Where can I get Stencels to spray on Mottling on German and Japanese aircraft ? Do they work.
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I have never used them but, regarding usage on aircraft, it seems to me they would be quite difficult to get a satisfactory result with for a variety of reasons.
Yes,it’s not just a matter of plopping down a stencil and spraying,still need to get the right mix and psi of paint to get that hazy mottled look and not just camouflaged spots.Practice and experimentation.also needed.
More fun to do it freehand anyway!
I have used stencils made from index cards with irregular holes burned through using thin incense sticks. Maybe a soldering iron with a fine point would work as well.
The trick is to cut the index card to a shape that will conveniently fit the model. I found cutting the card slighly oversize but approximately the shape of the area to be camouflaged worked well.
Also, I used small loops of masking tape as spacers between the card and model to get the fuzzy edges. You could use small balls of Fun Tack or similar. Silly Putty won’t stick well when made into tiny balls. Low pressure and thin paint are key.
Real G is right on. If you use that type of stencil you need space between that and the model so not to have a sharp edge. Free hand of course is another way to get the right mottle effect with a little overspray. I made the mistake of using masking on my D9 and went back to correct the sharp camo lines. Those stencil things are good for subtle paint effects either pre and/or post shading. Torn scotch bright pads also give you a random pattern.
BTW, I am just curious, Is this an ‘in general’ question, or you looking for a specific aircraft type/scheme?
I thought it would be easy to use on German and Japanese planes for Moltting.
Here is Huma’s 1/72 Triebflugel with mottling applied using a home made stencil.

Wings are easy to do, but curved surfaces like the fuselage require painting in the mottles a section at a time.
I’ve used index cards, too, but I used a pencil to punch holes of various sizes in the card.
I learned that tip years and years ago, when I was a kid, when I was a member of the second incarnation of Revell’s Master Modeler Club. One of the newsletters including a build article of their old Me-109G kit, and the builder used the “punched hole” technique.
I think it works pretty well.
Another vote for DIY, similar to Real G…though I used manilla folder stock, nice and stiff but easy to contour to whatever fuselage or wing surface you’re looking to mottle. About 20 min. with an X-acto, or poking holes with a variety of small sharp implements (back your template sheet up with a stiff cardboard box or rubber pad) and you can replicate a variety of mottle patterns in nearly any scale – I’ve gone as small as 1/144 with good results.
When it comes time to spray, ‘attach’ the mask with blobs of Blu-tak or Silly Putty; it’s a lot easier than trying to hold the mask and model in one hand while trying to spray with the other! [:D]
Green Stuff World makes some, though they’re not specifically described as stencils for mottling:
https://www.greenstuffworld.com/en/391-flexible-stencils
Freedom Stencils also has some stencils off the shelf:
https://www.freedomstencils.com/collections/camouflage-stencils
AK Interactive also offers various stencils, for camo and for weathering, and it’s worth it to have a look at their products, too.
Hope that helps!