How do you do "salt wash" for model paints?

[rickshaw]

As the tinlid says.  How do you do that "salt wash" for model paints?  I have a Japanese model I'd like to paint... 

[zenrat]

I presume you want a worn/weathered finish?
This technique seems to have been replaced by the hairspray technique, but this is how I do it.

Paint the model with the underneath colour.  When dry wet the model and sprinkle salt on it where you want the paint to be missing.
The salt will stick to the water but make it too wet and it will all dissolve and too dry and it will fall off.  Some experimentation will be required.  Also you will want a range of sizes of salt pieces so I use rock salt coarsely ground.  Make sure you don't get caught taking the best salt grinder to the shed.
If you don't like what you've done you can always rinse it all off and start again.
When you are satisfied paint over the salty model with acrylic paint.
When its dry scrub at the salty bits with an old toothbrush.  The salt will dissolve and come off as the water works its way through the acrylic paint.  You will be left with a patchy worn finish.

[Mossie]

I found a technique that seems to work well, although I've only used it small areas.  I weather in reverse.  I lay down the top colour, then selectively paint a thin layer of the underside.  Once it's dry, I work at it with a sanding stick.  I've found it looks more convincing and you have a little more control.

[Dizzyfugu]

Salt works fine as a masking medium for rusted areas, esp. at large scales like 1:35. Prepare the area with rust-colored paint, let it thoroughly dry. Then wet the area carefully with water (a drop of APC helps) and then shake some salt into it. Let thoroughly dry and then paint the model as usual - works best with a paintbrush, but this also works with a standard brush when you are careful. Once dry you rub off the salt, and the rust is revealed - plus some texture that looks very much like corroded steel plate.

I've tried this stunt in 1:72 (on both vehicles and aircraft, for a chipped paint look) but IMHO it the results were rather messy and did not look good, the effect is too coarse. Hairspray - though more difficult to apply - might yield better results at small scales. Personally, I have changed to lay down a metallic primer base, then apply the standard surface color, and finally thin the wet paint with an appropriate solvent and/or do wet-sanding to the area. The effect is similar, but I have better control over what's going on, also because I do not have/use an airbrush.

[ChernayaAkula]

Not sure hairspray technique has replaced salt weathering. It's just an additional technique.

These MiG-21 drop tanks were weathered using the hairspray technique. They were all spraypainted in AK Extreme metal (Dark Aluminium, I think), got a coat of hairspray and then their camouflage colours. Half an hour later some water was applied to activate the hairspray. I then used a stiff brush, tooth picks, bamboo skewers and tweezers to ding them up a bit. Different tools will yield different effects. Effects can be controlled from very subtle scratches to taking off the paint almost completely.
This was my first try using hairspray.

[rickshaw]

OK, thanks.  Dizzy, "APC"?  What is that?

[zenrat]

I must admit that salt is better on 1/25 cars than 1/72 aircraft.
However, finely ground salt on a 1/72 aircraft could be used to avoid the OTT weathering it is all to easy to end up with when using hairspray.

[Dizzyfugu]

OK, thanks.  Dizzy, "APC"?  What is that?

All Purpose Cleaner, or some other detergent/soap to break the water's surface tension. Otherwise you do not have much control about where the applied water ends up. Sorry, that's my professional side when you do advertising for Procter & Gamble... 

[rickshaw]

OK, thanks.  Dizzy, "APC"?  What is that?

All Purpose Cleaner, or some other detergent/soap to break the water's surface tension. Otherwise you do not have much control about where the applied water ends up. Sorry, that's my professional side when you do advertising for Procter & Gamble... 

Ah, OK, thanks.  What do you, professionally, apart from build models?

[zenrat]

OK, thanks.  Dizzy, "APC"?  What is that?

All Purpose Cleaner, or some other detergent/soap to break the water's surface tension. Otherwise you do not have much control about where the applied water ends up. Sorry, that's my professional side when you do advertising for Procter & Gamble... 

Ah, OK, thanks.  What do you, professionally, apart from build models?

Temporal Mechanic?   

[PR19_Kit]

OK, thanks.  Dizzy, "APC"?  What is that?

All Purpose Cleaner, or some other detergent/soap to break the water's surface tension. Otherwise you do not have much control about where the applied water ends up. Sorry, that's my professional side when you do advertising for Procter & Gamble... 

Ah, OK, thanks.  What do you, professionally, apart from build models?

Temporal Mechanic?   ;

More like a Temporal WIZARD! 

[zenrat]

A mechanic, if good enough at their job can give the appearance of working magic...

[NARSES2]

OK, thanks.  Dizzy, "APC"?  What is that?

All Purpose Cleaner, or some other detergent/soap to break the water's surface tension. Otherwise you do not have much control about where the applied water ends up. Sorry, that's my professional side when you do advertising for Procter & Gamble... 

Ah, OK, thanks.  What do you, professionally, apart from build models?

Temporal Mechanic?   

Specialising in Tardis repair, maintenance and testing