I have Imron on my mast and beams (and tiller arms)
besides marine, it is used on locomotives, planes and big-rig trucks
It is pretty tough stuff... but of course ... it's just paint

the proccess of painting spars includes media blasting, acid washing (etching), priming and painting.

As mentioned this is pretty toxic stuff (2 part paint) and full resperation gear is recommended for painting and required for removing

PS the stuff costs around 300 per gal plus 100 for the catylist

Having second thoughts yet? - just spray some white rustolium on it and call it a day