WIRING – HELPFUL HINTS
It is the middle of winter and you are busy working on your latest project. The construction is progressing nicely and you have visions of how nice it will look on the water this spring then it hits you the wiring of the motor, battery, speed control and sound effects has to be done soon. For some, (such as me), this is a task that is enjoyable, for most, this is an event to be despised. Either way, it is one of those efforts that should be done right the first time so that it does not have to be done again in the future.
As we all know, electricity and water do not mix. When our wiring and electrical/electronic equipment get wet, many undesirable things happen. The least of which is the problem of corrosion and the worst is a short circuit leading to fatal damage to the equipment. Therefore, we need to consider proper protection. This article will deal with the proper handling of wiring to prevent corrosion and inadvertent shorting. A future article will cover the water-proofing of the electronic equipment.
First, lets look at soldered connections. Before we worry about water-proofing the connection, take the time to make sure it is a good solder job in the first place. Before soldering, did you make sure the parts, (wire, connector, splice or whatever), were good and clean? Bright shiny surfaces are what you want to start with. Did you also flux the parts and use a good quality solder? The flux chemically cleans the parts and keeps them from oxidizing as the heat is applied. Using old oxidized solder is just asking for trouble. Solder is cheap, there is no sense in using old solder to save a dollar.
Once you have finished soldering, take a look to make sure all the joints are smooth and bright. A lumpy or dull surface is an indication of a cold solder joint. If you see this, re-heat the joint and apply a little more solder. Once soldered, the joints should be water-proofed. The best way to do this is with a conformal coating. This is a clear spray intended to seal electrical connections and in many cases entire pc boards from the atmosphere. It is specially formulated to burn away with the heat of a soldering iron should you ever have to re-solder the joint. This spray is usually available from electrical/electronic supply centers. If you can’t find it, let us know and we can get it for you. A poor mans substitute is clear lacquer spray. This works well and I have used it often. The choice is up to you but I strongly recommend the coating of the connection. This is the best defense against corrosion.
Another protective measure is heat shrink tubing. This should be used whenever possible as it serves three (3) purposes: The first is as a guard against water. By covering your solder joint with heat shrink tubing, any water splashed on the wiring will be deflected away. This is very important if you elected not to put a conformal coating on the joint. The tubing also protects against scuffing and abrasion and serves as a strain relief. This material couldn’t be easier to use. As the name implies it is tubing that shrinks in the presence of heat. Generally, the tubing shrinks to about 1/2 the original diameter and remains at this size when the heat is removed. The heat from a soldering iron, flame (lighter or match), or hair dryer is all that is needed. In use, select the smallest diameter tubing that will fir over the area you are truing to protect then cut a piece that is about 1/2” longer that the area to be covered. Slip the tube into place, heat it up and watch as your nice shiny solder joint is completely encased and protected.
The one thing that must be remembered is to make sure that you have a way to get the tubing into place after the soldering is done.
By this point all soldering is done, the connections water-proofed and protected by heat shrink and you think you work is done. I suppose it is, but there is one further step to be considered. Have you ever tried to troubleshoot a wiring problem when the wiring harness looks more like a rats nest than a harness? Do yourself a favor and neatly bundle the wiring. Once bundled, hold everything together and in place with cable ties (tie wraps). You will be amazed at how easy it is to sort out a problem when everything is neat and organized.