Wash to Weather a Tiger

I'd use a darker shade of your base paint. In this case, you'd get great results with Burnt Sienna (that's the name of a paint in the artist's range of colours, and that can be found in oil-based, acrylic or in watercolour formulae. Persnnaly, I'd use the oil or the watercolour as they give you more flexibility than fast drying acrylics.

I personally use Raw Umber on Dark Yellow base coats, with a little black at times on the lower sections. Raw Umber is more subdued then Burst Sienna. Burnt Sienna is more on the reddish yellow side. I use Burnt Sienna mixed with yellow for rust.

horry,

Raw Umber or Burnt Sienna are the colors of choice for nearly all color-camo schemes. I also use Black around the tracks and engine/exhausts. If it seems too light at first, you can always add more (remember, it's a wash not a paint)

Also, remember to cover the piece with a good gloss coat before the wash. This lets the color flow more evenly into seems and panel lines.

Good Luck!

Contrary to what Erock is sying, I would not do the glossy paint step... You can improve the 'flow' of the paint, in the cae of acrylics and watercolour with a drop or two of dishwashing detergent and a couple of drops of white vinegar. With oils, turpentine will do, but DO make sure your base coat, if oil based (enamel) is well dried first!