Thread: keeping blade cold while buffing to save temper?

When using a dremal tool, which I am sure a lot of us do you can lay the blade flat on a granite counter so that the edge is flat against the stone.
You can use a piece of flat stock aluminum to lay the blade on. You can even use a wet sponge to draw the heat off while polishing the blade.

Just take your time and be sure you are wearing your safty glasses or a shield. If someone has to watch make sure they were eye protection too.


Silver2

I have two goals when restoring blades. 1) Do not over heat and ruin the temper. 2) Get 'er done! What ever it takes to satisfy these goals and finish with quality work is what will be done. While I enjoy working metal I enjoy the finished results much more. With 20 + years of precision metal working behind me I can't help but do what ever gets a quality job done fastest and move onto the next task.

If the metal has a blue color to it after working it the metal in that area has been annealed (lost it's hardness) and will not hold an edge for very long. Buffing the blue off the metal will not increase the hardness. For this reason I am very reluctant to buy restored razors off of ebay or that have been restored by someone new to restoring and/or I am not familiar with their work.

Originally Posted by Mvcrash

If a blade was buffed and you can see that the blde has a blue colored hue is it ruined?

Short answer: Yes, if buffing was the source. If you have enough heat to create colored oxides, there has been enough heat to affect the internal structure of the steel and a proportionate loss of hardness. Now you can polish off the oxides and it will still look good...but performance will be much different than if the blade was hardened to its best potential. The blade can be re-heat treated, but in very thin shave-ready section thicknesses this can be likely to further ruin the blade.

Some blues/greens/yellows may be merely patina from exposure to oxide causing chemicals. E.g. the blade may have been used to cut bacon or fruit etc. Then the blade is not ruined.

Silver2's idea of using a heat sink is a good one, as are all the recommendations to do this with bare fingers. You can work "a little longer" with heat sink methods, but they will all require a learning curve until your wet computer can figure out the length of time that is about right for keeping the pressure on the tool/blade. This means you will ruin some steel until you figure out the upper limits.

Your hands are incredibly sensitive and can feel when the steel is getting too warm faster than any technological marvel toy. If you can feel heat at any level, get the blade into the cooling bath.

While the ice bath thing seems logical and, for ice cubes in water, will probably not hurt the blade to any degree, the caution I have is that if your fingers are in the cold water, there are changes to your sensitivity that may occur and you could be fooled by your sensors when the steel is really getting hotter than you thought.

There is a phenomena I call a heat bloom. I feel this as a time lag between fingers feeling the heat begin to warm the blade followed a couple seconds later by, for lack of better words, "Damn that just got too hot..." and the very heartbreaking visual appearance of colors I really did not want to see. In my mind, this means if you can feel the heat coming on, it's going to be much hotter in a couple seconds than you wanted it to be. Habit has grown on me enough so that if I can feel it, the blade gets wet, AND, is left in the water until it completely cools down to the water temperature. Just a dip and back on the buffer means it still has that residual heat in the blade that will equalize a second later, and mean I'm starting off again at a higher temperature than before.

Just a couple more thoughts...

Wow, great advice for the buffer wheels. Thanks for all the tips, guys.

Cheers,

Larry