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Bad Solder?

OmagaWright

OmagaWright

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So I got my hands on a Motley Mods predrilled kit and finally got the nerve up to work on it. When I got down to make my first solder connection (negative wire on the PWM board) my solder refused to cooperate with me. I spent a decent amount of time tryin to work the solder on the wire but it just didnt wanna solder the wire and board correctly. The solder just kept turning ashy and didnt want to turn into the silvery goo that I assume its supposed to be. Is there different types of solder or does solder go bad or something? Totally at a loss here and I really want to get this thing rollin.
 
The Cromwell

The Cromwell

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And yes solder can get old. The flux core dries out and the solder can oxidize.
This is a bigger issue on the really small diameter solder.

Use flux on the areas to be tinned. Also make sure the pad is cleaned of any coating... Gently.
Get the end of the wire well tinned and tin the pad you will solder it to then put the wire in place and heat wire with iron while pressing the wire into the place to be soldered with the iron tip.
When you see the solder flow then keep wire in place but remove iron and hold wire in place till cool. maybe 5 sec for a small solder job.
 
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OmagaWright

OmagaWright

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Thanks @The Cromwell I will pick up some new solder on my home tonight and try again. That solder must be at least 2 years old sittin in the old basement. Hopefully some new stuff will fix my problem.
 
Kitsune

Kitsune

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This probably comes a bit late, but what's your solder setup? Could be either too much or not enough heat, old solder or wrong solder for what you're doing.

Did you pre-solder the wire before soldering it to the board? That can help a lot.
 
OmagaWright

OmagaWright

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The solder I was using is about 2 years old so I went and bought new solder. When I was usin the old solder it would melt it, but then it would kinda turn ashy. Havent had a free moment to try again yet.

Now I do know about solder on wires first to prevent fraying, but what is tinning and pre tinning? Same thing I guess or is that something else to use?
 
The Cromwell

The Cromwell

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OmagaWright said:
The solder I was using is about 2 years old so I went and bought new solder. When I was usin the old solder it would melt it, but then it would kinda turn ashy. Havent had a free moment to try again yet.

Now I do know about solder on wires first to prevent fraying, but what is tinning and pre tinning? Same thing I guess or is that something else to use?
Click to expand...
Tinning a wire is to melt enough solder into it to coat the end with solder in a nice coat, not a big blob.
If the wire is tinned well and the pad you are soldering it to is also tinned just place the tinned wire end on the pad and press it down onto the pad with the soldering iron while adding a tiny bit of solder once it flows keep the wire on the pad and remove the iron.
 
OmagaWright

OmagaWright

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Thanks for clarifying that @The Cromwell

Yep, been tryin to do that and it just sorta sits there ashed up and clumpy. Not much I can do with the temp of the iron as it only has one setting, hot. Will try and give this another go tomorrow after work.
 
The Cromwell

The Cromwell

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And a small diameter rosin core solder the fat stuff will not work for ya.
Not the proper ratio of flux in the core to the solder used on a small soldering job.
 
CactusFanaticus

CactusFanaticus

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The flux makes the solder “wick” to whatever you are applying it to. What I do is first add flux to and tin both surfaces, then with a bead of solder on the iron connect the 2.
The Rosen flux will make all the difference, even if you use Rosen core you can pick it up online for cheap. Usually in a syringe tube or a needle tip dripper bottle. Also Analog BoxMods on youtube has a great how to soldering video.
 
G>O>M

G>O>M

Member For 1 Year
could also be oxidized wires

there are a few recipes online for cleaning them with white vinegar and neutralizing that with baking soda

if they are a dull dark brown they are oxidized and very difficult to solder
if they are gold coloured bright and shiny they are good to go
 
OmagaWright

OmagaWright

Silver Contributor
Member For 1 Year
G>O>M said:
could also be oxidized wires

there are a few recipes online for cleaning them with white vinegar and neutralizing that with baking soda

if they are a dull dark brown they are oxidized and very difficult to solder
if they are gold coloured bright and shiny they are good to go
Click to expand...
A good idea indeed. Bein as how the wires were prolly left open in a warehouse it could be possible, but thankfully the wires are bright and coppery. I havent had the chance or the balls to mess with this yet again, just a bit intimidated or too lazy after a 12 hour shift to deal with.

I admit though, I work on insulation copper wire ovens, and when the wire becomes oxidized from improper annealer temps it does have that dark but shiny glow to it. Even cooler when multiple paases are runnin through the oven at 300+ fpm, they turn into different colors of the rainbow.
 
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