I suck at SMD (I can't believe this even works) - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: February 26, 2017, 07:18:26 am
content: Thankfully that connector is just used for power.Tried to get rid of that solder bridge and could not, solder iron was too big to really do anything. Kept touching that inductor too, good thing it's just an inductor and not a diode or something.Really not sure how dependable this will be though, if it fails I may have to retry again. I really need to find a smaller tip for my soldering iron, as a start.I have the smallest chizel style hakko makes that I can find, but I might try a conical one.

author: james_s
author_rank: Super Contributor
timestamp: February 26, 2017, 07:50:32 am
content: Looks like it could use some solder wick to remove a bit of solder too, doesn't take much solder.

author: Cubdriver
author_rank: Unknown
timestamp: February 26, 2017, 07:54:17 am
content: Agree with blueskull - flux is your friend! It really does amazing things to solder.-Pat

author: Ian.M
author_rank: Super Contributor
timestamp: February 26, 2017, 08:04:27 am
content: +1 to both suggestions.Of course an appropriately sized bit in a good temperature regulated iron helps, but given flux (even simply a saturated solution of Rosin in IPA, but preferably a decent brand of Rosin gel flux in a syringe), and solderwick, one can do adequate work in an emergency working with the corner of a 6mm screwdriver type bit in an unregulated 'firestick' iron on a light dimmer to control the max power. If you are working with a grossly oversize bit, its essential to have some way of holding the board at whatever angle provides the best access so you can avoid neighbouring parts. Oversize chisel tip bits are more difficult as they don't have convenient corners.

author: tautech
author_rank: Super Contributor
timestamp: February 26, 2017, 08:29:55 am
content: Soldering and methodology used is more the key that equipment used.......BUT the PCB layout has a lot to do with the neatness and success of hand soldered job. Poor layout....results in difficult rework and a highly planned approach required for the initial component population where this might not be so for reflow.With a PCB like in the OP considerable thought need be given if attempting hand soldering...as the design was not intended for anything but reflow.

author: Ampera
author_rank: Super Contributor
timestamp: February 26, 2017, 03:35:01 pm
content: SMD soldering is like hard drugs.I don't do it.Flux is good, as a general rule.Or a heat gun. If you're having trouble with the chip moving, use hot glue.Reflow ovens are also a thing, but it can screw some components not designed for that, so when soldering an empty board, mount the SMD components first, and then the through-hole stuff.Or I am a madman and don't know wtf I am talking about, as I said, SMD is like hard drugs, I think I am getting a contact high.

author: nctnico
author_rank: Super Contributor
timestamp: February 26, 2017, 04:23:51 pm
content: IMHO the soldering tip used is way too small. That is rookie mistake number one.

author: Iwanushka
author_rank: Frequent Contributor
timestamp: February 26, 2017, 05:31:25 pm
content: 1.6D tip is good even for 0402 if you can see it...

author: james_s
author_rank: Super Contributor
timestamp: February 26, 2017, 05:35:25 pm
content: SMD soldering is easy once you get the hang of it. I use 0603 wherever I can in my own designs, sometimes I reflow on a hotplate, other times I hand solder with the standard wedge tip on my iron. It's less hassle than forming the leads of through-hole parts then snipping off the remnants. When I etch my own boards I don't have to drill holes for the SMT stuff either.

author: Kjelt
author_rank: Super Contributor
timestamp: February 26, 2017, 06:39:37 pm
content: Use solderpaste from a small syringe press and hold the component with a tweezer in the left hand and solder a few pins with the right, the solderpaste contains the flux so it works like a charm.Afterwards inspect the ics and remove any loose solderballs.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: February 26, 2017, 06:47:14 pm
content: It's not too bad. I learned to do it with those cheap Chinese practice boards and a 25W firestick. Flux is the key to success - makes you look like not an idiot

author: Red Squirrel
author_rank: Super Contributor
timestamp: February 26, 2017, 08:26:19 pm
content: Yeah tried to use solder wick to re-attempt but trying to manipulate the wick and the iron in that tiny spot was near impossible - was also having to hold wick with pliers making it even more awkward as it would burn me. I was thinking of solder paste actually could have carefully put some on each pin then lay it down then use heat gun for a few seconds.I forgot about using flux though so perhaps that was my main issue. Should have used a small wire or something to dab some on each pad and each pin first while ensuring I don't bridge. Could have used paste too I actually bought some a while back and forgot I had it until it was mentioned. Flux really is magical, When I did copper plumbing for my first time I felt like a dark wizard that just learned a new spell.

