Roger have you tried F9 BARC?
I've enquired to have some shipped over. I had a response on quantity to which 1 unit was my reply and I've not heard back yet. Think I'm being dodged now as it's not a large order.
No Lee I haven't, same here when I have tried to get even samples sent over, not interested if the volume is going to be small, saying that thought Techniseal did send over one of there "wonder" sands for block, and unfortunately it was crap!!
What are you trying remove with the Barc, as Chris stated Tensid do some good rust removers, pending on what type of "rust" it is. I have used a lot of there products, so let me know what you are removing and I might have the answer.