I picked up some Ryza Rust the other day. I have a lot of tanks and I'm looking to go the extra mile to bring some added detail here and there. I am also a big fan of the type of AFV tank models they paint in magazines such as Military Modeler magazine where it is all about adding rust and dust and mud and scratches and scrapes. So, being a fan of realism and trying to detail my tanks in similar ways, here is a ryza rust test on the exhaust pipes of my baneblade.
As a preface, the exhaust pipes were painted black, then painted with ironbreaker silver paint.
Here is the ryza rust right out of the pot on top of the ironbreaker with a little bit of water to thin it down because it is thick. It is essentially really thick orange paint on first glance. I painted it on with an old, worn brush and mottled it so it is thicker in and thinner in spots.
Here is the ryza rust with a wash of agrax earthshade.
Here is the ryza rust with the agrax and a nuln oil wash.
So there it is. I think it works. For me it was too bright out of the pot so it needed washes to darken it down. I would even hit it several more times with brown and black washes to get it really dark. I would even consider using some pigments on it. You could go back and brush on some silver parts again. I like it overall though.