Etching

Freds Edge

Well-Known Member
I am having a problem with etching for a hamon,I getting uneven etching by this I mean that there will be areas that have some spots that unetched and just a poor quality etch . Does anyone know if Ferric Chloride degenerates or brakes down over time.When I use heated vinegar and water solution I seem to achieve a better etch.
 
Ferric Chloride is VERY easy to contaminate. If you sprayed anything such as WD40 around it when the lid was off, even a tiny droplet can cause problems. A single droplet of windex in a container of Ferric with kill the entire container. Ferric will "break down" over time, but it takes a LONG time. Often as much as 2-3 years. Most folks tend to end up with it contaminated before it breaks down beyond use.

What you describe sounds more like a "clean" issue.... Anything you intend to etch in Ferric must be absolutely clean. Personally, I put on latex or nitrile gloves..... clean the item I'm etching with acetone, then again with windex..... and FULLY dry it. I also use a clean paper towel to "wipe" off the surface of the ferric.....if you see ANYTHING, even a discoloration floating on the surface of the ferric, when you place something into the ferric, the surface tension will cause whatever it is to get onto whatever you're trying to etch.... that is the most common issue that folks have.

Something that causes many folks problems, is the type of rags or paper towels they use to clean items for etching. If you use typical household white paper towels, they will leave a slight "rainbow" colored haze sometimes..... this has to do with the chemical used to "bleach" the paper for the towels. I generally tell folks to use ONLY the Scott Shop Towel brand of paper towels (the blue colored ones).... they do not leave any residue. If you use "rags", they need to be 100% cotton.... especially if you use acetone to clean.....acetone will "melt" most synthetics, and leave a film on anything you're trying to etch.

In the end if there is an uneven etch, or spots as you described, it's almost always a clean issue. OH! One more thing is the temp of the ferric. Ferric works best for what we do in the 70-80F range..... higher temps generally aren't a problem, but if the ferric is cold (below 70F) etching slows down dramatically.... I doubt any of that bears on your situation, but it's worth mentioning.

Keep us posted!
 
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Thanks Ed, I am think all the point you mentioned are having some bearing on my problem, my shop is cold even though I have a furnace and I can see some material floating in the Ferric. I do use the white paper towels so I will get some of type you mentioned. I do clean the blade with acetone then windex as well but I think my ferric is contaminated as this problem has developed over time.
 
After reading that, my educated guess would be it's a combination of cleaning and those "floaties" on the surface of the ferric. Once you clean a blade in prep for the ferric, look at it from various angles under a strong light....if you see ANY hints of "rainbow" looking streaks/lines, it's the paper towel's fault. Also, take a clean paper towel (the blue ones) and "skim" off all the floating stuff on the surface of the ferric. Those two steps will go a long ways towards solving many issues with etching.

CLEAN is the name of the game when etching with Ferric..... that point cannot be overemphasized.

Let us know how it goes!
 
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