Big Brass Ones

Everyone should have a Pair

of Big Brass Dice.

With Father's day coming up, I wanted to do something a little different. Now, dad plays a lot of board games and occasionally I've seen him have to squint a bit to see how the dice wound up.

I used to work in a gaming store (board, not video) and saw a lot of dice styles cross the counter. One of them was the long polygon style from Crystal Caste. I liked the basic idea and its stuck in the back of my mind ever since I first saw them.

Now that I thought of doing something for Dad, the two things, easy to read dice and the "rolling log" style from Crystal Caste clicked and I was off to the races. The fact that I could make up a little box and label it "Big Brass Ones - One Pair" when giving it to him was too good to pass up.

I did a test run with a threaded rod coupling nut (instructable here) and liked the result. Now it was on to the real stuff - Solid Brass 360 Alloy hexagon stock.

Here was where my love of steampunk came in handy. I have been following the adventures of Jake von Slatt at Steampunk Workshop and saw that he has a nice tutorial on etching brass with chemicals that I could get locally, unlike circuit board etching acid. At this point it was time to gather my tools and materials and dive in.

This is a continuation of my dice themed instructables. My dice tower tutorial is available here. This one should be towards the end of the dice theme - I'm running out of new ideas.

NOTE: As part of the Etsy/Instructable contest, I have made a few extra pair and put them up for sale on Etsy. While making your own is part of the fun, perhaps you don't have the time or tools needed. Not to worry! Now you too can have your own Pair of Big Brass Ones.

Check out the listing on Etsy and see if any of these bad boys are still available. Order early and often!

You will want a work area where some spilled not-that-toxic chemicals and water can be cleaned up. Keeping paper towels and some rags around is always a good idea.

TOOLS:

There are a lot of ways to cut brass into smaller bits. A hacksaw, miter box, files and sandpaper to smooth out the edges would work. I happen to have a non-ferrous metal cutting table saw blade from my old battlebot days. (Battlebot Flickr photosets available here and here) Brass is a non-ferrous metal so that would give a nice smooth cut on the ends - no sanding or smoothing needed. A new blade like mine at Amazon.com goes for $75.

Also,

• Plastic tubs and buckets to mix the chemicals in and do the actual etching. Glass is OK, do NOT use anything metal. I mixed up the chemicals in a cut down 1 liter seltzer bottle, and did the actual etching in a 2lb Imperial Margarine tub.
• Utility/Xacto knife & good tweezers
• Any color Spray Primer - I used black so any brass showing through was in high contrast and visable. I used the cheap stuff from the autoparts store - $2.44 a can
• touch up paint - could use almost anything, I used black acrylic modeling paint
• 12V DC Power Source with at least 1 Amp output. Could be a car or SLA battery. An old PC power supply converted into a bench supply. I used a variable power supply.
• 12V automobile lightbulbs - I used type 561 and those worked well. These are used for current limiting in the circuit. Cost $1.96 at the autopart store.
• 16 AWG (or thicker) wire to run from the power source to the brass bits. Alligator clamps are your friend.
• SOS pads for scrubbing the paint off the brass.
• small, 2" wide post-it notes
• Brasso & toothbrush to clean the brass
• Acetone

Materials:

The etching process is basically putting two pieces of brass in a bath of copper sulfate dissolved in water and running 12V DC between the two. We need both pieces of brass and the copper sulfate.

Brass Hexagon Bar Stock. At least five inches. Why five inches? So we can make a pair of dice at two inches a piece. I used 3/4" diameter hex bar, 5/8" diameter would work as well. I got mine off Ebay but you can get it online at places like onlinemetals.com or speedymetals.com. Check to see if you have a Metal Supermarket nearby. In the past I found having one within reasonable commute distance to be handy. Unfortunately I no longer live near one. Online with shipping, getting it new costs around $18 per foot.

A Brass strip to act as the cathode in the etching process - I had some spare brass bits laying around and a nice piece of 4" x 10" brass plate, 0.032" thick. Didn't need it that wide or thick, 2" x 10" and 0.025" thick is plenty. Most good hobby stores carry some metals from K&S Engineering. One that would work is K&S Part #239. Plenty of length at 12" and you get 3 pieces! Cost around $11.

Root Kill - this is the household chemical used in the etching process. What we are really looking for is Copper Sulfate - which this is 99% of. I originally wandered around the gardening area of the local home improvement store looking for this stuff and finding nothing in frustration. Later I discovered it's in the plumbing department, not gardening. They had plenty a few isles over from where I had searched endlessly. There are other "kill roots" type projects out there. Look at the ingredients and make sure the stuff you get is blue crystals and Copper Sulfate, not something else. Costs $9.89.

Vinyl Letters - the 1/4" sized ones. Cost $3.79 at Staples. I used these because my attempts at the classic toner thermal transfer method where a complete disaster.

Now that we have enough stuff to be dangerous, it's time to start cutting metal.

The first thing was to take the brass hexagon bar stock and cut it into 2 inch lengths.

As mentioned, there are many ways of cutting brass bar stock to length. I used a table saw and non-ferrous cutting blade.

