Weird etch.

E

elasmonut

Joined
Feb 15, 2006
Messages
663
:mad:I just attempted my first etch job and royally ballsed it up but don't know why:confused:
Iwas using a concoction of lemon juice,vinegar,salt,peroxide and water.The amounts were oh about THAT much of each,in a jam jar with the knife sitting point down in it,real scientific I know, but checking after a few minutes was getting good results and scrubbing in between with the green kitchen scotchbrite pad.All was going well until I checked a few minutes ago one side was a beautiful even grey,but the other side had a number of pits and deeply etched scratches or lines,deep enough to feel them catch on my fingernail.The blade was O1 polished to about 400 grit.The knife was sitting at a slight angle and the pitting and lines appeared on the low side,does this make a difference?The only other thing I can think of is something nasty from the old scotchbrite pad but I scrubbed both sides repeatedly and only one showed damage:confused:
I should be able to repair it with a 120 grit belt and some more polishing but it's one of those things that just pisses me right off.
So if anyone of you guys has had this happen or know why it happened .Could you please send some sagely and much needed advice my way so I can NEVER do it again:o

Thanks guys I hope I can help out some of you one day.
 
sounds like you didnt get all the scratches out the fist time ive done this before and that was the cause
 
I've etched a couple blades but have never seen one side be so much worse than the other. I would guess the side that turned out nice was the side you finished first. The side that turned out bad got sloppy seconds and the pits and scratches were there before the etch. Normally when I am hand rubbing blades I'll etch as I go. The etch will show the areas that needs more work. Sequence of grits I use for hand rubbing is 220, 320, and then 600.
 
Take it back to about 1000 grit and look it over very closely for scratches or pits. Acid will only make them bigger not smaller. Use 0000 steel wool between etches.
The initial dip will show the heat treating quality. A hard area will look dark and the soft will be grey. Is it possible you have a botched heat treatment? The scratches and pits were there before the etch but the gray color spooks me.
I just re-read your description of the color. Were both sides the same color? Any blotches?
 
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I'd agree that you didn't polish one side properly... In your weird concoction each of the items will etch .Why mix them ? I would wonder about possible inter reaction.You shouldn't have to do any 'scrubbing' as you are trying just to remove some loosly adhering oxides.
 
Some of the "scratches" you are talking about might be alloy banding that is etching much faster than the rest of the blade. Post up a pic of it. Also, might you have not ground through the forge scale on one side of the blade? That might be why one side is etching fast but the scale is not etching and showing just as flat grey, which scale usually looks like when etched.
 
When etching a blade, one must always be careful not to let bubbles accumulate on the steel. With peroxide in the mix, they might well be pure oxygen.
 
You may not have cleaned one side correctly. Or you layed the blade down on an oily rag before going into the etchant. That would be my guess.
 
I'm with the surface prep crowd here, but for grins....

Check with a very low impedance volt meter , grounding one lead on the blade and the other at the base of the jar.

It's rare, but some ballast in some lighting systems will 'broadcast' a measurable currant a few feet. (hardily worth mentioning as it dose not seem like it would be a strong enough currant)If thats the case, just setting the jar on something insulated would stop the flow. , or turning off the lights.
 
CrowValleyForge said:
I'm with the surface prep crowd here, but for grins....

Check with a very low impedance volt meter , grounding one lead on the blade and the other at the base of the jar.

It's rare, but some ballast in some lighting systems will 'broadcast' a measurable currant a few feet. (hardily worth mentioning as it dose not seem like it would be a strong enough currant)If thats the case, just setting the jar on something insulated would stop the flow. , or turning off the lights.
Click to expand...

This shouldnt be performed with an aluminum foil hat on, right?:)
 
Bruce Bump said:
This shouldnt be performed with an aluminum foil hat on, right?:)
Click to expand...

I am thinking tin-foil as I wrote it, it sounds whacked to me!

But I have worked and seen this sort of thing give you very weird reading on aircraft under ballasted lighting, anything could set up a galvanic response.

Some of the very first batteries were not much more then a conductor in an electrolyte.

For a dare, someone be the first to try etching a blade in a copper container?

The heavy duty tin-foil comes out asking if the blade was east-west or aligned with the magnetic poles?
 
CrowValleyForge said:
I am thinking tin-foil as I wrote it, it sounds whacked to me!

