reworking a fully restored car

thanks for the tips guys , the new rail pieces were sand blasted and then primed with zinc based weld through primer and enamel primer as well . I am going to use a rust converter on the remaining rail inners and then 2 part epoxy prime everything the welder won't burn .Then sealer and undercoating on the outside of everywhere prime and paint the inside . Just need to wait a day or two for these record breaking temps to cool off , I only get an hour or so in the evening where the sun isn't beating right on where I am working .Hopefully the cutting and grinding will be over tomorrow and then the extensions glued/screwed in place thursday for the welder to spot in when he's got time to come over .