Eurorack DIY & Soldering Tips

[lesstalkmoredisco]

Added in hindsight: I asked the mods to move this (semi off topic) convo to a new thread! Perhaps in the future, I or someone else can use this thread for any posts or questions regarding Eurorack DIY & soldering.

I DIY’ed a module!

Simple passive filterbank. Great kit for a first module to diy. I could’ve used a somewhat smaller soldering tip, as this kit has very little soldering holes or how they’re called. But apart from that a great first build, done in an hour I think.

PS curious to ask someone with soldering experience: if you zoom in, you’ll see half of the resistors aren’t in solder. The soldering is done on the other side. Should I ideally have used more solder so that it fills up the holes completely up till this other side of the board? Cheers!

[Markel]

If the solder looks good on one side then it’s usually fine, no need to fill up the other side I’d say!

[lesstalkmoredisco]

Thanks!

[skinpop]

Ideally the solder should flow up on both sides and adhere to the lead with that nice volcano shape. Absence of that doesn’t automatically mean anything is wrong but it could indicate a cold joint.

I had the the same thing happen to me when I started out. Try experimenting with temperature(I now use 350 degrees Celsius). Being diligent about cleaning the tip after every joint and making sure to properly heat up the lead before applying tin also makes a big difference.

[phaelam]

I think he’s talking about this…
And @Markel

Tell me to shut up if I’m wrong. I solder as well as a squirrel. [I haven’t seen leads left open, but I also know very little]

[Burpy]

I did some Befaco DIY modules, with a simple solder-iron and some patience.
Most of them worked immediatly .

Some after thoroughly investigating solderpoints and removing big solder blobs and on other joints soldering the back side to make sure both sides are connected.

@skinpop

Absence of that doesn’t automatically mean anything is wrong but it could indicate a cold joint.

One of the first things to look at if it doesn’t work in my experience

[DaGeek]

Usually there’s no need for the solder to pass on the opposite side of the PCB.
That is because usually the holes are just a little bit bigger than the components leads.
But in this picture it seems the holes are a lot bigger than the component leads. So it should be easy for the solder to flow to the other side if the soldering temperature and the whole operation is correct.
A look on the solder side may be helpful for a better idea of the soldering quality.
Looking at the image, I think the temperature was a little bit low and/or you used a pb-free solder and/or a low quality or not task specific solder.

[phaelam]

see what I’m sayin’…im a dumbass

[lesstalkmoredisco]

@DaGeek

A look on the solder side may be helpful for a better idea of the soldering quality.

It’s already soldered shut: the soldered side is in the inside of the module, so to say.

But I realize that would be best to show, when asking something like this. On the other side, all the leads were fully covered in solder like the tiny volcano shapes that were mentioned above. Hope that’s enough for now.

PS thanks for mentioning the 350 degrees, I was curious about that! (I had it set to 400…)

PS2 this also is a good tip, makes sense:

@Burpy

and on other joints soldering the back side to make sure both sides are connected

PS3 and thanks for chiming in @phaelam soldering squirrels are appreciated too

[lesstalkmoredisco]

Before doing the module I practiced on this educational soldering toy / thing. The size of the holes are different but the effect is the same: one side I’ve got the piramide solder shapes. The other side shows no solder through the holes.

Does this look ok? Or @skinpop with your remark that it should ideálly flow on both sides did you mean this, that i should try and get the solder to fill the hole more deeply?

[Lauli]

How are you liking these filters?
Thought about throwing together a cable-adapter (a 0hp module?) with a passive highpass for some basic cleanup duty, but haven’t found the right capacitor lying around yet.

[lesstalkmoredisco]

Yeah in a first playthrough yesterday it proved itself great! I used it as the only filter, and also on a broken Doepfer with only two octaves that I bought for almost free, to use with a waveshaper:) So sometimes I would still miss the tweakability of a regular filter.

But especcially when that’s not necessary it sounds great, and even has an upside of being static. I imagine using it on bass for example, and knowing it would always fit the mix when using the same passive filter.

But this is only after the first spin of course.

[skinpop]

The joins do look good on that side(might be a tad too much solder but that’s nitpicking) and 400 degrees is if anything a bit on the high side. It often happens to me that I don’t get the nice volcano shape on the other side but at least the solder will flow through.

Perhaps you aren’t heating up the pads/leads enough before applying tin? If the hole is connected to the ground plane it will suck more heat from your tip. I’m sure you already know this but you want to melt the tin on the pad, not on your tip. Solder flows to heat and if your pad is cold it won’t go through the hole.

What kind of tip are you using? A conical tip is bad at transferring heat because the contact surface area is so small. Changing to a chisel/screwdriver style tip can help a lot! I use a 1.6mm chisel tip and I find that to be a pretty good size. Any smaller and heat transfer would suffer.

Could also be the solder you are using isn’t very good. If it doesn’t have enough flux, or is no-lead then soldering would be more difficult.

Through hole can be tricky to get right. Just another reason why I prefer smd builds

[lesstalkmoredisco]

@skinpop

Perhaps you aren’t heating up the pads/leads enough before applying tin? If the hole is connected to the ground plane it will suck more heat from your tip. I’m sure you already know this but you want to melt the tin on the pad, not on your tip.

I think this is actually probably where it went wrong! Half of the time it touched my tip, wasn’t sure how wrong that was:) I think that’s exactly the solution to the problem then!

My solder should be good quality. And good to know about smd, i imagined it to be way more difficult.

[skinpop]

In practice it’s a bit more nuanced than “never touch the wire to the tip” but I think that’s a good place to start to get a feel for it. For example pre-tinning your tip slightly before applying it to the pad will also increase surface area and help heating it up faster. So yeah, just practice a lot and you’ll master it in no time!

For smd you can get cheap practice kits on ebay. Watch some videos on technique and try different approaches to find what works for you. I also highly recommend deliberately making mistakes and practicing how to fix them. You don’t want to wing it when you mess something up on your expensive module kit

SMD is nice because you don’t have to flip the board around or fiddle with leads so when you get good it’s very quick and clean. Just don’t sneeze on your components before soldering them…