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Tinning our Magnet Wire

The magnet wire we supply is manufactured by Superior Essex, Inc. and has a single-build (single layer coating) of Superior's Soderon® heat removable insulation. This is vastly superior (no pun) to chemical removable insulations or the kind that require scraping. While Superior has many different types of heat removable insulations, we chose Soderon 155 for its low-temperature removal characteristics compared to their other insulations. Following is a quote from their Engineering Dept:

"The minimum requirements for our Soderon/155 are specified by the NEMA Standard. NEMA MW-80C requires sizes 30-36 awg to solder a maximum of 4 seconds at 390 deg. C. The requirement for 37-44 is 3 seconds maximum at 390 deg. C. Our Soderon/155 product typically will solder at least 1 second faster than what NEMA requires."

What this means for our #38 wire is that without pre-tinning, the wire can be soldered to a typical solder pad by simply applying an iron (with solder and flux) that is at least 390 deg. C (734 deg. F) for about 2 seconds and the insulation will burn back and the solder joint will be made. What could be simpler.

However...

If we did that to the solder pads on our LEDs, they'd be cooked!

The maximum temperature/duration guidelines for soldering our LEDs varies slightly between the 2x3s and the Micro LEDs but is essentially 260 deg. C (500 deg. F) for 3 seconds maximum. For this reason, the soldering procedure we recommend is to pre-tin (thereby stripping) the wire. This does three things:

We control the quality and amount of insulation removal with worrying about damaging a component with excessive heat.
We are tinning the bare copper wire in preparation for step 3 and applying a small amount of solder to the wire which in the case of the Micro LEDs, will probably be sufficient for hookup without having to use additional solder. Practice makes this process easy and allows for a clean, low-profile solder joint which is very desirable when trying to get the Micro LEDs to "snuggle up" close to objects (like lampshades for instance).
By having at least some solder on the pre-tinned wire, and having solder pads on the LEDs that are either gold plated or pre-tinned themselves, the wires nearly instantaneously bond to the LEDs when touching the wire/solder pad junction with the iron. In nearly all cases a clean iron with a very slight amount of fresh solder on the tip will make this "perfect" low-profile wet looking solder joint. Hardly any cleanup will be necessary (possibly none). You may find it helpful to add a tiny (very, very tiny) amount of liquid soldering flux to the solder pad prior to this "touching" operation with the iron. This will guarantee the instantaneous flow of solder and a wet shiny joint. Liquid flux can be obtained at about any electronics store (including Radio Shack). Follow the directions for cleaning off the flux residue. Some brands cleanup with water, some with alcohol. In either case, do the cleaning carefully and use liquid sparingly. Do not saturate the LEDs with liquid. You may find there is sufficient flux in your wire solder that you don't need the additional fluxing agent. If so, that makes cleanup a little easier. A little practice of the above and this becomes a very easy and repeatable process.

We recommend using our 12 watt miniature soldering iron for soldering our LEDs because it is closer in temperature to the guidelines doe our LEDs than most small irons (it reaches 600- 650 deg. F when up to temp.) and its ultra-small size, flexible cord and short "fingers-to-tip" distance gives the best control. When you're working with tiny components like our LEDs or N-Scale locomotive decoder wiring in tight places, these features make the difference. Having said that...

To properly tin the magnet wire a larger, hotter iron is necessary. We recommend a 18-25 watt iron which will give about 750-850 deg. F. Radio Shack as well as most hardware stores carry such irons and they're relatively inexpensive ($10-$20). Most hobbyists probably already have one. Using this hotter iron will ensure a brightly tinned wire with uniform burn-back of the insulation. Too cold of an iron requires a longer period of iron-to-wire contact. This discolors the insulation further up the wire and makes a ragged tinning job with poor definition between clean insulation and shiny tinned wire. With very little practice, it becomes a quick, simple, one-step motion to tin/strip the magnet wire.

