well you would've thought an old bugger like me should know but heres a question.(been welding for over 30 years)
when I'm welding(mig 150 amp)the tube that I'm welding some times get arc burn or some thing like that(pitted).
is this due to poor earth? john
co2 is a bugger to weld with compared to co2 argon mix but it welds.
what do you mean by pitted? do you mean its burning through or where the wire isnt arking on the steel so its pushing the torch away. if its the latter i found that it was a common problem with all my welders in the first couple of hours use. if its not a new welder then i dont know mate. try attaching the earth to the workpiece if you can. make sue the steel is clean free from oils etc.
arc/pitted.. what I mean is that the tube tries to weld itself to the bench.
when I start to weld it some times does this and it sticks to the bench.
it leaves a burn mark on the tube.
these tubes are for grab handles for old bikes.these burn marks is difficult to remove without using a grinder,which I'm trying to use less as the parts get chromed and these grind marks etc stands out like a sore thumb,and if I don't remove them 1st .
all this is time consuming.
thats what i suggested. try getting some copper pipe or brass,sheet and wrap it round then attatch the earth clamp to that. stops it sticking when arking up
If you have any cleaning up to do, don't use a grinding disc - try a flap disc or a fibre disc on a backing pad. You can get a polish with them.
Otherwise, keep the bench clean and clamp down gently - you shouldn't get a weld that way. If you still do you could use a bit of copper or ally sheet in between bench and work.
I do use a soft pad not hard stone. grade 80.
funny enough I was considering using a sheet of alloy.
as for earth I will sort that out thanks chaps. john
funny how electricity finds it way. i have a large scrolled panel that is in need of repair work. A bit of tig, welded a few of the scrolls up nice, then i was going to weld up one of the collars. Touch the collar and nearly burned my hand. Looks like the collar was acting as an earth to the bench and got its self rather warm.
I have a couple of bits of 1" plate, about 3" x 4" with handles welded on that I use temporary weights. They're fairly heavy but quick and easy to place on top of the work ensuring that it's firmly in contact with the bench.
Does your bench have spatter lumps stuck to it? These could make a 'point' contact and cause problems. I have some thin sheets on the bench and they're 'disposable' so I can either run the grinder over them to get them flat or when they get too bad I just replace them.
The welding booths at work have sacrificial tops on, some have been cleaned with grinder/linisher that often they now have razor sharp edges - had to report them on PM sheets for replacement before H&S "police" spot them!
At work each booth has a copper plate to put under your workpiece...works great, easy to clean!
(works great, untill some idiot decided to steal them!!!)