Whatever method you use, put together a jig so you are consistent on length. It doesn't have to be exactly 2 inches long, but you want your pieces to be the same size whatever that is.

On my setup, I used the sliding miter table and put a stop block at 2" from the edge of the blade. I clamped the bar stock down with two C-clamps, put on my safety glasses and raised the blade so it would make the cut in one pass. If you try for multiple passes you will get a jaggy cut. If I did it again I would put a rag between the C-Clamps and the brass for padding and so the brass doesn't get dinged up more than can be helped. Brass is a soft metal and can get scratched up easily.

If you are doing it by hand with a hacksaw and miter box, put a stop block in place and clamp it and the brass as well. Take it slow and try and keep the hacksaw at 90 degrees to the brass.

When cutting metal using a lubricant is a good idea so I sprayed my blade and the brass with WD-40. This keeps the blade cooler and makes a smoother cut. A light spray of WD-40 would be helpful even doing it by hand.

When you are all set, put on the safety glasses, stand to one side and very slowly push the miter slide forward. Take your time. The blade will be spitting out little bits of brass and hitting you in the chest and arms - no big deal but know it's coming. Brass can really "grab" a blade when being cut so slow and easy is the ticket.

Now that we have the brass pieces cut to length, it's time to get them prepped for etching.

The etching process works by pulling brass molecules off the bar stock and onto the brass strip. Therefore we need to create a "negative" image of the words we want on the sides. I tried the well known toner transfer method and failed. That method might work for thin flat pieces but for more 3D thick pieces, a vinyl transfer method seems to work better. YMMV.

First thing - clean the brass. I used brasso and a toothbrush and got lots of black gunk off the pieces. Once it is cleaned up, I wiped it down with acetone to take off any residue.

Take a small 2" wide post-it note and put a mark in the middle of top at 1". Cut off the bottom two-thirds of the post-it.

We are using the post it note to make an edge that the vinyl letters are lined up on.

Put a piece of brass on the table horizontally. Line up the post-it on one face so the top edge of the post-it is slightly over the bottom of the face and the post-it is centered on the brass piece. The post-it should be about 1/16" up on the face of the brass piece. Use your fingernail and crease the post-it edge. The distance the post-it is "up" on the face of the brass piece is by look and feel. It's more important it be level across the brass piece than at the perfect height up. After you have placed some vinyl letters on the brass piece you will get a feel for how far up the post-it note top should be. The beauty of this system is that you can pull everything off (vinyl letters and post-it guide) and start from scratch if needed.

Once your post-it note is in place, it's time to start putting down the vinyl letters. Using the mid-point mark on the post-it, put down the middle letter of the word. So for one, the middle letter is "N". For three, it's "R". For four letter words like four and five, put one letter on each side of the mark.

I found a good pair of tweezers to be invaluable in moving the vinyl letters around to the correct place.

Character spacing should be in the 3/32" to 1/8" range. There is some undercutting so the letters grow larger in the etching process - give them some room to do so.

Once you have the middle letter/letters down, work from the middle out on one side then the other.

Once all the letters are down for one face, press them down firmly, rotate the brass piece and do it again.

If after you have put down an entire word (like "six") and after pulling up the post-it notice it's crooked or somehow messed up, do not despair. Take an xacto or utility knife, carefully pry up the corner of each letter, and pull them off the brass piece. Now you can try again.

I would do one word then rotate it and do another. I learned from my coupling nut dice and made sure the various numbers are not in sequence. I went (from side to side) one-four-two-six-three-five. So one and six where on opposite sides, three and four where on opposite sides, and two and five on opposite sides. Just like a normal d6. I had a little sheet of paper taped over the desk with this and made sure to do all the dice the same.

Now that the entire brass piece is lettered, it's time for the spray primer.

I found out via trial and much error that too many layers of primer makes the paint stick to the vinyl letters - a very bad thing. When spraying, put the brass piece vertically on something and spray one movement up and down on each face. Rotate it to the next face and spray that up and down and so on. When done, spray a little on the top to make sure that's covered in paint as well. Don't worry about the end that was down, leave that unpainted.

Now we wait as the primer dries. I would leave it over night just to make sure.

Once the primer is dry, inspect the brass piece. Everything except that one end should be painted or covered over. If there are some places where the primer didn't take or was rubbed off, take your touch-up paint and put it on. I used some acrylic black modeling paint and that worked fine.

Once the touch up paint has dried, it's time to remove the vinyl letters. Lay the brass piece down and with an xacto knife, gently pry up the edge of a vinyl letter. It's OK if the knife makes a mark in the brass underneath the letter, that part is getting removed via etching anyway. Don't mark anything outside the letter edges. Once a corner of every vinyl letter on a side has been pried up, take your tweezers and slowly pull all the letters up. If any paint or primer comes up with the letter you can cover over that bit with the touch up paint. If it's really a mess, scrub down the whole thing with a SOS pad and start again.

When done, you now have a "negative" image on the dice. Everything but the letters themselves is covered in paint. Now it's time for chemistry.

