How to Solder Protoboard: 5 Things to Know

Technology is pervasive, present almost everywhere, and an important part of many devices is a circuit board. While few will ever need to know more about circuit boards, much less build one, for those interested in doing so, creating a prototype, often called a protoboard, is a must. To do that, soldering is a vital skill to learn and master.

Soldering a protoboard is not an easy skill, requiring a great deal of practice to get good at, but there are some tips that can give you an advantage. By reading this article, you will learn the ins and outs of soldering a protoboard, including some tips you may not have considered trying before.

Protoboards and Soldering

An important thing to take note of if you are new to protoboards is the identity of a protoboard. While it may seem obvious, being a shortened form of prototype board, there are actually a few different things that fall under the category. In fact, you may even see it called a “breadboard” more than anything else.

It is important to know this because although breadboards can be used to create a prototype, they are the most basic type and do not involve soldering. Breadboards can be considered gentle proof of concept, a way to see what it will look like without any permanence.

For the purpose of this article, we will leave breadboards as that and move on to protoboards that deal with soldering. Namely, we will be dealing with prototype PCBs, short for printed circuit boards.

The 5 Things to Know When Soldering Protoboards

When soldering protoboards, a variety of factors can affect the final result. While we will be discussing specific tips and common problems, there are five things you should know above all else. These five things will be addressed as we go through the steps of soldering protoboards.

The five things that you need to know when soldering protoboards are:

  • Precision is everything
  • Not all solder is the same
  • Timing is key
  • Not every solder job requires a soldering iron
  • A lot can go wrong

Soldering is the process of melting metal to join electronic parts together. It is not only a difficult skill to learn and perfect, but it can also be dangerous if not approached with the proper understanding and precautions. With that said, the first thing we will discuss is safety.

Nothing Is More Important Than Safety

Soldering can be dangerous if taken lightly, and that is only more so when dealing with protoboards. However, if you take the proper precautions, it poses little risk. If you keep these things in mind, you will be much safer during the soldering process:

  • Soldering involves immense heat, so avoid contact with anything but the handle of the soldering iron when it is hot. Know that it retains heat for a time after being turned off. To avoid a fire, keep the iron on a heat-proof stand when it is not in use. A heat-proof surface is also advisable.
  • Sparks are common, and with protoboards, you often need to be looking closely. In order to avoid serious eye injury, it is best to use safety goggles. Plastic safety goggles wrap around the eye, providing far more protection than glasses, so use them even if you wear glasses.
  • All solder gives off fumes, even lead-free solder. Work with proper ventilation, and use a fan. A fume extractor is particularly effective at keeping the fumes away from your lungs.

Soldering Protoboards Requires Precision Tools

Protoboards are small and require precision, so to make things easier, you need to have the right tools. To start, make sure you have a few simple things, such as:

  • Wire cutters
  • Pliers
  • Tweezers

You may be dealing with parts too small or delicate to be handled using your hand, so these can be useful. There is even a chip extraction tool that could be useful depending on your needs.

Another useful tool is a clamp, though you can find more specialized products by searching for helping hands or circuit board holders. It makes the job both easier and safer by freeing your hands, allowing for greater precision as well.

Speaking of safety, do not forget about safety goggles and a fan, preferably a fume extractor. The Kulannder fume extractor only costs around $34, a price well worth your safety. Lastly, both a soldering iron stand and a silicone soldering mat are good ideas to minimize risk.

Precision Is Everything

Protoboards require precise component placement and soldering to work properly, and nothing impacts precision more than a soldering iron, which is responsible for how much heat is applied to how large an area. When dealing with a soldering iron, the type of soldering iron and the tips used change the precision offered.

While any soldering iron works, there are solder stations as well, an advanced type of soldering iron that allows for more control and the ability to precisely adjust the temperature, which eliminates a number of problems. There are also various tips that can impact precision. Two common tips for protoboard soldering are:

  • Chisel Tips: Its broad, flat tip distributes heat evenly. It is particularly useful for wires and large components on a protoboard.
  • Conical Tips: Its fine tip allows it to heat smaller areas without affecting the surroundings. This makes it ideal for use with protoboards.

