The Steampunk Forum at Brass Goggles
December 16, 2017, 09:55:05 pm *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with username, password and session length
News: Support BrassGoggles! Donate once or $3/mo.
 See details here.
 
   Home   Blog Help Rules Login Register  
Pages: 1 2 3 [4]   Go Down
  Print  
Author Topic: Brass etching - FAIL  (Read 50967 times)
rovingjack
Zeppelin Admiral
******
United States United States



WWW
« Reply #75 on: May 27, 2010, 02:24:20 am »

okay this is getting me very little result thus far. I tried the sharpy again on the brass half in and half out of the solution, allagator clipped to the side of a plastic cup, no wire or clip contacts the water just a two inch screw and the small peice of brass with the lines drawn in sharpy. Using a 9v

It was in there for over an hour and while it did give the surface a lovely aged look by roughing the surface and leaving a touch of discolouring the effort to remove the sharpy was enough to mostly obliterate the hint of etch it managed.

Does it help if the surface area of the negative is substancially more than that of the peice being etched? Is tap wtare vs. deionised or distilled better? table salt, kosher salt, rock salt?

I'm giving it one more try with a 9v and acrylic paint tonight. If I get a better result this time I'm going to invest in a rechargable 9v and a cheap bulb to protect it.

I wonder if there is a simple item or something that would allow for hooking to house current with a variable resistor and a quick release safety off? That way the fine tuning would be easier to do. turn it up or down as needed.
Logged

von Corax
Squire of the Lambda Calculus
Moderator
Immortal
*
Canada Canada

Prof. Darwin Prætorius von Corax


« Reply #76 on: May 27, 2010, 04:08:11 am »

I let it sit for a bit, and came back to it to discover, a two tone object. half brassy and half silvery. I was thinking it was a brass plated steel... now I wonder if it's possable that I just plated zinc or chrome or something onto the brass. I apparently had the set up backwards according to the posts above.

This is almost certainly what happened. In an electrolytic reaction, the negative electrons flow in one direction through the electrolyte (from negative cathode to positive anode), and the positive metal ions flow in the other direction, drawn to the negative electode — in your case, the brass plate. Assuming the wood screw was galvanized, you've now got zinc-plated brass.

Does it help if the surface area of the negative is substancially more than that of the peice being etched? Is tap wtare vs. deionised or distilled better? table salt, kosher salt, rock salt?

As I understand it, ideally you want both electrodes to have approximately the same surface area. Distilled/deionized water is probably your best choice as a base for your electrolyte solution, as it will have no odd dissolved minerals to participate unexpectedly in the process. For the same reason, you should probably avoid table salt (iodine compounds) or rock salt (various naturally-present metal salts); kosher salt is pure NaCl, or near enough for government work... Tongue

I wonder if there is a simple item or something that would allow for hooking to house current with a variable resistor and a quick release safety off? That way the fine tuning would be easier to do. turn it up or down as needed.

If you're not sure what you're doing, don't mess with mains current.
If you're not sure what you're doing, don't mess with mains current.
If you're not sure what you're doing, don't mess with mains current.

Mains current is alternating current, which means the electrons' direction of flow alternates rapidly, so using it directly means that your workpiece will rapidly alternate between anode (etching) and cathode (plating). While this might be an interesting experiment for an experienced etcher, I must reiterate: If you're not sure what you're doing, don't mess with mains current.

(If you already understand this, please regard the preceeding as being for the benefit of other, less-knowledgeable readers.)

You should get better results by replacing the 9v battery with a 12v car battery, which will yield the higher current you need. Make sure your circuit has some sort of current-limiting resistance in series with the etching tank; a car headlight bulb should do the trick. Do this outside, as lead-acid batteries give off both hydrogen and hydrogen sulphide gas, and if through some mishap the battery should crack you don't want sulphuric acid eating through the kitchen floor and dripping onto the downstairs neighbours. (Well, you probably don't want...)

I believe some have had success using an automotive battery charger as the power source; this would afford you some measure of overload/overcurrent protection, as well.

Good luck, and all applicable disclaimers apply. Let us know how you make out.
Logged

By the power of caffeine do I set my mind in motion
By the Beans of Life do my thoughts acquire speed
My hands acquire a shaking
The shaking becomes a warning
By the power of caffeine do I set my mind in motion
The Leverkusen Institute of Paleocybernetics is 5838 km from Reading
jringling
Time Traveler
****
United States United States


convicted Rogue and Vagabond…long story…


WWW
« Reply #77 on: May 27, 2010, 05:14:15 pm »

Unless you are working on PC boards, water is water and salt is salt. I would fine tune the set up before tweaking the solution. I will secod the replacement of the 9v battrery with something to provide more amps. I use a 12v 2/6 amp battery charger. I used to keep a 12v battery in parrallel as a buffer, but have recently removed it with no adverse effects. I do not use any load in line. If the amp draw is too high, I move the pieces further apart or dilute the solution. As far as the size of the negative electrode... atleast as large as the work piece. I use a large piece of sheet as large as the tank.

Hope this helps...
-Jerry
Logged

von Corax
Squire of the Lambda Calculus
Moderator
Immortal
*
Canada Canada

Prof. Darwin Prætorius von Corax


« Reply #78 on: May 28, 2010, 03:17:23 am »

What he said. He's done it a lot more than I have.

