I'm repairing a Jenn-Air oven (model W130W) for a friend. The oven elements were not getting warm. I was lucky enough to find the problem but I'm considering ideas about how to make a repair.

As you can see in the photos, one of the spade lug terminals has failed. What you can't see well is that the the male part of the terminal (on the thermostat) is still in decent shape and I think I can just polish it with a wire wheel on my Dremel. The female part on the wire is in better shape than the photos show, but the spring clip parts of it are shot. There's almost nothing left to hold the two flat plates together. So right now it's almost like I have two male connectors.

Any ideas? I don't have crimping tools, so I'm a little reluctant to cut off the old connector from the wire to replace it with a new one.

 

I don't think you can use the existing connector.
The non-ratchet crimp tools aren't expensive or in extremis you could squeeze with pliers and then solder the connection.

 

I have faked plenty of 1/4" spade crimps with a gentle hand and medium size wire biters. Whaddaya call them? Diagonal cutters?
If the current is pushing the limits, I solder them after crimping.
In this case, I carry 30 amp contactors in stock. I guess you don't.

 

I have faked plenty of 1/4" spade crimps with a gentle hand and medium size wire biters. Whaddaya call them? Diagonal cutters?
If the current is pushing the limits, I solder them after crimping.
In this case, I carry 30 amp contactors in stock. I guess you don't.

Current is definitely an issue since this appears to carry power to the elements.

So the wisdom here is to cut off the old female connector from the wire and apply a new one, possibly with soldering in addition to whatever crimp I can manage?

 

possibly with soldering

Definitely with soldering. Any connection that has fried from IR failure must be treated with every possible advantage to insure reliability...and sometimes it still fries again.
That's why I carry spare 30 amp contactors.

The surface damage on the male connector is almost impossible to renew perfectly because the coating metal is gone.

 

Once again, NEVER solder a crimped connection. If you don't have a crimper, get one. I don't think that this is a failure due to IR radiation - my guess is that the original crimp (or connector) was not up to snuff. There is evidence of arcing and a good crimp should not ever arc.

 

Definitely with soldering. Any connection that has fried from IR failure must be treated with every possible advantage to insure reliability...and sometimes it still fries again.
That's why I carry spare 30 amp contactors.

The surface damage on the male connector is almost impossible to renew perfectly because the coating metal is gone.

Got it. I'll tin the wire and the connector before I assemble them, and then solder afterwards.

These look right? They are actually rated "high temperature" but they also look better than most.
https://www.comfortgurus.com/terminals/132437-diversitech-fh32.html

 

Once again, NEVER solder a crimped connection. If you don't have a crimper, get one. I don't think that this is a failure due to IR radiation - my guess is that the original crimp (or connector) was not up to snuff. There is evidence of arcing and a good crimp should not ever arc.

By IR I think @#12 meant ohmic heating.

Why not solder?

 

Soldering a crimped connection basically undoes the benefits of crimping. This is because the solder is going to wick up the wire. Not a little, but a lot! This produces a region where the lack of flexibility will break the wire after a few flexes.

 

Why not solder?

Soldering a crimped connection basically undoes the benefits of crimping. This is because the solder is going to wick up the wire. Not a little, but a lot! This produces a region where the lack of flexibility will break the wire after a few flexes.

What he said. Soldering adds nothing to a good crimp - however, it does subtract on the reliability and life of the crimp.

 

Soldering a crimped connection basically undoes the benefits of crimping. This is because the solder is going to wick up the wire. Not a little, but a lot! This produces a region where the lack of flexibility will break the wire after a few flexes.

While what's you've said is quite true, it only applies to parts where motion is applied. e.g. a CNC machine, or automotive wiring. In this case, this is an oven, and the cable itself does not move, nor is it subject to vibrations. Soldering the wire to the lug/spade/terminal maximizes the conductor's contact area, and that's of great benefit.

 

These look right?

