I'm hoping to use some scrap structural steel pipes and plates to build a large BBQ/Smoker, but they're all pretty heavily rusted. I've seen people in tutorials use both wire wheels and preparation discs to do this, but none have explained their choice.
They all seem similarly priced and all have the same description of their function! Ideally I'd like to select the one which least marks the underlying steel.
I'm currently choosing between just about everything in this category:
http://www.screwfix.com/c/tools/cleaning-preparation/cat5990034
Best Answer
None of the above?
It's structural steel, you can just leave it rusty (if it happens to be corten, the rust actually keeps it from rusting further...) This may lack Wife Approval Factor for your backyard BBQ, however.
Least marking (and least direct effort, dust, noise) electrolytic rust removal - submerge it in a tub of water, outside, with sodium carbonate (washing soda) mixed in. Connect a low-voltage DC supply to the thing you want the rust off of, and a sacraficial electrode. Polarity is - to the thing you are derusting, + to the thing you are sacrificing. Both should be in the tub, but they should not touch. Turn on the power, let it bubble (that's hydrogen, which is why you do this OUTSIDE, only, not inside.)
For mechanical rust removal when looking for effectiveness/speed rather than "least marking" I use a knotted wire brush in an angle grinder. Conditioning disks will probably mark a bit less and definitely work slower, IME.