Complete Beginner to Soldering about to try a Repair

Thread Starter

PokeyMongo

Joined Jul 25, 2020
8
I just want to post these pictures here first and ask if this is something I should actually try or is it going to be too much trouble for me? This is a wire that came off of its joint and the old solder looks dirty to me. IMG_0900.JPG
 

MrChips

Joined Oct 2, 2009
21,648
Welcome to AAC!
Take another photo so we can see a bigger picture.
What is the device?
Where is the red wire supposed to be connected?
 

dl324

Joined Mar 30, 2015
11,251
Welcome to AAC!
something I should actually try or is it going to be too much trouble for me? This is a wire that came off of its joint and the old solder looks dirty to me.
It should be easy to reflow the solder to reattach the wire. Use some rubbing alcohol to clean the residue from the solder. Ideally you would remove the solder and attach with fresh solder, but reflowing should work because the detached wire is tinned. If it wasn't tinned, a little flux would help.

solder.jpg
That's a good example of how not to solder. There's way too much solder on the top two joints.
 

jpanhalt

Joined Jan 18, 2008
10,082
It loooks to me like more than a wire came off this joint:
1595713698852.png

That looks like raw PCB is showing. No solder will stick to that.
Recommendations:
1) Practice soldering on some scrap.
2) Clean up that "mess" with solder wick. It may be a plated through hole.
3) Check the other side.
4) If both are true, I suspect you have no way to test electrical continuity between the sides.
5) Remove a little of the solder mask (green paint-like coating over the PCB traces) near the hole on both sides.
6) Insert a piece of tinned/plated solid copper wire (22 - 32 AWG is fine).
7) Cut it pretty short ( I sometimes just squish it in a pair of vice grips, then cut)
7) Bend it over the cleaned trace on each side and do your best soldering.

Special tinned copper rivets are made for that purpose, but for a one-time repair, it is not worth buying 100.
 

Thread Starter

PokeyMongo

Joined Jul 25, 2020
8
Wow thanks for all the great replies.

Welcome to AAC!
Take another photo so we can see a bigger picture.
What is the device?
Where is the red wire supposed to be connected?
This is a shower AM/FM radio. The black wire is meant to be attached to that last little brown smudge which is last in line of those four points.

I'm going to try cleaning with alcohol then I'll post another picture to see if there's a better clue of whatever damage might be done.
 

dl324

Joined Mar 30, 2015
11,251
I'm going to try cleaning with alcohol then I'll post another picture to see if there's a better clue of whatever damage might be done.
It doesn't look like there's any damage to the wire or pad. It was likely just a bad solder joint and the wire pulled away from the solder.
 

MrChips

Joined Oct 2, 2009
21,648
Ok, I see it now. The black wire came off solder joint.

Step 1 - Plug in 25W soldering iron and allow it to heat up (10 min).
You know the iron is ready if the tip of rosin core solder for electrical work melts easily.

Step 2 - With solder in one hand and iron in the other, bring both together at the board joint so that a tiny bead of solder melts and flows over the pad (3 sec max). You should have created a nice dome of old and new solder.

Step 3 - Without any delay, drop the solder in pick up the black wire and position it on top of the solder done, while melting the dome with the iron (3 sec max). Remove the iron but hold the black wire steady without any movement. Blow hard on the joint (2 secs). Done.

(This is a quick repair job by DIY person soldering for the first time. We do not normally do it this way.)
 

Thread Starter

PokeyMongo

Joined Jul 25, 2020
8
OK, so good news is the repair itself works. My radio has been saved and it works again. Very happy with that!

The job itself was something else. I had to solder an extra wire after I accidentally picked up the case by one half and not the other, which stayed behind. The soldering itself didn't take long but I was not ready for the solder to stick to the iron so stubbornly. It had to be very carefully wiped on, and it took a lot of new solder over and over again until it worked. I wish the solder would have just flowed over the pad like we hoped but it refused.

I bought a cheap soldering kit on Amazon and I want to blame crappy solder it might have came with. Is that a thing? The package says %2 flux. As I understand it this is supposed to make it flow better. Here's a link to kit I bought: https://www.amazon.com/gp/product/B01712N5C4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

IMG_0908.JPGIMG_0905.JPG
 

Dodgydave

Joined Jun 22, 2012
9,313
It's a 60W temperature control iron, if the solder is sticking then increase the temperature with the dial, use the solder sucker to remove the old solder , then put fresh solder one it..
 

MrChips

Joined Oct 2, 2009
21,648
If you are new to the art of soldering with a brand new soldering iron then the first thing you need to do is to practice on a piece of old electronics board. You need to know your solder. All solder are not the same. Some need a temperature of 700°F and others need 800°F in order to melt. Know what was used on the PCB and what you have at hand.

Here are my 10 tips of soldering:

1) Firstly, note that solder for electronics has a hollow core that contains rosin in the core. Slice the solder with a sharp knife and examine the center core. There is no need for external rosin in most cases.

2) Set the temperature of the iron correctly so that the solder melts when brought to the tip of the iron.

3) Thin the soldering iron. (Read about this on the web.)

4) Dismantle some components off a scrap PCB. Use solder wick to remove excess solder. Clean the pads with solder wick.

5) Practice remounting the same components (resistors and capacitors) back into the same PCB.

6) Learn to use the minimum amount of solder and time.

7) Read up on what makes a poor solder connection and a good solder connection.

8) Learn other tips for proper soldering, for example, how to splice two pieces of wire together.

9) Learn how to care for your soldering iron.

10) Practice, practice, practice.
 

dl324

Joined Mar 30, 2015
11,251
I bought a cheap soldering kit on Amazon and I want to blame crappy solder it might have came with. Is that a thing?
No. It's more likely your technique. None of the joints looks very good. If the solder has lead, the joints should be shiny with a concave profile.

