Good morning. I saw a URL for a way to solder SMD that only uses a soldering iron.I wish I could still use a solder stencil. Here is the url: Destro II
The only tool I have for soldering is a soldering iron.
I would like to know what the soldering stencil should look like to solder this way (although I already believe that I should use a disposable stencil)?
Solder jet paste printing is an alternative to solder stencils.
But it may be a bit above your budget.
From your link, this looks horrible:
Normal people just put a dab of solder on a corner of the PCB footprint (it’s all right if it shorts a few pads in the first iteration) and then:
- Solder the IC in that corner.
- Carefully inspect the IC pins all around, (A stereo microscope is a really usueful additional tool).
- Correct the position if necessary.
- Start soldering the row on the opposite side.
I don’t like the sticky tape method because you can’t inspect the IC pins all around, and because there is still some movement in the IC when the tape is over it. A good alternative may be to use a weight on a lever. That way you can put a “heavy needle” or toothpick on the IC to hold it in place and do the inspection before you start soldering.
What’s the goal of this question?
Solder stencils come in two variants. Stainless steel and mylar. For both there are plenty of video’s on youtube, which show it better than text can.
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If you are going to use a soldering iron make sure you only use components that you can hand solder easily. Devices with thermal pads underneath are a no go as far as I am concerned. Devices without exposed leads are a no go. The key is to make life easy for yourself . . . .
If this isn’t an option and you MUST use devices that you cannot easily hand solder then you need a stencil, solder paste and some way of reflowing . . . hotplate, hot air gun, reflow oven.
If your devices are very fine pitch then things get even more critical . . . then you need a way to ensure that the stencil and paste work well together and you can get nice clean coverage with the paste.
I was never really happy with the way I was using stencils and paste, one day I saw an idea developed by a Maker on youtube, it used a vacuum to hold the stencil down onto the PCB while the paste was applied . . . so I designed my own version and now have very good results, even from paste that is 4 years out of date 
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Well. I dont know very well what you want that I answer but I will try do it on a paragraph.
I’m from Portugal ( just to remember a country from Schengen area, euro zone and european union).
I have a soldering iron, but I haven’t the proper tool to solder with SMD called hot air gun (It exists, under other names, or other tools that do the same, but I’m talking about all of them.) . I’d rather be able to use a solder stencil. But I’m not understand, in this particular case of not having such a hot gun air, how to use it, and mostly, I don’t know what material it can be made of. But I know more or less, what materials it could be in case I had my own tool to weld in SMD. I just believed, a little bit, that it could be made of paper.
The stress is that I only have soldering iron, and although I’ve seen some factories online I can try to send components for them to weld in SMD, and those factories are in countries where the post office works poorly with imports from the European Union, and the Schengen area. Like China
For soldering with a soldering iron, you can either solder the pads one by one as already shown, or you can use “drag soldering” which uses a big (and hollow) soldering tip and a big blob of solder, it is sort of a miniature variant of wave soldering.
If you want to use solder stencils, you also have to either buy a hot air gun, or use an oven or similar.
The combination of using solder paste with a stencil and a soldering iron does not make much sense.
Heating a PCB for DIY soldering can be done with a skillet, a dedicated hot plate, an ironing iron or a modified kitchen hot air oven. You can buy a small oven for EUR50 or less, and there are plenty of DIY projects (even commercially available on sites like etsy) for better temperature control and generating a temperature curve fit for various kinds of solder.
There are lot’s and lot’s of hobby like methods for SMT soldering. The search below is a good start to get some idea of what has already been done:
https://hackaday.com/blog/?s=smt+soldering
About the solder stencils…
There are lots of variants of solder stencil holders, but I suggest you start with a flat table, some left over pieces of FR4 and sticky tape. It’s far from ideal, but it’s very easy to start with, cheap and it works adequately. When you get some more experience you have a bit of background to choose (or make) one of the more fancy solder stencil printers.
