welding a coated header

i was reading on one of the header collector sites that headers can not be welded once they have been coated. is this true? i thought i could just grind off the coating and weld on a new collector.

Just grind the coating off.... its normal metal
under it... I've done it MANY times

ok, thanks mike

I saw someone use hose clamps on each side of a seam to limit what was ground off then it was tig welded.total of 1/2" was exposed.

That's a good idea HEMIFRED all you need is it ground off where you must make the weld. But most of the time I grind just a little extra because the heat will burn it off while welding it,there is no problem with that other than the smoke & fumes.