Shot blasting (or any other kind for that matter)

[pryantcc]

Has anybody got any very long term (20 years-ish) experience of the corrosion removal ability of media blasting?

I want to know if I get a panel blasted, will it remove absolutely any chance of it ever rusting again, or are little rusty microscopic bits still lurking there to make me sick 20 years later when I see them making my paint blister?

Anyone got any panels which were blasted, but got rusty again despite being painted immediately?

I'm assessing the value of giving the panels a rust-remover bath after blasting but before priming. Is there any point?

Thanks,
Paul.

[Grumpy Northener]

Paul - If it is properly blasted there should be no traces of rust visable - which is why you have had it blasted anyway ? - If the panel is returned fresh from blasting and you have no further work to do to the panel - other than paint preperation - I would suggest using a spirit / panel wipe prior to painting with self etching primer and then building the primer layers up with a high build primer - I would advise self etching primer on every bare metal area - I do not think that a further treatment of chemical rust treatment after media blasting would help - that is unless the blaster has not his job properly in the first place.

[pryantcc]

Paul - If it is properly blasted there should be no traces of rust visable - which is why you have had it blasted anyway ? - If the panel is returned fresh from blasting and you have no further work to do to the panel - other than paint preperation - I would suggest using a spirit / panel wipe prior to painting with self etching primer and then building the primer layers up with a high build primer - I would advise self etching primer on every bare metal area - I do not think that a further treatment of chemical rust treatment after media blasting would help - that is unless the blaster has not his job properly in the first place.

Thanks, this is exactly what I was after! I just didn't want to assume it & regret it later on!

[Luxobarge]

Not 20 years, but at least 10 - I blasted a LOT of components from my Midget in my home blast cabinet, and IMHO what GN says above is spot on. I don't think chemical rust treatments are a good base for paint, and after blasting they'd probably cause more of a problem than help. However etch primer is specifically designed to bond onto bare metal and I'm a great fan of it. The chances of it bonding onto metal that's been blasted is even better, because the rough surface left is an ideal key for it.

The blasted components on my car are still pristine after 10 years, here and there the top coat paint has chipped off, but only down to the etch primer - that stuff is on so tight you'd think it had been electro-plated!

I'm a major fan of blasting followed by etch primer - IMHO it doesn't get better than that, short of galvanising!

Cheers

[jimmyybob]

Any blaster worth his salt will etch prime it for you as soon as possible after blasting. even finger prints will start to rust in a day or two.