HELP! Soldering "Fresh-Cut" EMax PM1806 Motor Wires

[wootler]

Short background - I've been soldering off and on most of my 60 years, so not a pro, but not a newbie to the process. On my newest project I was gonna solder the wires directly from the the Small EMAX motor to the ESC. But after cutting the wires to length, stripping back 3/16" or so, I can NOT even tin the wires. Anyone had an similar issue?

I thought maybe I could gently scrape the wire (Scary because it must be like 28 gauge or so), but still I have heated the wire beyond the point of being nervous and solder just rolls off.

Any thoughts, tricks, something??

I have searched the forum but didn't see this issue discussed.

Thanks guys and gals!

Walt

 

[dgrigor02]

Are you trying to use the lead-free solder the big box stores carry ?

 

[FlyingMonkey]

Hi Walt.

I like to use a soldering paste (make sure it's for electronics, not plumbing) for all of my soldering.

 

[Tench745]

I've heard about this somewhere. There's a thin coating of varnish on the wires. You'll have to either sand it off all the strands, burn it off, or possibly use flux.

 

[jhitesma]

Enameled wires. With really gnarly enamel. Just made the same mistake myself on an emax 1806 not realizing I was cutting down to the enameled section.

Usually manufacturers use enamel that will dissolve at soldering temps. Emax didn't. Their stuff is tough. I tried scraping it but on such fine stranded wires it wasn't make much progress.

I ended up resorting to a small jewelers propane torch and putting the ends of the wires right into the hottest part of the flame for a few seconds. It melted the plastic insulation a bit more than I had hoped, but it got the enamel. A follow up with a little bit of acetone and fine sandpaper got them to where I could work with them.

I've heard lacquer thinner may help...but I'm doubtful. M.E.K. is another solvent that I'm told may be able to get these hardcore enamels off...but it's somewhat more hazardous than most household solvents so not a great choice.

 

[wootler]

Thanks guys!

Yep, the individual wires ARE coated with a varnish (or something). Fresh stripped wires have a dark orange color. Took my time and gentley scraped the wires with an x-acto knife and they began to (slowly) brighten up and get shiny. THEN they tinned up as normal.

Tried to burn off the coating with the iron, and I think I heard faint "laughter" coming from the wires. Like jhitesma, I was afraid the insulation was gonna melt off the wire before the varnish burned off!

I did pick up a tin of flux paste (Electronics-safe) for future use. I guess it's never too late to learn something new!

Thanks again Folks!
Walt

 

[Fyathyrio]

Often this stuff is called magnet wire, the "enamel" coating can be burnt off with a soldering iron if hot enough, like over 400C, but leaves residue that contaminates the joint in my experience. Mechanical cleaning afterwards is recommended. A Bic lighter will also burn it off, but like Jhitesma discovered, you can't really control how much conductor gets exposed. Great stuff for small projects like LED lights as it's very light weight.

 

[Craftydan]

Tried to burn off the coating with the iron, and I think I heard faint "laughter" coming from the wires. Like jhitesma, I was afraid the insulation was gonna melt off the wire before the varnish burned off!

Keep in mind, the varnish *IS* the insulation.

The trick is in the timing, but so long as you direct the heat to the end of the wire, the rest of the wire coil acts like a HUGE fin, sucking heat away, cooling as it goes. Catch it as it starts to burn away and stop and the rest of the coil will never get hot enough to worry.

Then as Fyathyrio mentions, a bit of abrasion to clean out the slag is in order. a little steel or brass wool would come in handy there.

 

[wavetrain75]

Radio Shack sells a heat sink like a metal clothes pin that you can clip to the wires and help curb the melting of the insulation.

 

[jhitesma]

Radio Shack sells a heat sink like a metal clothes pin that you can clip to the wires and help curb the melting of the insulation.

Problem is to sink heat it needs to have contact with the metal of the wires. If you just put it over the insulation it will still have to pull heat through the insulation and melt the insulation in the process.

I usually grab my wires with some hospital forceps right next to the plastic insulation. That way the forceps help sink away extra heat before it gets to the plastic insulation - but in this case my wires were so short there wasn't much room to work with.

The enamel on those emax motor wires is tough tough tough. By far the hardest enamel I've had to deal with.