We’ll begin by building the solder fume hood. Yes, we said “hood”, not just “extractor”. While there have been some nice fume extractors hacked together, this system integrates all of your soldering tools into and around the fume hood.

The purpose of a fume hood is to draw solder fumes away from the person soldering. Besides the health risks, these fumes are really annoying as they follow that pesky law of the universe: “No matter where you happen to be sitting, solder fumes will float directly towards your face.”

To start, let’s gather materials:

Once all the materials are gathered, we can begin cutting the plastic of the Rubbermaid container. To cut this material, use a plastic scoring tool. When you make your cuts, make sure to repeatedly score the line you want to cut until the blade goes all the way through the plastic. Do not try to score it and snap it like acrylic. This material has a bad tendency to crack in places you didn’t intend. If your plastic cracks, all is not lost. Since the plastic is soft, you can weld the cracks back together by touching it with the tip of a high temperature hot glue gun.

First, we need to cut a hole for the fan in the top of the hood. Take off the cover of the fan and use it to make a hole slightly smaller than the inside diameter of the fan cover in the top center of the hood. The fan is actually going to hang from the top of the hood and pull the fumes out of the hood when turned on.

Once the big hole is made, drill smaller holes for the screws used to hold the fan together. With the nuts on the outside, screw the fan assembly to the top of the hood.

To reattach the top cover of the fan, use some scrap solid core wire or twist-ties to connect the spars on the top cover to the spars on the bottom fan assembly. We used only three twist ties as this is plenty to keep the fan cover in place.

Now we are ready to mount the light. Mark a good place to attach the light in the back top of the hood. It is likely that the mounting screws that came with the lamp are too long. Additionally, the lamp might get too hot. To prevent the lamp from melting the plastic, we cut about five half-inch spacers out of some of the plastic cut off earlier. To make life easier, pre-drill holes in the center of each of the spacers. Use a couple of the spacers on the inside to lower the lamp away from the top of the hood, and then use a few on the outside to cover the sharp points of the protruding screws. Alternatively, encapsulating the screw points on the outside of the hood with hot glue works just as well.

Next, cut the main window of the fume hood. Ours goes all the way across the front and is about 7 inches high. It’s a good idea to start with a smaller hole and expand it to see what feel comfortable for you to use. Make sure it is easy to reach the top back wall of the hood. This is where the controls will go later.

At this point, you can use zip ties to attach the active carbon filter to the top of the fan.

Plug the fan and the light into a powerstrip. Make sure the fan and the light are turned on so you can turn the entire hood on and off from the strip. Plug in the soldering iron and you are ready to go. The adjustable base of the fan is used here to hold the excess wire from the soldering iron; keeping it out of the way.

A slightly more advanced option for the front is to cut another smaller window (about 6.5 by 13.5 inches) just above the first one and add a piece of acrylic. This greatly improves visibility. Make sure to cut the acrylic about a half inch larger than the window to give yourself a surface to glue. Attach the acrylic on the inside of the fume hood with hot glue.

To improve your soldering iron set-up, you can get a professional soldering station. But why spend $50 on a temperature controlled soldering station when you can build your own for cheaper! Afrotechmods has a rough guide to building a great adjustable temperature soldering station.

To install this soldering station into the fume hood, simply cut a hole in the back of the hood large enough to stuff the dimmer and the socket through it from the front side and small enough to make sure the mounting holes still have some plastic to mount to. The box will be attached to the back of the hood, but the faceplate needs to be on the inside.

You’ll notice that there is a different knob on the dimmer switch. We used a scrap knob with a flat bottom (comes complete with cool numbers) on the dimmer switch instead of the stock knob.

Regardless of what soldering station you use, if it doesn’t have auto turn off (which is good for fire prevention), put a grounded AC appliance timer inline with the iron. These timers allow you to automatically turn on or off any AC appliance at any time you want within a 24 hour period, but don’t rely on it to keep your iron turned off, as it will turn it back one every 24 hours. It’s better than nothing and is a cheap option, as they run between 5 and 10 bucks at local hardware and super stores. The one we use has increments of about 15 minutes. Setting it for 30-45 minutes works well.

For some reason, the designers of these timers want to take up all the plug space they can by placing the plug practically in the center on the back of the timer. Luckily, the scrap dimmer knob we found has a low profile, and allows the timer to plug in with little interference to the dimmer. A better option is to get an aquarium timer. These are designed with a better form factor and generally only cover one socket.

Many cheap soldering irons come with a sponge to clean the tip. If you think about it, it’s not really the best idea to use a sponge to clean your soldering iron; it works, but it also cools down the tip of the iron every time you clean it. If you are doing delicate work and clean your tip once every couple of soldering points, this can lead to cold solder joints and bad connections.

Professionals use a flux covered wire mesh to clean the tip. This method draws off the solder and uses flux to clean the tip. Every now and then, you just kind of stab the mesh with your iron a couple of times to clean it off. The problem is that this method costs around $10.

Instead of buying some job specific wire mesh, just use a copper coated scourer to clean your soldering iron tip. Usually used for cleaning pots and pans, these little guys can be picked up at your local grocery store for $1 or so a pack. The copper mesh isn’t coated with flux, but the copper itself will draw the excess solder from the tip of the iron. Do not get the steel scourers, as they are only good for cleaning dishes.

A great addition to our ti
p cleaner is the use of a simple $1 “locker organizer” picked up from the dollar aisle of the local super store. Just shove the scourer into the organizer to keep it from sticking to the iron. The magnet on the bottom will also weigh it down enough to keep it on the table when you make spastic stabs at the scourer in frenzied hacking sessions.

