I love this idea
I have an old chair really similar to this only, very rusty, but very sturdy. I have had it under the apple tree, for several years.
I have been wanting to do something with it, but, I actually like the rust. This idea appeals to me.
My plan is to spray 2 clear coats over the entire chair. That will protect it.
Then I am going to paint a design on it, giving it's age a focal point, and design having a aged look. Then seal it very well, to make it last.
A cabin feel, with a Pendleton vibe!