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Old 05-28-2009
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Quote:
Originally Posted by eolon View Post
Copper is very soft and ductile so cutting through a crimped connection smears the metal and indeed makes it look like a "solid mass" of metal. A proper metallurgical inspection of a crimped connection involves slicing a section of the crimp with a microtome and looking at the surface with SEM. The interstitial spaces are always present, and can be very small, on the order of angstroms, but no amount of force can fuse copper wires into a solid mass. Unless you melt it, which I wouldn't recommend.
This is why I polished it to remove any smear. If there were enough room for water to get in you would see black dots from the very soft tripoli polising rouge stuck to the surface. Lets not forget that your spar is held up by a similar concept called swaging where the metal is compressed into a near solid mass. Perhaps we should all weld/solder our swages??

Also what is the size of a molecule of silver as in silver solder? Is it smaller or bigger than an angstrom? Considering that every reference I have seen states that crimps must be applied BEFORE solder how is it that the solder can penetrate an angstrom??
  • One angstrom unit (A.O. or Ň)= 0.1 nanometers, or one ten-thousandth of a micron (10-4 microns), or one hundred-millionth of a centimeter (1 x 10-8 cm.) One angstrom is the diameter of a hydrogen atom -- the smallest element.
If hydrogen is the smallest element how large is silver? Would it do any good to add solder to a properly crimped battery lug if it can't penetrate?

Apparently you missed the part about the NASA requirement that the crimping of pre tinned wire is BANNED. Mil Spec also states teh same. As usual the 30 year veteran electrical engineer knows more than anyone else or the collective wisdome of the entire aerospace industry or the ABYC which is made up of people/voting members, in the industry, including electricians who work on boats every single day.

I also thought that a water molecule was nearly three times the size of an angstrom making it physically impossible for water to penetrate through a proper crimp.

This is a poor crimp made with a cheap tool & cut open with the same tool. You can see wires because this is a crappy connection. Like with soldering the right tool and the right method MUST be used only it is MUCH easier for a novice DIY to make a good connection with the proper crimping tools than it is for them to do the asme with solder, hence the current ABYC standards..




Quote:
Originally Posted by eolon View Post
Crimping is a great mechanical connection, and a servicable electrical connection.
Yep and plenty servicible for NASA, the aerospace industry, US Army, Marines, Air Force & USCG, Ford, Honda, Toyota, GE and thousands of other companies who rely on billions of crimps world wide every day..

Quote:
Originally Posted by eolon View Post
Solder, especially modern, lead-free solders, are also very soft, and better yet, not prone to embrittlement.
Really so how many 30 degree bend cycles will a tinned section of 14 ga marine wire handle with and without solder? I know the answer becuase I have tested and done it before. The non tinned wire will handle considerably more than 1000% more 30 degree bend cycles than the same wire tinned..


Quote:
Originally Posted by eolon View Post
A proper solder joint fills interstitial spaces, and a proper crimped connector will deform the soldered wire and make an excellent connection.
Keep telling your self that crimping after tinning is a good idea and soon enough you might even believe yourself..

Quote:
Originally Posted by eolon View Post
I sometimes use solder joints and sometimes crimped connectors, and sometimes both.

I am simply putting in my 2cents worth of 30 years of electrical engineering, take it or leave it, as usual.
Everyone can do as they wish on their own boat as you do. Is your 30 years of EE in the marine industry?? Sometimes applying theories learned in one industry does not always pan out in another.

Take for example the many mechanical and aeronautical engineers who have been proven wrong about propeller drag. For yeas they would pontificate on helicopter blade analogies and and use "lift" arguments and in geneneral be adamant that a locked prop caused more drag. It apparently does on a helicopter but does not not when dragged through the water at 4-6 knots attached to a boat...

Quote:
Originally Posted by eolon View Post
Oh, and how about the electrical failure that roasted 3 astronauts in the Apollo project?
How bout it? It was not caused by a solder vs. crimp situation and as suggested by the NASA investigation could have been caused by perforated teflon wire insulation. This is why you need to support wires and have proper strain relief. This was more likley chafe than a connection issue unless of course you are trying to re-write NASA investigation history..


Quote:
Originally Posted by NASA
4. CAUSE OF THE APOLLO 204 FIRE

The fire in Apollo 204 was most probably brought about by some minor malfunction or failure of equipment or wire insulation. This failure, which most likely will never be positively identified, initiated a sequence of events that culminated in the conflagration.


Quote:
Originally Posted by eolon View Post
...just because all the other kids jump off the Empire State Building doesn't mean I'm going to.

Best Regards,


e

.::.
By all means it's your boat and you should do as you wish.

You need to understand that some of us have actually worked in the industry and have seen lots of solder failures, incorrectly or correctly done, it does not matter because we know the vast majority of boater CAN NOT do it correctly. No one is disputing that solder makes an excellent electrical connection, it does, but the application is the tough part.

The many, many, many voting members, of ABYC, of which one is a friend, have also seen these solder failures. There is a reason the industry suggests crimping over soldering. Just yesterday I asked the electrician at the boat yard what are his two most common electrical failures. Answer #1: Corrosion & Answer #2: Soldered joints. I also asked about crimps and he said occasionally he will see a bad one but that it was poorly done to begin with. I also aksed if he has ever seen a failure of a heat shrink crimp connection and he said yes. He then went on to describe this failure as one that a boat owner decided to hang a winch handle from in a lazarette and the ring part of the terminal broke from the swinging handle after two seasons of this. He then laughed and said .... "A real failure? No.".....

You need to know that when you make blanket statements that you will be debated so that those reading this forum can make their own educated decisions. Just because you have 30 years experience as an EE does not mean you are always right and there are many other variables that one can and should consider.
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Last edited by Maine Sail; 05-28-2009 at 11:30 AM.
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