Photo Etching Brass

I wish to start etching my own parts for a few project ideas I have. Yesterday I bought all the supplies for etching (as far as online research suggests). Before I do a test run, I wanted to know if I have everything set up to do the etch right. The design/transfer process is already done (something I've done for other purposes in the past), so I know I'm good there. But as far as the solution, tub, agitating stuff; I'm still uncertain.

For agitating, I've read about heat lamps, aquarium bubbler's and electric current. Which would be the best technique, are all three necessary, or is something completely different best?
What is the best thickness of brass to work with? Again, I've read .005in is used the most, but I was only able to find .01in. Will this size work?
How long should I expect it to take?
Lastly, I saw something about adding the solution to water to make it stronger. I'm pretty sure my solution is not pre-mixed (test run will find out I guess). Is there a certain ratio of FeCL solution/water that works best?

If anyone is a veteran of photo etching and knows shortcuts, better techniques, or can just let me in on the basics of getting an etch done, it would be much appreciated!

Thanks
-Mark

 

Mark,

I know nothing yet about brass etching. I did a little googling over the weekend, and found a lot of good advice. It occured to me that many of the duplicate parts of bridges and ships might be a good subject for etching. And it seems that agitation by some method is critical.

This is basically a bump . . .

 

Micro-Mark.com

Dude,

Tomorrow I will be prepping brass sheets, exposing them with custom overlays to the sun, and shortly there after etching. Going to be a very busy day as I have about 20+ things to etch.

.010" brass takes about twice as long as .005 to etch thru. Here are some keys to etching!

* Warm your etchant to about 100 degrees. (I place my bottles of etchant in super hot water and let the heat transfer to the etchant thru the bottles)

* Aggitation is required for a fast even etch. (I have two main ways I etch. I use a Hikers "Nalgene" bottle with the wide mouth lid to etch the small stuff. I have a huge clear plastic container with a sealable lid for the larger stuff I got at the "Container Store".

I use Ferric Chloride for etching. I use it full strength. I do not dilute it. I can etch a .010" sheet of brass in 8 minutes +/-2 minutes with fresh strong etchant or average 12 minute+ with weak etchant. .005" brass can be etched in as little as 4-5 minutes with strong fresh etchant.

These are my results of about 100+ etches from home.

Reason I use a Nalgene bottle is I shake the hell out of it. With the tight sealed lid no etchant leaks. The larger container seals, but not good enough to shake. I will swirl, and swish the etchant around and back and forth trying to minimize large amounts of etchant splashing up to the lid.

Handling etched parts. I use a 8-10" orange plastic tweezers to reach into the etchant and recover the brass being etched.

Internet search for : Randy Gordon Gilmore and you will find lots of great home etching info from him.

Also, you might want to invest in the www.micromark.com etching kit. It has a beginners tank with fish tank aerator for aggitation. It works ok, but I like the super Nalgene shake better as it etches faster and more even, BUT is hell on the arms. 4, 5, 6, 7, up to 12 minutes is tiring on the arms.

Ok, hope this helps you. If you have other questions please message me. I'll answer any questions about etching!!!!!

Hobo Tim

 

Post some of my home etched brass!!!

Here are some photos of items that I made brass detail parts for. Remember, I model Z scale so most items are not commercially available so I have to make my own!!


Modern Tank Car - Styrene, cast resin and etched brass

Mi-Jack Translift cranes - Cast resin and etched brass

US Target Signals - Styrene, brass tubing, etched brass (Have 0602 Bi-Color LED)

Thrall 48' single well car - Etched brass and MTL coupler/trucks

The Thrall was a second test etch of the design. These were later produced by a professional etching firm, PEI, for Ztrack magazine.
http://www.ztrack.com/intermodal/index.html is the link to the page. I build these for Ztrack.

Ok, post photos of your etchings here to this thread!!!

Hobo Tim

 

Incredible! Thanks for the reply Tim. I've seen some of your work (including the well cars) in the Z scale forum and it amazes the hell out of me. It is almost tempting to get me to scrap my N scale and take the plunge into the challenges(aka fun) of Z.

I did a few tests last night and my results were horrible. I did find some .005in brass to test as well as the .010 I originally got. After about 3 hours neither had etched even half way through (swirling and brushing away the grit every 15min).

I will pick up the hikers bottle tomorrow and try that now.
*side note* I wonder how much a paint can shaker would run... Seems like that would be the perfect piece of machinery for the Nalgene bottle approach (especially if your doing 20+ pieces a day)

Now I just have two questions:
How do you know if the solution you have is full strength FeCL? The bottle I have just says "Contains Ferric Chloride". It does not specify if it is diluted or not nor does the MFG's website. I'm guessing that might mean it is full strength? It is a dark brown with slight red/orange tint if that helps in identifying.