To ensure the best performance, you will need to clean your tips, which you can do with a sponge. While conventional sponges work, they lower the temperature of the soldering iron since they have to be wet. A brass sponge works better and does not have the same problem.

Not All Solder Is the Same

Selecting solder is important for ease of soldering and safety. The recommended type is a lead-free rosin core solder, which is usually made up of a tin and copper alloy and does not contain lead, which is toxic. A few things to keep in mind when buying solder:

  • It comes in different diameters, with 0.4 to 1.0 mm suiting most protoboard needs
  • Do not buy acid core solder because it will damage protoboard components
  • Flux is located in the core of most modern solder

Flux helps the metal in solder flow and adhere to surfaces, and while it is already in most solder nowadays, that is not always the case. Therefore, it is a good idea to keep a flux pen around.

Also considering getting a desoldering pump. Mistakes happen, especially when working with something as small and delicate as a protoboard, and a desoldering pump, also known as a solder sucker, makes it easy to remove the solder and try again.

Setting Up for Success

Ensure that your workstation is exactly how you want it and that you are taking the proper safety precautions. Only once those two steps are complete should you turn on your soldering iron, which should be placed on a stand or on a heat-proof surface.

Tinning your tip is the next step. After the soldering iron has had a chance to warm up, use your sponge of choice to clean the tip. If using a wet conventional sponge, let the soldering iron heat up for a few seconds after, then take your solder and touch it to the soldering iron. The goal is for the solder to flow evenly around the tip.

Lastly, if you have not already done so, position the protoboard you are working with, preferably using a clamp of some sort. The goal is to ensure as little movement of the protoboard as possible during soldering.

Timing Is Key

The actual soldering process is simple, but it has to be done incredibly quickly. In fact, the entire process will only take a handful of seconds, which makes mastering the skill difficult. Keep timing in mind to avoid mistakes and potentially ruining your protoboard. The basic steps of soldering are:

  • Heat the Joint: At this point, the leg or pin of the component you are looking to solder should be inserted into the protoboard. Start by heating the joint, which means heating both the copper surrounding the hole and the pin or leg at the same time using your soldering iron. This only takes a second or two.
  • Apply Solder to Joint: The goal is to apply enough solder to form a “volcano” around the pin or leg, covering all of the copper around it as you do. The heat of the joint itself should melt the solder,not the soldering iron. However, if you take too long, the soldering iron can damage the protoboard since it remains there.
  • Finish Strong: Do not remove the soldering iron immediately. First, pull back the solder, then allow the iron another second or two to allow the solder to flow into the joint. Once the solder has cooled, and you are sure everything is perfect, you can then snip any excess wire or material as needed.

Desoldering

Remember, lingering on the protoboard with the soldering iron can damage it, so being too quick is better than taking too long. Since you have to be both precise and fast, there will be mistakes, no matter how skilled you are. When you do not get it right, desoldering becomes important.

Whether you choose to use the “solder sucker” mentioned earlier or the alternative option, a desoldering braid, the process of removing solder is quite easy. If using a desoldering braid, place it over the solder you wish to remove and then touch the tip of the braid with the soldering iron. Once heated, the solder will be absorbed by the braid.

Using a solder sucker is even easier. You heat up the solder with the soldering iron, position the solder sucker near the solder, then depress the plunger, quickly sucking away the solder. Many times, you will need to remove multiple bits of solder from protoboards, making this the more convenient option.

Not Every Solder Job Requires a Soldering Iron

What we discussed before was through-hole joint soldering, which is the most common type of soldering for protoboards. However, there is also SMD soldering, or surface mount device soldering, another form of soldering you may run into when dealing with protoboards.

Let us start by talking about the most common method of SMD soldering, reflow soldering. This is a method that utilizes solder, flux, and an oven, with no need for a soldering iron. It may be the most common method used for protoboards, and it is quite simple. The steps for reflow soldering are:

  • Apply flux to the pads on the protoboard, then add some solder.
  • Place the components carefully. Using tweezers works great.
  • Put the protoboard into an oven preheated to 200 degrees Fahrenheit, then gradually raise the temperature to 400, leaving it for a minute or two before removing it and letting it cool. Timing is still important here to avoid issues later.

