I have always had trouble with this.How do you guys make oil streaks on aircraft,vehicles,etc.?I am a very avid aircrat builder and really would like to know how to do oil streaks.

Hola!

Although Im no expert and have never done this, I have heard that people uses thin oil washes with burnt umber or black for oil, or whatever color for that matter, perhaps it depends on the color of the model that you are putting the stains on. I would think that an acrylic wash could also be used, although Id say the oil wash would be more realistic. Come to think of it I have done it once, on a fuel barrel, I used an oil wash of burnt umber and a lighter color, dont remember wich one, and it turned out pretty good. Try and see on a scrap peice

Dissolve a little brown, rusty or black (try a few and see what you like most) oil paint in some terpuntine, so you get a coloured yet transparent solution. Wash the areas with this solution. Then to add streaks, add just a little more paint to it and add fine lines with a fine brush to simulate rust 'leaks' or oil traces.
Jan

For recent streaks use a "streak" of Johnsons Future on top of the "OIL" just to give the correct feel to it.

I tried this once where it probably worked best on a dusty matt finish. Colour a little gloss coat with a dark colour like black or burnt umber and streak it away from or down with a dry, clean brush. It looked quite good. On an already gloss aircraft Im not sure what it would look like, but Id imagine it should give the right effect!

Lots of good suggestions here -- I like to use thinned oils or Testors Rubber for fuel drips and dribbles.

The secret to this is to not over-do it. You can always add a little more later, but it is really hard to remove too much. Unless you are modelling a rolling EPA SuperFund toxic waste site, try to keep the fuel and oil spills subtle.

Sheesh - I er' use real oil, like a penetrating oil, on a matt surface it looks great, as dust lands on it over time it looks even more weathered, try it on a old test model first, I have never had to remove it so be careful.

Hollowpoint does what I do. Spider has a cool idea too.

I will also use Tamiya flat back and water as my mediums and mix a wash and add a bit to the AC. Just as said above - don't over do it.

I typically use OILS (combining Black, umber, and/or gray). Put just a small dollop at the top of the stain area, and then use pure thinner to "stretch" the color downward toward gravity's pull.... the thinner does all the work!