Takefu suminagashi etching

[jeness]

Hello everyone!

The steel I want to ask about is the Takefu made suminagashi with white steel core from Dictum. I have used a few meters of it already, but I just can't find the reason why my etch is almost always uneven. Sometimes it comes out almost perfect, sometimes I have to re-etch lots of times to get it about right, but never perfect. Everything is clean to begin with, and the blotches appear in different areas of the blade every time I try to re-do it. I have tried everything I could think of, maybe you will find where my problem lies. My current procedure:

The blade is taken to a high grit finish, scrubbed with soapy 0000 steel wool, and than put into a pcb enchant diluted 1:3 with distillated water. I do short etches, maybe 30 seconds each, and scrub with soapy steel wool in between, wash it with tap water and back in the solution. I use rubber gloves the whole time.

If I do only 1-2 cycles, than the core doesn't get black enough, if I do more, than the finish gets more uneven with each etch. Sadly, the first etch is only seldom even enough to leave as is. Here is an example how it looks like when I am not happy don't mind the scratches, I re-sanded it already The dark and the shiny part is no good either:

 

[DAMNENG]

I can't give you a definite fix for your problem. But you might try etching NOT using steel wool and use a stiff bristled brush.
If you try this on a piece of scrap make sure it is heat treated the same as the blade.
Jim A

 

[Stacy E. Apelt - Bladesmith]

Several possibilities:

Wearing rubber gloves won't solve the problem if you touch things with the gloves that transfer grease/oil to the blade. - Put on the gloves and wash your hands with them on. Wash hands/gloves often while doing the preparation and etching. Don't touch anything with the gloves but the blade.

Steel wool has oil in it to prevent rust. - Get rid of the steel wool! Use a green Scotch-Brite scrubbing pad and dish soap or Simple Green.

Etchant may be too old or contaminated with floating oils. - make up a clean new batch of etchant and wash out etchant tang well with soap and water before putting it in the tank.

Finish may be too high. - Try re-sanding at 800 grit then clean up and etch. Never buff anything you want to tech.

 

[HSC ///]

I’ve use a lot of this steel and sometimes have the same problem as you but to be honest I don’t worry about it

it’s probably worse Visually for you since you didn’t forge the blade so you don’t really have a marbling affect

I think Stacy gave u some good information

 

[jeness]

Thanks gents, I gave them a try. The 800 grit finish helped a lot to get a homogenous surface, the color is much more even now. A bit more matte, but definitely better than before. I will have to experiment some more, because it is still a bit uneven.

 

[PEU]

I use trichloroethylene (TCE) to degrease my blades with a cloth prior to etching in a 1:3 ferric chloride/water dilution, here is the result.

Pablo

 

[Skiller1nc]

Adding to everything that has been said, I think Stacy made a good point about gloves. I also recommend degreasing the blade after you wash it with soap. Use some acetone to wipe over it one final time before etching.