What solder to use

[leathermaneod]

Hey all,

I need to solder the end on my alternator cable to get a better connection. The one on the large cable that connects to the stud on the back of the alt. I replaced it in the past and did a really rough crimp and solder job with pliers and a torch. I've learned some things since and want to re solder it to get a better connection. I got a 150/240 watt soldering gun with a pretty hefty tip to use. My question is, should I use rosin core or acid core, or does it not matter? I know you cant use acid core on electronics, but I'm not sure if it matters on something bigger like this...any suggestions? When is it ok to use acid core and when is it good to use rosin?

Thanks!

[Royal Squire]

Never use acid core on anything electrical. The acid causes corrosion 

[leathermaneod]

Thats not good. I think I may have used it on this connection when I did it the first time. I have a partly used roll and I cant think what else I would have done with it. Think I should cut the end off and start completely fresh? Or just get it melted and filled up with new rosin core if it still looks clean? Why do they sell acid core at auto stores anyway? lol

[Royal Squire]

You can use it to solder holes in steel and it is used for radiator repair on brass radiators. If you have plenty of length I would probably start over. However, there are others here that are more knowledgeable about these things than I am. You might wait for more responses 

[leathermaneod]

Well I don't have plenty of length, but I think I have enough lol. I guess we'll see. I'm anxious to see what it looks like after a little over a year in adhesive lined heat shrink. If it looks totally clean I may not cut it off. But if it's corroded, I certainly will. I do welcome any and all advice though as always. I would like to get it taken care of tonight though so hopefully anyone who has something to offer will do so soon.

[Haggar]

Leather,

 

If you have just recently done it, it should not be a problem.  Wash the flux off with warm water and soap.  The problem that happens is after you are done soldering, there is still flux left around the solder area.  It absorbs water and migrates the acid around.  Acid is not really good for copper.  You should be fine if you spend some time washing it as best as you can.   Use baking soda and warm water if you want too.  It will fizzle if there is still acid around.  (similar to when you are cleaning the battery)

 

Hag

[leathermaneod]

Thanks for the replay @Haggar! I actually re did it last night before I got your reply. Turns out I had more cable to work with than I thought. Here are the before and after pics

The old end after I cut it off

I decided to go with crimping and soldering to be safe on this. Also got a marine grade terminal from West Marine. I used a hydraulic hand held crimper from Harbor Freight. If anyone has seen them, or is thinking of using one of them, just test it out first. It seems to work best if you start with a die thats a little bigger and work down to the size of your wire. Also have to turn the connector or you wind up with a big flattened out wing on each side lol. Sorry I don't have pics of that. Just make sure to practice if you use one of these tools. They are great for $50 with a little practice. Anyway

And solder to be extra safe

Then plenty of adhesive lined heat shrink, also from West Marine.

It shrank more than I wanted so I added one more piece lol

All back together

Also ended up pushing the large cable down a little more to put less strain on the smaller cable. Its really lame how short they made that...Thanks for the help everyone! Glad I learned never to use acid core on electrical stuff again.

Edited August 19, 2016 by leathermaneod

[Haggar]

Tickled you had enough wire!  That way you won't ever wonder..."did I do the right thing?...."

 

Looks super!   thanks for the info on the harbor freight crimper! 

 

Hag

[leathermaneod]

Thanks hag, 

Unfortunately, I always find reasons to wonder if I did things right haha. Like on this, I wonder if that crimp is really better than solder because it crushes the lug so much that I wonder if it weakens it at the end there right before it goes flat ya know?....makes me think I should have just soldered the whole thing with no crimp, or just a pliers crimp, but who knows. Hopefully it doesn't ever break!