Making impressioning marks easier to see.

[pickmonger2]

A hint from The National Locksmith Tech Tips was to heat a brass key tip cherry red. This will anneal the metal making it softer and easier for pins to mark the brass blank.

The metal will be a bit weaker so be careful how hard you twist and turn the blank.

[femurat]

Good one. You could try to heat just the part of the blade you're going to file down. But brass is a good heat conductor so you're right, all the key will be softer.

Cheers

[Josephus]

Annealing brass is a bit weird. Brass can behave opposite of ferrous metals. Quenching will get the best results. Also, brass is more prone to snapping along differences in temper than steel. Uniform heating and cooling is treated as important in texts on the subject but I don't have any experience with that.

[capt-dunc]

i think depending on the rate of cooling you'll end up making the blank much worse. heating to red then quenching will soften it, but since it's easy to work as is, i don't think you'll gain much. if it air/slow cools it'll end up potentially harder and mark less.

however distempering a steel blank may prove useful

[pickmonger2]

It worked for me and made the marks easier for me to see.

I wonder if all bass keys use an identical blend of metals and come tempered the same.

As I understand it the poster of the tip, Joan Yarrington (a locksmith with years of experience) found it worked well for her,your mileage may differ .

I noticed that she did not say to quench it but to let it air cool.

Wikipedia https://en.wikipedia.org/wiki/Annealing_(metallurgy)says

Annealing, in metallurgy and materials science, is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable. It involves heating a material to above its recrystallization temperature, maintaining a suitable temperature, and then cooling.

In annealing, atoms migrate in the crystal lattice and the number of dislocations decreases, leading to the change in ductility and hardness.

In the cases of copper, steel, silver, and brass, this process is performed by heating the material (generally until glowing) for a while and then slowly letting it cool to room temperature in still air. Copper, silver[1] and brass can be cooled slowly in air, or quickly by quenching in water, unlike ferrous metals, such as steel, which must be cooled slowly to anneal. In this fashion, the metal is softened and prepared for further work—such as shaping, stamping, or forming.

[Jaakko Fagerlund]

Yeah, brass and copper doesn't have to be quenched after heating, they do not change the hardness after heating them. Usually they are quenched to get on with the work and not having to wait for it to cool down enough to touch

Better than a dead soft brass blank would be to make an impression of the blank in keycopy clay, the file the keycut are away from the blank, make some slots with a hacksaw for a tin-alloy to adhere to, put the filed blank in the keycopy clay thingie and pour the alloy in. Tada, you have a hard key backing with soft area for marking and filing. And if you file too deep, it is easy to cast it again. But you will want some low melting alloy which is hard enough, probably along the lines of Fields metal or similar non-toxic.