I have oak widow sills that have been weathered for 150 years. They are deeply crevassed and painting them is not a viable option.
I don't wish to replace them but would prefer to coat them in a layer of sand in a resin binding to give an imitation sandstone effect.
What would be the best adhesive and binding agent?

Hello Rich,
Thank you for your answer. Yes I'm sure it would do, I have Sandtex over a rendered extension that dates back to the 30's, but it isn't what I'm wanting to do. I want an end product that looks as close to a sandstone slab as I can get, without stressing the existing masonry and foundations with massively heavy and expensive blocks.
Hence my question "what would be the best adhesive and binding agent" for a sandstone effect?