Solder wont stick to power management board

Strip very small sections for soldering. Tin them well and make the connections at 90°. Skipping pads is fine as long as they are labeled the same - they are all internally connected on the same bus.

16 ga wire is probably ok for your application if you cannot get the 14ga wire to work well, but I would prefer the 14ga if it were my project.

I also prefer the 14 awg wire. But it’s so difficult. I put some solder on the pads, and I solder the wires. Then I try to melt the solder on pct and push the wire in. But the solder on pcb solidifies too fast.

I ordered some extra boards. Have no choice but to accept failure. I will try to remove all solder from this board and use it for practice.

Tin both sides. Let cool. Place the tinned wire on top of the tinned pad, make contact with the hot iron, and add a little solder to help speed heat transfer as you heat the entire joint simultaneously. Once the entire joint flows, hold the wire in place and let it solidify.

It seems like it takes 3 hands, but with a little fixturing with an alligator clamp or locking pliers/tweezers, you can make it happen.


You need to add fresh solder before pulling the iron away. Not so much for more solder but for the flux. And as @Yuri_Rage says get some version of “helping hands”. I sometimes use small pieces of Mylar tape to holes wires in place.


I don’t have flux. I don’t know why, but they only sell the kind of flux plumbers use here. Maybe not having flux is the issue. Everyone keeps recommending me to get flux, so it must be important.

It’s critical and you can’t use plumbers flux. If you add solder to the joint you will be adding flux if you don’t have any.

If I’m completely honest, I don’t often add flux beyond what’s in the rosin core solder I use. However, it can make a big difference when soldering those big pads, especially when they are as troublesome as you describe. But don’t use plumbing flux for electronics - that’s usually not a good idea.

While I know this is a US listing, a pen like this should probably be in your toolkit if you can find one.

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I have seen on YouTube that with flux, solder kind of automatically flows over and around the wires. What happens when I try to solder is that the solder melts on top of the wire, and I have to move around the iron a lot, move up down and around the edges and corners. It makes it very hard not to bridge pads

This will often result in a cold joint. The entire joint has to melt.

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That’s basically what happens, the result doesn’t become even at all. One side melts, one side stays cold.

That’s where a larger tip helps. There’s more efficient heat transfer into the joint from the larger mass and surface area.

(I know that isn’t super helpful when you’re having trouble sourcing equipment…but it explains the recommendations thus far)

What do you think about his technique? His board is very similar to mine, I noticed he didn’t solder the pads first.

Not the worst technique. His use of flux and fixturing is very good. Applying fresh solder to the tip just prior to contact adds a little flux and helps heat transfer.

However, he runs the risk of overheating the board by failing to tin the pad, first. Not recommended.

Im going to give it one more try when I get back home. I need to remove all the solder from the board with a solder wick first though. Hope the pads aren’t damaged.

I managed to order this flux from US:

Anyone tried it before?

I also got a 70w Weller iron and bigger tips for my solder iron. 1.6, 2.4, 3.2, 4.6 and 5.6mm.

and this pen

As this flux is not “No-Clean” you should clean it after soldering. To clean it is best to use isopropyl alcohol. In digital electronics, it is necessary to guarantee that there is no type of electrical derivation, however small it may be.

That advertisement is totally bogus. Rosin flux does not leave a protective coating. It leaves a mess that must be cleaned. Find another brand…

FWIW, you need this: SMD Rework Station.. It has every thing you need and the tip temperature is adjustable. The heat gun is also adjustable and it is perfect for heat shrink tubing.

You are in good shape. The higher powered iron and larger tips along with some flux will really help.

Try both the paste and the pen flux. Use the one that works best for you.

It may be easier to clean the paste flux residue with alcohol than to try and remove any residue left by the “no clean” variety, should you choose to try cleaning despite the “no clean” moniker.

I agree with Oldgazer. A “rework” station is great, I think his link is meant to point to something like this:

Good quality solder doesnt usually need extra flux unless there is some sort of contamination. Cleaning after soldering is something you should do anyway, and probably even spray on a coating

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