Has anyone here any experience making up their own anti-fouling paint?

On a face book page a suggestion was made to add copper powder to marine paint as a cheap and effective anti-fouling. Copper powder is readily available and not too expensive. My thought would be to add this to the cheapest anti-fouling paint (because of its ablative characteristics).

Has anyone tried this? If so how good is it.

My reason for asking is that we cannot obtain Pettit Trinidad SR here in Ireland. This worked extremely well for us - we have not had to repaint our boat 's bottom for over five years - and still no fouling. It has a lot of copper in it.