Is this solder ruined?

Hi!

I’m trying to learn to solder and man the beginning feels very difficult!

I tried to attach my stepper motor wires to a Arduino Easy Driver and of course I ended up bridging two solder points together with one big lump of tin. I tried to scrape it off and try again. But the job is so darn accurate, and it looks pretty awful…

Can you tell from the attached picture if this solder is ruined? If it is, what should I do next?

Is it bad if the tin is touching two separate “metal lines” that run on the circuit board? Will it ruin the functionality of the board? If that’s the case, then it makes the allowed area of tin in the solder so microscopic that I really don’t understand how to do it. :frowning:

Once you have soldered a joint, the flux in the solder has burned off, so if you reheat the joint then the solder won't flow well. Get yourself a plunger-type desoldering tool (aka "solder sucker"), use it to remove the old solder from the poor joints, and remake them using fresh flux-cored solder.

Thanks I will get one of those!

In the meanwhile do you think this soldering job can be used or will I break my board if I try to go with this?

I would not power that up as is, two traces look to be shorted. You can confirm with a multimeter. Check to each other, and from each to Gnd (unless one of them is Gnd). Another thing you need is a small brush with shirt, stiff bristles, and the purest denatured alcholol you can get. I got some 99% at an electronics supply store, you may be able to find 90% or 95% at a drugstore. Use that to clean the board, should get rid of the little splatter droplets and let you see just how bad the shorting is. Make sure the board is thoroughly dry before you power it up after cleaning. The 99% evaporites quickly, the 90 & 95% not so much.

You should also look for some fine guage solder. I think I use 0.023", the smallest I could find. Very small.

Hi! Thanks for helping!

I tested with a multimeter and the two solders on the right are definitely connected.

But my friend pointed out that they seem to be connected by design (the wiring of the board seems to run to both connectors). Could it be that they are allowed to be connected (by design)?

neutrinox: Thanks I will get one of those!

In the meanwhile do you think this soldering job can be used or will I break my board if I try to go with this?

a) If soldering goes bad, don't scrape/cut/poke at it. Heat the solder up again with a soldering iron, add more if needed. When it's all liquid flip it over and whack it on a notepad (solder side down). If you're quick the solder will fly off and you can start over.

b) Maybe it will work. Check for short circuit with a multimeter.

It looks like there is just a little too much solder on the joints now, but not too much that the joints cannot be reflowed.

I use a liquid flux and often just dip the end of my solder wire into the flux, and then wipe a small amount of flux on the joints I'm going to solder. The flux will help clean the surfaces and allow the solder to flow and stick to the surfaces you are heating. Often, contamination will prevent the solder from flowing onto the surface and making it "wet" with molten solder. If the solder is beading up on top of the surface, then the surface is either dirty or not hot enough.

I would fix these joints with a small application of flux, then bring the solder tip in to touch both the circuit board "pad" and the lead of the part. Hold for a few seconds until the solder melts and flows to wet the surfaces, then draw the solder tip up and away from the end the component lead. Solder should have a natural tendency to collect and ball up when liquid and form a nice joint around the lead.

Solder will not go bad, but can become contaminated. A bigger problem is overheating the board or component. If the board is overheated, the pad and even the trace can start to lift off the board and that can be hard to fix. But you do have to heat the surfaces at least to the solder's melting point.

Can't tell from what you've posted if the traces are connected or not. I see two pins with seperate traces.

First a all, sorry for my english, it’s very bad.
It seems you have a cold soldering. Maybe you can solve it adding a litle of flux at the soldering points and heating them again until the tin flows and seems regular.
One good thing is to tin the cable first, so the tin flows better.

I don’t know if you understood me, sorry if not, my english is a little poor.

An alternative to a solder sucker is Solder wick or braid. This is copper braid that comes in a spool and you can heat up against the solder, and eventually the solder will 'wick' up along the braid (You should see your braid turn to a shiny silver), removing most of it closely not adhered to metal. I personally prefer it over a solder sucker for removing excess solder. The sucker is better for cleaning up holes, but that is personal preference.

I have a few Easydrivers sitting around. The joints you show are the four wires leading to the stepper motor and should not be shorted. If your motor is still connected you should see the coil resistance of 10 to 100 ohms across each pair. I to like desoldering braid. If you use it make sure to use flux as it will help the heat transfer through the wick to the solder and make the solder flow more readily up the braid.

A good rule for life is that where the flux goes the solder will follow.

Practice soldering on something that doesn't matter until every joint you make is good - tips:

iron must be hot enough - there is no substitute for a temperature controlled iron.

always clean and tin the iron before every joint. Wet that sponge, it doesn't work dry.

always tin wires before soldering them.

place solder between iron and the joint, so it and the flux flow over the joint.

after the solder flows add a tiny bit more.

don't move the joint as it solidifies (this will make a "dry" joint, unreliable)

Hi!

Thank you very much to everyone for responding!

I finally decided to bite the bullet and power things up. Luckily I got the stepper motor working very nicely! So I guess I can answer my original question based on this experience: the solder, while not pretty, still worked.

Jroorda, you write that: "The joints you show are the four wires leading to the stepper motor and should not be shorted."

Sorry for asking this newbie question, but when there is a path (for the lack of a better word) between two of those connection points anyway, doesn't it mean they are connected to each other by desing. For example look at the metal "paths" between the two rightmost connections. The connection most to the right has a path that forks to the connection next to it. Does this not mean they are connected to each other by design?

neutrinox: Sorry for asking this newbie question, but when there is a path (for the lack of a better word) between two of those connection points anyway, doesn't it mean they are connected to each other by desing. For example look at the metal "paths" between the two rightmost connections. The connection most to the right has a path that forks to the connection next to it. Does this not mean they are connected to each other by design?

No, there is no path between the two rightmost connections. The light red areas are the pcb traces (the paths), the dark brown areas are spaces. The solder resist on the board has prevented your solder splashes from shorting traces together.