Grind them away....Notch the parent material joining surface....pre-heat with a butane torch....then weld away at the highest setting on the 135.

I have a Lindy 135 that I use for some things...but for applications such as this I prefer to use my friends MM210....hands down. If you have to use the 135, pre-heat is your friend....and it's no fun either. You'll end up with more penetration, however, you'll also get a more uniform crystalline structure (less of an HAZ). I personally don't like to pre-heat...as I feel like I'm messing with the parent material too much, but when you look at the big picture....that's all you're doing with more voltage on a bigger welder.

Not sure if Pre-Heating is recommended by those who are "certified". I would consider it a last resort. However, it is better than putting out welds with a lack of heat.

Max