But I have worked and seen this sort of thing give you very weird reading on aircraft under ballasted lighting, anything could set up a galvanic response.

Some of the very first batteries were not much more then a conductor in an electrolyte.

For a dare, someone be the first to try etching a blade in a copper container?

The heavy duty tin-foil comes out asking if the blade was east-west or aligned with the magnetic poles?
Click to expand...

The tin foil hat should shield against any or at least 99% of any negatively charged gammas unless they come up from underneath and in this case they may very well be. It wouldnt be a bad idea to run a ground connection to the electrolyte.
 
First off thanks for the great response guys,Ive just got up down here and seen all the posts so I'll try and fill you in some more.
The blade was pro heat treated so should be no problems there,and I THOUGHT the finish was pretty even,but I'll try again today.So far I'm going with the oxygen bubbles theory as it looks like little wiggly lines or pits like a bubble up the blade would leave.And it wasn't an electro etch but if you think a tin foil hat will help I'll give it a go,should it cover my ears as well?
Why all the different elements in the mix?Well I started with salt water and lemon juice,didn't seem to be working,added vinegar,better but still not really,then I found some peroxide and things started to move a bit quicker,and now this,arrgh.I'd read about the peroxide with lemon juice for blacking tsubas and thought it might work.
I'll polish everything up again today evenly,try and keep the bubbles out and let you know how it goes.
I'll try and post a pic if I can as i realise this would be much more descriptive.
Thanks again:D
 
With lemon juice and vinegar being acids, they will lose +Hydrogen ions. Peroxide, is unstable with a negatively charged 2- Oxygen.

It seems to me that the combination of the peroxide and the acids largely cancelled each other out and just made more water as the acids and peroxide mixed.

Even if you had good results, you will never be able to repeat it again with a little of this and that. It would make more sense to me to keep it simple and write down what works for you so you can do it again.

- me too thinking the side down trapped bubbles and affected the surface finish, but in acid, shallow scratches become deep scratches.
 
Steven Penner said:
With lemon juice and vinegar being acids, they will lose +Hydrogen ions. Peroxide, is unstable with a negatively charged 2- Oxygen.

It seems to me that the combination of the peroxide and the acids largely cancelled each other out and just made more water as the acids and peroxide mixed.
Click to expand...

This mixture has all sorts of stuff going on. Besides the acidity of the lemon juice and vinegar, the peroxide will act as an oxidizing agent in the acidic environment. Not to mention, it will generate oxygen (and that water Steven mentioned) as it decomposes. Add into that a little bit of steel-aggressive chloride ion being generated from the sodium chloride and acid, and all I could call this is a mess :), especially when the amounts are unmeasured.

I say that sentimentally, because it is the same type of basement chemistry I did as a kid that intrigued me enough to lead me into a career.:)
 
fitzo said:
This mixture has all sorts of stuff going on. Besides the acidity of the lemon juice and vinegar, the peroxide will act as an oxidizing agent in the acidic environment. Not to mention, it will generate oxygen (and that water Steven mentioned) as it decomposes. Add into that a little bit of steel-aggressive chloride ion being generated from the sodium chloride and acid, and all I could call this is a mess :), especially when the amounts are unmeasured.

I say that sentimentally, because it is the same type of basement chemistry I did as a kid that intrigued me enough to lead me into a career.:)
Click to expand...

Thanks for kicking in here Mike, I had my hands full and was almost out of suggestions.

Elasmonut, Why not use Ferric Cloride and water?
 
I'd try selling one of them tin foil hats and use the money to buy some ferric chloride from radio shack. :D
 
Thankyou for the wise words from those with MUCH more knowledge than I.
Why did I mix all that stuuf together for an etchant,well it SEEMED like a good idea at the time to put everything together, the more the better I thought.Clearly my tin foil hat had malfunctioned.
Anyway I ground the lines out,had to go back to a 60 grit belt,they were pretty deep.and have gone back to lemon juice and vinegar.
Well I won't be doing that again,and thanks for the help and explanations of how my Ill conceived plans went awry.:o
 
Ive never tried the lemon juice but I have used vinager with light results. Ive heard it will do a good job but needs to be left in much longer, like about 3 days.

I made the part up about the tin foil hat. :)
 
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