not necessarily - Zinc182 for example (the yellow and grey tin quite common in car shops) contains zinc phosphate which means it stick really well but its not metallic zinc which is what you get in weld thru primer. I use UPOL weld thru primer but not the one that comes in a Lime Green can - this is really expensive around £13-£15 in Halfords. UPOL also do a weld thru primer in a generic looking grey coloured can which just a white label on it with the name 'weld thru primer' on it. Its called the 'Powercan' range - there's other primers in the range like self etch, grey primer - all the cans look exactly the same - grey can - its the white label that details the contents inside. Its much cheaper at £8 on ebay and works just as good.