Prior to welding on an aluminum boat hull (rails, cabin, sides, etc.... NOT THE FUEL TANK), how many of you do any of the following:
1. disconnect positive and negative leads from both terminals of all batteries.
2. disconnect all hot wired electronics or motors at either the battery or the device
3. drill air relief hole on sealed tubing or other sealed compartments (not the fuel tank !)
4. remove, or drain and fill the fuel tank with water (even though you are welding on something else other than the fuel tank.
5. cover fuel vent openings with a wet rag.
6. remove and or disconnect any other fuel fired devices or their tanks (oil fired or propane).
7. stand on a rubber mat (and/or wear rubber boots) if you are on the boat while welding.
8. connect welder work lead close (within a foot or so) of the welding area.
I know you should drain and fill a fuel tank with water if you are going to weld on a surface touching the fuel or fuel vapors. I don't plan to weld directly on a fuel tank.
These questions are with regard to the rest of the boat. My understanding is the fuel tanks typically ARE electrically connected to the hulls via mounting bolts (i.e. they are not electrically separated by dielectric connectors), but it is not necessary to drain/fill with water or remove the tank. I asked a welder at one of the major NW aluminum boat building shops about this, and he said he welds on boats (not the tanks) with gas in the tanks all the time but does cover the vents with a wet rag if welding near the vent.
I have welded a bunch of loose stuff on the welding table in the garage, but nothing directly on a boat or car. Trying to get the safety stuff in order first .............