shaved gutters

my friend always plays with my propane torch when he comes over so maby he will do somthing usefull for once lol fing pyro

the torch will warp the hell out of your roof skin.

I'd lead it. You can buy kits from eastwood, have it shipped to your door. Better than any of that mud crap.

you got a link for that??

eastwood body solder kit

They got some pretty neat stuff. A lot of old school stuff when people used to do stuff right.

And that "used to do stuff right" comment wasn't meant at anyone on here, just a general statement about the way bodywork in general is done now.

don't fill it with lead. terrible idea. don't fill voids with any filler. its just a bad idea. either cut it off and weld up the seam or make a piece of filler sheetmetal to go from the corner of the gutter to the roof. just don't fill it. thats so hack-job/minitrucker(not in a good way).

If you span it with a piece of metal there will be a space in between that can condensate and will start rusting from the inside out.

i'm not taking offense or anything, or getting my panties in a bunch, but i just have a question for you.
Do you actually know how to or have you ever actually used lead? if so you'd probably not recommend it for your truck, or any newer vehicle for that matter, and know that its applied with a torch used to heat the lead enough that it melts, and you have to heat the parent metal hot enough that the lead will melt. back in the day, cars were made with real metal, and your mazda is, well, closer to tin. its several gauges thinner, therefore its going to warp to shit when you torch it. not only is lead poisonous (can't even get the real stuff in California) bondo (or whatever brand you like) has been developed and advanced for the last several years... i don't even know how long. its really come a long way, and if used properly, it will last forever, and its a lot less stressful on the piece its being applied to.
don't get me wrong, lead is badass if you know what your doing, and its a 50's chevy or merc or something, but its not even worth wasting the money on trying to lead a mazda. That stuff's expensive

you kind of cover that when you weld it up. airtight. unless you've got other problems, it shouldn't be able to get moisture in it. especially after its painted and clearcoated. remember bondo and primer are like sponges. water gets under them and will rust under them. thats why there's paint.