why cant i solder correctly?

T2urtle

Diamond Member
Oct 18, 2004
3,432
3
81
Well i'm attempt to solder some LED in my car and i wanted to test out my soldering skills and get used to it before i do it on my car. So i had a busted headlight and i thought i should solder the wires together.

I go to solder the wires together, i place the iron on the wire to warm them up a little. applied the rosin core to the wire and place my tip right at it. It melted but the solder stuck to the tip instead of the wire what gives?

i'ved tried a couple other times and i got the same results and after a couple efforts i manage to get the solder to stick to the wire. but why doesn't it stay the first time.
 

Nik

Lifer
Jun 5, 2006
16,101
3
56
You've got to heat everything that you're soldering together, not just the solder; you may just not be getting the wire hot enough for the solder to bind to. Remember, you're fusing the two metal items together. Solder isn't like glue that just sticks stuff together. Also, you can't solder steel and aluminum together, so know what you're trying to join.
 

T2urtle

Diamond Member
Oct 18, 2004
3,432
3
81
that could be it. i didn't apply too much heat to the wire thinking i would melt/ burn up the wire.
 

TheoPetro

Banned
Nov 30, 2004
3,499
1
0
if the wires are really thin then you may actually be overheating them. I know from plumbing that when you solder something you cant get the pipes too hot or the solder wont stick.
 

Scarpozzi

Lifer
Jun 13, 2000
26,391
1,780
126
Does your soldering iron have a temp guage? Mine's digital...it helps when you want to make sure the temp is hot enough. Get the leads hot enough to melt the solder and you'll be set.

-Scar
 

Ika

Lifer
Mar 22, 2006
14,264
3
81
Use some soldering paste. Apply liberally, but make sure you clean it off. It's worked for me almost every time.
 

91TTZ

Lifer
Jan 31, 2005
14,374
1
0
Use flux.

I've done plenty of soldering and solder won't stick to a dirty joint, no matter what the temperature is.

Either get it perfectly clean, or just use flux.
 

Nik

Lifer
Jun 5, 2006
16,101
3
56
Originally posted by: 91TTZ
Use flux.

I've done plenty of soldering and solder won't stick to a dirty joint, no matter what the temperature is.

Either get it perfectly clean, or just use flux.

You should purchase solder that's got a flux core that melts/spreads as you heat the solder :p
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: GuideBot
Originally posted by: 91TTZ
Use flux.

I've done plenty of soldering and solder won't stick to a dirty joint, no matter what the temperature is.

Either get it perfectly clean, or just use flux.

You should purchase solder that's got a flux core that melts/spreads as you heat the solder :p
OP mentioned that he's using rosin core.
 

duragezic

Lifer
Oct 11, 1999
11,234
4
81
Without knowing what exactly you are doing its hard to say but you want to evenly apply heat with the tip of your iron. Lay it flat against both wires at the same time (if its a small tip you might not have enough surface area to distribute heat to the wires). If I'm doing a lap solder with two wires, I usually apply a bit of solder to the tip, place it under the two parallel wires, then about a second later (but this depends on the wire gauge) I apply solder to the top of the wires (given its a thick enough wire say 18ga or larger, much smaller its pretty much the same point cause theres not much copper between the "top" and "bottom") where it should go right into reflow and in another second pull them away and your wires should be soldered. Also you'd probably want to tin the wires. Note something like a panavise sounds very useful here, its like a 3rd hand if the wires don't stay in place on their own.
 

T2urtle

Diamond Member
Oct 18, 2004
3,432
3
81
well this was just a home experiment,

but i need to solder a connection to the rear defroster, it used to be soldered on there and i'm just reattaging the connection. I need tips on that the most.


as for my wireing. i do what i normally do when i butt connect wires. i wraped and twisted both wires. i warmed up my iron warmed up the wire a little then just place the solder directly on the wire and place the iron right over it, once it melted i lifted up on it and saw that the solder stuck to the iron instead of the wire. i just re did it and i guess i got it this time
 

Nik

Lifer
Jun 5, 2006
16,101
3
56
Originally posted by: Howard
Originally posted by: GuideBot
Originally posted by: 91TTZ
Use flux.

I've done plenty of soldering and solder won't stick to a dirty joint, no matter what the temperature is.

Either get it perfectly clean, or just use flux.

You should purchase solder that's got a flux core that melts/spreads as you heat the solder :p
OP mentioned that he's using rosin core.

I can't read.
 

91TTZ

Lifer
Jan 31, 2005
14,374
1
0
Originally posted by: Howard
Originally posted by: GuideBot
Originally posted by: 91TTZ
Use flux.

I've done plenty of soldering and solder won't stick to a dirty joint, no matter what the temperature is.

Either get it perfectly clean, or just use flux.

You should purchase solder that's got a flux core that melts/spreads as you heat the solder :p
OP mentioned that he's using rosin core.


I have rosin core solder that still does that. But the can of flux I have fixes the problem.
 

T2urtle

Diamond Member
Oct 18, 2004
3,432
3
81
^ yea i realized that now. i saw people solder it before and i guess they never warmed it up too much or i just wasn't paying attention to that part. thanks guys.
 

zephyrprime

Diamond Member
Feb 18, 2001
7,512
2
81
The oxide layer is screwing you. Use flux. Scrape the surface of the item being soldered.
 

reverend boltron

Senior member
Nov 18, 2004
945
0
76
I would get a new tip. Sometimes if you have a nasty old dull tip a new one will do wonders. Also, I recommend tinning it too, that usually helps. And there are specific ways to do proper soldering, i.e. instead of heating up the rosin core, heat up the other side of the wire and place the rosin core against that and it will get a much better connection. All depending though, you're working with wires, which is fine to do that with, not sensitive electronics though (usually).
 

grrl

Diamond Member
Jun 21, 2001
6,204
1
0
Sounds like you are soldering with the tip too hot, that will cause the solder to bead up and not stick.
 

T2urtle

Diamond Member
Oct 18, 2004
3,432
3
81
bbut i dont have control over the temp... its just a plug in pencil, no on/off switch or anything
 

Kelvrick

Lifer
Feb 14, 2001
18,422
5
81
Hopefully your not using the pointy part of the end, but the flat part. To illustrate in ascii

_\______/_
__\____/__
___\__/___
*****\*/******
*********

You wanna use the part that I spaced with "_", not the tip of it.

That, and make sure you're heating what you're soldering from one side, then touching hte solder to the other side and the solder will "flow" towards the iron.

EDIT: Oh, and did you coat the tip of the iron with solder first to prevent oxidation?