DIY DC motor Trouble 7th Grade Science Fair

[wparkera]

Hey All,
I have been working in our school's new innovation lab, teaching the kids how to reproduce small dc motors that i have been designing for a few years.

the first real complication that I am facing is with the soldering of the coils of magnetic wire to the commutator.

I purchased sheets of pure copper, and the solder just doesn't want to stick. I realize that I should probably leave photos with my explanation, but I left the motors at the school.

I am wondering if anybody has any advice about make a connection for a magnetic wire to a thin strip of copper.

A video i discovered online recommended sanding the copper sheet down to a light pink which I will try in the morning. But I'd appreciate any and all ideas,
as I can't really afford too much of a delay as we plan to resume work on Tuesday.

it look just like this motor in the photo attached except that I used copper for the commutator.
Thanks in advance!

 

[gophert]

First, magnet wire has a polyester or polyurethane coating so it must be scraped, sanded or otherwise removed.

second, Thick sections of copper metal conduct heat EXTRMELY well. You'll need a bigger, higher wattage soldering iron to warm up a spot. Solder doesn't flow and "wet-out" a copper surface until the copper
- is hot enough.
- free from corrosion (sanding or use of solder flux help
- good quality solder (some all tin solders are more difficult to work with and don't wet-out well)
- clean solder tip (oxides on solder tip contaminates the melted bead os solder snd makes a powdery interface between melted solder and copper surface so the melted solder beads up). Change your solder tip, wipe/twist your solder tip across a damp sponge EVERY TIME you pick it up before you make a solder joint. The steam will remove the crusty bits.

 

[wparkera]

thank you thank you. I did know about the wire coating thank goodness or i'd have had no chance, but i'll try some of these things and get back to you! thanks

 

[wparkera]

in terms of the flux, would you recommend covering the terminal of the commutator with it? I've never used it and am watching some videos to try and figure it out. thanks again

 

[gophert]

in terms of the flux, would you recommend covering the terminal of the commutator with it? I've never used it and am watching some videos to try and figure it out. thanks again

I would use a q-tip and apply a thin amount right where I need it.