too thin to try H/T again?

[Alan Molstad]

My first knife is from 5160
I finished the blade edge to within 1/16 of an inch before doing the quench.
I clay coated the spine.
heated the whole blade in forge.
quenched in oil.
I tempered in oven ..and then finished sanding until I now have a sharp edge.

However after reading a few topics here about useing an etch to look at the Heat-treatment I decided to go get that to check my work.

I just did an etch and found that the whole blade is hard without that cool hamon line as found on a Foweler blade.

Due to already haveing sharpened the blade, is it too late to do another heat/quench?

 

[Karl B. Andersen]

Ed only heats the lower portion of the Blade with a torch, so only that portion is brought up to hardenable temp, and only quenches about the lower half of the blade. Without going into much greater detail, those are the basics of his quench. This is not a tutorial on Ed's whole process.
What you see on his blades is not a "hamon", but a quench line.
You probably DID get your whole blade hard.
Because of 5160's alloy, it does not show hamon well, and will harden underneath your clay.
When I harden my 5160 blades at full temp - 1525 - even above the oil gets hard back up the tang a ways.
Give it a good temper, draw the spine back with a torch if you want it softer, and you'll have a good knife.