|Design and Manufacture of Fine Scale Models by John Hunter and Laurie Green|
by Laurie Green
by Laurie Green
There are many forms of rust, and about as many different colors and textures. What is required are simple techniques to achieve these various rust effects that we see on the prototype. Some are easy to achieve and others more difficult. Following are the methods that I use. Very few materials are required and most can be obtained from our hobby shop, over the internet, art supply shop and local supermarket.
RUSTING DETAIL PARTS
Small detail parts like nut, bolt and washer castings that Grandt Line and others produce are easy to simulate rust on. I use a water based model paint by TAMIYA called 'RED BROWN' (XF-64), but any colour from deep red through purple to deep blue, as well as any brand of paint can be used as this base colour. This colour will depend on the effect you wish to finish with.
Once the detail parts are painted and allowed to dry, using a small still brush I dust them with weathering chalks produced and sold by BRANGDON ENTERPRISES™ there are other brands and types available. you can always buy sticks of pastel and grind them into powder, as seen in the 12 draw holder opposite. Finally, using pastel pencils in orange or brown (the brand I use are CONTE™ and are available from artist supply shops) I highlight the raised areas of the detail part. Vary this effect, as not all rusted parts are alike. The object is to achieve a set of pieces that look similar but have subtle differences in colour and rust spots.
Another effect that can be used is to simulate new wear on a rusty part. This is when the part has seen new wear and the base metal is showing. This normally occurs where high spots are rubbed or worm away, or where metal rubs on metal. To simulate this effect I use a flat paint such as Tamiya ALUMINUM (XF-16) and dry brush the paint onto the required areas. Dry brushing is when you dip the brush into the paint, wipe most of the paint off, then lightly drag the brush over to the area required. Normally this paints the raised parts or edges of the part. This can also be done using white or cream to simulate light striking the object.
Note: CONTE PENCILS - The only internet supplier I could find is at http://www.artmaterialsupplies.com
RUSTY METAL SHEETS
Method One (the easiest)
Often we use cast resin, styrene, paper, cardboard or plastics (and real metal sometimes!) to simulate metal on our models. To achieve a uniform effect on all these different materials I use a simple method that can be repeated over and over again.
We need to undercoat the material first to achieve a surface that will take paints, weathering chalks and pencils, as well giving a uniform base colour. For this I use spray cans of automotive etching undercoat in grey primer, available quite cheaply from your local auto shop or paint shop. These paints are also available in white and black. The colour you chose comes down to a personal preference. Black often works well if the part you are rusting has crevices or folds where the black will give a shadow effect.
Having a close look at rusty metal often reveals a base colour that can vary from brown through red and purple to deep blue. This base colour depends on the make up of the metal and humidity and often the altitude. To achieve this base colour of red through purple to deep blue I use two HUMBROL™ hobby paints in Wine Red #73 and Oxford Blue #104. These are thinners based paints and made in England and I use them because I haven't found better colours and I can buy them locally, but the choice is yours as to what brand or choices colours you use. You could also try Tamiya XF-6 Copper with XF-17 Sea Blue or XF-24 Dark Grey
Note: Humbrol Paints are owned by a company called AIRFIX. Their URL is http://www.airfix.com
With both cans open and a 1/4” chisel brush in hand, dip into the blue paint and apply onto the object, and with the brush still wet, dip into the red and over-paint the blue. Vary the amount of red used on each sheet so you get a variety of colours from red through purple to blue. A streak of brown often helps vary the effect.
Once the painting stage has dried, using a still brush, lightly brush various colours of rust coloured powders onto the and streaks of the painted surface. Use darker, browner colours for old rust and orange or ochre colours for new rust. Orange and brown CONTE pastel pencils can now be used to add runs of new rust. Don't overdo this effect and we want the sheets to vary in finish.
I use this method when I want sheets of metal or corrugated iron that are just starting to go rusty or have streaks or areas of rust. Whatever the material being used, I undercoat with the automotive grey primer. Once this is fully dry, I dry brush the surface with Tamiya ALUMINUM (XF-16) paint, mainly catching the top ridges of the corrugations.
For light areas of rust, I use a small stiff brush (one of those old ones lying around on your model table will do) and scrub on rust coloured chalks, finally adding some highlights with the orange CONTE pencil.
For areas on the sheet of heavy rust, I dry brush a brown artists oil paint (I use ROWNEY Series A - Gold Ochre ) but the final choice is yours, as their is a large range of oil paint colours. I use these because the oil paint takes a while to dry, so as well as using it as a paint, you can dab rust coloured chalk powders onto it and use the oil paint as an adhesive.
Oil paints as also useful because as you thin them down, using oil paint thinners, they still retain their pigment. You can thin the paint down and wash it over the part. This can take a bit of practice but the results can be interesting - make sure you do some testing on scrap first to get the method how you want it.
A WELL WEATHERED EFFECT
Model simulated corrugated iron is rolled aluminium sheet and comes in various scales and sheet sizes. Usually you have to cut these sheets up. The type I use is very thin and close to scale thickness and I cut it into approximately 3 scale feet wide sheets. This aluminium sheet is manufactured by “VR Models" here in Melbourne, Australia and sold at a few local hobby shops. Normal model corrugated iron is a bit thicker. To etch this thinner and more realistic corrugated iron I use ‘LIQUID DRANO - Professional Strength™’, available from most supermarkets. It is used to clear domestic drains. Pour the DRANO™ into an old metal tray and place the sheets into the liquid gel. Liquid Drano is a very mild acid, and will take several hours to etch the aluminium. This etching allows paints and chalks to adhere nicely. Just keep an eye on the process and remove when the desired effect has been achieved. Wash the sheets well in water to stop the chemical reaction. Once etched this material is very thin so handle with care. They can be used as is and give a nice well weathered effect witha non rusty finish.
For thicker sheets of aluminium, use Ferric Chloride (available from Electronic Stores - it is used to etch circuit boards). If you use this enchant take all safety precautions when using it. It can be toxic so use it in a well ventilated area. again, pour some into a metal tray and place the metal sheets in to liquid. Beware, that this is a chemical reaction, and once the reaction starts it can etch very quickly. Once you have the desired effect, wash the sheets in water to stop the chemical reaction and lay out to dry.