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Because I tried to wire-solder a protoboard which failed miserable, I'm intending to order a PCB. However, to minimize the area, I want to use some SMD1206 components. I ordered some basic ones (resistors, capacitors etc).

However, now I read that for example SMD 1206 MLCC (Multi Layer Ceramic Capacitors) are very difficult to hand solder. e.g. here. That there is a need to preheat every component for 90-120 seconds and/or to use a heat gun.

I do not have a heat gun or other professional equipment.

My questions are:

  • Can I hand solder SMD 1206 resistors? (1/8 W and some 1/2 W)?
  • Can I hand solder SMD 1206 ferrite beads?
  • Can I hand solder SMD 1206 diodes/LED diodes?

Btw, my soldering skills are far from perfect.

bitsmack
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Michel Keijzers
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    1206 is fine to solder with thin solder wire, tweezers, and a good iron. – Colin Jun 20 '19 at 13:57
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    1206 is no problem to solder by hand, 0805 and 0603 are easy. 0402 is harder, I can manage 0201 with an iron but it involves copious amounts of swearing. I would not standardise on 1206 because capacitors, ferrites and LEDs are becoming hard to obtain in that size. 0805 or 0603 are your best option. – Steve G Jun 20 '19 at 14:07
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    1206 is monster-sized. You should barely need tweezers. So help me, on first read I thought you were asking if a normal iron can pass enough heat to solder 1206's! – Scott Seidman Jun 20 '19 at 14:18
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    @ScottSeidman Well I read on some articles that e.g. 1206 MLCC is not easy to hand solder (I now see I forgot to add the link, so I will add it). – Michel Keijzers Jun 20 '19 at 14:23
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    I would just like to add: Make sure the first pad you tin is not one that connects to a ground plane or other heavy copper area. I have been burned (or, rather, my components and PCBs have been) by this several times before the light bulb turned on. – calcium3000 Jun 20 '19 at 14:26
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    A trick I use when soldering really really small smd things is to use a [hemostat](https://en.wikipedia.org/wiki/Hemostat) (peang in Swedish, the more you know), they have the perfect shape (especially ones that are long) and perfect force to hold the darn small things in place. For those who don't know what it a hemostat is, it is a scissor-looking tool that has flat ends, if you press it together it holds something together and can only be released if you push the handle sideways. It is used in hospitals, specifically in surgery to hold certain things in place. – Harry Svensson Jun 20 '19 at 14:29
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    Gigantic 1206 SMD components take *more* board space than through hole resistors; for capacitors you might come out ahead because there's not a lot of market for through hole versions, but **take time to understand the issues with MLCC caps** before you go putting them everywhere. Ironically, the larger physical size *can* help manufacturers with some of those. – Chris Stratton Jun 20 '19 at 14:40
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    You'll be fine with 1206. I don't know who said or why they said you would have difficulty with them. 1206 can be really pricey though (and I say that as someone who doesn't really care about the price of components). 0603 is probably the most well-priced and workable, but if you're really not confident you might want to go with 0805. – DKNguyen Jun 20 '19 at 17:51
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    I commented on an answer but should probably also comment here: Most answers don't address the problems in the link you posted. The link specifically mentions why you _shouldn't_ just hand-solder a MLCC cap like you would hand-solder a 1206 resistor etc, while the answers just say "hey it's easy just solder one point first and then the other". What's the actual question? – pipe Jun 20 '19 at 19:41
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    _"Because I tried to wire-solder a protoboard which failed miserable..."_ - Do you mean through-hole components and wires on a board with just the metallized 0.1-inch-spaced holes? If so, you might just want to try again a few times; it's good practice! Also, there are "SMD soldering practice boards" available on Ebay; they often are just repeated rows of random SMD components (included). They are great for trying out SMD soldering for a few dollars delivered! Also, make sure you have a decent and appropriate soldering iron; preferably a station. – marcelm Jun 20 '19 at 23:23
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    Possibly helpful: https://www.freetronics.com.au/pages/surface-mount-soldering-with-a-toaster-oven#.XQwVpYhKguU – StackOverthrow Jun 20 '19 at 23:25
  • @marcelm WIth that remark I mean a protoboard where I also tried to solder the wires, thus no PCB but besides all through hole components, also solder all the wires. That got a mess (because the distances were too small to keep all wires separated, resulting in solder blobs. So I want to use a PCB where I only need to solder the components, and not the wires. – Michel Keijzers Jun 20 '19 at 23:41
  • @TKK Thanks ... but I guess I need quite some expensive tools (like some microscope which I do not have). But it is an interesting way to 'solder' that way. – Michel Keijzers Jun 20 '19 at 23:42
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    @MichelKeijzers In the US at least, universities are always unloading microscopes and other scientific equipment online or at their own local auctions. – StackOverthrow Jun 21 '19 at 00:05
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    As others have already said it, 1206 is actually huge for SMDs. My first SMD soldering experience was with 1206 components and it was way, way easier than I expected. I really only experienced the difficulty I first expected for soldering 1206 with 0603 components. 0805 are easy enough to hand solder but it's always good to have access to a microscope to inspect the soldering. I would recommend you get one of those ultra cheap USB microscopes just for inspection. – Chi Jun 21 '19 at 19:49
  • @TKK I checked at 'marketplace' (Dutch app) but nothing to be found cheaply, especially not from universities ...and shipping costs from the US are not worth buying there. – Michel Keijzers Jun 22 '19 at 01:27
  • @Chi I will check into such USB microscopes, sadly in the Netherlands products are quite expensive, and from China we can only order until about 25$, above we get import tax, and handling cost by DHL or similar services which double the price. – Michel Keijzers Jun 22 '19 at 01:28
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    @MichelKeijzers I think the best place to buy this type of cheap stuff is ebay. A quick search for "USB microscope" turns up a few different options for about 15€ with free international shipping. – Chi Jun 22 '19 at 15:08
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    @Chi I just bought one for indeed about 12 euro, I viewed an EEV blog about them (566: https://www.youtube.com/watch?v=H2P1_JZYnVc), which was mostly complaining about the bad stand, so I bought a separate stand for about 10 euro, so hopefully for 25 euro I have a somewhat useful microscope. – Michel Keijzers Jun 22 '19 at 15:31
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    I've hand soldered 0402's, sometimes without a scope, you'd be surprised how solder can help align parts.. 1206's should be easy – Voltage Spike Jul 18 '19 at 21:13
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    @VoltageSpike I hope to find out in a few weeks ... I hope I can solder 0805's ... than I would be satisfied, but I will try all of them (1206, 0805, 0604). – Michel Keijzers Jul 18 '19 at 21:16

