Cold Gal is good stuff. My old galvanised boat trailer had 2 cracks when I bought it. After prepping and MIG welding them, I sprayed it with Cold Gal.
That was 10 years ago, it's not rusted at all since.
Another product `Galmet' is similar.
Both these products are also available in tins, for brushing. Not cheap, but it works well. Next best thing to hot dip galvanising.
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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
...if you are trying to lose weight....its heavy stuff 