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Soldering 8 AWG aint fun

PostPosted: Tue Jul 27, 2010 10:48 pm
by takilara
Rant warning, need to fill some time while im charging my 5000mAh batt...

I finally received my last pieces for my TREX 600 ESP, some EC5 connectors.
(i was very unsure what connectors i should use, the batts from HK had 5.5 mm bullets (wich were impossible to find in norway, and i Truly hate soldering Deans (and they are kinda low rating anyways), so i fell down on EC5's.)

I've always liked soldering bullets, easypeasy, just pretin the wire and the bullet, then fill up the bullet and let it melt :)

however this turned out not beeing so easy with the 8AWG wire on the batt. Simply too much metal for my 48W soldering station. So i brought out the "big guns", a 100W soldering "pistol". Soon got into trouble trying to heat the bullet and the wire at the same time even with the gun.. Well time solves everything so i kept heating...

Suddenly my workspace was filled with magic smoke from the pistol. after checking the manual, i'm only allowed to have it on for 10seconds at a time, then a 46 seconds break....

Well, I was to close to completing the build to give up, so a butane soldering pen, that i never quite managed to get to work before was what i turned too..

First challenge,, how the he** do i fill it? It keeps going empty after 5 secs..,, after much cussing, i end up reading on the can,, "turn it upside down", ahhhhh

Turns out the pen is real good for this work, heats a bullet in about 3 seconds, turns the solder on fire in 5..
Some quick experiments, and i'm ready to go :) Figure out i need to refill it first, manages to overfill it so it is spewing out gas in the rear,, well well, I am really close to finished now, so i went ahead anyways, needed to watch the flame though, as it kept growing as gas percentage increased in the room..

Anyways,, with the pen it was quick work,, just try not to set anything on fire, like insulation, workbench, solder??? or yourself..

Another tip,, wear some good gloves thats not rubber coated,,, everything melts...

Well gotta go

Re: Soldering 8 AWG aint fun

PostPosted: Tue Jul 27, 2010 11:10 pm
by RCModelReviews
Yeah, copper is a great conductor of heat and heavy, fine-stranded copper wire also acts like capillary tubing so it sucks solder up like a sponge.

It takes real technique to solder that kind of wire without ending up with a mess.

Too much heat and the solder will wick right up the lead, making it stiff and promoting fracture.

Not enough heat and the solder will go cold -- leaving a length of solder stuck to the wire and a nasty rough blob on the end.

Practice (and the right tools) make perfect though.

It's a shame they don't offer decent crimp connectors -- a (properly) crimped connection is not only lower-resistance but also significantly more reliable than a soldered one. Crimps are normally required for mission-critical electrical connections in the full-size aviation industry (or at least they were when I was doing avionics work).

Re: Soldering 8 AWG aint fun

PostPosted: Wed Jul 28, 2010 4:12 am
by takilara
But then again, there would be a need for a 200$ crimping tool :)

Re: Soldering 8 AWG aint fun

PostPosted: Thu Jul 29, 2010 1:53 am
by Mr Ed
Well, I don't know about a $200.00 crimping tool or crimping to bullet connectors, but I have a crimping tool for 15, 30 and 45 amp APP connectors and will crimp an 8 ga wire on the 45 amp connector in about 5 seconds. The crimper cost me a grand total of $39.00 and I have crimped all of my connectors since I bought it. Soldering is OK, but I always liked the crimp better myself. Only problem I have found with a crimping tool is that you can't take the connector off and put it on another wire like you can with soldering. This crimper is made for APP connectors and is the ratchet type. Once you start the crimp you are committed. It's super easy to use and the only time I regretted using it was when I grabbed a 30 amp connector and put it in the 15 amp hole by mistake. Took awhile to go that thing crimped believe me. I thought I was going to have to run over it with my car for awhile there.


Re: Soldering 8 AWG aint fun

PostPosted: Thu Jul 29, 2010 4:32 am
by takilara
Hmm those connectors look nice.
Can the entire range be used with crimping? They had connectors for 120 and 180A wich would suit me perfectly..

Re: Soldering 8 AWG aint fun

PostPosted: Fri Oct 22, 2010 11:15 am
by disco stu
Bruce: your comment on crimping interests me. I have never really trusted crimped connectors, as I have had a few pull out. So for all connectors, jst, JR style etc, I normally solder (not to mention I am a stinge, who already owns a soldering iron but doesn't a crimper :D ). I also thought that a soldered connection would be capable of more current, as all around each strand would be solder with a full connection via solder on the whole available surface, if you know what I mean.

So, my thinking (as a home bodgier) is therefore in contrast to what you said (as a professional). Are you able to explain a bit more why crimping is better?

Re: Soldering 8 AWG aint fun

PostPosted: Fri Oct 22, 2010 11:43 am
by RobC
just about all motorcycle and auto connectors have been crimped for years, and the start and charge circuits take some pretty heavy currents through connectors smaller than we normaly use for EF. Your servo connectors are all crimped too. Anyone remember carrying a 12v soldering iron for field repairs in the days of soldered servo plugs? The wires were forever fracturing where the solder had wicked up them.

Re: Soldering 8 AWG aint fun

PostPosted: Fri Oct 22, 2010 7:30 pm
by RCModelReviews
If you do a search on Google you'll find out a lot more than I can tell you here but basically crimping is good because there is nothing between the connector and the wire to increase the resistance and the physical act of crimping doesn't cause the same "stress risers" that soldering does.

If you think about it -- solder isn't a particularly good conductor of electricity (compared to copper) but in order to create a soldered joint there must be a layer of solder between the two parts being joined. This means that electrically, a soldered joint has a higher resistance than a well-crimped one. With crimping, the wire and the terminal are pressed so tightly together that there's no resistance other than the resistance of the wire and the terminal itself. While this might not matter for low-current connections -- the resistance of the solder can become an issue at very high currents.

As for the physical side -- when you solder stranded wire, solder is drawn up the wire by capillary action. This means that the end of the wire becomes stiff due to that solder-wicking. Where the solder wick ends and the free movement of the strands starts there's a huge stress-riser that will see the strands fracturing with movement over time.

In a properly designed crimped connection, there is good physical support for the wire beyond the crimp point and no "hard end" to the wire itself so the stress of movement is spread over a much wider area -- hence it becomes less likely to fracture.

So, a *properly* designed and executed crimped connection is more reliable and electrically superior to a soldered connection.

For this reason, crimped joins are often mandated for safety in aviation and other areas where a failure can mean disaster.

Re: Soldering 8 AWG aint fun

PostPosted: Sat Oct 23, 2010 11:11 am
by disco stu
Thanks for that. Good to read.

Might be worth checking out some crimpers in that case. Is there a difference or will all electrical crimpers do all the typical connectors?

Re: Soldering 8 AWG aint fun

PostPosted: Mon Oct 25, 2010 1:43 pm
by Flash1940
I'm one of those hardheads that solders my connectors also. I suppose that comes from installing many rf connectors such as Pl-259....N.....BNC and the like where there is no support for the wire. There is no support for the wire when you install a bullet connector on your ESC or brushless motor. Just don't avoid using heat shrink tubing on these style connectors. The industry is in agreement on crimp-on connectors that have wings that grab the insulated wire for support. Look at those itsy bitsy servo connectors.....they have wings for wire support and should be crimped. There is room for both techniques.