What's up with all of the solder splatter? That shouldn't happen unless you had water or something involved.

If you want a better iron, buy a used one on eBay. I picked up a good Weller for about 2X what you paid for that cheap thing on Amazon. New, the Weller would sell for $100-200.
 
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Thread Starter

PokeyMongo

Joined Jul 25, 2020
8
No. It's more likely your technique. None of the joints looks very good. If the solder has lead, the joints should be shiny with a concave profile.

What's up with all of the solder splatter? That shouldn't happen unless you had water or something involved.

If you want a better iron, buy a used one on eBay. I picked up a good Weller for about 2X what you paid for that cheap thing on Amazon. New, the Weller would sell for $100-200.
Yea like I said, the solder didn't draw itself to the area where the joints are supposed to be, it drew itself to the iron. I had to wipe it off onto the joint the way you would wipe off a booger from your finger onto a napkin. What you think is splatter is just the product of that wiping process. I didn't have the space for an optimal wiping angle, so some of the solder went places it shouldn't have.

It's a 60W temperature control iron, if the solder is sticking then increase the temperature with the dial, use the solder sucker to remove the old solder , then put fresh solder one it..
So you're saying the problem could be that the iron wasn't not enough for the solder to behave ideally? Or is the purpose of increasing the heat only to remove the old solder?
 

dl324

Joined Mar 30, 2015
11,251
So you're saying the problem could be that the iron wasn't not enough for the solder to behave ideally?
The temperature needed depends on the solder being used:
clipimage.jpg
clipimage.jpg
clipimage.jpg

Even though the melting temp for the leaded solders is under 400F, temperatures of 600-700F are commonly used. I use 700F for just about everything so I don't have to change tips. My iron is a W-TCP (modified to be a W-TCP-L) and tip temperature is determined by the tip.
clipimage.jpg

Also important is the thermal mass of the tip. If it's too small, it will lose heat too quickly. If it's too large, you start burning things up if you let the iron linger too long.

Or is the purpose of increasing the heat only to remove the old solder?
The heat melts the solder. It doesn't matter whether you want to reflow, remove, or apply new.

Regardless of the type of solder that you're trying to remove, adding a little more fresh solder often makes removal easier.
 

MrChips

Joined Oct 2, 2009
21,648
Besides knowing your solder, learning about the rosin is important.
Solder without rosin does not flow easily.
When working on an old solder joint, add fresh solder to the old joint as you try to melt it. The fresh rosin in the solder will do its trick. If you work the solder for too long you will burn off all the rosin. Discard old solder from the tip by wiping it off on a slightly damp rag or sponge. Add fresh solder with rosin to your renewed joint.
 

dl324

Joined Mar 30, 2015
11,251
@PokeyMongo If you're interested in a better soldering iron, there's a W-TCP on eBay for $30 (buy it now, not an auction), plus shipping.

The iron alone is $100 new. A heating element is around $25, and tips $3-10. Listing says the low voltage cable has 3 nicks. Didn't say whether it had been tested, but used implies functional.

https://www.ebay.com/itm/Weller-Soldering-Station-Model-WTCPL/274443034720?hash=item3fe6146060:g:L9EAAOSwMk5fIY8P

Note that they mention WTCPL; which it isn't.

I'd buy it myself if I didn't already have more than enough.
 

jpanhalt

Joined Jan 18, 2008
10,082
Buy a new tool with temperature control. It may be $150 versus $50 (you will need a new tip), but you won't regret it. Tools are capital. I still use a soldering iron that is more than 50 years old -- actually probably dates back more than 60. I bought my temperature controlled iron in 1993. It's still going strong.

It's not worth the risk to go used on something so relatively inexpensive. Besides, buying new means replacement parts will be available longer in all likelihood.
 

djsfantasi

Joined Apr 11, 2010
6,713
Before you start worrying about rosin, solder type or iron temperature, make sure your technique is proper.

When you say that the solder sticks to the iron instead of the joint, my first thought is that you haven’t heated both sides of the joint sufficiently. For example, when soldering a through hole component to a PCB, both the component lead and the PCB trace must be hot enough.

Place the iron tip at an angle so that it touches both the lead and trace. Hold it there for a few seconds to heat up both sides. My iron needs a count of three to accomplish this.

Then, apply the solder to the joint of the lead and trace. DON’T apply the solder to the iron tip. There should be no solder on the iron.

If done properly, the solder will flow into the joint. It will “tent” with concave sides. There will be no blob. The spaces in the joint will be filled.

Check the image following.

38232B53-D195-48C7-B8DB-06A07836D050.jpeg
When done, wipe excess flux and solder off the tip with a damp cloth or sponge. Every so often, melt some solder an the tip, to re-tin it, and wipe as before.
 

Thread Starter

PokeyMongo

Joined Jul 25, 2020
8
Before you start worrying about rosin, solder type or iron temperature, make sure your technique is proper.

When you say that the solder sticks to the iron instead of the joint, my first thought is that you haven’t heated both sides of the joint sufficiently. For example, when soldering a through hole component to a PCB, both the component lead and the PCB trace must be hot enough.

Place the iron tip at an angle so that it touches both the lead and trace. Hold it there for a few seconds to heat up both sides. My iron needs a count of three to accomplish this.

Then, apply the solder to the joint of the lead and trace. DON’T apply the solder to the iron tip. There should be no solder on the iron.
So would it be effective to move the iron away the same moment that you apply the solder? Or is the iron supposed to be resting nearby while the solder is melting to the joint? It's hard to picture touching both ends of the joint with the iron and applying the solder while it still sitting there without the solder just going to the iron. There really isn't enough distance at least in the case of this repair.
 
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