Uploaded June 2026 | Updated September 2026, 3 hours ago
If you've ever taken a few bites out of an apple and left it on the counter, you've probably seen it turn brown. Oxygen in the air reacts with the surface and changes it over time.
The same thing happens to metal. The moment copper is exposed to air, it starts developing an invisible layer called oxide.
In my previous soldering video, I talked about using a small blob of solder to bridge heat into stranded wire. Afterwards, I was flooded with comments like these.
So let's talk about flux. Flux's main job is to remove the oxide layer that forms on metal, exposing a clean surface that solder can bond to.
If I use this copper wire without any flux, even with a blob of solder to help transfer heat, the solder simply doesn't want to bond. But when I add a few drops of flux, the oxide layer is disrupted and removed, allowing the solder to finally flow onto the copper.
The solder wire I have here was designed for stained glass work and contains no flux at all. But most electronics solder already contains flux in the form of a rosin core.
I'll cut a piece off, place it under the microscope and use a heat gun to heat it up. Watch closely and you can actually see the rosin bubbling out from the center of the wire. What’s left is a hollow piece of solder.
So, is flux important? Absolutely. In fact, it took me a while to find solder without it. The good news is that most electronics solder already contains flux built right into the core, so it's usually one less thing you need to worry about. You'll really only need extra flux if you're working with old, dirty, or heavily oxidized metal.
Like step by step projects? Check out the second channel! → @makethingswithrob
Become a patron! → patreon.com/makethings ←
Huge thank you to my patrons that keep this thing going!
*MAKER TEAM*
Michelle B
Keith Current
Rich Lightfoot
Tutor the Barbarian
Aubrey G.
Nukebert
Sam W.
Aaron Knows DIY
G. Salazar
David B.
Marc B.
Richard B.
Ben. K
Bill Patterson
D. Lundman
Make Things
#MakeThings #mtbitesize
If you've ever taken a few bites out of an apple and left it on the counter, you've probably seen it turn brown. Oxygen in the air reacts with the surface and changes it over time.
The same thing happens to metal. The moment copper is exposed to air, it starts developing an invisible layer called oxide.
In my previous soldering video, I talked about using a small blob of solder to bridge heat into stranded wire. Afterwards, I was flooded with comments like these.
So let's talk about flux. Flux's main job is to remove the oxide layer that forms on metal, exposing a clean surface that solder can bond to.
If I use this copper wire without any flux, even with a blob of solder to help transfer heat, the solder simply doesn't want to bond. But when I add a few drops of flux, the oxide layer is disrupted and removed, allowing the solder to finally flow onto the copper.
The solder wire I have here was designed for stained glass work and contains no flux at all. But most electronics solder already contains flux in the form of a rosin core.
I'll cut a piece off, place it under the microscope and use a heat gun to heat it up. Watch closely and you can actually see the rosin bubbling out from the center of the wire. What’s left is a hollow piece of solder.
So, is flux important? Absolutely. In fact, it took me a while to find solder without it. The good news is that most electronics solder already contains flux built right into the core, so it's usually one less thing you need to worry about. You'll really only need extra flux if you're working with old, dirty, or heavily oxidized metal.
Like step by step projects? Check out the second channel! → @makethingswithrob
Become a patron! → patreon.com/makethings ←
Huge thank you to my patrons that keep this thing going!
*MAKER TEAM*
Michelle B
Keith Current
Rich Lightfoot
Tutor the Barbarian
Aubrey G.
Nukebert
Sam W.
Aaron Knows DIY
G. Salazar
David B.
Marc B.
Richard B.
Ben. K
Bill Patterson
D. Lundman
Make Things
#MakeThings #mtbitesize
