Salt water etching

H

Headmanbrewing

Joined
Aug 5, 2012
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Hi all, new member here. I'm looking for some info on etching stainless steel. What I'm doing is trying to decorate a backsplash behind my stove using salt water etching. The sheet of steel (unknown composition, it's a piece of 1/16" steel that is used for the skin of an elevator door) is 24" by 30", and my thought is to etch a replica of some sheet music onto the steel. I understand using a super saturated salt solution and am not going for a deep, dark etch, more a look like frosted glass. I have a "4-6 amp, regulated DC power supply" with a 13.8v DC output. While this is probably out of the usual wheelhouse of most here that have done this type of etching, I was hoping for some direction on where to look for more information.

I realize this probably doesn't really fit in this particular forum, and am happy to move it to wherever it fits best. TIA
 
A lot of stainless doesn't oxidize much which is basically what you would be doing with salt water. You might do better with an acid or ferric chloride (circuit board etchant). You could possibly use a layer of wax where you scrape the wax off where you want the etch.

You will probably get a better answer in either the tinkering & maintenance or the makers forum. A mod will probably be along to move it shortly.
 
I realized there was probably a better place to post this, but didn't know the best place. I have searched the web and have found plenty of info about etching small jewelry type pieces, or large pieces to be mounted on the side of buildings, but none of it seemed to fit what I am looking at doing. Thanks.
 
It might be more to your liking, a type a engraving. It would definitely look more frosted. The etching might end up giving you a darker more burnt/corroded look. It all depends what method employed.
 
To RevDevil - So you think that a saltwater etch will be darker, approaching a "marker on paper" appearance? Hmm, def not what I'm looking for. Maybe frosted isn't the right word, more that I want the etched areas to be a different color silver, or possibly a light gray on the stainless. Thanks, I will see who is available locally to engrave it. Not looking forward to the cost involved...
 
Let's see if someone in Shop Talk has an idea. These guys have done everything there is to do with metal. :)
 
I wonder if it is stainless steel would some type of sand blasting be more appropriate .You would have to find a suitable masking material then find a suitable blasting material. Acid etching stainless usually requires some strong acid so blasting might be more convenient ans safer.
 
A friend asked me to make a little plaque for her dog so I picked some 316 stainless. I used a photo paper, laser printer resist and FeCl for the etch. I kept reapplying to keep it fresh and every now and then, blotted off the ferric and put new stuff on. It took about 20 minutes but it actually etched fairly deep and left a nice dark mark. You might be able to do a salt water etch but with a flat surface you will need to make a ring around the area you want to etch and fill it with solution like a small puddle.
 
What I have seen is to use an electric current from a DC source. Clip one (negative?) end to the metal you are working with, and the other end to a Qtip or cotton ball soaked in the salt solution. Remove the resist where you want the etching to take place, and wipe the cotton across the metal. A longer wait on the spot means more metal removed. It is only supposed to take a few seconds per application, but you have to use new cotton regularly. I guess it's time for some trial and error.
 
I don't know that you would have very much luck with keeping it even over such a large area, but you could try it. You clip the positive to the metal and use the neg on the swab and the salt water does not have to be super saturated, just water with a bunch of salt will be OK but, the make regular electric etching solution that works better. You could just cover the piece with something like contact paper and use a razor knife to cut out your pattern. Instead of a cotton swab you could use a small piece of stainless steel say 1/2" x 1" screwed to a piece of wooden dowel with a counter sunk flathead screw. Cover with some felt held on with a rubber band. Wet the felt then remove excess salt water with a sponge. Pad should just be damp. Hold it down for 5 seconds then move of a second and back on, this gives the etch a second to gas off. After your done you will need to buff the piece a bit to get the etched part shiny.
I also think with a bit more power say 24v and 5 amps you could use a bigger pad.

