Please HELP, wootz etch not working very well
 

Hi, could someone advise me on etching wootz, as I seem to be doing the right procedure....but without the results :confused:

I am using ferric chloride granules mixed with distilled water (approx 150g to 150ml of water approx. 5oz to 1/3 of a pint).

Before applying the etchant, the blade was cleaned with solvent, and then warmed using the gas 'rings' of the cooker. The etchant was also heated to a temperature of a 'hot coffee'.
Immediately the blade/etchant was hot enough , the etchant was applied by brush to one side of the blade.
I continually applied etchant as it started to 'dry out', however, several attempts, the last time I left it on for 30 minutes, has not really brought the 'pattern' out. It definately appears to be wootz but it seems I am not getting the 'bite' I need. The mixture is slightly more concentated than is advised on the etchant packaging (250 g to 300ml ) :shrug:

What am I doing wrong ? Has anyone had this problem before?

Thankyou
David

Perhaps, the blade is not wootz to start with?

Hi Ariel,
could be a possibility but, it does not even show laminations etc either. The blade gets discoloured (covered with a dirty dark purple layer and has to be 'cleaned' using very fine abrasive paper) ....is that normal ?
There seems to be a pattern but I can't get it 'defined'. When I cleaned the rust from the blade I used a lot of oil to lubricate the abrasive paper, and coated the blade thoroughly 'between cleanings' ...could the oil penetrate the surface and possibly create a barrier to the acid :shrug: (bearing in mind I do not have a 'mirror finish'.....there is still a certain amount of pitting which would require too much metal removed from the blade.

One has to keep in mind that not all wootz patterns are bold. Some patterns are rather fine and not easy to bring out in an etch. I would recommend taking the piece out in good sunlight and have a close look at the blade as this will help you see a faint pattern. Some patterns are quite faint due to lack of heat control during forging. Some blades, while it appears you have some wootz peeking back at you, turn out not to be and may not have any laminations at all. You just never know until you give it a try.

From my humble experience, a blade of good high contrast pattern will show up fast and clear, with whatever acid used for etching. When I travel I use Coca Cola from the hotel room fridge to test the blades I purchased and with good wootz it works well. Also, with good wootz the pattern will show even if the blade is not highly polished. It is a bit more difficult to bring out the pattern of wootz of lesser contrast like Indian Crystalline or Sham wootz, or some laminated blades.

After many years of trial and many errors I use a mixture of Iron Chloride with Nitric Acid. Both very diluted 3-5 %. The Nitric acid is added to remove the Yellow / Brown tint sometimes appears on the blade with Iron Chloride. Let me also suggest to use room temperature acid on room temperature steel. Heating will only accelerate the etching and might be that it works too fast and mask the pattern. Direct sun light will help to bring the pattern faster.

The following basic rules should be kept:

- Clean polished blades, without any traces of oil or grease.
- Diluted acids
- A lot of patience.

Good luck

Perhaps the Coca Cola works because it has phosphoric acid in it?

Yep, the acid works on your teeth, too!

I agree you may be overetching, the recommended percentage on the package is probably for eating through copper, getting a pattern on steel requires less stength.
When I want to check out a pattern, I polish a small section up to 1500 grit with sandpaper and give it a short bath with very dilute FeCl or nitric, this shows up even really subtle structures that tend to get muddy or indistinct with more thourough etching.
If the pattern is fine-grained, a rough finish (120-220 grit) can entirely obscure it, 600 - 1500 is easier to get something to show.

Thankyou All, for your excellent advice.

.....it seems that my impatience (heat/ concentrated acid) could be the cause of not seeing what I had hoped to see.....a life lesson perhaps......'all will come, to he that waits' ;)

Regards David