Exhaust Effects

[Herrick]

I'm just finishing off my P51-D and I want to give it some exhaust marks. There are tons of 'How To' videos out, it's like looking for the proverbial needle...

I've just seen these :

AK Interactive - Exhaust Stains Weathering Set (https://elementgames.co.uk/paints-hobby-and-scenery/paints-hobby-and-scenery-by-manufacturer/ak-interactive/sets/ak-interactive-exhaust-stains-weathering-set?d=22&gclid=CjwKCAjw0qOIBhBhEiwAyvVcfznCl9eGyzd3aMRY2CIf7LSY89giXRyDsK6gcvjk7l2xX11W17LAHxoCefgQAvD_BwE) (Yet another £20 odd for an effect...)

Has anybody got any experience of using these? Any other advice? Can I just use thinned down paints?

 

[Mark Harmsworth]

I use artists chalk pastels for exhaust and gun stains. Rub onto a piece of sandpaper and apply with an old brush or cotton bud. Probably the same stuff as those sets and a lot cheaper. I've got one set of greys and another of browns.

Mark

[Dr. Quack]

Another vote for pastels - cheaply available in a huge range of colours. A stick will last a modelling career. I would suggest getting a few colours including black, a few browns and a few greys. They can be powdered by rubbing on sandpaper and mixed to vary the shade. Apply onto a satin finish which will have some `grab` using a brush or cotton bud. Seal with a clear coat of your choice otherwise it will smudge and smear.

Q

[dogsbody]

Though I haven't used them very much yet, I have these Tamiya pastels. Inside each set is a small applicator, with a brush on one end and a pad on the other.

You can see them here: https://www.tamiya.com/english/products/87080weathering/index.htm

 

 

 

 

 

 

 

 

Chris

[Ray_W]

14 hours ago, Herrick said:

Can I just use thinned down paints?

 

Yes, it is my preference.

 

I use a heavily thinned mix of Tamiya Flat Black XF-1 and NATO Brown XF-68 thinned with Gunze's Aqueous Colour Thinner or Tamiya X-20A. Ratio is a bit of this and that until I achieve something not black but a touch reddish brown depending on the subject. I like using the Tamiya XF colours as they are very flat. The exhaust staining comes after all finish coats are done. It is one of the last jobs.  

 

I spray it using my Iwata HP-B Plus 0.2 mm needle (although I have used my HP-CS 0.35 mm with good effect) . Pressure, if you can believe my gauge, is around 10 psi. I build it up with narrow streaks close to the surface varying the length with more density near the exhausts. Airbrush always moving. Often start the paint flow on my gloved hand to ensure I have the quantity I want and ensure my trigger control is in order.  

 

 

If unsure, I attach a piece of paper or tape on the model close to my spraying location and go to that to check spray. I find this handy also with mottling. 

 

The coating is thin on the aircraft and darn hard to see so your looking to position the model so you can see the moist reflection. I model in 1/48 so it is easy to hold in that gloved hand and watch what is going on. Key thing, again, airbrush never idle to avoid pooling in a location. If unsure if you have achieved your desired effect, it is better to finish up with too light a coat and set the model aside for 10 minutes and come back and check the effect. It is one of those things where it easy to go too far. 

 

Some examples:

 

 

 

 

I will vary the colour of the mix based on the subject material. For example a lighter grey for a leaned mix. 

 

 

As with all things modelling, it is one technique in the tool bag. I'll use some pastels, the Tamiya weathering pastels, water soluble pencils or oils thinned with odourless spirits to enhance or modify depending on the desired effect and application. 

 

Ray

 

 

[Herrick]

Thanks for a full reply. I think I will try this approach, although my airbrush technique is not the best, the only way to improve is to practise.

Your Me110 is lovely, is that really 1/48?

[Ray_W]

4 minutes ago, Herrick said:

Thanks for a full reply. I think I will try this approach, although my airbrush technique is not the best, the only way to improve is to practise.

Your Me110 is lovely, is that really 1/48?

 

Yep, Eduard 1/48. Lovely kit.

 

Practice is the thing. Try mottles and various line thicknesses. Gives you a chance to understand what distance you need to have to the surface and get that trigger feel. 

 

When trying to get the hang of this, that practice sheet (a post-it label/masking tape/gloved hand), close to the where you will spray, can allow you to ease up to the point just before paint and then move it slightly more for paint to flow.  Soon you do not even need to think about - mind/hand memory kicks in. 

 

With my dual action air brush I ease onto the paint flow. Full paint is rarely used and certainly not for exhaust streaking.

 

Also, remember that when using very thin mixes and dual action airbrushes, if you shut off air rapidly before paint you may get a splatter when you start the next line. Either ensure you operate the air brush with the cycle - (1) air on (2) paint on (3) paint off (4) air off - and/or do a practice to ensure the start is what you want. No paint splatter clearing residual left over from the previous cycle. Even better, experiment and learn what trigger operations produce what results.

 

And finally disasters always happen. The best learning and associated confidence is built off corrective work.

 

Ray