Etchant

[JeffreyPrater]

I was looking for Nital etchant, do I have to buy nitric acid and then mix it with alcohol
myself?

Will nital be the best etchant for looking at 52100?

thanks,

Jeff Prater

[Ed Caffrey]

All I can tell you is DON'T! Nitric is not something you want to play around with. Handled incorrectly its pretty dangerous stuff. The fumes alone CAN be lethal.
My strong recommendation is to leave the Nirtic alone, and use Ferric Chloride. Go to Radio Shack and buy a bottle of PCB Archer etchant, dilute it 3 to 1 with distilled water, and your good to go.
The trick to etching anything to do with cutlery is a milder etch, for a longer duration. Remembering this will give you cleaner, smoother, and just plain better appearance than using one of the harsher etchants.

[Kevin R. Cashen]

Jeffery, are you looking to etch and entire blade to see different colors along the edge versus the spine due to heat treating, or are you looking to cross section something for microscopy? For one the nital will be useless for the other the FeCl will be useless. The ferric chloride will work fine for dipping a blade and seeing differing heat treating effects down the side. Nital is what you will need to see microstructure under a microscope, but you will also need loads of specialized polishing equipment and of course a good reflected illumination microscope.

Ed is right you do not want to mix your own nital unless you have a good handle on things, getting the acid will be much more difficult than getting the nital and if you use the wrong alcohol it will fume and be a real problem. Even properly mixed nital will give off enough fumes to be able to tell if it has been opened anywhere in the building in the last hour or so.

If you want to actually look at the grains (crystalline structures) and other microscopic features the aforementioned equipment will be necessary. You may have been told that dipping a blade to get contrasting colors down the side will show you the "grains" or other things but that is absolutely false, all it will show you is the big picture as far as where martensite peters out into pearlite, basically macroscopic effects of heat treating.

On the other hand you may also have gotten the impression that you may need a microscope to make knives, and you may have gotten it from me. If so I am sorry about that. My microscopy is a side hobby from knifemaking that eats up cash and time from the latter. I have the lab equipment to satisfy my obsessions on odd topics of metallurgical research, I have a forge and a grinder for making knives.

However if you have the same burning obsession and still need to slice up steel with a water cooled diamond saw and then stand in front of a polisher all day with the resin mounted sample, well here is the most popular place that services the metallography business:

http://shop.buehler.com/

[JeffreyPrater]

I actually want to look at the microsture. I want to measure the grain size in small pieces of 52100 that are heat treated by different methods. I also want to examine the grain fracture.

Do I need 2% nital for etching to determine grain size?

[mete]

Yes you would use nital to examine grain size, assuming you have a proper microscope etc. But you can also measure grain size by examining the fracture . There is a correlation between the diffrent grain size measurements.

[JeffreyPrater]

Do you use etchant to examine the grain in a fracture?