What am I doing wrong?

Brad Walker

Brad Walker

Well-Known Member
Hello everyone. I keep getting blotchy spots when I etch a blade. The last thing I do before I dip in the etch is to clean the blade thoroughly with acetone. Other things I've tried is alcohol and degreaser, all with the same results and normally in the same place. This particular blade is hand sanded to 400 grit. How does everyone get a smooth consistent color?


spots1.jpgspots2.jpg
 
First, you might try ditching the acetone. It can leave a film that isn't etch friendly.

But I don't think that's what is going on here.

What is the steel? 1095?
 
Yes, nitrile gloves, but I was only pinching on the handle. Cotton ball with acetone to wipe the blade.
 
Brad Walker said:
It's 1084
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Ok. My next questions:

What is your heating source?

What was your quench temperature and how did you verify it?

What did you quench the steel in?

Because of the location and relative symmetry of the spots on both sides, it looks to me like some form of auto-hamon where the thicker steel near the spine and by the ricasso didn't get hot enough to harden, didn't cool fast enough to harden or a mix of both.
 
That one was heat treated using my forge. I was wondering if it had something to do with the heat treat. I used Parks 50 at a temperature around 100 degrees. I used a laser thermometer to verify.

Luckily, that was the last one I did using my forge. I now have a kiln that works so much better!

So cotton balls are bad?
 
J. Doyle said:
it looks to me like some form of auto-hamon where the thicker steel near the spine and by the ricasso didn't get hot enough to harden, didn't cool fast enough to harden or a mix of both.
Click to expand...
This was my thoughts as well.
Brad Walker said:
I used Parks 50 at a temperature around 100 degrees. I used a laser thermometer to verify.
Click to expand...
FYI- If you are purposefully heating your Parks50 to 100F prior to quenching, you are wasting some time. Parks50 spec sheet says it's working temp range is ambient/room temp to 120F.
 
I've read through all the replies.... and believe John's explanation to be likely.

I do have a question.... you don't happen to grip/hold blade in the location with tongs or pliers when quenching do you? I've seen things like that a number of times when folks quenched blade that were held by tongs/pliers in the that location.

Ever cleaned a freshly hand sanded blade with acetone, and noticed a sort of "rainbow" look the the surface? That's the film that John mentioned. How to fix it? Clean first with acetone, then a second cleaning with windex....being sure it is completely DRY before placing the blade into the etch.

You also have to be CERTAIN that there is anything floating on the surface of the etchant....if there is, as you lower the blade into the etchant, surface tension will pull anything floating onto the blade. I don't think that's what occurred here, but it is another circumstance that often confounds people having etching issues.

Contrary to popular opinion, straight steels are more difficult to get "clean" prior to etch then damascus..... CLEAN, and in ABSOLUTLY CLEAN, is the name of the game when etching any steel.
 
I did some quickie experiments a lot of years ago and reported on them. Mickley may remember.

Anyway, as a laboratory chemist, I had never expected much from solvents purchased in a can at an Ace Hardware. I was correct. The easiest way to check this yourself:
Take your float glass plate. Clean it very well with a light (ONE DROP) of mild dish soap and rinse the heck out of it. Now rinse it with acetone. Twice. Then leave it to dry. Check the surface under bright light for a film. It'll be there, and it'll interfere with etches, epoxies, etc.

So, your industrial-grade solvents have crap in them. Go figure. If you want super clean, buy a quart of "electronics grade" from AMZ. At the same time, buy one of those "boatload of cheap cotton rags" and use those instead of paper towels or tissue when you have a critical application. Paper products usually have emollients, fragrances, and a load of other chemicals. They all leave residues.

One note: I would gladly entertain any arguments to this reasoning right now. Over on another forum, a person who was not well informed called me stoopid and said I didn't know what I spoke of. 5 years after the fact. Pity I wasn't there for the repartee'.
Clean is everything in lab chemistry. So, I learned a bit along the way. Rinse with distilled water and hang to dry or wipe with clean cotton (NO DAMNABLE BOUNCE). :)
 
EdCaffreyMS said:
I've read through all the replies.... and believe John's explanation to be likely.

I do have a question.... you don't happen to grip/hold blade in the location with tongs or pliers when quenching do you? I've seen things like that a number of times when folks quenched blade that were held by tongs/pliers in the that location.

Ever cleaned a freshly hand sanded blade with acetone, and noticed a sort of "rainbow" look the the surface? That's the film that John mentioned. How to fix it? Clean first with acetone, then a second cleaning with windex....being sure it is completely DRY before placing the blade into the etch.

You also have to be CERTAIN that there is anything floating on the surface of the etchant....if there is, as you lower the blade into the etchant, surface tension will pull anything floating onto the blade. I don't think that's what occurred here, but it is another circumstance that often confounds people having etching issues.

Contrary to popular opinion, straight steels are more difficult to get "clean" prior to etch then damascus..... CLEAN, and in ABSOLUTLY CLEAN, is the name of the game when etching any steel.
Click to expand...
No sir. I Grip at the back of the handle. I have noticed in the 2 times I've used my vertical air bath, that the entire knife is a uniform color when I pull it out to quench. I have yet to finish one of those blades. I will etch one and see if happens again. Thank you
 
fitzo said:
I did some quickie experiments a lot of years ago and reported on them. Mickley may remember.

Anyway, as a laboratory chemist, I had never expected much from solvents purchased in a can at an Ace Hardware. I was correct. The easiest way to check this yourself:
Take your float glass plate. Clean it very well with a light (ONE DROP) of mild dish soap and rinse the heck out of it. Now rinse it with acetone. Twice. Then leave it to dry. Check the surface under bright light for a film. It'll be there, and it'll interfere with etches, epoxies, etc.

So, your industrial-grade solvents have crap in them. Go figure. If you want super clean, buy a quart of "electronics grade" from AMZ. At the same time, buy one of those "boatload of cheap cotton rags" and use those instead of paper towels or tissue when you have a critical application. Paper products usually have emollients, fragrances, and a load of other chemicals. They all leave residues.

One note: I would gladly entertain any arguments to this reasoning right now. Over on another forum, a person who was not well informed called me stoopid and said I didn't know what I spoke of. 5 years after the fact. Pity I wasn't there for the repartee'.
Clean is everything in lab chemistry. So, I learned a bit along the way. Rinse with distilled water and hang to dry or wipe with clean cotton (NO DAMNABLE BOUNCE). :)
Click to expand...
My acetone comes from the big blue can from Lowes. HOWEVER, in an effort to save a couple dollars, I bought a gallon of alcohol at a beauty supply store. It has a perfume added. Like the guy said in Oh Brother, Where Art Thou, "I like the smell of my hair treatment, the pleasing odor is half the point!"
 
I would not be surprised to find out those one gallon cans are sprayed inside and out at the can manufacturer with something to inhibit rust, which the solvent promptly dissolves.

The residue in solvents and even most tap water can even interfere with etching logos. I know I sound like a zealot, but...
 
There is definitely "stuff" in acetone. Everytime I wipe some on a clean shiny blade there is a film. It's great for dissolving whatever crapola I get on there but after acetone I have to clean it again with rubbing alcohol.
 
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