So I have the regular hakko chisel tip. I'm good at soldering but surface mount has never been done. When you were first starting out with electronics how would you go about soldering this? Can it be done with simple rosen core solder and the iron? Or do I need to glue down the really small parts on the right (to help as a beginner)?
This kit wasn't terrible expensive and I don't even remember ordering it I think I clicked by mistake and it showed up at my house. But I don't want to fuck it up.
The youtube tutorial videos I have seen all seem to use hot air guns but I don't have one.
Image has a 31 ga 3mm needle a 30 cal bullet and a penny for scale. Those little SMA caps look scary small.
As far as the too small to see aspect:
I will be getting this awesome 32" wide screen (Almost 4k resolution) video screen magnifier that sits over a X Y axis sliding table and you can adjust colors; B+W; optical and digital zoom; change to invert colors; invert B+W. You can read any color code resistors with it; even ones on blue bodies because you can enhance the colors. You can snap grid lines on the picture too and does UV light and filters. Some how you can see through the pages of a book with it (XRAY vision!
) It does more stuff like take pictures that I didn't get to play with while testing today. It costs a lot(!) around $5-6k I think but I think its worth it as a family member is paying for it as an early xmas present. It will be a while until I get it but I'll be sure to make a thread and brag about it.
The capacitors look like 0805 which is huge ( see
https://www.eevblog.com/forum/beginners/soldered-0805-vs-0603-vs-0402-vs-0201-vs-01005-vs-008004-today-)/msg1134443/#msg1134443 )
Ideal way is indeed solder paste + heat air gun.
You will still do very good with solder paste + soldering iron.
You can get by with resin core wire + soldering iron. I would recommend flooding the pad with liquid flux, holding down the component with tweezers and touching one terminal at a time with soldering iron tip with decent amount of solder on it.
As an aside note, its good practice to blunt the tips of needles if you're using them for chemical dispensing onto stuff you're working on. Otherwise guns and drugs paints an interesting picture.
Using a bullet for a scale reference in electronics is a new one for me... and in Australia is of little help.
Ideal way is indeed solder paste + heat air gun.
You will still do very good with solder paste + soldering iron.
You can get by with resin core wire + soldering iron. I would recommend flooding the pad with liquid flux, holding down the component with tweezers and touching one terminal at a time with soldering iron tip with decent amount of solder on it.
This is my advice also.
The first thing you will learn is that even the "huge" 0805 packages will dance along your PCB and bench at the slightest excuse - and surface tension will make them respond like neodymium magnets. You are going to need something to hold them in place while soldering. If you are concerned about using metal implements, then a long toothpick is an option.
The next is - DON'T drop them. You will never find them unless you are working on a plain, smooth, light coloured surface - and even then it's a "maybe". Carpet is a black hole.
For the SMD ICs, tack solder ONE end pin, check alignment, reheating and correcting as required, tack solder the other end pin on the same side then drag solder the opposite side and finally return to drag solder the first side.
See
EEVBLOG #186, for detailed methods.
There are hundreds of "smd soldering" videos out there. You should be able to find out all about the various ways to do it. Then focus on "smd hand soldering" if that's what you aim to do.
Vision equipment is helpful, but these parts are big enough that it's not necessary for most.
I have much better luck using a toothpick to put (very) little dabs of solder paste on the pads on my board and then the parts, and then simply heating it up on a hot plate until it melts, and then turning it off.
Get yourself a couple of dental instruments with tiny tips. Also, get some gluetack or funtack. Put the tiniest piece of gluetack in the middle of the SMD mount. For the soc-8s use a bucket tip and drag is along the pins. It takes a little practice. For the other smds, tack one down with gluetack, and use the dental instrument to put a tiny bit of flux on the ends and solder pads. Hold the part with a tweezers also. Solder and tweezers in one hand, iron in the other.
No hot air required for most smd work. You need an appropriately sized tip though.
As an aside note, its good practice to blunt the tips of needles if you're using them for chemical dispensing onto stuff you're working on. Otherwise guns and drugs paints an interesting picture.
HAHA. Just things I had lying near by. Most American TV shows compare size to football fields so those caps are about 0.00001 football fields long. You can actually see blood in the tip of the needle. I have to take medication with them so I clean the old ones and use them for gluing and dispensing chemicals.
I do a lot of SMD assembly of quadcopter flight control boards with 0.5mm pitch QFN and 0805, 0603, 0402 passives - huge stuff
I started out with a Polyimide stencil and a PID controlled toaster oven which I love but for expediency I have been doing a lot with paste and hot air. I also use a toothpick and apply a very small amount of solder paste which also tends to hold even the passives in place. Gently heat with hot air until it reflows. Too easy and fix any bridging with a good liquid flux and drag soldering technique. I have used paste and iron for passives and legged IC's but QFN cannot be done like that.
So it looks like solder paste kapton tape and a small tip is in order. Or wait fr my magnifier to come.
No hot air required for most smd work. You need an appropriately sized tip though.
normal tip can do the job, just not as nice as in the video..
Buy some solder wick before you start, you will need it.
Buy some solder wick before you start, you will need it.
Not just *ANY* solder wick. It needs to be fresh good quality wick
(Chemtronics is one of several respected brands), and fairly thin and narrow if you want to clean up SOIC IC joints with good enough control that you don't have to re-do the whole side. Heavier wick is better when you have removed a part and have a lot of pads to clean and level. If you buy a larger reel, *DO* *NOT* touch the wick with your bare hands before use, dispense it onto a smaller working spool, ideally the soft plastic type that covers the coiled wick apart from the working end, and keep the main reel in a sealed bag, as it will tarnish easily due to fingerprints and atmospheric contaminants, which render it nearly useless. That dusty reel of wick you may have inherited from your grandpa is probably *WORSE* than useless.
