Harbor Freight is currently listing this four-piece set of locking pliers for $5 — cheap enough that you could lose them or foul them while welding and not worry much. And before you comment, understand that I’m fully aware that these are nowhere near the quality of a set of Vise-Grips or other quality locking pliers. But I know two things about locking pliers:
1) They’re easy to lose and foul, and
2) When you need more than two of them, you often need a lot of them.
This is especially true of welding clamps, which HF also sells. I have a drawer full of ’em.
As far as these go, you get a 4-3/4″ needle-nosed set, a 4″ straight-jaw set, and two 5″ C-clamp sets. Maximum jaw openings are 1-1/2″, 1-3/4″, 1″, and 2″.
4-Piece Mini Locking Pliers Set [Harbor Freight]