Rebar vs. coil spring for forgeable steel, which side are you on?

I keep seeing folks online swear by rebar for making tools, but every piece of rebar I've pulled from a job site has a different spark pattern and hardens like glass. Last month in Austin I tried a coil spring from an old truck and it moved so much smoother under the hammer, plus it held an edge after a simple quench. I know some smiths say rebar is fine if you normalize it three times, but is the mystery metal really worth the gamble for a knife or a punch? What's your rule for when scrap steel is actually worth the fire time?

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paulw8716d ago

Rebar is a total crapshoot because it's whatever got melted down that day, so you get mystery steel that might air harden on you or crack in the quench. Coil spring is 5160 most of the time and it's dead reliable, so that's my pick unless I'm just making a hot cut or a punch where edge holding doesn't matter much. My rule is if I can't get a spark test to match a known steel and it won't harden right after one quench, it goes in the scrap pile instead of the forge. Normalizing three times won't fix bad alloy, it just fixes grain growth from the mill.

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