Author Topic: Questions about using copper for keycaps  (Read 1356 times)

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Offline Mxted

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Questions about using copper for keycaps
« on: Fri, 25 September 2020, 14:13:32 »
Hi guys I am almost done my key cap design and am in the process of deciding what material to use.
I am thinking about using copper because I like the look. I want my keycap to stay shiny and not patina, if anyone can help me with suggestions on what I should do I would be appreciate that alot.
« Last Edit: Fri, 25 September 2020, 14:15:45 by Mxted »

Offline nevin

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Re: questions about using copper for keycaps
« Reply #1 on: Fri, 25 September 2020, 14:18:10 »
you'd have to coat it with something to keep it from patina-ing. even then the clear coat would probably wear eventually if it was in use.

though paina would look really nice, little bit of the turquoise.... you can get one almost instantly with an amona mixture, then seal it with a clear coat. still wouldn't last forever if it was in use. or just let it patina naturally... end up looking like an old penny.

if you want that look, i'd suggest working with someone that does anodizing and try to get an anodization that's close to a copper color (probably a along the lines of a "rose gold") ... and of course, the cap would be made out of aluminum if anodizing.
« Last Edit: Fri, 25 September 2020, 14:22:42 by nevin »
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Offline hvontres

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Re: Questions about using copper for keycaps
« Reply #2 on: Fri, 25 September 2020, 15:52:38 »
Also, keep in mind that finger oils will accelerate the corrosion process (the "patina") and if you don't coat the keys, you will likely get green fingertips every time you use the key.

Another potential issue with using copper is that is an absolute b*&ch to machine. It is soft and gummy and will clog up cutter like nothing else. The guys in our shop at work absolutely HATE to work with it.

Brass or Bronze will be much easier to work with and while they are more gold than orange will also polish up to a nice shine.
Henry von Tresckow

               
1986 Model M 1390131, 1987 Model M 1391401 , 1993 Model M2 Modded Reddragon k556(work keyboard)

Offline Leslieann

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Re: Questions about using copper for keycaps
« Reply #3 on: Fri, 25 September 2020, 22:30:01 »
Beware, brass and bronze formulations often contain lead.

Not a good idea for something you will be touching for long periods.
Filco MJ2 L.E. w/hand milled Vortex case, custom feet/paint/winkey blockoff plate, HID Liberator, stainless steel universal plate, 3d printed adapters, Type C, sound dampened,  Thick PBT caps (o-ringed), Cherry Jailhouse Blues w/lubed/clipped Cherry light springs | GMMK TKL | Magicforce 68 | YMDK75 | KBT Race S L.E. | Das Pro (Costar model) | GH60 | IBM Model M (x2)

Offline Mxted

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Re: Questions about using copper for keycaps
« Reply #4 on: Sat, 26 September 2020, 12:24:49 »
Also, keep in mind that finger oils will accelerate the corrosion process (the "patina") and if you don't coat the keys, you will likely get green fingertips every time you use the key.

Another potential issue with using copper is that is an absolute b*&ch to machine. It is soft and gummy and will clog up cutter like nothing else. The guys in our shop at work absolutely HATE to work with it.

Brass or Bronze will be much easier to work with and while they are more gold than orange will also polish up to a nice shine.
That is good to know that copper is hard to work with and gets gummy, green fingertips would also be bad. Have you worked with Beryllium Copper that is used in kitchenware and instruments?
I am also worried about the CNC machine not being able to do these corner spots on the design.
I was thinking about trying the lost wax casting method where they 3d print the wax.
Yea I like brass too, I am going to use it on the back plate i am designing. I was thinking about using that as well as aluminum.

Offline hvontres

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Re: Questions about using copper for keycaps
« Reply #5 on: Sat, 26 September 2020, 13:32:28 »
Also, keep in mind that finger oils will accelerate the corrosion process (the "patina") and if you don't coat the keys, you will likely get green fingertips every time you use the key.

Another potential issue with using copper is that is an absolute b*&ch to machine. It is soft and gummy and will clog up cutter like nothing else. The guys in our shop at work absolutely HATE to work with it.

Brass or Bronze will be much easier to work with and while they are more gold than orange will also polish up to a nice shine.
That is good to know that copper is hard to work with and gets gummy, green fingertips would also be bad. Have you worked with Beryllium Copper that is used in kitchenware and instruments?
I am also worried about the CNC machine not being able to do these corner spots on the design.
I was thinking about trying the lost wax casting method where they 3d print the wax.
Yea I like brass too, I am going to use it on the back plate i am designing. I was thinking about using that as well as aluminum.
For a casting, copper might work. If you go that way, you probably will want to make the cross cuts for the stem under size and machine them to size after the fact, otherwise you will probably end up with either a wobbly fit or won't be able to get it on the switch.