I would still use a current limiter, but then I am a devout Murphyist — you're probably safe without one, especially if you use a battery charger with builtin circuit breakers.
Logged
rovingjack
Zeppelin Admiral
******
United States United States



WWW
« Reply #79 on: May 28, 2010, 05:20:24 am »

I'm thinking that I'll be posting some of my experiments on my blog, but am wondering if people would like me to start a new thread and post the settup and experiment and a few other parts of the experiment. I guess I should just start the wip post and see if folk are interested.
Logged
Professor Damien Tremens
Officer
***
United States United States



« Reply #80 on: May 31, 2010, 07:09:19 am »

I still have great results using one or two standard "D" batteries, canning or kosher salt, and distilled water.

Other refinements one should keep in mind:

1) Mask off the rear side of the plate that you are etching. If it is left exposed, it will etch, and slows everything down.

2) Keep the connection point of the wire leads to your etching plates out of the salt water bath.

3) Make sure you have solid connections (mechanical or soldered) to both the anode and the electrode plates. Surface
area does seem to make a difference for me here, although theoretically it shouldn't. Also make sure that the points of
connection are not corroded or oxidized, as this will inhibit the electrical flow.

4) Keep the anode and electrode parallel to each other. It will keep the etch more consistent over the entire face of the etched plate.

5) Positive to the part, negative to the non-part. Positive always attaches to the part you are etching.

6) While not 100% necessary, I still recommend the use of an aquarium style bubble bar to encourage movement of the water,
to keep particles from setting on the surface and slowing the etching process.


I'm going to be doing a live demo of my etching process during Anime Expo this year on Friday evening from 5 to 7pm.
Feel free to drop by if you're attending and ask any questions you may have.

Logged

rovingjack
Zeppelin Admiral
******
United States United States



WWW
« Reply #81 on: May 31, 2010, 08:35:27 am »

3) Make sure you have solid connections (mechanical or soldered) to both the anode and the electrode plates. Surface
area does seem to make a difference for me here, although theoretically it shouldn't. Also make sure that the points of
connection are not corroded or oxidized, as this will inhibit the electrical flow.


5) Positive to the part, negative to the non-part. Positive always attaches to the part you are etching.

I will start up a step by step for a project with my now working setup in a few days. But the two factors above and a crumby battery turned out to be issues for me.

The first mistake I made was being backwards but figure that one out quickly enough.

 The second was the crudy 9v I used. That took some thinking but I came up with something that works better and hopefully will do so for a good while longer.

The final peice of the puzzle came when trying to position the peices properly to get them facing each other but not touching and yet keep the clips out of the water. I repositioned the clip on the small item and it moved on it's own to having a broader area of contact and a shallower angle, and the reaction took off like crazy.
Logged
Gozdom
Snr. Officer
****
Hungary Hungary

Gravatar


« Reply #82 on: May 31, 2010, 05:06:29 pm »

I use a car battery charger  rated at 6A, with no current limiting component. The charger can be switched to either 6 or 12V, both work well, I use 6V for more delicate ornaments but not sure if it makes any difference (except the time it takes). The tank is 3 litres, so it won't boil. The only risk is shorting out the charger, which would blow the fuse or a capacitor, if this happens, I replace them.
Logged

Professor Damien Tremens
Officer
***
United States United States



« Reply #83 on: June 01, 2010, 01:33:47 am »


The final peice of the puzzle came when trying to position the peices properly to get them facing each other but not touching and yet keep the clips out of the water. I repositioned the clip on the small item and it moved on it's own to having a broader area of contact and a shallower angle, and the reaction took off like crazy.

I actually use a custom made holder with slots, sized for the usual K&S sheets of brass that I typically use. There are 3 slots, which allows me to do a double sided etch if I want with negative (cathode) plates on both sides of the positive (anode) plate that is being etched.

It's made out of 2 sheets of plexiglass, spaced out with wooden dowels, and the slots are formed by strips of 1/4" by 1/8" plastic glued to the plexiglass.

Works well, and also keeps the spacing nice and consistent for optimal etching.
Logged
peps1
Deck Hand
*
United Kingdom United Kingdom



WWW
« Reply #84 on: September 30, 2010, 02:41:11 am »

got to say I much prefer using a chemical etching methods over electrolysis.....and with Copper Chloride Aqueous Hydrochloric Acid (hydrogen peroxide + hydrochloric acid) the solution can be recharged simply using a bubbler from a fish tank, so no environmental contaminants, and free etching solution for like!    Grin
Logged

jringling
Time Traveler
****
United States United States


convicted Rogue and Vagabond…long story…


WWW
« Reply #85 on: September 30, 2010, 02:43:11 am »

Here is a new 2 sided etching tank... and the first piece out of it...

Spoiler (click to show/hide)

Fresh solution etches very nice...
Logged
Troppo Laird of Dunans Ca
Guest
« Reply #86 on: October 01, 2010, 04:50:08 pm »

I`ve been interested in etching for a while and i have to say that is amazing work there sir.
Maybe one day i could actually achieve something of that standard
Logged
Professor Damien Tremens
Officer
***
United States United States



« Reply #87 on: October 04, 2010, 05:17:09 am »

Examples of some of the labels I've been doing for friends in The League of S.T.E.A.M.
Spoiler (click to show/hide)

The patina/antiquing comes from applying gun blue to the brass after it is etched, then using
fine grit sandpaper to polish the high points and leaving the etched parts darker.

The next batch should be interesting, as I have gotten access to a benchtop adjustable
power supply at the Dallas Makerspace. Fully controllable current and voltage should make
things easier. We're also going to be getting in a laser etcher/cutter in the near future, which
will allow me to create my mask by coating the brass with paint, then using the laser to burn
away the paint as needed.
Logged
Pages: 1 2 3 [4]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!
Page created in 0.372 seconds with 16 queries.