With a steel roof, we primed the steel beams by submerging them in a trof of primer. The C section used on the very top to support the roof panels have also been sprayed inside with a gloss coat.

The welders plan is to then, spray it all when it is up on a couple of weeks time.

Where the welds are, should they be sealing the welds with primer soon after the weld, so they don't get surface rust and it makes it clean.

the welder is of course saying no, but he is really bloody lazy, to me it is logical, going to be much more work to get all the rust off later.

Should any special paint be used? or just the same metal primer?

If you can get hold of some " Hammerite " that would be good for painting steel welds.

If not primer will be OK but preferably not thinned out.

If he dipped the beams (vs. painting), he must be lazy. Anyway... oxidation is almost instantaneous - but takes a while to become rust. Should be no problem to wait the week.

If you'd really like to take control switch primer colors too. They likely used the red color for the first coat....have them switch to grey for the welds so that you can more easily verify where they've reprimed. Then have them paint the whole thing in a third color, white (that way you can see where rust is forming).

...At least that's what I did for my house.

Make sure he gets someone to chip of the slag and clean up the the weld area .

For galvanized, exterior metal after welding:

have the burned area ground smooth to bare metal;

then one coat metal primer,

then one coat TOA 'Syncormate' or equal zinc chromate paint.

For patching paint at welds for attic metal -protected from elements but not important to look great:

metal primer & enamel paint labelled suitable for metal.

If the "welder" leaves it a couple of weeks all your welds will be rusty, and to get a proper surface to paint on, one would literally need to blast it.

Post welding oxidation occurs within a few hours, you would use the same prime as the "dipped" sections

If the "welder" leaves it a couple of weeks all your welds will be rusty, and to get a proper surface to paint on, one would literally need to blast it.

Post welding oxidation occurs within a few hours, you would use the same prime as the "dipped" sections

Agreed. Your welder is just being lazy. He should be cleaning and coating all his welds as he goes, certainly no later than at the end of the workday.

Thanks for your input.

All the primer had be thinned, that's ok, so I bought more original primer, They refuse to use it, say it's to hard to paint with. They have only painted the once with the thinned paint.

I then chipped some of them that they just painted over, <deleted>.

I can see thunder storms coming, they are still refusing to paint a nearly completed roof welds.

I am just reaching the point being completely fed up. How many slaps in the face can one take before just walking away.