It is also possible to SMD solder protoboards with a soldering iron. You still place flux down on the pad and use tweezers to place the parts, but the soldering method becomes more tedious. You must carefully place parts while heating the solder with the soldering iron, which may mean going corner by corner.

Soldering Wires

It is recommended to use a clamp device when dealing with wires, as trying to do it without can be dangerous. The steps to solder wires are:

  • Remove the insulation from the ends of both wires with wire cutters
  • Hold heated soldering iron to the tip of one wire for several seconds
  • Apply solder to the end of the wire, then repeat on the other wire
  • Place the soldered tips of the wires together and bind them using the soldering iron

A Lot Can Go Wrong

The actual steps involved in soldering a protoboard are not all that complex, but getting the perfect result from the process is challenging. After all, the quality of your soldering will greatly impact the quality of the protoboard as a whole, something true for both through-hole soldering and SMD soldering.

Let us start with some of the more basic problems you may encounter with protoboards:

  • Too Much Solder: Often seen in the form of large solder balls.
  • Insufficient Wetting: Less solder than necessary.
  • Cold Joints: Dull and messy in appearance, even pock-marked.
  • Burnt Joints: Appears burnt or oxidized.
  • Solder Bridges: Solder connecting two or more connectors.

Too much solder and insufficient wetting are what many beginners will struggle with. Soldering is a fast process, and it requires precision and experience to do well. As for cold joints, they come from not allowing the joint to get hot enough to melt the solder before application, something we touched on earlier.

Burnt joints are the opposite, occurring when the iron is left in place for too long. This can leave serious damage, potentially even ruining the board. Solder bridges can also be hazardous to the board if not caught, causing it to potentially short circuit. While not mentioned, webbing and splashing of solder can cause problems with a board as well.

SMD Problems

When you fail to reach the necessary temperature when connecting components such as transistors, the final product will not be straight. What happens is that one or more sides will lift, something called tombstoning due to the tombstone-like appearance. Tombstones occur in oven-based SMD as well, occurring when heating is uneven.

There are also parts of a protoboard and its components that can be easily damaged by the heat from soldering. Therefore, ensure you go in with a plan and know what can and cannot withstand the heat.

Helpful Advice

Soldering takes a long time to perfect, especially when dealing with the small components of a protoboard. One of the most important aspects of soldering is practice, especially how to identify and avoid the various mistakes one can make when dealing with protoboards.

  • Practice both perfect soldering and common mistakes related to protoboards. Knowing what each one looks like and what role your actions play will help you grow your skills and perform when it counts.
  • Cleanliness means a great deal with protoboards. This is not just reducing instances of splashing and webbing but also having a clean environment. You want to prevent the pads and joints of your protoboard from being contaminated, potentially rendering your hard work pointless.

Conclusion

Reliability is important, especially with technology, and for a reliable protoboard, proper soldering is vital. While it may seem easy at first glance, there is a lot to look out for to ensure a perfect end product. However, if you keep the five things we have discussed in mind and put in the time, it is a skill you can soon learn and even master.

Sources:

https://learn.pimoroni.com/tutorial/sandyj/the-ultimate-guide-to-soldering
https://electronicsclub.info/soldering.htm
https://www.pcb-repair.com/resources/pcb-soldering-techniques/
https://www.wellpcb.com/blog/pcb-soldering-process.html
https://www.electronicdesign.com/industrial-automation/article/21126406/common-pcb-soldering-problems-to-avoid

Alexander Berk

A bit about myself: I am a certified international welding engineer (IWE) who worked in different welding projects for TIG, MIG, MAG, and Resistance Spot welding. Most recently as a Process Engineer for Laser and TIG welding processes. To address some of the questions I frequently got asked or was wondering myself during my job, I started this blog. It has become a bit of a pet project, as I want to learn more about the details about welding. I sincerely hope it will help you to improve your welding results as much as it did improve mine.

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