvas not A4 as shown here. (Pics 6-9) Once that is complete, it is time to lay out the masks for the slabs, using a strip of tape to get the spacing correct and uniform.

(Pics 10-12) Once the whole base is covered I can begin to paint the black edges and highlight lines. The tile masks are removed the effect is really starting to take shape, In this case, I chose to add the number 3 (Pic 13-14) because I didn't like the crack I had initially painted so, after cutting a mask, I went over it with some Red paint.

(Pic 15-17) The next step is free-handing around the slabs and edges and adding other detail to the cracks which I did like - job done. So, now that I'm familiar with the procedure for this design I can replicate it onto a larger one on some decent material, and not make the same mistakes again.

This is a common automotive technique, but using blue-tac on the fan spreader of a car gun, blue-tac didn't work with my airbrush so, in a scrabble to find something else I, by chance, picked up the peg and in using the inner curve it works a treat. Paper works too, but the peg is much better and it doesn't get soggy.