Salt Weathering

Simulating paint chips and wear with salt

Rust_on_side_of_AFV

This close up shows how rust had caused the paint on the side of this AFV to flake away.  Paint can also be removed due to regular wear and abrasions.

Introduction

This tutorial will provide a step-by-step guide to a technique that simulates paint chipping and rust effects using common table salt.  The method is quick, easy and relatively forgiving.

Background

The pristine appearance of combat vehicles and aircraft when they come out of the factory does not tend to last very long when subjected to the hard realities of life in the field.

Even during times of peace, military equipment gets rough treatment since it will be subject to exercises that simulate combat.  As a result, the upper coats of paint will often show the underlying layers due to wear and tear, corrosion, or accidents.

Figher plane with worn paintThis German fighter plane exhibits unusual paint wear near the nose.

Unless you intend to make your models as they appeared when brand new, then you will have to face the problem of simulating wear, damage and dirt - generally known as 'weathering'.  Part of weathering a vehicle is simulating areas where the top coat of paint has been removed in places to show previous coats of paint, primer or even bare metal and rust.

Simulating chipped paint can be done in a number of ways:

  • painting with a fine brush, or even a cocktail stick;
  • dry-brushing;
  • applying metallic pencils or graphite along edges;
  • actually scraping or chipping the top layer away.

These methods can be very time consuming and require a lot of skill.  Paint chips that have been painted often look - well -  painted on!  Using the following salt weathering technique is quite quick and easy.

Chips With Everything

Do not fall into the trap of thinking that every model needs to have copious weathering and paint chipping to look realistic.  Some vehicles are well maintained and painted regularly.  In some conflicts, vehicles and aircraft were regularly destroyed before they had a chance to exhibit any significant wear.

If you do decide that you model would benefit from some paint chipping, then carefully plan where should be.  Where are the places where wear would take place and what would cause it?  This is when reference photographs prove invaluable.

Finally, make sure that you know what the underlying surface should look like.  Paint chipped from an aircraft is likely to reveal a shiny metal surface.  On a tank it may reveal the primer coat or previous different coloured paints.  For example, many AFVs in the Gulf Wars had sand coloured paint hastily applied over Nato three colour camouflage.  Places subject to regular wear will show as shiny metal, whereas other places will quickly become rusty.  Knowing your subject also helps - many modern light AFVs have aluminium hulls which do not become rusty.  Also note that realism often comes from variability and you should avoid identical paint chips placed evenly all over the model.

Step By Step Guide

 

1. Assemble tools and materials

The tools and materials needed are very simple and easily available.  You will need a small pile of ordinary table salt, a small container of water and a paint brush or two.

Although this technique is not particularly harsh on the paintbrush it is probably best to use an old one because you may end up doing a little bit of scrubbing with it.  In this case I have used ordinary salt, for large scales, or where you want to have larger paint chips, consider using rock salt intended for salt grinders.

Adding a little dishwashing detergent liquid to the water helps to make it spread out evenly and avoid beading.

Salt weathering materials

2. Prepare the model

The other essential ingredient, of course, is a model.  For this demonstation I am using my 'stunt double' tank which is an old model that I keep for experimenting with new techniques (see the tutorial 'Using a stunt double' for more information).

The front end of the tank has been sprayed with Vallejo Rust which is a good base colour to show through the overcoat of paint.  This colour can represent both rust and primer, but would not be suitable on a vehicle made of aluminium since that would not corrode.

 Model before salt application

 3. Apply the water

Using the paint brush apply water where the paint chips and wear are to appear.  Apply the water sparingly - only a thin coat is needed and if it starts to run the process will become messy.

Depending on the amount of weathering and your confidence, you can cover the whole model in one stage, or apply the technique to each part of the model separately.  What you need to be aware of though is that the added salt will be very delicate, so you will not be able to handle parts of the model that have had salt applied.

 Salt weathering-applying water

 4. Apply salt

Sprinkle salt over the areas that have have been wetted.  Carefully use your fingers or the brush to move the salt into position where the paint would be worn away.

It may be helpful to pick up the model and tilt it so that the salt falls onto a horizontal surface.  After a couple of seconds it will adhere due to the moisture.  Odd grains of salt will spread out a little and can be brushed away or left depending on the effect you are trying to acheive.

Remember that although you are trying to position the salt where the paint will be worn away, do not fall into the trap of making the wear appear too regular.  In real life paint wear can form unusual and random patterns (see the picture of the fighter aircraft above right).

Avoid moving the salt around too much because it will dissolve.

 Salt weathering-applying salt

5. Let the salt and water dry out

After the salt has been applied and positioned as required it should be left to dry out thoroughly.  At this point the salt will stay put, but will still be fragile.  If it looks like there is too much in any area it is easy to brush it off at this stage.

The model should be handled with care until the top coat has been added since any shocks may cause the salt to fall off.

 Salt weathering-salt applied

6. Apply top coat of paint

Now the top coat of paint can be applied.  It must be done with an airbrush and care should be taken not to get too close to the model with high pressure spray in case the paint jet blows away the salt.  A few grains are sure to fly off but this does not matter and may even improve the effect.

This is the time to apply any post-shading or highlighting with the airbrush.

The paint needs to be left to dry thoroughly.

 

 

 Salt weathering after top coat

7. Brush off salt

The final stage is to brush off the salt.  It should come away quite easily to reveal the previous coat.  In the photograph on the right, you can see that the salt is being washed away under running water.  I did this because this was the method I read about in an article.  However, I have read other articles that say this is unnecessary and I believe this to be the case.

If you hold the model over a piece of paper and collect the salt it can be used as an abrasive to rub the paint and create further paint wear if required.

Salt weathering-washing off salt

 8. Sit back and admire the result

The photos on the right show the final effect.  However, depending on the distribution of salt the result can vary enormously.

If the salt was sprinkled on to an almost dry surface and left alone, the effect will be very grainy simulating chipped and peeling paint.

If the salt was applied to a wetter surface and moved around so that it becomes partially dissolved, then the edges will be smoother and the patches will join up giving the impression of gradual wearing away of the paint.

Using salt to further abrade the surface along edges can enhance the appearance of wear, but do not overdo it and rub through the undercoat.

 Salt weathering-completed

Salt weathering completed-close up

 

Salt weathering gone wrong

Salt Weathering Gone Wrong

Salt weathering is fairly simple and quick, but I would strongly advise practicing before using it for real on a precious model.  In the photo on the right you can see my first two failed attempts at salt weathering.

On the left side of the model I used 'Marmite' yeast extract which I had heard works like salt.  On the right side of the model I used large grains of rock salt and too much water.  In both cases, far too much of the top coat came away and the edges did not look at all realistic.

Summary

Salt weathering is a simple and quick way of getting realistic paint wear and chipping on scale models.  It is not foolproof though and like almost all scale modelling techniques requires a little practice to get right.  Furthermore, it is very easy to overdo it and works best when used sparingly.