12v welder help.

[Stoogecurly]

i am trying to make a spot welder using a 12v 300 cold crank amps battery with a 12v cylinoid with a switch im using 10gage leads to copper roofing nail tips. the welder isnt getting a good contact for welds for some reason. whether i do a quick burst or hold it there for abit and get it red in the area. im just not getting a consistent weld. i attempted to use a 650cca car battery too but that was just blowing holes through the nickle strip.

also what is everyone using to connect the leads to the copper roofing nails?

i have messed with diffrent designs and i did manage to get some nice welds but after 3 welds the connection from wire to my nails was just starting to melt. and since i just havent replicated it.

any help would be greatly appreciated im starting to get abit frustrated and i know i shouldnt. im sure its something small im missing.