HotplateSMDSolderingWorkshop

Using a stencil, solder paste and a hot-plate to reflow-solder SMD components

About this workshop

Intro

Surface Mounted Devices (SMDs) are small compared to Through Hole (TH) electronic components, and some electronics hobbyists find them difficult to work with: difficult to see and handle, when you sneeze, you loose them and you can not easily use them on 2.54mm raster prototyping boards. On the other hand, SMD devices allow much more lightweight and compact projects,are most often much cheaper than TH variants, and sometimes there simply are no TH variants available of a component, requiring the use of break-out or adapter boards - both kludgy and expensive. Also, Printed Circuit Board (PCB) prototype manufacturing prices have become much lower, CAD tools to design them have become more accessible to hobbyists, and a proper PCB is much easier, reliable and often faster to assemble than the identical circuit on a 2.54mm raster prototyping boards - especially when you make a (small) series of the same board. So, if your hobby-elecronics work-queue is long enough to wait 2 weeks for PCBs to arrive, NOT using 2.54mm raster prototyping boards and TH components makes sense and may save time and money. The question then becomes: how can you deal - in a hobby context - with SMD components that are difficult to see handle, and that you loose when you sneeze.

Beginners

If you are an absolute beginner, you will make a badge during this workshop. The badge will take about one hour (more if a lot of people participate). It can be done much quicker. The record time is 12 minutes.

The badge workshop uses a workflow that alleviates some of the difficulties using tricks, (simple) tools, physics and appropriate materials.

Instead of solder wire, you will use solder paste to solder. You will apply the solder paste to specific areas of the PCB using a stencil. While we are doing this some physical properties of the solder paste, the metal and flux it contains and the properties of the materials in the PCB will be discussed and explained how this helps the soldering process.

Next we will use a mirror and tweezers to place the SMD components on the PCB in their correct position and orientation, with an explanation of tricks, tools, rituals and environmental factors that make this more enjoyable. In addition, while we are doing this, the function of the electronics components will be briefly explained and what to watch out for.

After we have finished placing the SMD components, the assembled PCB will be "baked" on a stove. Again, there are a few do's and dont's, but in general this part is quick, and somewhat "magical" if this is the first time you see reflow soldering in action.

If necessary, small problems will be fixed, a battery holder attached using a normal soldering iron, and the badge will be tested. Success rate is almost 100%

Finally you will return the tools, discard your garbage, clean-up your workspace and wash your hands.

Experienced

If you have some experience with the workflow and can work independently, you may opt to make a game. This will take about two hours. It can be done much quicker. The record times is 41 minutes.

If you want to make the game, it is assumed that you have worked with solder paste and a stencil before. You may pick up a few tricks, but there is less time for explanation.

After finishing you will return the tools, discard your garbage, clean-up your workspace and wash your hands.

Warnings

During this workshop you may come into contact with potentially harmful materials and tools like lead, flux and soldering equipment. Please,

• Do NOT eat or drink during the workshop UNLESS you wash your hands with soap first.
• Do NOT pick your nose, ears or rub your eyes during the workshop UNLESS you wash your hands with soap first.
• Do NOT go to the toilet during the workshop UNLESS you wash your hands with soap first.
• DO wash your hands with soap AFTER the workshop
• When using pliers to cut component leads, HOLD the wire-end you are cutting to prevent it from being launched at someone or something
• Be careful with the stove. If you touch the hot stove your hand, it may stick to it. This can be painful and may require an emergency room visit
• In general: treat tools (litteral and figurative) with respect - "accidents" can be painful

About the Projects

During the workshop you will make either a badge or a 'blocktris' game. The badge contains a larger variety of different components. The game contains a larger number of components. Neither is very difficult to make, but I consider the badge better for beginners: you learn more, and it costs less.

The workshop can also be fun for more experienced people: how quickly can you make a badge or a game, and how well does it look? (hint: rework must be avoided). The current record times for succesful hotplate reflow soldering are 12 minutes for a badge and 41 minutes for the game. The record time for succesful hand soldering the badge is 21 minutes. So far no one has even attempted to hand-solder the game.

The Badge

Contains 24 blinking RGB LEDs, various support components, a microcontroller and you can actually write your name on it.

image of the hackwinkel badge

You can see it in action in [this video]

Both | hardware and | software of the badge are MIT licensed open source.

The 'blocktris' game

The game contains 200 RGB LEDs in an array of 20 x 10 pixels controlled by an ESP32-C3 microcontroller module, ideal for playing 'blocktris'.

Image of the blocktris game

You can see it in action in [this video]

Both | hardware software of the game are BSD 3-Clause licensed open source.

Costs of this workshop

The Costs depend on what you do:

• Badge: 0 euro + a voluntary donation to the space each
• Game: 8 euro + a voluntary donation to the space each

Planning / Poll

general notes

First of all we need to select a date, but also get some idea who may come and how much material is necessary.

If you want to join the workshop, please indicate your preferences for dates in the table below, and what you would like to make (badge and/or game). Add more lines if necessary. Depending of the number of people, we can do multiple sessions

Doors open 11:35, first session start: 12:00, last session start: 16:00

Note: The "ideal" number of participants per session depends: Beginners/kids (with adult supervision): 5-10, People with some prior experience working with stencils, solder paste and a hot-plate: ~15, Experts: 20 (tools bottleneck). The maximum for a session so far was 42, and that was only possible because there were lots of experts helping others out, but the tooling (stencil and hotplate) bottleneck resulted in an overrun of ~ 2 hours. If this is your first time working with stencils, solder paste and a hot-plate OR if you are younger than 14 OR if you have never done any soldering before, put this in the remarks - it is definitely not a problem, but affects how the workshop flows.

(prospective) participant list

Date Poll

#	name/nick	2025-10-18	2025-10-25	What	remark
0	The0	Yes	Yes	Both	Organizer
1	Host?	Maybe	No	Example	Example
2	Wheeze_NL	No	No	Badge	After 14:00
3	Juerd	Yes	No	Badge	After 14:00
4	Oops	Yes	Maybe	Badge	Absolute beginner, done SMD once for the n-teller
5	Oops1	Yes	Maybe	Badge	Absolute beginner (under 14), only TH experience
6	BigMistake	Yes	Yes	Both	Beginner
7	noopwafel	Yes	Yes	Game	-
8	Mystery	Yes	No	Badge	Beginner
9	Example	Example	Example	Example	Example
10	Example	Example	Example	Example	Example
11	Example	Example	Example	Example	Example
12	Example	Example	Example	Example	Example

What if...

You can not add your name to the participant list

Please drop a line with your details in the | relevant forum topic

If you can't, please get in touch with the organizer (The0), for instance on IRC (OFTC)

You put your name on the list but can't come

Shit happens. No problem, do nothing. Maybe see you next time.

You only noticed this workshop at a late date

Try getting in touch, and we may work out something. If you just show up and it is busy, then you may not be able to join. If there are places available: FCFS

Your badge or game doesn't work

You will be the first. We may try to fix it, but no refunds