If you're going to make several lights (or whatever you're going to use the magnet wire for), pre-cut the lengths of wire you want to tin/strip. Using a small piece of masking or double-sided tape (no more than 1/4" wide strip), stick the wires side-by-side on the tape so that about 1" hangs past the tape sticking straight out in space horizontally pointed toward you. The wires should be spaced next to each other no closer than 1/4 inch. This will prevent them from getting tangled. Have good eye magnification and lighting and adjust this "wire holding fixture" up to a comfortable eye level so it's easy to work with. You could also make a wire holding tool using a Radio Shack Smooth Clip (see Twisting wire below for details).

With your iron hot and clean (freshly tinned), touch the iron and your solder (we recommend 63/37 rosin core wire solder, Kester's a good choice), to the wire simultaneously and pull it away. You'll hear a slight "SSSSTTT" and the wire should be brightly tinned with a very defined barrier where the tinning stops and the clean (not discolored) insulation starts. You may also find that sliding the "bubble" of fresh solder on your iron tip up the wire and back will tin and strip the wire easily. The key is a little practice to find what is easiest for you. It doesn't matter how long the tinned portion is (1/8" to 1/2" is fine), because you'll trim it to the length you need at hookup time. This part is covered in LED wiring tips.

Too much heat and solder

It may take several attempts before you get the "rhythm" and resulting consistency, but it's easy once you've tried it a few times. What we're looking for here is a definite "line" where the tinned wire becomes the insulated wire. This ensures us that when we position the tinned portion over a solder pad and solder it in place, insulated wire is leaving the other side of the pad. That way there will never be a chance of shorting to an adjacent pad or wire. When you dealing with these small components and wire, good clean soldering jobs ensure reliable connections that will work after everything's assembled and not fail later.. Enough said. Try it, it's easy and you'll like the results.

Good tinning with clean transition to insulation

Twisting magnet wires

Unless you're going to be running four #38 wires inside the .018" tubing, or "hiding" the wiring in cracks and grooves in structures to make the disappear, we think you find that twisting the wire pairs makes them much easier to handle. Also, if your doing external "old-fashioned" wiring, pole-to-structure wiring or hanging lamp wiring, the twisted (then painted) wires look great.

Here's a simple method to get uniform twists in virtually any length of wire pairs (or more than two), without kinks or breakage. Go down to your local Radio shack and purchase a pack of #270-373 1-1/8" Smooth Clips. These are copper (possibly copper plated) alligator clips without the teeth. they're cheap and plenty in a pack. From your scrap brass rod bin, cut two 4" to 6" lengths of 1/16 diameter rod (slightly smaller diameter is OK). Crimp one end in the crimp portion of a Smooth Clip and solder it in place. Do the same with the other rod and a second clip. Cut small pieces of electrical tape and stick them to the smooth jaws of each clip (or you can use shrink tubing). This will provide a simple cushioned jaw.

Cut the magnet wires you're going to twist to approximate length leaving them a little longer (twisting shortens the overall length slightly). Place the ends of a pair of wires side-by-side (not overlapping) in the jaws of one clip with 1/2" to 1" protruding out the back of the clip. Clamp that clip in your bench vise so the wires are pointing toward you.

Carefully place the other wire ends in the second clip's jaws. Pull the second clip toward you until there's just a slight tension on the wires, just enough to keep them straight. Start spinning the clip with the rod in your fingers while keeping slight tension on the wires and you'll see the twists forming evenly along the full length of the wires. Don't over-twist them, but sufficiently to get the appearance you're after.

f you're planning to pre-paint the wires prior to tinning/stripping the ends and soldering them, just place the clip you had in your fingers in another vise or holding fixture and dip a brush in the color you want (we recommend acrylic paint here) and slide the brush up and down the wire to give it an even coat. Let it dry and remove the finished product. Nothing to it!

General handling of magnet wire

The insulation on our magnet wire is quite durable considering its thickness is only about .0003" on average. It will standup nicely to most normal handling so you can work with it with confidence. If you feel you may have nicked a section or kinked it unnecessarily, cut that portion off and throw it away (or use it for N-Scale 3/4" cabling somewhere). It's not worth the risk of an electrical short or broken connection to try to fix the possible damage. Keep the wire clean and make sure your hand a oil-free when handling it so that if you wish to paint the wire you'll get good, even adherence. That's about it.

Last modified: May 31, 2007