Ally or steel floor (and tank)?

[aerosam]

My floor is 2mm ally chequerplate. This is mainly due to the fact i was given the sheet by cjtheman for nothting!

Getting back onto the subject of tanks, I'm planning on making mine from steel and mig welding it all up - has anyone else done it?

I need to make mine bespoke to fit my donor's pump/level sender assembly and it would be much cheaper to fab one up myself than have one custom made for me.