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2013-04-29

Crimping and saving

Cognizant of the fact that much in the way of wiring is before me, I recently made a long-deferred purchase:
In real life, it's much higher resolution.

Behold the Ancor Double Crimp Ratchet Tool. Amazon in the States was having a sale on this and even when some adhesive heat shrink tubing and marine-grade crimp connectors were thrown in, plus the inevitable shipping, it was cheaper to buy online and "foreign".

UPDATE, 2013.05.10: Having used this crimper a fair bit now, I realized that it's important to adjust the little +/- adjustment cog on the side. I had mine too much to the "plus" side, meaning I had to bear down really hard (and I am not a lightly built, stringy individual) in order to get that final "click" of the rachet mechanism that would release the crimp. I found a few notches back gave an equally serviceable crimp (visible as practically solid stranded copper in the middle of the crimp) that I could finish with one hand, and not with a three-pound mallet strike. Still haven't figured out the "release lever", but that doesn't solve the problem of a crimp setting that requires a gorilla's grip.

A bit tinny, resolution-wise


I was schooled (remotely) in the art and science of marine-wire crimping by a character known only as MaineSail, a guy who is like a one-man Practical Sailor of demonstrably good advice and real-world testing on boat repair techniques and products. This photographic tutorial, plus the premature failure of a couple of my own crimps, made me think I needed not only the right tools, but the right techniques to create reliable, strong, and corrosion-resistant crimps.

I am guilty, your lordship, but I promise to do better in the future.
Those interested in the details are encouraged to read MaineSail's excellent treatise, but the gist is this: Marine wire is tinned copper, which resists corrosion, making it last longer (but not forever!) in the terminally damp (pun intended) marine environment of salt air and inevitable splashing. You therefore want tinned connectors.

This fellow gives an introduction:



A second factor is strain relief. A properly crimped connector can support a surprising amount of weight and belies the old idea that twisting a couple of wire ends together and soldering it over (to be followed by a few wraps of Grandpa's best roll of black electrical tape) will suffice.

Look closer. That's a crimp in the middle. Photo from http://www.pbase.com/mainecruising/wire_termination&page=3
A third element is accurate wire stripping. That involves not the home handyman's method of running a pocketknife around the wire and then pulling off the insulation layer with one's teeth...yes, we've all done that...but by using a tool with dies (are we sensing a pattern here?)

Insert "I've known a lot of strippers in my time, but..." joke here.
This is the Ideal Stripmaster. It handles 10-22 AWG wire, sizes that would include the majority of boat electrical work outside of battery lugs and cables, and will strip both stranded (marine standard) and solid (house standard).  As is often the case, I found a place near me with no connection, pun suggested, to the sea or boats: an electrician's tool supply place. I find increasingly that my needs for tools and supplies are met by "industrial" concerns and not "boat gear shops". I also find if I do need something definitely marine, I poke around in professional mariners and fishermen's catalogues to find it, rather than chandleries geared toward the recreational sailor. C'est la sea.

Speaking of battery cables and lugs, they are thick and expensive things that not only vary in price with that of copper and tin as commodities, but which carry high enough currents to get seriously hot if poorly crimped or sealed. And I will need a lot of 'em for my house bank and other parts of the fairly complex charging systems I wish to use. Once again, the mind of MaineSail has produced an excellent primer on the topic, and made a case for doing the job correctly by doing it for oneself.

Like this. Photo from http://www.pbase.com/mainecruising/battery_cables&page=3
So while many sailors will have heavy crimps made by a shop or a chandlery, I am looking at buying yet another tool to "get 'er done": a hydraulic hand crimping tool:


If I had two 12 VDC batteries that I needed to link to a switch with four or six cables that required crimping with lugs appropriate to Group 27s, I would have a store do it. But I need to do perhaps 20 to 30 8 AWG down to 2/0 AWG crimps of various lugs and high-current conduit connecting L-16s or an equally large form factor of flooded battery, so a tool like this will, in fact, save me money. That's my story, anyway, and I'm sticking to it.

Because boats run electrical power (and increasingly so) in a generally hostile environment, special and generally agreed upon standards constitute best practices. The ABYC documentation (which is similar to that of Transport Canada's rules on boat wiring) on these standards may not be compelling reading unless you've ever had an electrical fire. Nor do they mention the role of anchors in crimp testing. But they do emphasize the strong correlation between a good, tight, moisture-excluding wire crimp and a safer boat where things reliably happen when switches are flipped that don't include a follow-up MAYDAY call. So scrimping on crimping is a false economy.

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