You'll also need extra flux - I prefer pure liquid Rosin (R) in IPA, and aren't fussy about the brand as long as it dries to a hard light amber residue, but many like gel flux: e.g. Louis Rossman recommends Amtech NC-559-V2 Tacky Flux (genuine, not fake crap off EBAY shipped from China).
When wiping a pad, initially apply pressure with the bit *WITHOUT* movement, then wipe away from the track with virtually *NO* pressure. Use extra flux, and always clip back the used stiff part of the wick, leaving a short stiff end with the remaining stiff part no larger than the face of your bit. This initially solder saturated section gives you good initial heat transfer so you don't cook the pad off the board, which can happen if you try to heat a pad with a dry bit through a dry wick.
That was way easier then it looks. I just taped the IC down put a lot of gel flux on each side and wiped the solder iron down the side with a drop of solder on it. The flux makes it so that the solder doesn't stick where its not supposed to. I thought I was going to have to solder each individual pin one by one. I haven't tried to do the caps yet but it seems like you just put a solder blob on one side tape down heat then solder the other side. Hardest part is reading the numbers on the chips.
IMO you can do a lot of stuff that you'd expect to be impossible if you can actually see what you're doing. A good optical aid (microscope) will go a long way. As you're probably discovering, you can often get away with a bigger tip than you'd think.
Hot air has a lot going for it, but be wary of blowing other parts off the board - get in, do the job and get out again.
IMO you can do a lot of stuff that you'd expect to be impossible if you can actually see what you're doing. A good optical aid (microscope) will go a long way.
I totally agree. Once I got a good optical microscope and could actually see what I was doing, my results are much better and now I am confident doing down to 0402 on double sided boards.
But don't try this with a USB microscope - the latency is far too long.
0805s seemed intimidating to me at first too, but once you develop some strategies, it's really doable. No need for magnification either, though that might help when it comes to smaller sizes.
0805s seemed intimidating to me at first too, but once you develop some strategies, it's really doable. No need for magnification either, though that might help when it comes to smaller sizes.
I'm just having trouble with these caps going to try super glue in a syringe; the CA- stuff that's like water . Hopefully it will flow through a 31 ga needle.
I sent one flying and thought I was crewed until I noticed a black speck on my flux gel tip. It was the part about 5 feet away from where I flung it out.
I'm just having trouble with these caps going to try super glue in a syringe; the CA- stuff that's like water . Hopefully it will flow through a 31 ga needle.
I sent one flying and thought I was crewed until I noticed a black speck on my flux gel tip. It was the part about 5 feet away from where I flung it out.
I don't use glue. My method with regular SMD parts is to tin one pad. After tinning that one pad, I add some flux to that pad and put the part on top of both pads with tweezers in the place it should end up. This is the only time a wayward part could escape. A brief touch with the soldering iron remelts the tin. It should cool quickly and afterwards, the part is stuck in place. Now you can do the second pad at your leisure.
It's basically what you would do with something like a QFP. Fixating first, soldering it in place after. It's just that the after is only the other pad, rather than many pins.
You don't need glue for SMD passives, flux the pad, hold the passive with tweezers and touch with the iron tip....tacked. If you have the iron set too hot it won't hold bugger all solder that you need to wick into the joint. Solder other end....just don't dwell too long on it as the heat will transfer to the tacked end and melt the solder there too. Touch the first joint again...done. Bent end tweezers I hear are best but the straight fine stainless non-magnetic ones I have work fine.
Eyesight can be a issue but a simple Optivisor works well for most without the expense and hassle of additional magnification.
I never needed hot air until wanting to do SMD rework, then it's a must !!
I just spent about an hour soldering 4 caps on. Only to realize I soldered the wrong value. I did use super glue with water out f another syringe to activate it. But that takes just as long. Fuck this. The chips were fun this is tedious without magnification. I am just going to clip the leads real short of through hole parts and use those. It just one of those 30$ ebay scopes and I might have a chip up side down but no way to get it off so all could be for nothing. The flux wipes of the lettering on top and this one chip has no dot.
You can get flux core solder as small as 0.3mm diameter, and its certainly worth having some small diameter solder (<0.5mm) of the same alloy as your regular solder or solder paste when you are dealing with small passives and discretes and need to add a controlled amount of solder to a pad or joint quickly to avoid cooking the pad off the board or remelting the tack-joint at the other end.
Without suitable diameter solder, there's more fiddling around, and the risk of pad damage or is much higher: If the solder wire is too thick, its very hard to control and you often end up with excess that has to be wicked off, and paste is problematic when using an iron because you have to preposition the right amount, and its very hard to control how much ends up on the pad or joint and how much on the bit, so you are lucky if its right in one shot. When you are using hot air or bulk reflow, that isn't a problem as all the solder in the paste in the immediate vicinity of the pad or joint will end up on the pad or joint.
Beware of kits with precisely counted small passives and discretes. You *WILL* loose a few, its virtually unavoidable, and when hand soldering, you may loose some that stick to the soldering bit. While it *may* be possible to quickly scrape the part off the bit, by the time you've cleaned it up, it will have been badly cooked, and you don't know how badly its terminal metallisation has been eroded by the solder so reusing such parts is unwise. There's also a problem with unmarked caps - if one flips away, and you *think* you've found it, are you 100% certain it isn't one of a different value you gave up on finding earlier?