Its raining out and I've been putting together a small wireing harness while in the house this morning. I got to thinking about all the discussion about the way to attach wires and connectors. Most are crimped alone, and I've seen so many failures from those connections that they would be uncountable, I immagine you've probably see a couple of hundred of them fall apart before your very eyes or corrode beyond recognition in short time yourself. Here is how I do it, as stated in an earlier post. Some folks don't like it, good for them. I wrote this up for posting elsewhere so it reads like a how to. Hope you don't mind.<br /><br />There has been a lot of discussion about the right way to make a connection between an electrical connector and a wire. Some folks suggest crimping as the only acceptable method of attachment, some prefer to solder, and some of us combine the two common methods. You often see Coast Guard regulations paraphrased as a justification for crimping as the only means of attachment but in fact nothing requires a crimp as the preferred method of connection, just the solder may not be used as the only means of attachment. There are also industry association formulated standards in place which suggest crimping alone but they have no force on anyone and in fact are primarily formulated to indicate to their members the least expensive, but acceptable, method of attachment. Is the least expensive method good enough for your work on your boat? Not on mine.<br /><br />The main argument against soldering really doesnt because of any failing of soldering itself, it a matter of the simple fact that few people solder well. Its not difficult, requiring only that you first heat the surfaces to be joined to a temperature just hot enough to melt the solder, to then apply the solder sparingly, and then to remove the heat as quickly as possible.<br /><br />My method of attachement, which Ive mentioned here and on other pages before, is to first crimp the union between connector and wire, then to solder the now-crimped connection and seal it. This is followed by the final step, which is to cover the joint with shrink fit. Here, pictorially, is how it is done:<br /><br />Step one is to strip the wire. Strip it back about 3/16 for wire of about 16~12 guage. Also, this is usually when you have to slide your shrink fit over the wire for later use.<br /><br />
<br /><br />The second step in making the joint is to prepare the fitting. Do this by removing the plastic sleeve with a pair of needle nosed pliers while holding the fitting, like this:<br /><br />
<br /><br />After the sleeve has been removed the wire end and the fitting itself needs to be fluxed. Use rosin flux, not acid flux and you wont have corrosion problems in the future. You can buy this flux at any Radio Shack. The tube you see in the picture has lasted me more than 3 years. You use very little of the flux, like this<br /><br />
<br /><br />With the barrel of the connector and the wire end both fluxed use your crimpers to make a good solid crimp. Do not crimp with such force that it distorts the connector but make sure that you have a sound connection. Tug on the wire while holding the fitting. Also, notice that if you use the type crimper that I prefer, like the one in the photo with an anvil on one jaw and a hollow on the other that you should position the connector so that if there is a notable seam in its construction that it is opposite the anvil side of the crimp. The crimped connection should look like this:<br /><br />
<br /><br />With the connector now crimped in place solder the joint. Solder quickly by applying heat to the connector, not the solder, and then allow the slightest bit of solder to flow onto the working joint. Remove the heat immediately after the solder flows. Notice that there is no charing of the wires insulation in the picture below.<br /><br />
<br /><br />With the soldering done wipe any excess flux from the fitting and wire and then seal the junction between the connector and the wires insulation. I often use 3Ms 5200 to make this seal but I also use liquid electrical tape and 3ms Scotchkote Electrical Coating (available at Lowes) as shown in the picture. Once again, as shown in the picture, very little of this material is required.<br /><br />
<br /><br />With the wire and connector crimped, soldered, and sealed its time for the final step. Slide a short section of shrink fit over the wire (in many cases you need to do this before you begin the stripping or any other earlier step). Most shrink fit will shrink down to 50% of its size when heated, so make sure you do not use a size that is too large for your application:<br /><br />
<br /><br />Finally, shrink down the shrink fit over top of the sealed, soldered, and crimped wire/connector. <br /><br />
<br /><br />As with any wire run good support is a key to longevity. I usually support wires within 3 or 4 inches of their termination and generally about once per foot along long runs.<br /><br />I know that there are people who think there are better methods than this to attach fittings to wire and I also know that there are folks who think that going to this much effort is a waste of time, materials, and consequently money. I do not agree with them and personally will only accept this level of detail in my own boat, I do the same when I work on other peoples boats. For me it is worth the time, materials, and cost.<br /><br />Thom