I was going to comment on the sharp corners, but I wasn't sure how you were planing on making this. If you do decide to machine the cap, one other fun option might be anodized titanium. You can get some really cool color patterns by varying the voltage (https://www.reddit.com/r/Damnthatsinteresting/comments/99t69k/titanium_changes_colors_with_different_voltages/ ) I have seen some really neat gradients done that way.

Good luck getting this made.
Henry von Tresckow

               
1986 Model M 1390131, 1987 Model M 1391401 , 1993 Model M2 Modded Reddragon k556(work keyboard)

Offline Leslieann

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Re: Questions about using copper for keycaps
« Reply #6 on: Sat, 26 September 2020, 21:35:32 »
There's a reason most metal caps are zinc.
Bronze and brass have lead, copper is a pain in the neck... It should be noted some people also react to zinc, you can also react to aluminum if it's not oxidized/anodized though it's usually if ingested, so beware handing these then eating finger foods (and yes, you can wear through the oxidation and anodizing). Generally you want to use food safe materials. If you do aluminum you probably want 6061, it's one of the cheapest but also one of the easiest to work with and takes anodizing well. Titanium would be nice but EXPENSIVE, same with silver. Stainless Steel is actually something to consider, it's easy to machine, not too pricey and is food safe.

Something else to note, and relates to Hvontres mentioned, the stems are a hassle. The first metal caps had massive problems with this, pretty sure most of the ones sold today are from the same factory that did the first ones since they figured out the sizing, though with that bad bunch of box switches it may not even be possible to make a metal cap that fits everything. Yes, you can usually bend them to clamp bit then they may be too tight, I have 2 from some of the first ones and it's a hassle to get them to stay in place and still go onto the stem as a result they often go flying.

Regarding the small corners and such,
Machining will not be cheap, they need multiple bits and multiple sides, it all adds cost. Casting eliminates this and also offers nicer edges (other than the parting line) but its also trickier and not easy to find someone capable of doing it these days. If you just want one, I'd highly consider just getting it 3d printed or asking local hacker/maker spaces if they ever do any casting (also talk to jewelry shops they can do it). Machine shops will not be happy getting an order for just one of these, prototype or not it's a lot of work for a single, tiny part.
Filco MJ2 L.E. w/hand milled Vortex case, custom feet/paint/winkey blockoff plate, HID Liberator, stainless steel universal plate, 3d printed adapters, Type C, sound dampened,  Thick PBT caps (o-ringed), Cherry Jailhouse Blues w/lubed/clipped Cherry light springs | GMMK TKL | Magicforce 68 | YMDK75 | KBT Race S L.E. | Das Pro (Costar model) | GH60 | IBM Model M (x2)

Offline Mxted

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Re: Questions about using copper for keycaps
« Reply #7 on: Mon, 28 September 2020, 00:31:19 »
All of you are such a big help.
I am going to be using a company that 3D prints the wax and does the casting, they usually make for jewelry,  medals, and sculptures with aluminum zinc alloy, bronze, brass, copper, silver, and gold.
Its good that you guys brought up the stem and wobbly keys.  Our goal was to fix this problem by reducing the tolerance by designing the stem from the switch out, hopefully we solved this issue by designing the stem ourselves. I think as long as the 3D printer is accurate it should technically work, but I am still worried that it wont fit right.
Here are some of the dimensions, please let me know if there is anything you guys see that I should change.




« Last Edit: Mon, 28 September 2020, 00:33:58 by Mxted »

Online yui

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Re: Questions about using copper for keycaps
« Reply #8 on: Mon, 28 September 2020, 01:03:08 »
There's a reason most metal caps are zinc.
Bronze and brass have lead, copper is a pain in the neck... It should be noted some people also react to zinc, you can also react to aluminum if it's not oxidized/anodized though it's usually if ingested, so beware handing these then eating finger foods (and yes, you can wear through the oxidation and anodizing). Generally you want to use food safe materials. If you do aluminum you probably want 6061, it's one of the cheapest but also one of the easiest to work with and takes anodizing well. Titanium would be nice but EXPENSIVE, same with silver. Stainless Steel is actually something to consider, it's easy to machine, not too pricey and is food safe.
bronze and brass can contain lead does not mean it obligatorily does,especially if you mix it yourself, and in very low quantities lead is not dangerous, don't go make yourself a lead Popsicle but 1% lead in your keycap will not poison you, lead and mercury are fairly safe in their metallic form either way they become unsafe when they react and form salts that can be absorbed but even if the tiny amount on the surface of the cap did it would still not be enough to give you any problems, you eat more than that in fiches, and copper is fairly toxic as well either way. Zinc, aluminum, titanium, nickel and chrome all are very reactive but form a very strong and inert oxide layer, and i doubt you could wear through the anodization on the aluminum, try wearing down a ruby, and aluminum will form an oxide layer very quickly when exposed to air just much thinner than the one you get when anodizing, and stainless has a weight problem, as does brass and copper, already aluminum makes for heavy keycaps that have trouble on some switches.
vi vi vi - the roman number of the beast (Plan9 fortune)