7 Answers7

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You will likely find that 1206 are actually quite easy to hand solder. When you get used to SMD boards, you will find they are actually quite large.

With a standard iron, I find it quite simple to hand solder 0603 components, and with a small precision iron, 0402 can be done.

Your best bet and my recommendation if you haven't don't it before is to pre-solder one of the pads, then heat up the solder with your iron, and place the component with tweezers. Once you are happy with the position, remove the iron then simply solder the other side. This is by far the best way if you aren't sure about your soldering skills.

If you have access to some flux, then make sure to use it!

If you want, you can make a PCB with a few different footprints on it, have a few 1206, a few 0805, some 0603 and so on, and use it as a 'practise board'. This way, you can develop your SMD soldering skills, and when you get more confident, you can switch to making PCBs with 0805 or 0603 components, as the larger sizes are getting harder to come by!

After @pipe pointed out the link in the question, I don't really have much to say on it. I have never ended up with a cracked capacitor or any component. The article seems to be talking about the heat shock of the component, and cracks occuring during the rapid heating and cooling of the component and the solder. By only soldering one side at a time, that should reduce these stresses anyway, the article seems to point to both sides being soldered very quickly, or at the same time. It also mentions that is can cause failures during a "board bending resistance test" which I assume is not needed in your application! So really, I wouldn't worry too much about it. If you do find on the off chance you have a broken capacitor, just replace it!

