Acrylic Experimenting

I am attempting to use acrylic paint to portray or create the look of rust on various different mediums.

 I began by working into a tree stump i found this hard to scratch back into without the use of metal utensils I wouldnt really use this method either as no matter what I would do I cannot change the fact that this is a tree and it just looks slightly odd when put like this

I attempted using the spine of an old book but that wasnt very successful it just looked like a painting.

I tried using a shard of brick but however I found that I am unable to get the layers I would like and be able to take them away I feel that oil paint would be a more effective choice

I found working on clear plastic was the most versatile method I used as I could create multiple compositions using just one piece 

I found that the effect when I took away some of the layers was quite effective on this bright yellow card so I decided to put some of the same material over the top in tesalated pieces to give the impression similar to pain peeling away on a metal surface

  I decided to try using metal and then took away the paint I put it onto some card board and the effect is unusual but i didnt like the effect that i got on the metal so i attempted it again but this time used a sponge to apply my pain to the surface.

 I experimented on melted plastic and I found the effect different and in a way effective as the warped surface provides a nice surface to work on