Offline hvontres

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Re: Questions about using copper for keycaps
« Reply #9 on: Mon, 28 September 2020, 01:41:13 »
All of you are such a big help.
I am going to be using a company that 3D prints the wax and does the casting, they usually make for jewelry,  medals, and sculptures with aluminum zinc alloy, bronze, brass, copper, silver, and gold.
Its good that you guys brought up the stem and wobbly keys.  Our goal was to fix this problem by reducing the tolerance by designing the stem from the switch out, hopefully we solved this issue by designing the stem ourselves. I think as long as the 3D printer is accurate it should technically work, but I am still worried that it wont fit right.
Here are some of the dimensions, please let me know if there is anything you guys see that I should change.
It looks like your stem cuts are wider than the mount on the switch. In order for the switch to fit snugly, you need them to be a little smaller or at the most the same size. this being a metal key cap, if it is a bit too small, it will shave down the stem rather then damaging the cap. I don't know how many of these you were planning on making, but it might be good to cast the slots fairly small (probably ~1mm) and then using a small file or some emory board (nail files work well) size them by hand until the cap fits snugly on the stem. This will also help by removing any burrs or imperfections from the inside of the slot.
Another option could be to cast the stem solid and then using a slitting saw in a mill, cut the slots after the fact. But it will be difficult to hold the key while making the cuts and obviously you would need acess to a milling machine.

Good luck with the casting and post pictures once you get the finished cap.
***
Henry von Tresckow

               
1986 Model M 1390131, 1987 Model M 1391401 , 1993 Model M2 Modded Reddragon k556(work keyboard)

Offline Leslieann

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Re: Questions about using copper for keycaps
« Reply #10 on: Mon, 28 September 2020, 03:39:37 »
bronze and brass can contain lead does not mean it obligatorily does,especially if you mix it yourself, and in very low quantities lead is not dangerous, don't go make yourself a lead Popsicle but 1% lead in your keycap will not poison you, lead and mercury are fairly safe in their metallic form either way they become unsafe when they react and form salts that can be absorbed but even if the tiny amount on the surface of the cap did it would still not be enough to give you any problems, you eat more than that in fiches, and copper is fairly toxic as well either way. Zinc, aluminum, titanium, nickel and chrome all are very reactive but form a very strong and inert oxide layer, and i doubt you could wear through the anodization on the aluminum.
I've seen anodizing worn through it's tough to get poisoned by aluminum.
It's not contact that is the issue, the problem is touching it then handling your food, particularly lead, it doesn't take much when ingested.
Filco MJ2 L.E. w/hand milled Vortex case, custom feet/paint/winkey blockoff plate, HID Liberator, stainless steel universal plate, 3d printed adapters, Type C, sound dampened,  Thick PBT caps (o-ringed), Cherry Jailhouse Blues w/lubed/clipped Cherry light springs | GMMK TKL | Magicforce 68 | YMDK75 | KBT Race S L.E. | Das Pro (Costar model) | GH60 | IBM Model M (x2)

Online yui

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Re: Questions about using copper for keycaps
« Reply #11 on: Mon, 28 September 2020, 04:08:13 »
I've seen anodizing worn through it's tough to get poisoned by aluminum.
It's not contact that is the issue, the problem is touching it then handling your food, particularly lead, it doesn't take much when ingested.
you need a relatively very large amount of alumina (aluminum oxide) to poison you, it is even used in water purifying and cosmetics so that is fairly safe, and yeah if you handle pure lead or things with high lead contents i would also be worried but here we are talking up to 3.5% in brass used for fittings, the amount of lead on the surface able to be reacted will be most likely less than what you get in a can of tuna so fairly safe, the reason behind the reducing of lead contents in everything is not for the consumer, it is for the employee at the foundry who will breath in lead vapors, that are very dangerous, and the landfill where the lead will have centuries to leech into the water and reach potentially dangerous levels. So yeah lead is bad but not as dangerous as you may be lead to think.
vi vi vi - the roman number of the beast (Plan9 fortune)