MCG
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  • I have some 0 603 components (I think) but they look so small, I ordered 1206 (for simple components easy to get). The main reason is that I have through hole ferrite beads which take up a lot of space, and in 1206 they are (relatively) small. – Michel Keijzers Jun 20 '19 at 14:21
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    @MichelKeijzers they look small at first glance, but after you have had a bit of practise with SMD soldering, they aren't too difficult if you use the method I mention. Go for the 1206 for now, and perhaps make yourself a 'practise PCB' you can use as it'll be very cheap to get a few made in china! I have a few at home I use for some IC packages if I haven't done them for a while – MCG Jun 20 '19 at 14:24
  • actually I never made a PCB (by ordering one) but I will, and I guess I can better start with a practice board. – Michel Keijzers Jun 20 '19 at 14:26
  • So I don't need to preheat or use a heat gun as said in the article I mentioned? – Michel Keijzers Jun 20 '19 at 14:28
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    @MichelKeijzers Once you start, you won't look back! Chinese PCBs are so cheap now, and SMD components are usually cheaper than the through hole counterparts. The only real downside is the shipping time! And no, I wouldn't bother pre-heating. I never do. If you have one side connected to GND, pre-solder this pad first, then while the solder is still melted, place the component with tweezers. Once you are happy with the position, remove the iron, then solder the other side. Easy! As long as you have some flux to help you, I am sure you will find it quite a simple task :) – MCG Jun 20 '19 at 14:30
  • Thanks for these tips ... btw, can you check Calcium3000's remark? It said NOT to start with the big GND plane (opposite of what you say?). – Michel Keijzers Jun 20 '19 at 14:33
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    @MichelKeijzers with good thermal relief, this shouldn't be a problem. I always solder this side first as it's the most difficult pad to heat up, and this way you guarantee a good connection with the component. It can be done either way, but that is just my personal preference. If you decide to make a practise board, you can always try sticking a ground plane on it and seeing what you find easiest – MCG Jun 20 '19 at 14:37
  • In the PCB's I created (actually one is a test SMD PCB and the others are 'tryouts' for learning KiCad but which should be close to my real project, I have all ground planes. Actually one is a DMX splitter which has 5 different ground areas (one for each isolated area), but I guess that counts too. – Michel Keijzers Jun 20 '19 at 14:39
  • Sorry for asking another question ... what do yo umean with 'good thermal relief' ? (thermal relief of the PCB, should I make that on my PCB or does it mean something else?). – Michel Keijzers Jun 20 '19 at 14:40
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    @MichelKeijzers yeah, that should do it! Maybe on your test one you can add a few random components to test your soldering. As for the thermal reliefs, I answered a question about them a while back which should explain it: https://electronics.stackexchange.com/questions/439756/why-are-gnd-pads-often-only-connected-by-four-traces/439758#439758 – MCG Jun 20 '19 at 14:42
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    Thanks for the answer (and read some more about it). I will add some 0603 'test footprints' to the test PCBs. – Michel Keijzers Jun 20 '19 at 14:52
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    @MichelKeijzers good luck! – MCG Jun 20 '19 at 14:57
  • @MichelKeijzers I see that you have accepted this answer but it doesn't address any of the points of the article you linked to. What are you actually asking? Obviously you can hand solder small components, but I thought you asked about thermal stress from doing that, which the answer (and most other answers) ignores. – pipe Jun 20 '19 at 19:39
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    Apologies @pipe but I wrote this answer before there was a link in the question. It is only now you mentioned it that I have seen it. I'll have to look into it tomorrow and I'll edit something in when I'm a little more awake! – MCG Jun 20 '19 at 21:49
  • @pipe In principle that is true, however, in the 6th remark above this remark he mentioned the answer via another answer. And indeed I did add the link later, so MCG is not to blame. I just added an example of a component that 'could' not be handsoldered. – Michel Keijzers Jun 20 '19 at 22:01
  • @MCG I see, I usually look at the edit history when whining about an answer, but this time I missed it, sorry! – pipe Jun 21 '19 at 08:31
  • @pipe not a problem, it was likely in the same hour that my answer was posted, so the *'x hours ago'* would probably read the same, so I can see why it was missed! – MCG Jun 21 '19 at 11:47
  • I have edited the answer, to include some comments about the article (or at least, my opinion of it)] – MCG Jun 21 '19 at 12:00
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    I would add one minor comment to this answer - you mention using tweezers. While that can work fine, I find that a TINY dot of blu-tac on the end of a single tweezer tong, or even a toothpick, works even better for picking up and positioning small components. The blu-tac means your part will just stick out of tackiness and you don't have to think about the fine motor skills of manipulating the tweezers while you're also trying to manipulate a soldering iron, etc. – dwizum Jun 21 '19 at 19:03
  • @MCG Thanks for the additions, probably I will keep ceramic throughhole capacitors anyway most of the times, but for other components they are really space-saving. – Michel Keijzers Jun 22 '19 at 15:33
  • @dwizum Thanks for that addition. – Michel Keijzers Jun 22 '19 at 15:34
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I hate to contradict Murata; they are a solid company with good products and helpful documentation. However, I've been hand-soldering MLCC's for a decade and have never had a known MLCC failure. I don't preheat the board or components, and I'm not more careful with MLCCs than I am with any other SMD components.

