DVD-61C Splicing Wires - IPC Training Home Page

DVD-61C TranscriptThe first step is to strip both the wires. The insulation that we remove should typically exposethree to five wire diameters of the stranded wire. It’s important to note that the mesh splice is theonly soldered splice where you won’t be pre-tinning the wires.If you are creating the splice inside a chassis, without access to one of the wire ends, be sure toplace the heat shrink tubing onto one side of the splice BEFORE you make the splice and start thesoldering, and keep it enough “upstream” to be away from the heat source. Also, make sure thatthe length of the tubing will cover the insulation on both ends of the splice - plus a minimum ofthree wire insulation diameters.Now, form the mesh splice by fanning the wire strands on both un-tinned wires into a cone shape.Gently begin meshing the wires together a minimum of 1.3cm, or one half inch – so that thestrands interlace evenly and are of equal length. Twist the wires slowly to restore the original layof the wire. It’s important to avoid over twisting. Let’s watch how it’s done one more time -- soyou can better understand what’s involved. Notice that conductor strands are smoothlyinterlocked for a minimum of three, but not more than five wire diameters.Once you are satisfied with the splice, it can be soldered. 260 degrees C is a recommendedstarting point, which may need to be adjusted based upon tip selection, wire size and the type ofsolder being used. First we select a soldering iron tip. Generally a medium chisel tip is veryeffective.Now, we solder the connection. Add just enough solder so it can penetrate the splice area, butleave the outline of the strands visible. At this point, we clean the soldered splice if cleaning isrequired. Then we inspect it. An acceptable mesh splice is where the solder is wetted to bothwires -- and you can still see the outline of the wire strands underneath the solder.To complete the mesh splice, we position the heat shrink tubing over the spliced area. Thenapply heat to shrink the tubing to a snug fit -- over the splice and the wire insulation.The mesh splice is considered defective if there are any sharp points or projections covered by theheat shrink tubing; if the conductor strands pierce the tubing; if the wire splice area is exposed; orif the tubing doesn’t overlap the wire insulation on both ends for a minimum of three wirediameters.Now, let’s take a look at the wrap splice. Wrap splices require a longer amount of wire tocomplete the splice. The wire should be stripped to allow a minimum of three wraps – not twists– of each wire around each other.After stripping the wires, they should be tinned. Generally, using a solder pot creates a thinner,more uniform coating. A thick coating of tinning will make it more difficult to form a goodsplice.Now we're ready to place the heat shrink tubing onto the wire. Make sure that the length of thetubing is sufficient to extend over the wire’s insulation -- on both sides of the spliced area – adistance of three times the wire insulation diameter. After shrinking, the tubing’s inside diametershould allow a snug, firm fit over the wire insulation.4