So, I was going to stay out of this thread as I have been down this road in the past in other forums. But, some persons made some very good points that I wanted to touch on, while other's comments were so inaccurate that I felt their comments should be addressed/corrected.
1st, my qualifications: I'm in the professional motorsports industry and I have worked in almost all facets of motorsports from F1 and Indy Cars to Top Fuel Drag Cars and Professional Off-road racing. I have been manufacturing electronics and electrical components for the motorsports industry for over 20 years, and I continue to do so today. My training has come from both the aerospace industry and the computer industry and many many years in motorsports . I was trained how to properly solder by one of the gentlemen that built the very first computer, a 1000sqft + room full of wires and tubes that would add numbers from 0-9. And I have also been credited with establishing new design and manufacturing standards in both motorsports and the general automotive industry.
Regarding Solder vs crimp failures and their root causes;
The most reliable results will come from a complete understanding of both, and the individual performing the connection's ability to do so in a proper manner.
The more common failures that result from solder of multi-strand conductors are; Excessive Heat causing the solder to wick up the wire beyond the solder joint, Cold Solder Joints that have not properly joined the solder to the conductors, and Corrosion resulting from the Rosin. Rosin is an acid and must be removed with a proper solvent to prevent future damage to the individual conductors. If not properly removed, overtime rosin can and will cause excessive corrosion possibly leading to wire failure. The problem associated with the solder whicking is the solder eliminates the multi-conductors flexibility which induces increased stress at the point were the wire becomes rigid. Now this will normally not pose a problem in a non-moving application, but an automobile and trailer will be subjected to extensive hours and hours of movement, both low and high frequency.
The more common failures related to crimp connections are a poor quality crimp (a result of poor quality tooling (crimper)), and poor quality terminals. The cheap terminals most persons purchase over the counter at their box store and/or auto parts store should be banned from use on the highway. These two aspects are responsible for 90%+ of failures I have seen. The next common cause are from either under crimping and/or over crimping of wires.
Quality tooling whether it be the proper size solder iron and/or proper hand crimp tool along with quality terminals, and practice will significantly increase reliability for all.
Myself, I find the greatest reliability in crimping over soldering. I will not put a solder joint in a motorsports application unless there are no other options. The aerospace industry has almost completely done away with all soldering and require all crimps to be performed with a regularly calibrated Mil-Spec crimping tool. As other have mentioned, I too lace all of my harness in motorsports, but I use a kevlar lace. Also, I apply heat shrink in an application where the wire is singled out from a bundle and/or may be subjected to environmental contaminates. To prevent environmental contaminants, I use Dual Wall heat shrink. Dual wall heat shink is the heat shrink that contains a hot-melt adhesive which when applied correctly, will seal both ends of the tubing. Also, regarding butt splices, I never use butt splices, I use parallel splices. Parallel splices allow the two wires to lay adjacent to one another within the terminal, and allow for a more integral crimp and shorter splice.
Also mentioned in this thread are what many refer to as Solder Seal Terminals. These terminals are great for field splices and termination of braided shields. The terminal incorporates a low temp solder for bonding the wires, and is pre-encapsulated in a dual wall heat shrink. When you heat the terminal, the solder will bond the wires, and the dual wall will shrink and seal the connection.
Now, for manufacturing your trailer, anything that is AC powered (Alternating Current) use only UL approved components. If it is a DC application, use which ever method (solder or crimp) you have the greatest experience with as most failures are human related. But, take note of my comments above regarding root cause of failures and try to insure your terminations are proper. If you have little experience, practice makes perfect. Nobody wants to open up their trailer wall to find the broken solder joint and/or a pulled wire from a terminal.
And the pink, blue, yellow and brown Scotchloc connectors should be banned from anything automotive related. I personally believe the aftermarket car stereo and car alarm installation industry owns most of 3M's stock.
Hope this helps.
Just my 2-cents............!!!