I generally use a Weller WES51 soldering iron with an 0.031" conical tip. I've probably soldered a thousand components from 1206 (these are huge) to 0201 (I need a magnifier for these). Sizes down to 0603 are basic. 0402 is a pain. I'll only hand-solder 0201's if I have a really good reason :) These are imperial units.

Here's my technique, which seems to differ from others I see here. It's not necessarily better, but it works for me:

  1. Apply a small amount of solder to one of the two pads. Remove the iron.

    If I have a lot of components to solder, I usually prepare each location (one pad per component) in one pass. More time efficient :)

  2. Place a component on the pads. It will be resting with one connection on the lump of solder, and the other connection on a clean pad.

  3. Hold down the component with a toothpick.

  4. Touch the iron to the lump of solder. When it melts, the component will sink down to the level of the board. Remove the iron, then the toothpick.

    Note that this isn't a good solder joint yet! It just holds the component in place.

    I do this with each component before proceeding.

  5. Now that they're all tacked in place, I solder all of the unsoldered edges. This is straightforward; just use the iron and solder wire.

  6. Finally, I go back and retouch all of the original edges. This is critical, as some of them may have cold solder joints. Either add flux or just add a little more solder (for its flux).

So, basically, I tack them into place, then solder the other side, and then resolder the first side. It doesn't take long!

bitsmack
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  • Thanks for sharing your experiences, and your method of soldering I will try out (I have a Aoylue soldering station so it should be good enough for hobby projects), and 0 experience in SMD components so that will change :-). – Michel Keijzers Jun 20 '19 at 22:07
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    I'm largely the same, but tend to do one part at a time instead of tacking them and finishing them all at once. Slower, but faster than finding the one component I forgot to finish! – Scott Seidman Jun 21 '19 at 13:50
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1206 (Imperial, 3216 metric) is very easy to solder by hand.
It's very big in the SMD world.

With an normal, 0.5-1mm chisel, iron you can go down to 0603 (imperial, 1608 metric), then hot-air becomes a requirement to do it with reasonable quality.

The need for optical assistance depends on the operator.

Soldering with an iron is easy with these 3 steps.
1. Tin one pad, the other one must be clear.
2. Place component with tweezers while the pad is molten by the iron.
3. Solder other pad, this is where you need thin solder.

It is essential that you own at least lower or equal than 0.5mm solder with flux core. It is also important that the iron is not too hot, so you have some seconds before the flux is gone.

If you're pulling solder away with the iron (little spikes), you're out of flux. Add more.

It might work poorly with leadfree solder, add more paste flux in that case. (eg: SMD291)

With hot air, just tin both pads, add flux paste, drop component, and heat it. It will literally "flop" into place.

You can never add too much flux. Although it might smoke a bit. Just clean it afterwards and don't breathe the smoke.

Note that above method of soldering is not the recommended method by the manufacturer. It violates the thermal profile recommendations of the manufacturer, and might introduce physical stress on the parts due to uneven heating. This might not give you any failed parts immediately, but it might reduce the MTBF, and in the long term, or high volume, you may see higher failure rates then when correctly reflowed. Basically you work out of spec.
It's just like ESD, you may never observe cause and effect directly, but it's definitely a factor.

If your intention is to do this professionally, please invest in a hot-air station. It's worth it.
One trick when soldering with hot air is to use the surface tension of tin, it's amazing and does all the hard work for you.

