Hi, I finally gave Vallejo chipping medium a go. I tested it on a Sentry Bot and I’m happy with the results. I’ve undercoated with Vallejo Rust and also Dry Rust, then apply the chipping medium and paint over in green. It’s going to take more practice to get it right but it is good fun attacking the model. One thing I’ll do next time is apply a varnish over the undercoat and then add chipping medium as I found that chipping sometimes takes off the paint to bare resin.
This other Sentry Bot is how I usually paint over rust which is quick and effective.