Offline Mxted

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Re: Questions about using copper for keycaps
« Reply #12 on: Mon, 28 September 2020, 13:42:01 »
There's a reason most metal caps are zinc.
Bronze and brass have lead, copper is a pain in the neck... It should be noted some people also react to zinc, you can also react to aluminum if it's not oxidized/anodized though it's usually if ingested, so beware handing these then eating finger foods (and yes, you can wear through the oxidation and anodizing). Generally you want to use food safe materials. If you do aluminum you probably want 6061, it's one of the cheapest but also one of the easiest to work with and takes anodizing well. Titanium would be nice but EXPENSIVE, same with silver. Stainless Steel is actually something to consider, it's easy to machine, not too pricey and is food safe.
bronze and brass can contain lead does not mean it obligatorily does,especially if you mix it yourself, and in very low quantities lead is not dangerous, don't go make yourself a lead Popsicle but 1% lead in your keycap will not poison you, lead and mercury are fairly safe in their metallic form either way they become unsafe when they react and form salts that can be absorbed but even if the tiny amount on the surface of the cap did it would still not be enough to give you any problems, you eat more than that in fiches, and copper is fairly toxic as well either way. Zinc, aluminum, titanium, nickel and chrome all are very reactive but form a very strong and inert oxide layer, and i doubt you could wear through the anodization on the aluminum, try wearing down a ruby, and aluminum will form an oxide layer very quickly when exposed to air just much thinner than the one you get when anodizing, and stainless has a weight problem, as does brass and copper, already aluminum makes for heavy keycaps that have trouble on some switches.
If I can I will try to go with something that is unleaded however if that's not possible I am fine with trace amounts,  I probably get more exposure from soldering. I am only doing the esc, enter and spacebar so it shouldn't be that bad. Yes I am going to swap springs for the heavier keycaps, I am going to try 150g MX springs on the space bar.

All of you are such a big help.
I am going to be using a company that 3D prints the wax and does the casting, they usually make for jewelry,  medals, and sculptures with aluminum zinc alloy, bronze, brass, copper, silver, and gold.
Its good that you guys brought up the stem and wobbly keys.  Our goal was to fix this problem by reducing the tolerance by designing the stem from the switch out, hopefully we solved this issue by designing the stem ourselves. I think as long as the 3D printer is accurate it should technically work, but I am still worried that it wont fit right.
Here are some of the dimensions, please let me know if there is anything you guys see that I should change.
It looks like your stem cuts are wider than the mount on the switch. In order for the switch to fit snugly, you need them to be a little smaller or at the most the same size. this being a metal key cap, if it is a bit too small, it will shave down the stem rather then damaging the cap. I don't know how many of these you were planning on making, but it might be good to cast the slots fairly small (probably ~1mm) and then using a small file or some emory board (nail files work well) size them by hand until the cap fits snugly on the stem. This will also help by removing any burrs or imperfections from the inside of the slot.
Another option could be to cast the stem solid and then using a slitting saw in a mill, cut the slots after the fact. But it will be difficult to hold the key while making the cuts and obviously you would need access to a milling machine.

Good luck with the casting and post pictures once you get the finished cap.
***
Yes the female part of our stem is 0.1mm bigger then the male switch stem on each side or 0.05mm tolerance between the switch and stem all around.  I think that casting or CNC would be more accurate 0.05mm is thinner then human hair, I would highly likely mess up if I tried filing down or milling it is definitely beyond my human ability for accuracy.
Thanks man, I will definitely share photos on the process and the keycap when its done :thumb:





