Soldering - beginners tips?

#1

hi,

so got of my a*** and sorted out some electronics components etc, so I can start playing with axoloti and some diy hardware :slight_smile:

first thing I have to do is a AxoControl from @Thonk and @Tombola :slight_smile:

anyway, so i do not make a complete mess of it and my axoloti, I'm doing some practice soldering (first time since school!) on a spare copper board. below is my attempt, Ive tested and resistance seems ok, and no short circuits, but would be happy for some advice, and to know if its 'close enough'

IMG_1093.JPG1484x1266 516 KB

ok, top right is a mess, this was 'dropped solder', and I'm really having an issue using a desoldering wick, to get off...
the wick, just doesn't seem to suck up the solder at all... ive tried putting flux on the wick as suggested on YT, but nada de nada. if I could get the wick to work, Id desolder the whole mess and do it again :slight_smile:

apart from that...
do the joints look like they have enough solder? any obvious issues?
(I suspect, I'm overheating a bit, as I'm obviously not too quick)

a couple of things I'm not clear on (from videos/guides etc):
a) they say clip the lead before soldering as after can weaken joint, but doing so means I seem to need to bend the leads more, to ensure component doesn't fall out. whereas ideally I think id like the lead to be quite vertical.
(Im using a helping hands to hold it... be careful that the clips dont damage the copper rails)

b) I thought after soldering, the solder was suppose to be visible on the top side of the board, but there is nothing.
but if i apply more solder, it seems to just be on the bottom side of the board.
is this correct, or should the solder be being sucked through?
(I think my solder has flux, as it smoke when held to the iron for tinning etc)

c) whats the best temperature to set the iron to? 700F/375C ?
(Ive tried different from 300-375C doesn't seem to make much difference)

anyway, its a lot of fun, looking forward to building some more circuits on breadboards etc over coming weeks.
(apologies in advance for dumb questions :wink: )

#2

Looks good to me. Only the one blob in the upper right needs reworking.

a: Views on this are divided. I've not heard of any real problems with cutting after soldering, and it has its advantages in ease of assembly. Even milspec soldering allow it. If you do cut after soldering, make sure the flat face of the cutter blades are facing the board. I sometimes insert the component, then pull/bend the leads slightly so that the component stays in place, then cut the leads before soldering. (Read some military soldering standards here)

b: The solder will not flow through unplated holes, and that's a good thing to avoid a mess. Through plated holes sucks the solder right through. Most solder have flux cores, and that quite rightly smokes a bit.

c: The optimum temperature depends on exactly what you're soldering. Some components have quite detailed soldering specifications w.r.t. temp and time. However, use your judgment. I use around 370C most of the time. If massive components or big ground planes suck away the heat, you might have to use a higher temp. In other situations you can use a lower temp. A too low temperature mean longer heating and bad flow and bonding, so avoid that. Basically adjust until the solder flows nicely almost immediately (put wetted iron tip to joint, wait a sec to preheat the joint, then apply the solder - it should flow nicely immediately), and don't use a much higher temp that needed for that. Your joints looks fine though, so you seem to be "feeling it", which is what manual soldering skills comes down to. With experience, a slightly higher temperature can mean quicker soldering (which is a point when you have thousands of joints to do).

Edit: Desoldering wicks and the iron-tip need to be wetted a bit, then the solder will be absorbed very well IME. Also, working the wick by wiggling/rolling the tip and/or wiggling/moving the wick slightly will help. It's important to use a high enough temperature since the wick sucks away a lot of heat. A dry iron and wick or too low temperature wont work very well. It requires a little technique to get the best out of wicks. I use both wicks and soldering pumps. The former is good for large blobs and areas, and the latter is good for more targeted work, like sucking tin from a single pin in a through hole.

#3

Those joints look OK.

