Welding Nickels

[bswinn]

No I'm not good enough to welding Nickel Alloys so stop drooling

I'm litterally welding Nickels together. It's for a Christmas present to the family. Hell all it's going to cost me is $0.25 in raw materials, but a whole hell of a lot more in practicing. Good TIG practice for small thin items.

So here's my question. In welding these Nickels together (sources say it's a 25% nickel, 75% Copper) I'm getting what appears to be maybe some oxidation on the back side?

I place the Nickels heads down in an overlap joint fashion on an aluminum plate for grounding. I juts simply juice the pedal to fuse the Nickels together. It's plenty strong for decorative purposes. Take the Nickels over to the bench grinder and with a polishing wheel and compound polish up. Where the welds are they polish up nice. But on the heads side (side facing down during welding) it polishes to a nice bright polish but in a sort of indirect light settings where the heat was it's blacker (patina maybe I dont' know).

This black area can be polished out with a small focused polishing wheel on a Dremmel tool so I have no worries about getting this project done for the holidays. My question is this: Is this black area due to the Nickel or Copper content reacting with the atmosphere? If so how in the hell do I get shielding gas to the back side of what is essential a VERY tiny plate? I can't exactly clamp the arrangement due to sizes and layout. It has to rest on something flat.

[Rambozo]

It could be from a lack of shielding or from arcing to your ground plate. There are perforated blocks to provide back shielding, and blocks with a slot for the shield gas. Probably more trouble than it's worth for this project, but something for the future.

[DaveO]

Would a grid of aluminum roofing nails do the trick? The coins rest on the points, and the nail heads provide contact to ground. The elevation could provide access for the shielding gas. Multiple contact points could reduce the arcing that Rambozo suggests.

I'm wondering if the patina may be from gunge accumulated from years of circulation boiling out of the material?

[sportbike]

If it is an arcing issue, it is likely due to the aluminum backer. Try a piece of copper.

Hit aluminum with no argon on or watch what happens when you stick the tungsten to the aluminum....black soot.

[youngnstudly]

I'm glad to hear that I'm not the only one intending to use (useless) pocket change for a purpose. Of course, my plan was to weld some copper pennies together, which would form small blocks for use as "backing" material (when welding thin sheet metal). For less than a dollar, you could make a nice block of copper that could be formed/shaped to meet whatever needs your sheet metal (or light duty) project required. They might even work to help keep something warm or preheated for a short time too...Don't mind me, just thinking out loud here.

There are perforated blocks to provide back shielding, and blocks with a slot for the shield gas.

Sorry for the stupid question, but are these perforated blocks something you would buy at a welding shop, or simply a homemade item (as I first suspected)? I'm picturing something very simple that would raise the base metal off the welding surface enough to allow shielding gas to cover the backside. Have any links or pics, or is this as simple as I think it is? I've never had the need for such a device but the idea sort of intrigues me.

[bswinn]

Thank you all for the replies. I may show my ignorance here but I don't believe it's an arcing issue. The reason I belive this is that I had arcing issues with one practice run. The nickel moved on me while lit up and when I looked there were the tell tale black soot marks from arcing to aluminum.

What leads me to believe it's a reactive issue is because this discoloration appears only on the back side, where I presume there is little to no shielding gas, and not on the front side where the arc and gas jet are.

It's a bit of a peculiarity because with light directly on it you can't see the discoloration. But turn the nickel at just the right angle and there it is, right on the back side of where the heat was applied.

If I touch heat VERY fast the nickel just starts to discolor to a blue/purple/bronze type of thing almost like steel as it's tempered or welded stainless. If you apply the heat for a fraction of a second longer than this the Nickel starts to blacken but can be polished off quickly.

[Rambozo]

Of course, my plan was to weld some copper pennies together, which would form small blocks for use as "backing" material (when welding thin sheet metal). For less than a dollar, you could make a nice block of copper that could be formed/shaped to meet whatever needs your sheet metal (or light duty) project required. They might even work to help keep something warm or preheated for a short time too...Don't mind me, just thinking out loud here.

Pennies have not been made of copper in a long, long time. That is just plating. Price of copper made a penny worth more than 1¢ quite some time ago. The core is zinc and not good around welding.

Sorry for the stupid question, but are these perforated blocks something you would buy at a welding shop, or simply a homemade item (as I first suspected)?

Both! Some welding supply shops will have them. There are also copper backers, even some with magnets, to hold them in place on steel. For open joints, sometimes just having a copper backer will trap enough argon to do the job.

http://www.sears.com/eastwood-4-and-...-SPM6316756604

[youngnstudly]

Yeah, I was aware of the pennies changing over in 1982 from copper to zinc, so I started saving the pre-1982 pennies 4 or 5 years ago. I think I read somewhere that nowadays, the cost of producing one penny is 2 or 3 cents! I weighed a pound of pennies a while back and you're correct, copper value makes those pennies worth around twice their face value. Back on track....

I will have to look for perforated block ideas on the internet. I have an idea of my own (just off the top of my head) but it's so simple that it's stupid. Possibly too stupid to work (haha)! I have seen those copper backers in the link you posted. The HVAC shop I worked for had a few laying around but they were never large enough for the jobs we were doing (they're pretty "dinky"). Plus almost none of the stainless we welded had magnetic properties which made the magnets useless.