Learn to Surface Mount Solder Using an SMD Challenge PCB




About: I'm a content creator. I make open source projects and videos for said projects. My goal is to create free and open knowledge for everyone.

I feel like surface mount soldering has a bad reputation. It can seem daunting to someone who has never tried it. Since a lot of my project involve using surface mount components, I thought it would be a good idea to make something to inspire people to try it out(without risking expensive components or their custom project). I created my own version of an SMD Challenge kit. The idea was inspired by a few others with the same and similar names. I will continue to create new circuits so that people can collect them and maybe learn a bit about open source hardware, building and designing PCBs, and just technology in general.

I have made a special edition for my patrons, who will be receiving a new version each time I come out with ones. Check out my patreon for details. patreon.com/seanhodgins

Step 1: Watch the Video

Step 2: Gather Your Parts

Decide how you want to assemble your SMD Challenge Kit (re, the video) you can choose to use a soldering iron, or a reflow oven. They take about the same amount of time but using the soldering iron can be a little more challenging and doesn't require a cheap toaster oven.



Step 3: Choose Your Method.

Choose if you want to use a Reflow oven, or the soldering iron

If you want to do the soldering iron method, skip to Part 7

Step 4: Reflow Method(Easy) - Solder Paste

Begin by putting solder paste carefully on each pad for the components of one side of the board. Try not to apply too much.

Step 5: Add the Components.

Place the components on their corresponding pads, they are labeled by sink screen, but it can be handy to have a computer open with the schematics as well, if the sink screen is hard to read. Make sure the LED and the 555 timer are placed in the right direction.

The number 1 most important thing is to make sure the pad and the corresponding part contact are both touching the solder paste. You may have too much, you may have too little, but as long as some solder paste is touching both of those things, it should work.

Step 6: Stick It in the Oven.

Carefully move your populated board to your reflow oven. I have mine set to as hot as it can go(230C).

Turn it on and carefully watch the board for the signs of the solder melting. This is a visual process. When all of the pads of melted, count to 3, turn the oven off and slide out the tray. Wait for it to cool a bit so the solder can harden. Afterwards I like to place it on a heatsink to speed up the cooling process.

Skip to step 9 to mount the battery connector. The following parts are for the soldering iron technique.

Step 7: Soldering Iron Method - Tin the Pads

You want to apply a bit of solder to ONE solder pad for each of the components. Make sure only to tin ONE pad, to make your life easier. Example, one side of a two pad resistor, or one lead of the 8 pin 555 chip. Soldering more than one pad will make it difficult to make the part flat on the board.

Step 8: Attach Components to the Tinned Side Then Other Side(s)

Apply a bit of solder flux to the tinned side of the pad, pick up your component with the tweezers and use the soldering iron to reheat that pad and attach the component. This will hold it in place so you can solder the other side. This is the tried and true method of surface mount soldering with a soldering iron. You'll get the hang of it pretty quick. Try not to shake!

Step 9: Attach Battery Connector

Now that all of the components are on the component side, turn over the board and somehow support it so its level(I used an extra button). Same way as before, tin one pad, add flux, pick up battery connector, and wait for it to flow onto the battery connector metal. This could take longer than the other components, because the connector will soak up a lot of heat. The solder won't connect until it is hot enough.

Step 10: Add a Battery.

Make sure its the right way!

Step 11: Press the Button!

The circuit makes the LED blink. The LED will blink faster or slower depending on the temperature of the thermister (TH on the board). You can see when I touch the soldering iron to it, the LED speed changes rapidly.

The circuit is simple, it doesn't do much, but you made it! That is what counts.

As you can see, these two methods are not very difficult. However, as you add more components to your project, you will notice a drastic increase in time with using the soldering iron, while the solder paste method, doesn't increase much. More efficient.

Step 12: Support My Open Source Projects!

I made custom SMD challenges specifically for my patrons. Some patrons will receive the PCB and some will receive the whole kit! Check out my Patreon for details. However, I will have them available in my tindie store for everyone else, or you can order your own using the board files in the GitHub.

If you would like to support my projects, Consider becoming a patron, subscribing to my YouTube and following on twitter and Instagram. I would love to be able to rely on the support of my viewers, so I can keep creating free open source projects like this one.

Subscribe to my YouTube!

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You can also send me bitcoins, here - 19s7hAVkm54Ev7QZEsWAfoyECy1CwXSrhL



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    13 Discussions


    1 year ago

    I actually like the speed of the GIF's. Excellent tutorial! This is I think one of the best Instructables I've read and watched that covers the very basics of SMD soldering. We can search the web for more information on temperature controlled reflow ovens, using heat guns and maybe a wick to clean pads if were more sloppy. Other than that, I can't think of anything at the moment to add. Maybe temp of hot iron and work fast? Thanks!

    1 reply

    Reply 1 year ago

    Oh, some soldering pastes are recommended to be refrigerated. High volume I've seen automated pump stations for paste made from glue dispensers. I think on Instructables.com also.


    1 year ago

    Why all these fast moving pictures ?

    After a few seconds this Instructable gave me a headache and I stopped looking at it, definitely not recommended for epileptics !

    2 replies

    Reply 1 year ago

    When I make a GIF, there is a tradeoff between length, quality, and file size. I try to keep them under 5mB, but sometimes I want to show more. Sometimes they end up too fast like the one above... Sorry about that.


    Reply 1 year ago

    Some gif editing tools allow you to edit the display frame rate to slow them down as they should be. This won't change their size any. See, for example, https://ezgif.com/speed .


    1 year ago

    Can one combine the solder paste with a soldering iron instead of a reflow oven? I know one *can* -- I did it once -- but is it a good idea?

    3 replies

    Reply 1 year ago

    It does work, doesn't hurt anything. Solder paste is just balls of solder suspended in flux(check it out under a microscope, its cool). I don't see any reason why not to do it. I just wouldn't do it if I had the tools at hand. But I often fix unconnected leadless ICs by shoving a bunch of solder paste in there and touching it with the soldering iron.


    Reply 1 year ago

    How careful do I need to be not to get paste between the leads? Or will it all wick to under the leads?


    Reply 1 year ago

    On this one? Not overly careful. The pads are pretty spaced out. You'll be surprised how much surface tension plays in your favour. Its less about soldering joining pads and more about the amount of solder. For example if I do a QFN package chip by hand(e.g. without stencil), generally its just a small stream of solder across all of the pins. The solder does this anyway when you heat it. It takes some getting used to, to know what you can get away with, and what will cause problems.