author: james_s
author_rank: Super Contributor
timestamp: February 27, 2017, 01:33:01 am
content: Solder paste with a heat gun does work, provided you don't blow parts around with the air. You can even just tin the pads with an iron and regular solder then add flux and reflow. Flux is the real key here, use plenty of flux. Afterward I scrub the board off with acetone and a toothbrush to remove the flux.

author: Ampera
author_rank: Super Contributor
timestamp: February 27, 2017, 01:36:13 am
content: Quote from: james_s on February 27, 2017, 01:33:01 amas I said, hot glue.

author: Dielectric
author_rank: Regular Contributor
timestamp: February 27, 2017, 04:08:57 am
content: Ugh, I hate trying to rework USB connectors like that. The solder just loves to run up the leads toward the body for some reason.I got mad and clipped the back flap off of the connector shield last time so I could reach the leads easier.Also, while I'm at it, extra hate for anyone who designs-in a USB connector without through-hole lugs. There is like zero mechanical stability there, it completely relies on the bond of copper to fiberglass while allowing enormous leverage from the cable.

author: 6581
author_rank: Unknown
timestamp: February 27, 2017, 05:56:43 am
content: Thanks for sharing Red Squirrel. I'm an anonymous smd butcherer and done similar quality - sometimes you may get one part neatly soldered and then another just... moon and sun doesn't line up. My mistake is not practicing enough. Now that I know I'm not alone, I may have enough courage to go try some of those practice boards and diy kits again.Haven't tried paste + heat gun - but I may. Thanks for everyone in this thread for valuable tips.

author: ludzinc
author_rank: Unknown
timestamp: February 27, 2017, 06:03:16 am
content: Quote from: Dielectric on February 27, 2017, 04:08:57 amIf you know a source of mini / micro USB sockets with through hole pins, I'm all ears!Otherwise, dang-it.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: February 27, 2017, 12:32:13 pm
content: You really need a widefield microscope and then you need to slow down, use more flux and less solder.But yes... those pins under a micro USB connector are a b***h.... why don't they just make them a bit longer?Whilst we are on the subject... if you were hot-airing that USB connector on... what temperature would you use?

author: idpromnut
author_rank: Unknown
timestamp: February 27, 2017, 12:47:47 pm
content: Quote from: Red Squirrel on February 26, 2017, 07:18:26 amI use the FX-888D with the default tip that comes with it (it's a 1.5mm, maybe 2mm wide chisel) and I have no trouble soldering SMD parts, and even those annoying mini-B SMD connectors (with the super crowded data header). Keep practicing, buy a good bottle of flux (although when I started out, I was just using a flux pen from Kester I think it was:http://canada.newark.com/kester/83-1000-0951/flux-pen-no-clean-0-33fl-oz-pen/dp/82H2047) and get some magnification if you have trouble seeing the pads/leads. I use a little jeweler's loupe to inspect my work, check for solder bridges, etc.Another thing that I picked up from this group is that it is a bit easier to control the amount of solder you use if you put a small amount on your iron tip (works well with larger tips!) and then cover the pads to be soldered with flux and go in and dab at the pads slowly. You will be able to control the amount of solder much more and be able to just add more if you don't have enough (solder wick is a must; you /will/ put too much solder on!)

author: brabus
author_rank: Frequent Contributor
timestamp: February 27, 2017, 01:43:51 pm
content: Quote from: nctnico on February 26, 2017, 04:23:51 pmThis.I actually use an enormous solder tip i compared to the components: large heat capacity and loads of flux are your friends!