Jeroen3
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  • Thanks for this extensive explanation ... I asked the question, e.g. due to https://www.murata.com/en-sg/support/faqs/products/capacitor/mlcc/mnt/0001 where it seems to be quite complicated to solder a capacitor, due to micro cracks. – Michel Keijzers Jun 20 '19 at 14:16
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    @Michael you should include that information in your question. – The Photon Jun 20 '19 at 14:20
  • @ThePhoton I just did, and yes, it should be in the question. – Michel Keijzers Jun 20 '19 at 14:26
  • @Michael Why did you accept an answer that doesn't address this part of your question? – The Photon Jun 20 '19 at 14:43
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    EVERYONE who works on SMD boards should be using hot air. I thought it was some kind of crazy-hard skill until I bought a rework rig and started doing pick and place and paste and all the other things. Boards mostly come out looking professionally done, and that was with maybe 10 or 20 hours of practice. As you said, the parts just flop into place. – Julie in Austin Jun 21 '19 at 01:30
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    @JulieinAustin Ehhh, I disagree mainly because you have to deal with solder paste storage and lifetime issues. It has it's place though. – DKNguyen Jun 21 '19 at 19:15
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    @JulieinAustin -- works fine until you're reworking a densely populated board and parts go flying. Hot air is a tool like any other, and the right tool needs to be matched to the right job. – Scott Seidman Jun 21 '19 at 19:35
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    @ScottSeidman - That’s just another piece of the “how to use hot air” skillset. Turn the air volume down and turn the heat up. If the part you’re working on is the small one, get a smaller tip. – Julie in Austin Jun 21 '19 at 20:05
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Why wouldn't you be able to? I (and I am by no means special) can do everything up to 0603 (that is imperial, not metric) easily, and 0402 if I have to. Just get tweezers and you should be fine. It takes some trying the first time you do it, but once you get the hang of it it is easy.

There are these wizards (by which I mean our lab tech) who can even do 0201 by hand with a regular soldering iron but I don't even wanna think about how that is done.

Once I started using SMD for PCBs, I never went back to through-hole components apart from when I have to. It is so much neater and easier to do SMD once you get the hang of it...

Joren Vaes
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  • To answer your first question, because of e.g. https://www.murata.com/en-sg/support/faqs/products/capacitor/mlcc/mnt/0001 where it seems very difficult for capacitors at least. – Michel Keijzers Jun 20 '19 at 14:18
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If you are like me, your hands are just not steady enough to position the component and solder it at the same time.

My method is certainly not a production soldering technique, but I like to use a toothpick to place a tiny drop of glue between the two solder pads and then plop the component on top. I have a few minutes to gently nudge the component into the best position. After a couple hours my old eyes and hands are then able to solder the component with no trouble.

Elliot Alderson
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    For that kind of board work, I use tack flux instead of “regular” flux. The other “trick” is to tin the pads, then a little flux on both pads, and re-heat. If you hold the part down with fine-tipped tweezers you’ll keep the free end close enough to the tinned pad that capillary action will wick the solder up and onto the other end of the component. The key, however, is flux as it will help prevent oxides and a bad joint. – Julie in Austin Jun 21 '19 at 01:26
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    @JulieinAustin Thanks for the tip, but it is the "hold the part down with fine-tipped tweezers" that is physically difficult for me. My brain knows what should happen but my hands don't always cooperate. – Elliot Alderson Jun 21 '19 at 11:26
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    It's a skill, that's for sure. I started soldering 45 years ago, so I have a LOT of practice with an iron. If it's just practice, practice more. If it's something else, well, there are ways around a lot of problems. One thing I've learned when doing fine board work is to watch my breathing, and my coffee intake. – Julie in Austin Jun 21 '19 at 13:34
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    fully agree with the coffee intake, after the 3rd cup things start getting ugly. –  Jun 21 '19 at 23:05
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The way I see it.

A modern high end PCB can contain literally hundreds of MLCCs, a single field failure can doom the whole PCB to the e-waste. So for production use the reliability of the capacitors needs to be extremely high.

If you want to maintain those extremely high levels of reliability with hand soldering you probably do need to take precautions that go beyond what most people would consider reasonable.

But frankly you usually don't need to, only a masochist would be hand-soldering hundreds of SMT capacitors onto a product they are mass-producing. In the hobby/proof of concept/prototyping world MLCCs hand-soldered without special precautions are IMO unlikely to be a significant contributor to your overall failure rate even if they do have a much higher failure rate than reflow soldered ones.

Peter Green
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For me it's possible, but I think it is also feasible for you to do it by hand. The easiest way is to first put tin on the pads. then you can grasp the component with tweezers, warm the pad and then press the component on it. And also use solder flux ;).

here you can find a video how to do it.

Joost
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