Offline hvontres

  • Posts: 91
  • Location: Oceanside, CA
  • Buckling Spring Enthusiast - Full Size Evangelist
Re: Questions about using copper for keycaps
« Reply #13 on: Mon, 28 September 2020, 13:55:49 »
There's a reason most metal caps are zinc.
Bronze and brass have lead, copper is a pain in the neck... It should be noted some people also react to zinc, you can also react to aluminum if it's not oxidized/anodized though it's usually if ingested, so beware handing these then eating finger foods (and yes, you can wear through the oxidation and anodizing). Generally you want to use food safe materials. If you do aluminum you probably want 6061, it's one of the cheapest but also one of the easiest to work with and takes anodizing well. Titanium would be nice but EXPENSIVE, same with silver. Stainless Steel is actually something to consider, it's easy to machine, not too pricey and is food safe.
bronze and brass can contain lead does not mean it obligatorily does,especially if you mix it yourself, and in very low quantities lead is not dangerous, don't go make yourself a lead Popsicle but 1% lead in your keycap will not poison you, lead and mercury are fairly safe in their metallic form either way they become unsafe when they react and form salts that can be absorbed but even if the tiny amount on the surface of the cap did it would still not be enough to give you any problems, you eat more than that in fiches, and copper is fairly toxic as well either way. Zinc, aluminum, titanium, nickel and chrome all are very reactive but form a very strong and inert oxide layer, and i doubt you could wear through the anodization on the aluminum, try wearing down a ruby, and aluminum will form an oxide layer very quickly when exposed to air just much thinner than the one you get when anodizing, and stainless has a weight problem, as does brass and copper, already aluminum makes for heavy keycaps that have trouble on some switches.
If I can I will try to go with something that is unleaded however if that's not possible I am fine with trace amounts,  I probably get more exposure from soldering. I am only doing the esc, enter and spacebar so it shouldn't be that bad. Yes I am going to swap springs for the heavier keycaps, I am going to try 150g MX springs on the space bar.

All of you are such a big help.
I am going to be using a company that 3D prints the wax and does the casting, they usually make for jewelry,  medals, and sculptures with aluminum zinc alloy, bronze, brass, copper, silver, and gold.
Its good that you guys brought up the stem and wobbly keys.  Our goal was to fix this problem by reducing the tolerance by designing the stem from the switch out, hopefully we solved this issue by designing the stem ourselves. I think as long as the 3D printer is accurate it should technically work, but I am still worried that it wont fit right.
Here are some of the dimensions, please let me know if there is anything you guys see that I should change.
It looks like your stem cuts are wider than the mount on the switch. In order for the switch to fit snugly, you need them to be a little smaller or at the most the same size. this being a metal key cap, if it is a bit too small, it will shave down the stem rather then damaging the cap. I don't know how many of these you were planning on making, but it might be good to cast the slots fairly small (probably ~1mm) and then using a small file or some emory board (nail files work well) size them by hand until the cap fits snugly on the stem. This will also help by removing any burrs or imperfections from the inside of the slot.
Another option could be to cast the stem solid and then using a slitting saw in a mill, cut the slots after the fact. But it will be difficult to hold the key while making the cuts and obviously you would need access to a milling machine.

Good luck with the casting and post pictures once you get the finished cap.
***
Yes the female part of our stem is 0.1mm bigger then the male switch stem on each side or 0.05mm tolerance between the switch and stem all around.  I think that casting or CNC would be more accurate 0.05mm is thinner then human hair, I would highly likely mess up if I tried filing down or milling it is definitely beyond my human ability for accuracy.
Thanks man, I will definitely share photos on the process and the keycap when its done :thumb:

Casting can have surprisingly high tolerances. One of the things that can bite you there is that the part will shrink in the mold, so your model will need to be about 1-3% bigger that your final size. And predicting that shrink is kind of an art. I don't know if the vendor you are talking too will take that into account when they make your wax model or not.
Also, keep in mind that it is always easier to take metal off of a part then trying to add it back in. :)
As far as the tolerances go, you would be surprised just how little metal you can take off with a fine jewelers file. I would suggest casing in undersized stem cuts and then slowly filing them open while checking against a switch stem to make sure you are getting the fit you want.

If all else fails, I have some older Hako True switches that still have the oversized Kahlih Box Stems for a tighter fit. :)
Henry von Tresckow

               
1986 Model M 1390131, 1987 Model M 1391401 , 1993 Model M2 Modded Reddragon k556(work keyboard)

Offline Mxted

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Re: Questions about using copper for keycaps
« Reply #14 on: Mon, 12 October 2020, 22:34:20 »
The factory finally sent me these dimensions and it all looks good. I put my order in today to be made in brass, I am hoping I will have something by next week.

Offline nevin

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Re: Questions about using copper for keycaps
« Reply #15 on: Tue, 13 October 2020, 08:48:02 »
excited for you
Keeb.io Viterbi, Apple m0110, Apple m0120, Apple m0110a, Apple 658-4081, Apple M1242, Apple AEK II, MK96, GH60/Pure, Cherry g84-4100, Adesso AKP-220B, Magicforce 68

Offline Mxted

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Re: Questions about using copper for keycaps
« Reply #16 on: Thu, 22 October 2020, 11:39:35 »
Update.
So the lost wax method isn't working and won't be consistent enough for me. Here is the photo from the factory lol
I have found another vendor that can make it for me with a 5 Axis CNC machine, however it is much more costly but the good thing is they have more materials to choose from, alumnimum, brass, copper, steel and titanium. Hopefully I will have something good to show soon.