author: Dielectric
author_rank: Regular Contributor
timestamp: February 27, 2017, 03:59:15 pm
content: Quote from: ludzinc on February 27, 2017, 06:03:16 amThis is what I like, at least it has solid lugs but still SMT leads:http://www.mouser.com/ProductDetail/Hirose-Connector/ZX62D-B-5PA830I actually wouldn't want through-hole on the signals, at least not for USB 2.0 or higher.

author: Red Squirrel
author_rank: Super Contributor
timestamp: February 27, 2017, 04:16:24 pm
content: The connector I used had two small plastic pins that went in the PCB. The connector was the exact same as the one I was replacing so it fit nicely and lined up right. I guess there is somewhat a standard for how these are made, or I just got super lucky. But yeah it seems it mostly relies on the solder for plug/unplugging.But yeah my main issue is the solder tip I was using is so big compared to the connector/components in the area that I was touching more than just the pins and was just dragging solder around. Tried to use braid to get some out but trying to hold braid with pliers with solder iron in other hand I could no longer hold the board steady. I'm thinking this tip might be better for SMD:https://www.hakko.com/english/tip_selection/series_900m.html#type_hThey also say not to apply solder to the iron but is something like this an exception seems it would be easier to add a bit to the iron but not to the work too otherwise it's too much.Oh and this is the connector I used:https://www.amazon.ca/gp/product/B00EZBERZ4/Keep in mind that is mini USB and not micro USB. (ex: what the older blackberries used) It's not as common anymore, but the particular device I was working on used it.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: February 27, 2017, 04:22:41 pm
content: Big tip on the iron, plenty of heat, plenty of flux, and use solder wick to wipe up any excess. It's really not that hard, but if you get even one of those wrong it will screw the entire thing up and make it much more difficult than it needs to be.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: February 27, 2017, 04:28:35 pm
content: Quote from: Red Squirrel on February 27, 2017, 04:16:24 pmThat doesn't matter. With flux the solder will avoid the gaps and go where you want it to go, plus some braid to mop up the extra if there ends up being any.Quote from: Red Squirrel on February 27, 2017, 04:16:24 pmHuh? Why pliers? Why can't you hold the board down by resting your palms on it or putting something heavy on it or putting it in a holder? Put board on bench, rest palms on board, hold braid with one hand, hold iron with the other. Place braid on area to be mopped, place iron on top of braid, wait a second or so and it'll start sucking the solder out of the joint. When you've pulled enough out, remove the braid and heat. If the braid gets full before you're done, shift it down a cm to a clean spot and repeat.Quote from: Red Squirrel on February 27, 2017, 04:16:24 pmLike with the braid, put the solder on the joint first, exactly where you want it to be, and then touch the iron to the joint (passing it "through" the solder). With some flux (even the flux inside the solder is usually enough, if you have decent solder) enough heat and a big enough tip, it will melt it instantly and flow right into the joint. If you get too much or get a bridge, it doesn't matter, it takes like 2 seconds to wick it back out.

author: idpromnut
author_rank: Unknown
timestamp: February 27, 2017, 04:31:52 pm
content: Quote from: Red Squirrel on February 27, 2017, 04:16:24 pmThis will work, providing you use flux where you are trying to solder. Flux will also help the soldering braid do it's thing.Quote from: Red Squirrel on February 27, 2017, 04:16:24 pmI use the D-tip, 2.4mm.

author: Red Squirrel
author_rank: Super Contributor
timestamp: February 27, 2017, 04:41:07 pm
content: Braid is highly heat conductive, I tried to hand hold it. Once.But yeah I need to find some kind of way of holding a board steady. I don't like it in the air like it would be with helping hands as it's too flimsy I'm thinking some kind of weight that just pushes down on it. I'll have to come up with something. Maybe even rubber bands and a 2x4.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: February 27, 2017, 04:44:23 pm
content: Quote from: Red Squirrel on February 27, 2017, 04:41:07 pmYou still don't need to touch the braid itself, isn't it on a little plastic spool? Hold that. You only need to get it in roughly the right position, the iron is what actually holds it down while using it. No reason for your fingers to be any closer than 2-3" away holding the plastic spool, far removed from the heat of the iron.