You can make solder stencils yourself. They have been laser cut from soda cans to vareous sorts of plastic film and made with a cutting plotter.
https://www.youtube.com/results?search_query=cutting+plotter+smt+stencil
Especially this video from MikesElectricStuff is noteworthy. He does not make many video’s, but all of them tend to be quite interesting.
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One thing I would add . . . OK maybe two . . . get some good small tips for your soldering iron (or a new iron if yours is not small enough for delicate work) and get some flux paste in a syringe with a fine needle.
Added flux makes re-flow by soldering iron work so much better.
Flux paste:
Yes, extra flux is essential.
However, I do not like small soldering iron tips. I prefer to have a tip of around 1.2mm (round with flat sides, is this called “oval”?).
I also bought a stereo microscope years ago, and I find it to be an extremely useful tool. Both for soldering and for inspection.
Depending on what components you have on the board, you can choose to have the common components (SMD resistors, capacitors, diodes, transistors and some common ICs) supplied and soldered by the PCBA house (they are incredibly cheap) and you do the special parts yourself. It’s actually not that hard to do SMD ICs with drag soldering.
I was thinking of taking advantage of components I was using in the pcb breadboard. Probably the best thing will be for them to weld the ones they can easily arrange, and if there are any that they don’t easily arrange and that may even be expensive to pay them me.
You can look at my project Modularnixie | Hackaday.io where the PCBA house mounted everything except the 2 THT resistors and the 74HC595 chip (and even that was available from the PCBA house if I wanted), and the nixie of course. The common components were incredibly cheap. Here’s page where I describe the manufacturing files required and example pricing: Costing assembly service for my PCB | Ken Yap | Hackaday.io It’s simply not economical to ship components to them, unless you have a huge commercial order and there is a special component which they cannot, or you don’t want them to, supply.
If you thought of sending them elements you were already using than it is wrong idea.
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Do you need to solder elements you are not able to solder using only soldering iron?
We (very small firm) moved (around 1995) from soldering iron to semi-automatic placement device and oven. That semi-automatic device had a function of pushing soldering paste dot after dot and using it you put paste dot at each pad (or several dots at bigger one). The only risk was that you could miss a pad and then it was not soldered. So even assembling those time PCBs in series of about 50 we didn’t used stencil. 10 years later we moved to use contract manufacturer to assemble our PCBs and stencil is not our problem 
I have never used (and even seen in real) a stencil. I don’t see special problem with assembling ICs down to 0.65mm (or even less) raster (with pads not hidden under the device) using soldering iron.
So my advice is: Consider if you really need stencil or you only wish because of wish.
I have heard that amateurs assemble devices with thermal pads by doing one big plated hole under device and soldering its thermal pad from backside. I think it is good solution ensuring even better thermal connection to zone at bottom than a serie of 0.3mm vias.
Nice! I need to dig out my box of nixies and do something with them someday. I also have some vfds which are also a fun look (and lower voltage). I even have a small stash of the giant burroughs alpha-numeric nixie tubes they used in stock tickers.
You all gave good tips.Just to share another method. Here’s a video solding SMD components using sand How to Solder SMD Components using Sand - YouTube .
Nice
In case anybody is curious (I was) I found a video with some nice exploded view and showing the functionality (no affiliation)
Yeah, years ago I made mylar stencils with my cameo. There was a script that would take the knife off to one side to start it cutting in one direction, then go make actual cuts in that direction, then go off to the side again to get the knife cutting in a different direction… That got nice clean corners on the pads. Took a pretty long time and the stencil quality was just ok.
Now I can get a nice stainless laser-cut stencil for seven dollars with my jlcpcb board order – the cameo is in the closet.
Hah, just realized that was my post from ten years ago – funny! That was back when I got a little TM220A pick-n-place machine and someone on the dangerous prototypes forum had written an eagle script to extract centroids and generate a file for the 220. Was pretty cool at the time. The 220 still makes small batches for me from time to time.