You might want to invest in a solder-sucker, as an alternative to desoldering braid. I've always used a sucker, and it usually gets the job done. Generally-speaking, though, you should avoid desoldering if at all possible. It's all too easy to damage a pad or trace when desoldering, so best to spend a little extra time making absolutely sure you're soldering the right component to the right place before melting any solder. It's not like coding, when you always have an 'undo' just a key-press away, unfortunately.

Good luck with it- soldering is fun!

a|x

#4

Thanks guys,

well its all built... and amazingly it worked first time :tada: :slight_smile:

IMG_1094.JPG3264x2448 1.66 MB

in some ways it seems simpler than my tests, I guess because the strips allow the solder to flow across them, whereas this had rings so solder stayed put.
one thing of the things I learnt is some components take longer to heat before the solder flows.
( I also found clipping leads before soldering easier, as it also meant quicker to heat to solder)

the only thing I really 'struggled' with, was soldering the header pins (all 40 of them) to the axoloti core, seem to take a long time to heat before solder would flow, and even then was not as 'satisfying' as others.
the solder seem to be going on the tip and not on the pins/board... despite holding the tip firmly on pad and pin... as i had for other components.

do the header pins take a long time to heat? or is there some other 'trick' or something I could do to help it?

#5

Header pins do not take significantly more time, but the GND and VDD pads will be harder to heat up than the others, because inside the circuit board they're connected to big copper areas, and those will conduct a lot of heat away from the solder tip. It is for those things that the quality of the soldering iron makes a huge difference, a "slow" soldering iron will cool down when a lot of heat conducts away via the circuit board, and you'll have to be patient for the solder pad to reach the melting point of solder.

Yes, a good circuit board with soldermask and good plating is so much easier to solder than stripboard.

For me, solder wick does the "undo", I never liked solder suckers.

#6

A few things that I've picked up in my short time soldering.

You can never have enough flux, you can always clean it off afterwards.
Lead free solder is pain.
Don't use overly thick solder.
Your joints should be shiny and smooth.
Don't slide your braid around too much when de-soldering on a PCB, lift and replace if you need to move about.
Cheap irons with little thermal capacity can make (de)soldering a chore, especially items with large mass or on ground planes.
Take care of your iron tips and replace if needed.
A good chisel tip is way better for most jobs than the fine conical points that come with a lot of irons.

#7

Congrats on the build success! :slight_smile:

Agree on avoiding round tips. You can get very small tips with flattened sides (chiseled), which provide the best heat conduction and wetting.

If you're going to be doing a bit of soldering, consider investing in a soldering station. They hold the tip temperature well, the handles are small and light, and you get lots of tips, handles and extras. Well worth it as with all good tools.

#8

Thanks.

Yeah Ive got Aoyue 60W soldering station, I also bought a chisel tip, but then promptly forgot to fit it. (until you mentioned it) ... It seemed ok, but If I start doing a lot of soldering and notice the temperature is not stable... I'll consider replacing it with a better brand.

braid, yeah, I did manage to finally get it to work... not dragging it, is a useful tip to remember.

solder, Im using : 22SWG - Sn63/Pb 37, 2% flux

Ive got flux paste, just not worked out how to apply it, I guess i need a small brush?

#9

I tend to use a flux pen myself, but I guess a small brush would work.

#10

I use a flux pen, too, but don't find I use it much with through-hole components.

Some variety of flux is essential when soldering surface-mount components. Best not to attempt those until you've had a bit of practice with through-hole, though.

a|x

#11

What I also use when soldering is a big magnifying glass with a light under it, and the entire unit clamps to the work desk, so the area I am going to solder is extremely well lit up and the work is well magnified, this transformed me into a sloppy solderer with lots of rework, into a solderer with a lot less re-work. Oh and a secure way to clamp the work, and there are lots of ways to do this. I have a hobby vice which can be twisted into all sorts of angles.:grin:

#12

Glad you got it working! I'm really tempted to get on of these kits myself, but they seem to be sold out at the moment, sadly.

a|x