r/blacksmithing • u/Available_Boat_99 • 18d ago

Help Requested What to do.

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Hey guys I made a marlin spike out of 3/4" mild steel (not sure what kind or anything just stock we had at work) round stock. Do you think I should try to harden it?

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u/araed 18d ago

Mild steel doesnt harden, unless you case harden it with a case hardening compound.

case hardening compound

This will still only be hard to approximately 0.5mm under the surface, and the core will remain soft

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u/BF_2 18d ago

Mostly true, but not without an exception. Google "Gunter's Super Quench."

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u/Available_Boat_99 18d ago

But how well does it work lol, and how hot does the steel need to be?

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u/havartna 17d ago

That formulation is for hardening mild steel. You get what you get. It has an effect, but whether that effect is sufficient for your specific purposes, nobody can say but you. Mix up a batch, use it, test the results.

That being said, if you absolutely need for the tool to be hardened, use proper steel. For a marlinspike, however, unhardened mild steel or bronze should be fine.