Need Panel Beater Advice

[Wacky Dee]

Bit of background...

My 34 has some nasty rust on the strut towers and the only way to clean it all out is to cut the top plate off and replace with a new one and obviously at the same time, protect the plate below by rust proofing it for the future...

I've already sourced new top plates from wreckers so now just need to take it to the panel shop to take out the old strut tower top plates (they will cut them out and pop the spot welds so that we don't have to remove the WHOLE top plate which goes under the front guards as the section towards guards isnt rusted).

Anyway, the new top plate will need to be welded on top of the strut tower. However before we do that I need to rust proof the bottom/main strut tower plate underneath so that rust doesn't come back. But since this is going to be tig/mig welded I'm thinking any rust proofing like Penetrol will melt away from the whole area once the welding starts due to the immense heat. And also obviously once the top plate has been welded on I can't rust proof any more as the bottom plate will be sealed off and inaccessible..(other than through tiny gaps UNDER the strut towers which are the source of the moisture .. friggin sandwich plates)

QUESTION:

Is there ANY rust preventing stuff out there like Penetrol that won't melt away/disappear from the protected surfaces if you weld nearby ???

[Dan_J]

etch primmer? its used to spray before you weld bare metal