Keith,

I’m curious about that first etching cycle, where you “went a bit far.” How long did you leave the blade in the etchant? When etching, the oxides eventually stop the action of the etchant. But, it doesn’t always stop evenly. Sometimes, you’ll have a spot that continues to etch long after it has stopped everywhere else. This can burn pits in the steel.

I only do about 30 second etches, cleaning the oxides off after each etch. Sometimes takes 10 to 15 cycles to do a deep etch on damascus. But, you get an even etch, with no pits.

LOL!! I've got to clean my computer screen! I had to scroll your picture up and down to make sure I was seeing the pits in your blade and not dirt specks on my screen. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//blink.gi f' class='bbc_emoticon' alt=':blink:' />

Another possibility. Keith what did you use to clean the blade before etching? Those could be shiny areas where there were oil spots. I use dawn dishwashing detergent to clean the oil off , then etch, making sure you rinse the blade well. I found acetone just was not doing the job, and I was getting spots that did not etch. I usually do two to three 10 second etches, with cleaning in between.

Brion

Thanks Steve and Brion for your replies. I know, I know its not the best photo. But they are in there, not many mind you but they are there <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//angry.gi f' class='bbc_emoticon' alt=':angry:' /> I also have used acetone and found it to be streaky, I now use flouro hydrocarbons ( wax and grease remover ) then I wash with a detergent on a cotton cloth. My first etch was probably for 2-3 minutes each and as stated before, I rub the oxides off with 0000 steel wool under the garden tap, keeping it wet until I put it back into the acid ( a method shown to me by Shawn McIntyre, Thanks Shawn ) That is when I first noticed the pitting Thats when I went back to 400 grit. Believe me all those little buggers were gone way before I got to 1000 grit. I have heard of acid rests when you leave the blade in the acid for to long, so thats the reason for the shorter time in the bath the second time. Low and behold they seem to have appeared in the same areas. I would pull my hair out but I,m already folickly challenged.

Cheers Keith

It is hard to tell from your picture but assuming that it is the result of uneven etching, I would suggest adding fantastic to the cleaning process. I have not used ferric for etching hamons (and I know many do) but it seems to me that it is to strong an acid, and etches to quickly. I use hot vinegar, maybe a minute or so a cycle, somtimes less. Typically it only takes 2-3 times, cleaning with flitz and fantastic between etches.

I would also suggest instead of taking it to 1500g and etching to add a powdered abrasive to the pre-etch polish. I have had best luck with rock tumbler pre-polish, but am currently out and will be trying pumice powder on my next knife. The powdered abrasive brings out a good deal of contrast and much of the activity in the hamon pre-etch. Then the etch itself doesn't need to be as deep.

Nice looking blade by the way.

Hi Justin, Thank you for your reply. Living " down under" We do not have the same prodicts as you guys. What is fantastic? I have not tried hot vinegar, but will give it a go. How hot do you make it? I have used pumice( the finest grade I could get from jewellers supply co ) and found that it was too coarse. I use a product called rotten stone, it is used for french polishing, so it is really really fine. I use it post etch in a slurry with wd 40. Polishes very nicely, have not used it pre etch but will experiment with it. Looks like I will have to back to the linisher and start over and that really gives me the ***** as I have a lot of time invested in this already, but hey thats knifemaking. I will post a pic when its all done.

Cheers Keith

Fantastic is a cleaning product that comes in a spray bottle, mostly ammonia I would think, but works really well for getting the blade completely oil free. I have heard of rotten stone but not used it. The abrasive I have been using I would guess is around 1500g, give or take 500.

I like the vinegar just short of boiling.

Another option, that I have had some luck with, depending on the severity of the pitting, is polishing it out. I typically use an automotive polish, for mag and aluminum wheels, above the hamon and pumice (2f or 4f) or such below. I have found that unless the pitting is very bad, I can usually polish it out, at least to where it isn't obvious.

Okay, this is the heat treat section so let's take another look at this. If the holes are really deep and they keep re-appearing after you have sanded the blade down and finished it to 1500 again, maybe your pin holes have nothing to do with the etch. I am guessing it is the etch, but there are events that can cause the same outcome. First, your forge could have been contaminated with a substance that is highly reactive to steel. I experienced this once with an alloy from a scrap yard that was not steel. I had to redo the lining of the forge after destroying a couple of blades. I do not think that is the case, but it is an alternative. The other unlikely option is that you overheated the steel and lost carbon creating small pin holes where the carbon sparked out of the blade. I still think it is the etch and the others are probably correct, but without examining the blade it would be hard to tell.

Recently, I was asked to re-finish a knife that had been in a house fire. It had thousands of tiny pin holes everywhere. They did not go too deep but they certainly went deeper than any messed up etch I have ever done. Those pin holes were (my guess) the result of the oxidation that occurred in the fire.

When someone asks why I try to look for all the alternatives that might lead to a certain outcome. I am sure there are other possible causes though most of them are likely some form of oxidation or even a reactant's effect.

Dan

Thanks Justin and Dan. I to like to explore all the possibilities and that is the reason for the post. I think its just the etch solution as I am very carefull with the forgeing and what goes into the forge, as I also had a problem with contamination once. Thanks again for your input.

Cheers Keith

Keith, I don't know where you got your steel, but there is a distinct possibility that it came with the pin holes already in it. I had that experience with some 1095 one time.

By the way, Haley and I are heading your way in a couple weeks. Love to drop by for a visit if you aren't too busy.

Good luck.

Adam.

|quoted:

Keith, I don't know where you got your steel, but there is a distinct possibility that it came with the pin holes already in it. I had that experience with some 1095 one time.

By the way, Haley and I are heading your way in a couple weeks. Love to drop by for a visit if you aren't too busy.

Good luck.

Adam.

Hi Adam, Yes I have also experienced this and don't use that material any more. You are more than welcome to drop by for a visit. If you have time, maybe we could get some shed time! We have room for you to stay if you like. When are you going to be in Australia? I'ts nice and warm over here at the moment, why just the other day it was a balmy 115. A tad warmer than your place hey.

Cheers Keith