Oh yeah. Those are the fat ones.
If you need a right angle connector, that's the way to go, but they are most un-cooperative for a crimp, unless you have exactly the crimping tool that places that connector at the end of the squeezy jaws. The cheap $5 crimpers will have the crimping notch in the middle of their length and tend to bend the slide-on part of the connector. Then it doesn't have the spring tension right and you will probably solder it just because the crimp is so ugly that you know it's not right, and the shape is wrong for adding a strain relief device like shrink tubing. I think you don't need a right angle connector, but you're the one who can see the actual layout.

As for wicking a lo-o-o-ng way up the wire? I'm sorry some people can't solder any better than that, and I'm sorry they don't know about strain relief, but this wire is going where it will never move for the rest of its life...not even a wiggle. What if you skipped the crimp connector and soldered the wire directly to the male spade? Some people would still say you're wrong because of flexing...which ain't gonna happen. You can even use zip-ties to make sure the wire never moves again! Why do you think wiring harnesses were invented? To hold the wires still!

the lack of flexibility will break the wire after a few flexes.

I call BS. I have soldered crimps in a furnace 30 years old and they are still working like the day they were born. I have soldered RCA jacks on my stereo and they are 40 years old with no problems, and the stereo has been moved half a dozen times in 40 years.

 

So the wisdom here is to cut off the old female connector from the wire and apply a new one,

Yebbut...you have to look out for oxidation running up that wire when it got hot. If the strands are ugly, replace the wire, too.

I rape old air conditioners for their parts. I have a gallon bucket full of wires with 1/4" ends on them. Lotsa colors, lotsa lengths, lotsa diameters. I will not hesitate to replace the whole wire and both ends if the strands took damage during the melt-down.

 

I considered soldering to the male lug but I don't know anything about it's ability to take the heat. That thermostat is likely an expensive part and I don't want to risk it.

The wire looked ok at first blush but I won't know until I cut it. I'll back up the wire as far as I need to. I have no desire to try to solder to oxidized wire.

Strain relief is irrelevant in this application, other than not connecting it with built in strain.

And you just reminded me to check my parts bin for a connector. I've harvested them for years so maybe I've got the right thing already.

 

I considered soldering to the male lug

Don't. I was using a stupid example to illustrate a stupid point.

 

This produces a region where the lack of flexibility will break the wire after a few flexes.

How often are people in there flexing the wiring? I've repaired more bad crimped connections on wires than bad solder connections. But then, that was when we were using 60/40 solder.

 

How often are people in there flexing the wiring? I've repaired more bad crimped connections on wires than bad solder connections. But then, that was when we were using 60/40 solder.

Fragile connections have more to do with the type of cable used than to what type of connector of soldering/crimping technique was used.
Usually it's the cable that's the most important, and it's related to how many fibers it has, and what their caliper/diameter is. And if auxiliary fibers were used and how. Such as if there's cotton or nylon fillings, and if they're located at the center or perimeter of the wire.

Normally all wires that are connected to a lug or terminal are not subject to dynamic bend exactly where they meet, but rather at a point further down where they go through some sort of grommet or strain relief component.

 

@cmartinez while I agree with everything you said, that still does not justify not soldering that connection in the picture. The failure point of that connection was the focus point. I know it's not nice to assume things, but at some point, one must assume some form of baseline knowledge.

 

Strain relief is irrelevant in this application, other than not connecting it with built in strain.

One interpretation of, "strain relief" is about fastening the wire down so it can't flex between the fastening point and the electrical connection, a la' cable clamps. Another interpretation is the military style loop fashioned between the last cable clamp and the electrical connection. Just mentioning these in case they might be options you could use, or, strain relief isn't just some shrink tubing right behind the crimp.

 

@cmartinez while I agree with everything you said, that still does not justify not soldering that connection in the picture. The failure point of that connection was the focus point. I know it's not nice to assume things, but at some point, one must assume some form of baseline knowledge.

Right... if it's any help to this conversation, what I do when I use a terminal that's supposed to be crimped, is I both crimp and solder it. But I only use solder at the tip of the cable and the front of the terminal, so as to avoid the situation that @djsfantasi just described. That way you get the best of both worlds.

The reason why I do that is because I've worked with automated crimping machines, and I know that manual crimping techniques (even when using the proper tooling) will never have the same quality.