Are there any metallurgists out there? Chain from a chandlers in horrendously expensive (£4 a metre for 4mm I was quoted) so I looked aound elswhere. I picked up 5mm chain at £2.20 a metre in a builders merchants. It claims to be galvanised but the finish is bright, compared to the grey galvanised chain in a chandlers. It is probably thinner galvanising than marine chain, but for occasional sea use I would expect it to last a few seasons anyway. The question is - what is the difference between builders galvanised chain and marine galvanised chain - is it galvanised in the same way?