Secondly. It seems you use the UV resist approach. I prepped a sheet with laser toner a few days ago. Have you tried this approach? If so, pros?/cons? or why you use the UV over toner?

If I can get a hold of a Nalgene bottle tomorrow and get a test done, I'll post whether I had success or not.

Again, thanks for the replies!
-Mark

 

Success!!

Thanks for the tips Tim!


Hey, maybe we can get this into the "How to" forum!

 

Tim,

Thanks for picking up this thread! I'm really going to try it.

 

Tim.. you da man!

So, what do you do your artwork in? I seem to remember a rule about the smallest width you should have a line be, based on the thickness of what you're etching?

 

The thinnest should be 1.5 times the metal thickness. During etching, the etchant starts in on the metal from under the resist. Etchant knows no artwork boundries and begins to undermine the metal slightly that we want to keep. This is almost always an equivilent of 1/2 the metal thickness and artwork should always be adjusted for undermining. Going to smaller lines usually requires very strong acids and/or near boiling temps to etch through fast before attacking the metal under the resist.

Strong Ferric Chloride can be purchased at Radio Shack. You can also "cook" up your own etching acid by following this simple tutorial. I was sent the link some time ago by another home etcher, but I have not tried the acid even though the chemistry is right.

http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

 

But what about Brass!

Bob, do you think this solution will work on brass just as good as the copper?

Hobo Tim

 

Brass is a metal composed primarily of copper and zinc. Copper is the main component, and brass is usually classified as a copper alloy. The color of brass varies from a dark reddish brown to a light silvery yellow depending on the amount of zinc present; the more zinc, the lighter the color.

 

He says "What's happening is that you're dissolving the copper from the board and turning it into cupric chloride. In the long-run, the cupric chloride will be doing most of the etching (instead of requiring disposal)."

So, since I'm no chemist.. will this method work with brass as well?

 

Sheesh.. I must have been looking at the cached page.. as i just read the posts ABOVE, about what brass is LOL

 

First off thanks for all the replies. I think I really have a good handle on etching now.
I just finished a set of N scale scaffolding (pictures attached).
You can see where some of the edges are not too great (at least compared to HoboTim's work), which makes me wander...

In Tim's post, he says he uses photo resist. For mine, I used the "laser toner, iron transfer, does not work so great" approach. Does anyone know any main differences between these two ways of adding resist to the brass?

I searched online and could only find little information about using photo resist, so if anyone has (or could write) a tutorial and list of materials for this technique, I'd like to try it out.

Anyways, here's some pictures of my very first completed etching project! *cheers*

 

Photo Resist Film!

Due to $$$ constraints, I have never been able to purchase a large roll of photo resist film. The only thing I have been able to buy is the small supply that Micro-Mark.com has. I know if I added up all of the $$$ I have paid Micro-Mark in the past for the Photo Resist I have bought from them, I could have bought probably two large rolls with plenty to spare but alas, didn't happen!!! So....................

In 2004 I had a strong desire to make a 3 bay PS2 covered hopper in Z scale. Only problem was I only knew how to scratchbuild them one at a time for production. This was when I looked into other ways of mass producing the parts. In 2004 I learned how to use RTV 2 part rubber to make molds, mix 2 part resin to cast parts, and the long process of prepping/exposing/etching brass. Was a busy year for me.

I searched the internet for answers on etching brass. The best resource I found for Home Etching was from Randy Gordon-Gilmore. I studied his means of etching and shortly there-after Micro-Mark introduced a beginners home etching kit. As far as I know I was the first person to buy one!!! he-he!! As with making RTV molds and casting resin parts, Etching was a learning experience.

http://www.prototrains.com/
http://www.prototrains.com/etch1/etch1.html
http://www.prototrains.com/etch2/etch2.html

Home Etching is an art and a pain at the same time. The "ART" part comes from experience in your evolving creations and the "PAIN" part comes from the long process of etching each time.

PHOTO RESIST!

I have only ever used the Photo Resist film that Micro-Mark offers. It comes in small rolls. Enough in one package to completely cover 4 K&S 4"x10" sheets of brass with a few small pieces to spare.

Note: Resist film is light blue in color. The film is actually one light blue sheet of resist sandwiched between two clear protective sheets. When Resist is exposed to UV rays it hardens and changes to a deep blue color.

I have learned to cut the resist film to fit the 4"x10" sheets. I use scissors to cut the lengths I need. When I prep brass sheets, I will coat 3,4,5 at a time. I place the resist coated sheets in a file, deep in my file cabinet where the light of day never reaches. The resist stays in perfect condition till I need it. day, weeks, months have gone by with no change. Why coat one sheet or half of a sheet when you can coat many and keep them for when you need them.

