Jump to content
CoinPeople.com

How to make clad coins?


Recommended Posts

So I was watching the History Channel. There was a show about welding. I've heard of some cool ways to weld metals together, but I never heard of explosion welding. Basically, two metals are placed in near proximity to each other. Think two gigantic sheets/slabs placed only a quarter inch apart. About 3 inches of explosive are placed across the surface of the top slab. Then BOOM! The top slab is rocketted downwards into the bottom slab and they are "zipped" together so fast that all air and oxides are expelled. The benefit of these two methods is that 2 incompatible metals (in other welding processes) can be joined. Many explosion welds are found in reactors, pressure vessels, and the like.

 

They said that the process was developed in the early 1960's and was used to create clad coins for the US mint. But since it's such a crazy way to weld, why would they waste that much energy on making coin blanks using explosion welding??

 

So what method do they use to create clad coins?

Link to post
Share on other sites

Pretty soon when all the coins are stainless steel and aluminium it will not matter. They should have made them from cupro-nickel from the get go instead of the clad coins. In a way they made it easier for people to distinguish the silver coins and remove them from circulation, adding to the then coin shortage.

Link to post
Share on other sites

Don't think The History Channel is correct on this point. While certain applications requiring a very tight bond still use explosive bonding, cupro-nickel/copper clad is produced by roll-bonding. See www.cladit.com

 

If I recall correctly, the reason for the clad was to maintain the electromagnetic properties so coins would still work in vending machines.

Link to post
Share on other sites
Don't think The History Channel is correct on this point.

 

I wasn't fully paying attention at the time because i didn't expect them to mention coin cladding (though I was thinking of coin cladding earlier in the segment). But I heard them distinctly mention early use of this method for the 1960's coin cladding. Interesting, eh?

Link to post
Share on other sites
  • 12 years later...

Sorry to all the naysayers, but explosive bonding is indeed how the start of copperclad voins started with quarters and indeed explosive bonding process was used and I was personally involved with this process. (yes, I'm that old). I was 18 and basically a swamper. But it was the most amazing thing I saw. It was done in a cave like structure away from population. I didnt see the documentary you guys are talking about, but its as factual as you reading this. RH

 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...