Could I make a carabiner's pin/rivet out of copper instead of steel? 8

[panosjapan]

Hi,
I am making a carabiner which won't be suitable for climbing, but designed mainly to carry keys.

In order to achieve a beautiful contrast, I want to make the pin/rivet of the carabiner out of copper.

Would that create a problem with the longevity of the carabiner? Is copper not strong enough to sustain the everyday use of a carabiner keychain?

Best,
Panos

 

[EdStainless]

Pure Cu is too soft, and it doesn't work harden much.
Maybe you could use a brass, still has some color but more strength.

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Plymouth Tube

 

[weldstan]

Be Copper alloy would work and the color matches that of copper.

 

[panosjapan]

Edstainless and weldstan, thank you very much for your replies!

Edstainless, actually the manufacturer suggested brass because copper wouldn't work and we are making the first prototypes with a brass pin, but the copper looks so much sexier in our 3D renders that I wanted to dig deeper and make sure he's not bullshitting me.

Weldstan, that is an amazing suggestion. One that I didn't think of. Does the copper alloy have about the same strength as brass?

One side-question for both of you guys. I was also thinking of making another version with a pin made of gold. Does gold have the same limitations as copper? And if yes, is there a way around this, like weldstan suggested with the copper alloy?

Panos

 

[Compositepro]

Electroplate steel pins with gold or copper.

 

[panosjapan]

Compositepro, thank you very much for your reply.

One question: Since the carabiner is made for use as a keychain, meaning a lot of rubbing and grinding against coins and keys in the user's pocket. Will the electroplated pin's finish chip or fade with use?

 

[Compositepro]

All coatings will wear at high points. Even solid metal will wear. It a question of how long you want it to last (or look good) versus what your customer is willing to pay. Copper rivets are not unusual so it may very well work for your application. It will certainly work with a steel sleeve on the pin.

 

[btrueblood]

I'd avoid Be copper, the Be is Beryllium, which is quite toxic, and creates a higher cost for machining due to the care taken during cutting and afterwards for disposal of the scrap.

Look at alloys C18200 (chrome copper) and 145 (Tellurium copper) if you want harder, but non toxic, copper-colored alloys, and purchase them in half-hard or higher hardness.

I don't think a plated finish would hold up well, unless you could keep the head of the rivet/pin below flush with the surface. A gold color would be easier to obtain with any number of bronze/brass alloys, and hold up well to wear/corrosion.

 

[btrueblood]

Another thought - if you just care about the appearance of the head of the rivet/pin, why not use a steel roll pin (hollow tubular shape of high hardness steel or stainless steel) and pass a soft copper wire through it, then peen the end of the wire to form a rivet head that hides the roll pin under it.

 

[panosjapan]

Compositepro, I aim for a more luxury approach, in looks as well as in price, so I would say that looking good and lasting for about a year with normal use (if there is a way to quantify and define a keychain use as normal) as a successful outcome.

btrueblood, thank you for your input. Toxicity and the higher cost are very important factors that I need to take into consideration. I'll look at the alloys you suggested. Your reply is gold.

Panos

 

[panosjapan]

Another thought - if you just care about the appearance of the head of the rivet/pin, why not use a steel roll pin (hollow tubular shape of high hardness steel or stainless steel) and pass a soft copper wire through it, then peen the end of the wire to form a rivet head that hides the roll pin under it.

Besides the appearance, I do care about the longevity of the carabiner. But the suggestion is sneaky and clever and I like it. I'm not sure how much it would change the cost of manufacturing, but I'll look into it.

Panos

 

[weldstan]

Beryllium copper is extremely strong and is available in small diameter bar stock. There is very little Be in the alloy.

Gold alloys are quite soft. Gold-Nickel alloys are quite strong and are available in wire & rod. I believe that South African Krueerands were alloyed with Be to harden them.

 

[panosjapan]

Gold alloys are quite soft. Gold-Nickel alloys are quite strong and are available in wire & rod.

So, to my understanding, whenever I want to use a metal that is soft, I always look for alloys of that metal.

Thank you for wisdom, weldstan.

 

[weldstan]

Pretty much the case.

Gold-Nickel alloys most likely will be White Gold.

 

[EdStainless]

There are some gold colored alloys that have little or no gold in them.
These are usually Cu-Zn alloys (brasses) some with a little Sn and/or Ni.
Too much Zn and the alloy turns white, too little and it is red. I believe that most 'gold' ones are 12-25% Zn.
Costume jewelery and architectural details are made from these alloys. A little less Zn and bit of Sn or Ni makes them stronger and keeps the color about right.
There is brass flatware sold that looks gold, the old stuff is called Dirilyte and Dirigold, but there is new stuff also.

The other option is gold filled. This is much heavier than plating, but still doesn't use much gold.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[panosjapan]

The other option is gold filled. This is much heavier than plating, but still doesn't use much gold.

And this is the kind of alloys I need to look for. I really want to avoid plating to achieve a longer longevity and combine that with a beautiful luxurious color.

Thank you very much EdStainless, weldstan, btrueblood and Compositepro for your replies. I've learned a ton and you made my life much easier.

Panos

 

[kingnero]

I've seen similar carabiners, and they always were inscripted with something along the lines "not for climbing use".
I don't know if that's a necessity in your country, but it sure ruins the design.
Not mentioning this might possibly lead to lawsuits. I hope you have a solution for this that doesn't ruin your design.

 

[jwhit]

I will agree to some extent with btrueblood about BeCu. I worked with the stuff in pure and alloy form 40+ years ago and have lung issues to go along with that experience. Having said that, as long as the Be is tied up in the alloy and not floating free, where either inhalation or skin contact is possible, working with it should not be a problem. When I worked with it, they didn't realize or else admit that there was a contact issue with certain people in addition to the known inhalation issue, the estimate is that 2% of the population may have that extra sensitivity, which can cause slow (30-40 yrs) to develop issues. There is a blood test for it, the Beryllium Lymphocyte Proliferation test. Cause of death is more often than not, lung cancer or heart disease, which seems to accompany it. Some useless trivia to go along with the topic of using Be bearing products.

 

[panosjapan]

I will agree to some extent with btrueblood about BeCu. I worked with the stuff in pure and alloy form 40+ years ago and have lung issues to go along with that experience. Having said that, as long as the Be is tied up in the alloy and not floating free, where either inhalation or skin contact is possible, working with it should not be a problem. When I worked with it, they didn't realize or else admit that there was a contact issue with certain people in addition to the known inhalation issue, the estimate is that 2% of the population may have that extra sensitivity, which can cause slow (30-40 yrs) to develop issues. There is a blood test for it, the Beryllium Lymphocyte Proliferation test. Cause of death is more often than not, lung cancer or heart disease, which seems to accompany it. Some useless trivia to go along with the topic of using Be bearing products.

Thank you for your input, jwhit. I'll definitely keep that in mind.

Panos

 

[dwallace1971]

kingnero makes a very good point. If you're making these in the U.S. and you don't want all of your profits to fund some injury lawyer's vacation home, you might have to ruin your design with that silly warning.

"On the human scale, the laws of Newtonian Physics are non-negotiable"