blackening stainless with a chemical etch machine

rustyrazor

rustyrazor

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Oct 13, 2011
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I have an old chemical etching machine. it doesn't etch and mark... just marks the blade black where the stencil was, it doesn't etch deep. the question i have is can i modify this machine to blacken a stainless blade completely and uniformly? i have tried it by just rubbing the pad all over the blade but it is really not a consistent finish.

thoughts?
 
I dont think its possible. I tried doing something Similar and fix a spot on one of my blades and i ended up blowing the fuse and didnt get any darkening.

Best way Ive Found to etch is to use sulfuric acid n the form of drain cleaner followed immediately by a neautralization with baking soda. This gives me a dark etch that stays. Also sulfric acid is Really caustic so I like to do the etch outside and always wear a respirator.
 
Huntsman Knife Co. said:
I dont think its possible. I tried doing something Similar and fix a spot on one of my blades and i ended up blowing the fuse and didnt get any darkening.

Best way Ive Found to etch is to use sulfuric acid n the form of drain cleaner followed immediately by a neautralization with baking soda. This gives me a dark etch that stays. Also sulfric acid is Really caustic so I like to do the etch outside and always wear a respirator.
Click to expand...

Thanks Hunter... to clarify, this will work on stainless? and which cleaner worked best in your experience? and was it liquid gel or crystals mixed with water or something similar? sorry for the 20 questions, but i'm ready to head to the hardware store after work and give this a try.

cheers

Royce
 
Hey Royce,

I get the sulfric acid as a liquid drain cleaner. They sell it at lowes for $10 a bottle. It comes in a white bottle with a red and yellow label inside a sealed safety bag. I usually dilute the acid with some vinegar or water to a 1:2 acid/water ratio. The acid is extremely powerful and under the right circumstances can eat a hole in your blade. When you etch make sure your blade is completely clean. Little bits of steel dust can oxidize rapidly and eat into the steel around it.

There are many ways to etch but I have a PVC pipe with a lid that I fill with the acid/vinegar mixture. I lower the knife in on a string and submerged it. Check on it every few minutes until its dark. Then to neutralize, pull out your blade and dip it or cover it in baking soda. This method keeps the color on the blade. I used to dissolve baking soda in water and neutralize but then the oxidation would rub off easily. Im not sure why this method works but it has for me. Then clean the blade and repeat if necessary.

Be very careful with the sulfuric acid. wear gloves and eye protection + a p100 respirator. If you spill it on the concrete in your garage you will end up with a really ugly floor and alot of caustic fumes.
 
Huntsman, I question your choice of respirator, P 100 filters are to filter particulates. Wearing one around fumes might even concentrate the amount of vapor you are exposed to. There are chemical cartridge filters designed to filter out acid gas vapors.
 
I use the 3M P100 organic vapor filters. They stop the acid vapors completely. At least I've never smelled any acid vapors while wearing P100 filters
 
Might consider ferric chloride. They sell it at Radio Shack as "pcb (printed circuit board) etchant solution". It works very well on stainless. Won't get black, but a dark gray. Probably safer too.
 
I used ferric chloride on a kudu blade. A 2 hour soak yielded a gray finish similar to gray primer. It was cold outside so maybe that makes a difference. Made a hell of a mess when I neutralized the remainder with baking soda.
 
tried muriatic acid last night... i have to do some more research on it, but it didn't darken anything. make it really shine though. good cleaner, lol
 
Here's a 52100 blade I finished recently. This is after about 4 minutes in a fresh acid solution using the method I posted above. Black as sin. I've also done ferric chloride and muratic acid. Muratic acid does not darken in my experience and ferric chloride works well but its not as quick as sulfuric acid and they only sell it in tiny bottles.

20150116_164213_zps43f18842.jpg
 
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