Hope someone can offer some advice. I've often seen finished vehicles that have the dirt streaks left by rainfall/ runoff replicated on them. How is this done? I've thought about using oils, but my attempts so far have been less than realistic. Anyone able to offer some guidance with this?

Thanks,

Grant

I've used heavily thinned water colours for this with some success. Just the really cheap kiddies sets you can get for a couple of bucks at the dollar store (are there 'five and dimes' anymore?, ..but I digress.......).

I've used white, very pale pink and light grey for rain streaked dust and even browns and oranges for rust streaks as well. I use a 1/2 inch pre-wetted brush so the bristles are seperated and uneven. Dip the brush in the mix, wipe most of it off and then streak it downwards in a fairly quick motion with the brush barely touching the surface. Once the water streaks dry it leaves behind a faint colour streak. As with any technique, not overdoing it is important.

Play around with the thinning ratios but the key is to use, at most, something like 95% water and 5% paint.. Try it out and experiment on a few painted surfaces, it works.



Bob

Look here.
http://www.missing-lynx.com/rare_world/rw01.htm

Grant,

Here are a couple of photos of my M41 with some rusty run off. This was done with rust color paint (MM enamel) and some acetone. 95 % acetone and 5% paint, be careful to not go over glued joints as the acetone will eat the glue.







Basically just drip it on and let gravity do it's thing.
Hope this helps out some.

Thanks, guys! That was quick!

Some good ideas there. I really like the watercolour idea, Bob! The Mig article also looks really tempting, as does your method, Steve.

Grant

I use el cheapo watercolors too.I like them,as they do not interact with my enamel base coats.

Grant,
I use what I call the "dot technique." I use tube oils applied with a 000 brush. I then streak the dots down the sides of the vehicle in question. Here are some of the results on my Char B1 bis:



Note the really faint streaks on the turret bin of my Hungarian Tiger I:



BTW, I use browns for dirt streaks and reds for rust (not too much!). Hope that helps.
Regards,
Georg

Depending on the surface you want to replicate the water streaks on you can add glyserine to the water colour as a wetting agent. It reduces the water tension in water and will allow a finer more controlled steaking effect. It would work best on acrylic dull coat but has its uses on gloss coat as well. You can find glyserine at any pharmacy in small bottles.
Bill