Mete is right about the sandblasting. If you glued a thin layer of rubber on the piece and then razor knifed the pieces out to form your pattern then had a sand blaster hit it for a little bit you would get a more frosted look. Works great on glass. Worked in a shop with a blaster and some of the guys put logos and such on the rear window and made little art pieces.
 
I would cut the desired pattern in a piece of vinyl or mylar to make a stencil, and then soda blast or fine sand blast the steel to get a frosty pattern. Any blasting shop can do the work if you have made the stencil.

Here is one way:
Use sticky backed contact paper, like used for drawer liners or putting on faux woodgrain. Draw the patterns desired in marker, and then cut out with a #11 Exacto blade. Carefully peel away the backing and apply the contact paper to the steel. Blast with the desired media to get the frosted effect you want. Remove the paper ( a heat gun may be helpful) and wipe off residue with acetone.
 
Thanks for all the ideas, everyone! A question about blasting though. How small of an area can be affected? The design I'm shooting for (sheet music) consists of parallel lines and small dots to signify the notes. I'm not sure how much of the music I'm trying to copy, probably 2 or 3 pages, but the dots would probably be 1/4" or thereabouts in diameter, with the lines narrower yet. Can blasting get that detailed, or should I limit the number of pages to make the size of the notes larger?
 
The problem comes in the amount of etching you want. It will be very difficult to do by hand. Take the metal, and an exact copy of what you want on it, to a commercial engraving/etching place or a trophy shop. They can load it in the computer and either laser or power engrave it in every detail. I have had photographs done this way. BTW, photographs often look best when etched as negatives for some reason.
 
If you can remove the piece and put it in a tank, I don't see a problem with etching it evenly. I wouldn't use 13v, I would hook it up to a couple D cell batteries and let it etch for an hour. Here's a link to a tutorial and a picture of a blade I did this way. I painted it with clear urethane and my wife scratched with a needle. Clip a battery to it and a cathode in a bucket and let it etch for a while.
http://heronskeep.wordpress.com/2010/12/30/salt-water-etching-class/
purpleheart.jpg
 
Charlie,
The problem is he is etching pages worth of sheet music in fine detail on 720 square inches of surface........not going to work with a couple of D-cells and a needle.
 
Actually, it would be 1440 square inches of surface area(both sides), and building a 24x30 tank would be a big issue, definitely. However, the amount being etched is probably only a few square inches total depending on the thickness of the lines. That's not that much. Spending the time to scratch it out with the needle would be time consuming. If it is too much for a long, slow etch, then you could tape off sections of the sheet and only do a portion at a time. I've seen old cookie sheets etched in this manner and the artist claimed he did it with D-cell batteries in this method. Only, he filled the sheet with solution and put the cathode in the middle of the sheet held about 1/4" from the sheet by spacers. No tank needed.

Remember your cathode(the part not being etched) should be the same size or bigger than the amount being etched. Compute surface area as both sides. It should be easy to figure the area of the lines and notes. It also should be the same type of metal.
 
if you want to try do it first on some piece of scrap metal. Create a stencil from vynil, tape or whatever with a glue side. Prepare a solution of salt and vinegar (around 70% vinegar/ 30% salt). Clip the positive to the metal and on the negative clip put a qtip head (cut a bunch of qtip heads off, you will need them). Connect, saturate the qtip with the solution and start "brushing" on the metal. Keep a paper towel handy to wipe out the scum as the acid bites into the metal and creates a bubbly black froth. Replace qtip when its black, but you can dip into the solution several times before you get rid of it. If you don't want a deep etch don't dwell too much on it, just keep regular brushing strokes, dabbing away with the paper towel. When you think it's done, disconnect, clean everything and peel off the stencil. Wash with warm soapy water and scrub away with steel wool. If you don't mind polishing the whole piece, you can sand away while refining the grit size. The lines will stay as they ate into the metal.
 
I say send it to Charlie ( zaph), he has it all worked out. He should be able to do it cheap.
 
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