I mixed 1/2" cup of Root Kill with 16oz of water to make the etching solution. I only needed 16 oz with the plastic tub I was using. You might need to make more depending on your container.

Root kill solution is not something you want to drink but getting it on your hands is not that big an issue, unlike the Ferric Chloride acid used in PCB etching. It's designed as a product to go down drains, so when you are done dump it in the sink and run water after it.

Take your brass strip of 2" tall and 10"+ long and bend it around in a circle with the can of spray primer. It's not going to be perfect, just close to a circlish kind of shape is OK.

You need some way of applying the positive wire from the power source into the brass dice piece. I stripped a little bit off the top of the brass piece end where there is no paint. Using a scrap piece of 3/4" wood, I used popsicle sticks and a spade crimp connector to make something that would provide power to the brass dice when it's in the etching solution.

Put the dice piece into the tub and fill with etching solution until it's higher than the longest word (in this case, "three") and lower than the scraped off part on the end. The brass strip circle will displace some but not that much. Put that in and check the level again - I would put in and take out a plastic spoonful of etching solution at a time to get the height correct.

From the power supply, the ground goes to the brass strip circle surrounding the brass dice piece. The positive connection went into an automobile lamp to control the current. Testing showed the lamp burned at 955mA or so, so that's what the power would be at. Putting the auto lamp in series with the etching tank, run a wire from the auto lamp to the brass dice piece. When power is applied, brass moves though the etching solution from the positive (brass dice piece) to the negative (brass strip circle). This digs out the exposed bits (the words of numbers) and leaves the parts covered in paint alone.

How deep and how quick the dice gets etched depends on the current and voltage being supplied, how close the brass strip circle is to the brass dice piece, how much copper sulfate is dissolved into the etching solution, if it's before or after the 2nd Tuesday of the month and who won the last World Series. In other words, everyone's situation will be different.

I let it run about a half hour, turned off the power and pulled it out. It was covered in brown gunk that washes off easily but the etching wasn't so deep. I let it run another 30 minutes and checked again. A little more etching but not deep enough. In the end I determined that in my setup, it needed to run 2 hours to get the etching level I wanted.

If you are running it with a current limiter, check it every 20 to 30 minutes. If you are running it full bore, you might want to check it every 10.

The brown gunk that collects on the parts being etched washes off easily in water. Keep a spare tub with water nearby you can dump it in when you pull it out of the etching tub.

When you get an etched depth you like, pull it out and wash it off. Now it's time to scrub off all the paint.

This step requires an SOS pad and elbow grease and not much else.

Take an SOS pad and start scrubbing the paint off the brass piece. At this point you will see how good the etching came out. Did any of the small islands like the center parts of the "R"s get etched away or did it all come out well? It really feels good to see the final result come out from under the paint and gunk.

Keep scrubbing. It might not look like the paint is coming off but it does in the end. I tried taking it off with acetone but the paint would flow into the etched parts and stick in there. It took some effort with Q-tips to get it out. After that it was back to the SOS pad only.

Scrubbing the brass with the SOS pad makes it shiny and takes out some small imperfections, an added bonus. In the end you will have an etched piece of brass that's close to being done.

The ends are right now a hard edge that needs to be beveled. You can use files and sandpaper to do this but since I had this nifty table saw setup, decided to do that. I cut a 45 degree bevel at the 1/16" mark on every face of both sides of the dice.

Again, I setup a stop block jig to hold the brass piece in place and carefully moved it into the spinning table saw blade. My setup had the issue that if I pushed it too far, the blade would hit the C-clamp. Not a good thing. So I watched and pushed very slowly and pulled it back after the bevel was cut.

This time I made sure to have a rubber pad between the C-clamp and the dice piece.

Doing one cut per face per end means twelve cuts per dice, with each one having to be set and clamped and pushed into the blade just far enough but not too far. Be careful to pay attention to what's going on on every placement and cut - it would be easy to get bored and careless when doing a repetitious task like this.

Once this is done it's all over but the polishing.

Now it's a matter of the level of polish you want and if you want to put on a clear finish like Lacquer.

I used Brasso, a toothbrush and a micro-fiber cloth to polish it. The micro fiber cloth was good for getting into the etched letters.

Once it was polished up, I put on a thin coating of wax to keep the air out and then made a small cardstock box with felt lining to keep them in. I'll make a nice wooden box sometime this week for Dad.

<Optional>

You could put some paint down in the etched parts to make them really stand out, like the pips are painted in regular d6 dice. I decided to go with the natural look.

You could put on a protective coating of some sort like Lacquer. I tried spray lacquer on one piece but it didn't come out well. I sprayed it vertically like I did on the primer and the lacquer flowed to the bottom and stayed there in a big blog of the stuff. Other's might have more experience with spray or brush on finishes for brass and hopefully they will give good advice in the comments. Be warned - something that might work well for flat 2D pieces might not work for a 3D piece like this.

</ Optional>

Thanks for getting this far on the Big Brass Ones instructable. If you want to see some of my project logs and pictures of failed attempts on this one, check out my site at whamodyne.com.