Here is a step-by-step process of what I do. All of this is done in a very dark room, yet enough light to see what you are doing.

* Pre-cut Photo Resist to proper sizes, store in UV protected bag (Micro-Mark shipping bag).
* Plug in/turn on the laminator.
* Fill a container with Distilled water (I use a plastic Shoe box lid I got at the "Container Store") to put the sheets in after scrubbing them.
* Top off a small sprayer bottle with Distilled water (Used to add water to the brass before applying the photo resist film).
* Make sure I have all the supplies I need: Scotch tape, Scotchbrite pads, Scissors, Laminator carrier sheet, cotton cloth, Pre-cut resist film in UV bag, scrubbing back board, a hot, ready to go, laminator, and running water.
* I use the kitchen, with only the light coming thru the sliding glass door for illumination.
* Turn water on at a slow drip/stream.
* Put scrubbing back board in bottom of sink, put brass sheet on it and scrub it with the Scotchbrite pad till it is shiney. This is to remove the lite layer of enamel, from both sides, that the brass company sprays on the brass to keep it from tarnishing.
NOTE: scrub the brass till the water beads on the entire surface. Scrub up-n-down, left-n-right! Rinse thoroughly!
* Place clean sheet in the distilled water and repeat till all sheets are cleaned.
* Fold the cotton cloth slightly larger than sheet of brass. Wet near soaked with distilled water.
* Place one sheet of brass on cloth. Spray distilled water on the sheet till it is completely beaded with water. No dry spots! (a dry spot on the brass is like a instant epoxy if the resist film touches it)
* Tear off a small piece of Scotch tape. Take one sheet of pre-cut resist film from UV protective bag.
*Use a fingernail to scrape a corner of the resist film to "rough it up" making it easier for the tape to separate the protective clear film from the resist film. Take care not to let the bare resist film touch itself. Instant stick!!!! Only remove one side of the protective clear film.
* Carefully place the film on the soaking wet sheet of brass. Hold one side with your hand and with the other hand gently run your other hand across the film to remove the water between the film and the brass. NO AIR BUBBLES or KINKS!!!
* Flip the sheet of brass over and repeat this process till both sides are covered with resist film.
* Using the scissors, remove any resist film that might be hanging over the edge of the brass. Sharp scissors work best.
* Immediately place the brass sheet in the laminator carrier and put it in the laminator. Once the thru the laminator, remove resist coated sheet from carrier and inspect. Place sheet in a dark place. (A spare UV Resist bag works well, so does the inside of a Walther's HO book, till all sheets are done and go into the file cabinet.
*Clean up mess and return all materials and items to storage!

That is what I do to coat my brass sheets near exact step-by-step. Once coated I cut what I need till I need to coat more!!!

Exposing the brass. You need a strong UV light to expose the brass. The faster the better. Noon to 3pm direct sun is the best at 60 seconds per side. If you expose resist to UV rays for a long time the UV rays tend to get under your Clear Overlay and can really mess up your etching. (Example, I made Z scale perforated roof walk pieces for my PS2 covered hoppers. Too long exposure screws up the perforation)

I hope this helps!!! I am always open for Questions!!!

Hobo Tim

 

This is really good. I'm just getting into this myself and this answers 1000 questions....

I've got the Micro-Mark photoetch kit and have been too afraid to use it. Confession is good for the soul.

Tim, I just don't want you to think that all that typing is going to waste!

I'm very comfortable with scratchbuilding and resin casting and have been doing that now for a couple years. It's been difficult to learn, but now that I have the hang of it I'm getting consistently good results. Photoetching is the next big hurdle. Learning resin casting did teach me how much you DON'T know that comes with the kits.

And this from a B- chemistry student.

 

Ha! me too.. I even bought a small fish tank got the pumps all set up and ready, for bubbling.. but I just stare at my micro mark packet...

someday, I'll take the leap!

 

Been some time..................

It has been some time since this thread was started. What new home etched brass have you been working on.

The Scaffold system in the photo looks real good. With more experience the edges will be crisp and details fine tuned.

Post more photos!!!!

The home etching process may be a lengthy one, but it is just as rewarding when the project is complete!!!

Post Photos!!!!

Hobo Tim

 

I'm going to have to wait a while before plunging in. I have a million little pieces to etch for my ships--like bulwarks stays, K-gun throwers, electrical junction boxes, depth charge racks, etc. I've been cheating on bulwark stays by spacing them twice the distance as the real things because they are hard to make one at a time, and might be too small to cast realistically in resin.