Connection of VERY short nichrome wire?

I have a VERY short piece of 32 gauge nichrome wire that I want to connect to 2 copper wires. When testing, I have connected them like on the picture, using tweezers and a pair of pliers. But I really need to find a more professional and durable way of doing it.

It's important to keep as much as "free" nichrome wire as possible in the middle. I don't want to waste all the length inside a butt crimp, or wrapped around the copper wire.

Is there a tiny, minitature terminal somewhere, that only steals 1-2 mm of the nichrome wire? Or am I wishing for something impossible?


Picture of Connection of VERY short nichrome wire?
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Downunder35m5 months ago

When I have to work with the stuff I prefer thin copper tubing.
The kind used for the temp control in fridges or if available (on the scrap) even thinner stuff.
Crimps easy enough and is able to fit the connecting wire as well for an even better connection.
Usually I only need 2-3mm long pieces and use a small nail to "clean" the hole with a slight tap on either side.

karolina81 (author)  Downunder35m4 months ago

I'm about to try this method soon but I wonder which is the correct way of crimping the copper wire? 1, 2 or another way? Could you tell me?

coppercrimp.JPG

With these tiny copper tubes it does not really matter much if you have the right crimping tool.
Those for normal ferules like used by electricians are fine if big enough.
Otherwise these hexagonal crimping tools are just great for this as they really compress all empty space around the wires.
IMHO it comes down to how and how much the system is used.
If all is installed with no possible movements and a slight allowance for heat expansion (for example by coiling the nichrome wire) then even a simple wire cutter does the job if you compress in 2 or three spots.
Method 2 is prefered if you don't have the proper tools although I prefer to wrap the copper wire around the nichrome wire as well for a few turns.
Gives better contact and allows for the use of simple tools.
Method 1 is only good if you have the correct tools and can make sure the copper tubing is fully compressed around both wires.

steveastrouk5 months ago

I'd go with capacitor welding too, easy and very repeatable. You don't care that its a very short piece mechanically, only electrically, so you COULD just solder it, with the right fluxes.

Don't bother soldering as there won't be anything that sticks or stays solid at high temps.

Not given the highly transient nature of what she's doing. I doubt the ends would warm up before the charge goes off.
seandogue5 months ago

Yes, there are, but they're not all that easy to get a hold of. Many of the crimpable pins for mil style and aviation grade connectors can be used, allowing one to reuse the feed wiring and simply replacing failed sections of nichrome.

Another solution (is probably not one you want to entertain) is by drilling a hole through the threaded section of a screw so that the nichrome and feed wire can be pinched using a nut or pair of nuts

I've used both methods in the past. I don't recommend the twist-tie method as it generally produces poor continuity. Same goes for trying to solder a joint. Nichrome resists soldering fiercly.

(the other things about aviation/mil-grade pins and sockets is that unless one has access to bind of varying sizes to find the one(s) that work for them, it's difficult to judge which one to get based solely on distributor info.)

PS as reference, I spent 10 years directly supporting combustion research at NASA low gravity facilities during the 1990s and over a ~ten year period went though hundreds and hundreds of feet of nichrome and similar igniter wire supporting the various experiments we served.

iceng seandogue5 months ago

Cool as in Heat Hot...

As a rankin pack rat who never threw out left over pins, I have such material pins in a great manny gauges.

Jack A Lopez5 months ago

There exist machines for making very tiny welds, like for thermocouple junctions, or for welding metal tabs onto battery cells.

Often the energy source for the weld is a charged capacitor. In fact this gizmo might be called, "capacitive discharge spot welder".

Both professional, and amateurish, home made, versions of this tool exist.

Probably the best way to learn more about this thing, is to ask Youtube about

"capacitive discharge spot welder", or "welding battery tabs", or "welding thermocouple junctions"