Checking my soldering job.

Hey, so I’m new to soldering and I just did the connection for two of my ESC to motor cables using bullet connectors and I was wondering if someone could check my soldering?

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try sliding the silicone down with you finger stretching it, but after you reflow that joint needs more solder.


Yeah, I haven’t put the shrink wrap on it yet but I’m planning to do that too

For both wires, or the one that is more messed up?

What kind of soldering iron are you using? Those joints don’t look like they are getting hot enough for the solder to flow down into the bullet connector.

You are going to need more heat and more solder.


It’s one they have at my colleges shop.
I’m pretty sure it’s this model, 50W

I did have trouble heating it. It seemed to only heat up if I placed the solder iron tip on its side.

Looking at the temperature specifications, it should be able to get hot enough for what you are trying to do. Maybe it’s defective. Is there another iron in the shop that is available?

Yeah, I’ll try another one next time. It might have been the tip of the iron that’s a problem? It seemed really blunt compared to others I’ve seen

It could be a problem with the tip, but I haven’t experienced that before.

You can also do bullets super easy with a butane torch. Clamp just the tip of the connector or orient the whole thing upright, partially fill connector with solder under flame and without removing heat, dip fluxed and tinned cable in from above. Let it cook for a few beats and you’re golden.

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Interesting. Have to try this just for fun


An oxidized tip is usually the biggest problem with non-smart soldering irons / if you don’t care for them properly. As long as you can get a pool of solder to make contact with the hot metal part of the iron, you can still work with it, but it’s not ideal. Luckily, soldering iron tips are cheap to replace.


It’s difficult to assess the solder joints from these pics. There’s a simple test that you don’t have a cold joint.

Here’s what happens when you don’t have the right equipment or the right technique. You get the solder flowing on the connector but once you put in the wire it immediately stops flowing and the cable sticks to the connector. That’s how you typically make a cold joint. If that sounds familiar you may want to redo the soldering.

You’ll want to make sure you can move/wiggle the wire inside the connector before you remove the heat. Only then it should become solid.

It takes some practice to get it right. If you’re struggling best if you take a piece of wire and the bullet connector and solder it on repeatedly until you get the hang of it. Only then do it on the motors. I hope this helps.


Yeah, I think my problem was that the solder was to hot. I definitely had cold joints before but now I put the solder iron on the bullet connector until it melted the solder I out inside, and then I stuck my wire in.

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That doesn’t look too bad. It will probably work fine. Take it for a careful ride and then check that the connectors are not getting hot.

My first attempts on soldering motor connectors were terrible and it still never caused an issue.