So, I came to assemble my first shields with the arduino - first off, soldering stackable headers on a Adafruit CC3000 wifi shield.
I didn't expect to be expert but my first attempts are, I have to say, poor. I will be spending tomorrow night trying to undo it with solder wick (I tried a desolder pump but found it impossible).
I'm using a Hakko FX-888D iron/station with 63/37 lead/tin rosin core solder. Two things you can perhaps help me with:
I set the iron temp to 350 Celcius (I read a guide somewhere). Is this too hot / cold?
the iron came with tip T18-B Shape-B HAKKO | HAKKO Corporation I found this tip to be difficult to use and somewhat large compared to the tiny pins / pads. Could someone tell me if I would be better using a different Hakko tip from their range HAKKO | HAKKO Corporation
I found myself touching the solder on the iron tip to get it to flow ... I guess this is causing me problems?
I appreciate soldering comes with practice and their are lots of guides out there. Maybe some advice on the above will really help me though.
You don't say what went wrong exactly. What problems are you having? 350°C sounds about right.
I'm more familiar with the Weller equipment but the Hakko B-shape appears to be a conical tip, and the T18-B has a 0.5mm radius, so yes that's a bit large for surface mount or smaller through-hole work but typical of tips that come on irons from the factory. I prefer the screwdriver shape tips, the Hakko T18-D08 looks to be almost identical to the Weller tip I use the most. Tip size is a bit of a double-edged sword, smaller can be easier to work with, but the tiny area at the end will not get as hot or be able to transfer as much heat.
Without more information, I wouldn't blame all the problems on the tip. Be sure to keep the tip clean. I tin my tip very frequently by applying solder directly to it and wiping it in a brass-sponge type cleaner. The tip should be shiny and wet looking, even without a large amount of solder on it. This is the key to getting it to transfer heat. Don't leave the iron on for long periods if it's not being used as this just causes the tip to oxidize. I turn mine off or at least down even if I have to pause for a couple minutes.
Keep in mind that everything has to get hot enough to melt the solder, meaning the pad and the wire for through-hole components. Ideally, apply the iron to contact both pad and wire, give it a second to heat up, then apply solder to where the pad and wire meet. Sometimes it will be necessary to apply solder to where the iron meets the work. This is OK, but apply just a little at first, give it another second to heat up the wire and pad, then apply more solder to finish the joint. You'll know when things are hot enough because the solder will flow easily and fill the via.
You're using too much solder - it shouldn't bulge outwards like that. Feed ~1mm
at a time of the solder in till the joint is fully wetted but not overloaded.
That's plenty hot enough if your iron is accurate.
Cleanliness is everything, if the board is tarnished or covered in fingerprints
clean it first. Copper is much harder to solder to than tinned copper, using wire
wool to get it clean and free of oxide is usually the first step with bare copper.
Make sure no fragments of wire-wool remain on the board though.
The most reliable way to wet a joint is to place the end of the solder between
the iron and the joint, so as the iron melts it the rosin flows all over the joint
and prevents oxide formation. Rosins job is to destroy oxide (its a reducing
agent).
When handling lead based solders always scrub your hands thoroughly clean
after working. Consider safer alternatives.
Everything sounds fine, iron, temperature and solder specs. Whether the solder specs from eBay can be believed is anyone's guess. Personally, I wouldn't use no-name solder from eBay on a bet.
I'd get some real solder. This is my favorite. New parts that aren't visibly oxidized should not require cleaning. This solder has a more active flux if needed.
For through-hole work on new parts, additional flux is not usually needed, but it's a good idea to have one of these around just in case, and I do use it a lot for SMT work. This flux is a bit more active for those tougher jobs. While you're at it, get some desoldering braid.
Don't give up. Get some solder of known quality and try it again.
Desoldering is 10x harder than soldering. Just a warning.
Use the Hakko T18-I tip for small stuff. Its what I've been using with the same Iron and I've been able to reasonably do surface mount parts with it. (Admittedly, I have a lot of experience) 350C sounds right for Leaded solder, though 60/40 might be easier to use than 63/37. Smaller diameter solder is also easier to work with.
As for simple instructions on how to solder parts, especially through-hole (Surface Mount are a little more complicated, but the principle is the same):
Wipe off the tip of your iron on a damp to wet sponge. It should not however be floating. The tip should be shiny
Place the part held firmly where it needs to go. If its a through hole part, maybe bend a few of the leads over to hold it in place (Don't do this with parts with lots of leads though, they become impossible to desolder). A good mechanical connection is essential to a good solder connection.
Add a little bit of solder to the tip, so there is a small blob, maybe 1mm in diameter or smaller.
Place the tip with the blob so it touches both the pad and lead of the part. Slowly add solder to the blob until it wicks out and covers the pad, creates a cone shape around the lead. It should also be a bit concave, unless you've added too much solder. Take the iron and solder away and investigate. Make sure you haven't bridged to another pad and your solder joint should be shiny.
For parts with a large number of pins, try to tack down corners first, as this will help you hold it to solder the rest of the pins. You can often do Step 4 without adding extra solder afterwards for an intial joint, but once you solder the other pins, make sure go back and redo the initial tacks so they are good joints.
Oscar_Zeta_Acosta:
Thanks for the help guys. So, I won't get away with leaving it as it is?
I have some desilder braid but I struggle to get the molten solder to soak into it.
You can probably get away with leaving it the way it is. I did not see any places where the solder bridged the gap between pins. The main problem with your soldering job is that you wasted solder. But practice makes perfect. Or at least practice makes you better. So I would just try to improve next time.
I'm surprised that you are having trouble with the desoldering braid. That stuff usually works pretty well.
Just put the braid on top of the solder you want to remove and press down on the braid with the tip of your soldering iron. Make sure you press down firmly, or the heat will not make it through the braid to melt the solder. And be sure to move to a new spot on the braid when the old spot has turned silver with solder.