Hey all ,
I've been wondering, after the quench , whats the best way to get the black residue off?

Thanks

A over night soak in vinager then rinse with bake soda and water.  Might have to srub a little with a scotch bright, but your finishing belts or paper will last a lot longer.

James

I've got a little 4-1/2" angle grinder that works well and those discs are cheaper and last a lot longer than belts or paper.  Once the hard scale is knocked off I go to the belt grinder.

I have a 6" flap wheel on My grinder @ 320 grit.I recomend a respirator too!

Thanks everybody,

I think I'll give the vinegar a try first.

Wire wheel or flapper on your angle grinder. SAVE THE BELTS for grinding after that nasty scale is gone!

Vinegar works great and saves on sanding paper and belt costs.  I soak mine for two days and scrub it off with a tooth brush.  Then dip in baking soda saturated water and give a good scrubbing.  This neutralizes the acid and helps prevent rusting.  Another good trick is a bead blaster.  A wire wheel on a 3/4 or 1 hp bench grinder will knock it off as well and leave a burnished finish on the steel.

Jason Knight uses hydrochloric acid 1:4 water in a soak of just a couple of hours...works quite nicely.  Doc

I usually do a light hand sanding with whatever grit I finished with before heat treat and quench, but before I temper it. It removes most of the hard black stuff. I also like the vinegar soak. I put a little dish soap in the vinegar and let it sit overnight then nuetralize it and scrub a little bit.