Soldering Q:

[Directconnection]

Need some suggestions on getting the solder to hold on the wire of my VNT's engine harness. The wires I am soldering adhere greatly to the solder itself (or the other way around), but the big wire they connect to just plain won't adhere. It's like it's teflon coated. The solder I am using has the rosin in it and is part silver solder.... but I guess I need a flux. What kind do I look for? I have some flux for house plumbing water lines...

[yogurt_slinger]

get some soldering flux from radio shack. I honestly never tried water pipe solder, it *might* work.. Another thing, the wire your trying to solder might be too big for a standard 35watt iron(if thats what your using).. bigger wire, higher watt iron, especially if your talking about the larger batt and ground wires..

flux on wires,

clean tip on iron, and get some molten solder on it, it transfers heat better,

apply hot iron to flux coated wire and hold,

apply solder until you can barely make out the copper color of the wire(the bigger the glob, is NOT a better job), done.

hope that helps.

[Tony Hanna]

You shouldn't need flux with rosin core solder. It sounds to me like you either aren't getting it hot enough, or the wire is contaminated with something. Try giving the wire you're having trouble with a shot of break cleaner, then after the break cleaner has evaporated, heat it good and tin it. How big of a wire are we talking about? Maybe your soldering rig doesn't have enough output to bring it up to temp.

[yogurt_slinger]

How big of a wire are we talking about? Maybe your soldering rig doesn't have enough output to bring it up to temp.

thats what I'm thinking..

And get rid of that rosin core crap..

[Whorse]

Is it lead free solder? It needs a lot more heat and generally sucks arse.

[Skibbe]

Rosin core is fine. DO NOT use plumbing flux or any flux/solder that contains acid. It may work for awhile, and there are ways to neutralize it, but it can cause problems down the road so your best bet is to just avoid the acid.

Dirty wire and not enough heat, as mentioned already, are the two main culprits. The larger the wire, the more it acts like a heatsink. I use a 45 watt iron for most anything car related. If you're using a 25 watt radioshack jobber, that's likely your problem.

[Directconnection]

40 watt iron. Should have gone with the 150 but I thought it would have been overkill. Guess not. I'll go back to radioshack and look for some flux.

[Directconnection]

Sorry for the crappy pic...but it was dark in the garage and the battery was dying. You can see the wire I am talking about. Today, I got some flux and it almost worked...stuck a bit but once the 3rd wire was on, they all came off as one


Is there an alterantive? I am thinking some kind of crimp on the outside that crimps all the wires together, and then I can add sodler as an extra bonus.


BTW...the green and the red wires that come in from the left are part of the solderless "press" that I was talking about. No problem with those. The three wires I need to add to the black exposed wire are the ones being a beeotch and aren't in the pic.

[Tony Hanna]

That's alot of copper to try to heat up. If you keep having problems with it, you might try some crimp-on ring terminals and a terminal block.

[Directconnection]

That's alot of copper to try to heat up. If you keep having problems with it, you might try some crimp-on ring terminals and a terminal block.

That's what i was thinking of...but not sure exactly what to look for. Got a description?

[Tony Hanna]

Well, the ring terminals are easy. Any parts store should have them. Just be sure to get the right size terminals for the wires you're dealing with. As for the terminal block, you probably only need a block with 2 screws. An older chevy truck should have one mounted on the firewall if you're junkyarding. They probably have something similar at parts stores or radioshack if not. I scavenge most of my stuff off of junk cars, so I'm not 100% sure about buying them new, but I feel fairly confident that somebody sells them.
If you're in a bind, need the car, and can't find a terminal block anywhere, just run a bolt through the terminals and insulate it good with electrical tape. That's pretty ugly, but it'll do in a pinch until you find a block.
HTH,

[Whorse]

A large gauge distribution block would work, or even just getting a cheap aftermarket battery terminal and screwing one wire into each end and then taping it off.

[Skibbe]

That 8 gauge wire is what's doing you in.

Remeber that solder is meant more for fastening than passing current. You want a good physical connection before adding the solder, ie twist the wires together.

But, crimp terminals are better for something that large anyway.

[SwiftTech]

Time to break out the tourch! Just be careful not to catch anything on fire.

[Whorse]

But, crimp terminals are better for something that large anyway.

That's exactly right. You can probably buy a couple butt connectors from a car audio shop for a buck and if you don't have a proper crimp tool, just tighten a set of vice grips as tight as they go and have at it.