Recommendation? Blade over etched?

[Diego_B]

So last night I was working on a couple blades that I would like to stone wash. I have limited experience stonewashing blades and have only done a couple so far. So one of the first blades that I was doing I think was over etched? I say this because I ended up with a dark spot in the middle of the blade right at the bevel line on BOTH sides in the same spot.

My procedure for this blade was 36-80-120 grit ceramic belts followed by a A100 then A45 trizact belt, I do have a cork belt but I didn't do that step. My acid etching solution consists of a 50/50 ratio of Ferric Chloride and distilled water where I etched for 9 minutes total in 3 minute intervals. On the first two intervals it was going great, then on the last interval when I pulled it out of the acid that's when I got the dark spots.

My question is what happened here? I have done this a couple times with the same procedure before. Also, do I need to be hand sanding for an acid etch or is belt finishing a good enough prep surface? If it is "over etched" can I fix it by taking it back to say the 120 Ceramic and sand it off? Or is it screwed up for good?

 

[eric brinkerhoff]

You didn't say what kind of steel, but maybe there's a slight "Hamon" ,or differential heat treatment going on there. Nice looking blade!

 

[Stacy E. Apelt - Bladesmith]

An etch is only surface deep. Sand it down and try again. 50/50 mix is pretty strong. Try 3:1 up to 5:1 ( water to FC).

A dark area is sort of normal. I usually rub the blade down with oil and a very fine abrasive sheet (3M pink or white cloth) or 0000 steel wool after etching to remove excess oxides and even out the etch.

 

[Diego_B]

You didn't say what kind of steel, but maybe there's a slight "Hamon" ,or differential heat treatment going on there. Nice looking blade!

Oops, it’s 1084 from NJSB.

An etch is only surface deep. Sand it down and try again. 50/50 mix is pretty strong. Try 3:1 up to 5:1 ( water to FC).

A dark area is sort of normal. I usually rub the blade down with oil and a very fine abrasive sheet (3M pink or white cloth) or 0000 steel wool after etching to remove excess oxides and even out the etch.

I have a 3:1 ratio already mixed so I’ll give that a go today.