Surface mount soldering is becoming more common amongstl hackers and hobbyists. This work is notorious for being one of the most tedious and annoying practices known to man. Of course, having the right tools for the job helps. The cheapest surface mount rework stations cost upwards of $100. In the past, our own [Will O'Brien] showed how to make your own surface mount reflow iron.

A reflow iron or pen isn’t the only tool you need for surface mount soldering. Sometimes you’ll need a hot plate or oven.

For smaller jobs we’ve found that using a candle warmer can be useful. We got ours for $5 from a super store. The plate might not get completely hot enough to melt the solder by itself, but it does help a lot when you use a soldering iron or a reflow iron by decreasing the time and effort it takes to warm the joints. The sweet spot on these warmers is usually directly in the middle of the black steel plate.

Simply place a PCB in the center of the candle warmer and allow it to raise the temp of the solder joints. Use a reflow pen or soldering iron to heat the particular joint you want the rest of the way. It will take a lot less time to melt the solder this way. This is especially useful when placing surface mount parts, but can also be useful when taking them off of a PCB.

Placing all of these components together inside the fume hood, the Hacker’s Soldering Station is complete. With this project we set out to make a simple, cheap solder fume hood complete with a time and temperature soldering station. We ended up with a great soldering station and fume extractor set up. In fact, this has now replaced one of the WLC100 soldering stations we usually use.

[photo: Nick Bilton]

[photo: Nick Bilton]

The first step of the process is finding electronics you don’t mind taking apart. Next place the PCB you’ll be stripping in a vice, with the components facing away from you and the solder side facing towards you. Grip the component you want with a pair of pliers, and apply a hot soldering iron to the solder that is holding the component. The solder will melt and allow you to safely and cleanly remove the component.

This process can be applied to virtually any component on an PCB, and the author of the guide, [Patented], got a lot of components this way, including resistors, capacitors, switches, audio jacks, and much more. Don’t forget to toss any free-floating metal or plastic parts in the recycle bin when you’re done. You can feel good about the fact that nothing was wasted, you found parts for your next project, and you cleared out some space.

We covered many of [Jason Rollette]‘s personal projects in the past and are happy to welcome him as our newest Hack-A-Day contributor.

The electronics industry has shifted to lead free compliance, but most hobbyists haven’t even considered the personal impact of using lead. Today’s How-To will cover what it takes to switch from tin/lead solder to completely lead free. Our previous posts Introduction to soldering and the follow-up still apply to lead free. You may have never considered switching to lead free before, but we hope to help you make an informed decision.

The reason we are even talking about this is because of the Restriction of Hazardous Substances directive. RoHS was adopted in February 2003 by the European Union; all electronics sold there must comply. The substances restricted are: lead, mercury, cadmium, chromium VI also known as hexavalent chromium plating, and pbb, pbde flame retardants used in plastics. We will focus on lead. Solder joints must contain less than 0.1% lead to be compliant. RoHS is not currently required in the US, but California RoHS, effective September 2003, had a compliance deadline of January 2007.

Although the electronics industry has been directly targeted it only accounts for a small percentage of the lead used in manufacturing. The battery industry consumes nearly 80% of manufactured lead. Tire wheel weights also account for a larger percentage.

There are some good reasons for the hobbyist to convert to lead free solder, both personal safety and environmental. Lead poisoning can occur when lead enters the body through inhalation, ingestion or dermal contact such as direct contact to mouth, nose, eyes, and skin lesions. Even if you keep using tin/lead solder, wash your hands before and after you do anything. Most poisoning cases are from lead building up over time. The main environmental issue is lead leaching into drinking water or watersheds when disposed of improperly.

There are many different varieties of lead free solder. Two alloys seem be the most popular: SAC305 contains 96.5% tin, 3% silver, and 0.5% copper and melts at ~217C, SN100 contains 99.3% tin, 0.6% copper, and some nickel and silver and melts at ~228C. Choose whatever alloy and brand you feel is appropriate for you. Compare those alloys to traditional 63% tin and 37% lead melts that melts at ~183C. The higher melting point is part of what makes lead free harder to work with. We use SAC305 with a “no clean” flux core.

In addition to picking an alloy, you also need to decide on the diameter. We recommend for through hole .032″,.020″ and .015″ for SMT. Choosing the right diameter solder is very important to success. A finished joint viewed from the side should look like a little Hershey’s kiss, not an inflated balloon. The correct diameter solder makes this much easier to control.

A high wattage soldering iron with temperature adjustment is the best choice for precision work. Get a soldering iron with several sizes of replaceable tips for different soldering applications. Having a good iron makes soldering with lead free easier because of the higher melting point. It also helps to keep the dwell time as short as possible reducing damage to components caused by excessive heat.

Choosing the correct size tip for the job is perhaps the most important part for a new person learning to solder. Lead-free is less forgiving and the right tip will go a long way in preventing defects.

Using a tip that is too small will take longer, abuse the tip, and will not efficiently transfer heat to the joint. A small tip will seem too cold or too slow.

Using a tip that is too large will damage the circuit board, over heat and damage the parts, and burn off the flux too soon causing a bad joint.

Use tips that are designed for lead-free. Tips designed for lead free will have the longest life. The iron temperature should be set to 700-800F. Do not use pressure to compensate for lack of wetting and heat transfer; this will cause damage to the circuit board. Heat transfer is optimized by providing the best contact area.

Differences from tin/lead soldering

Tin/lead solder should not be mixed with lead free solder because it decreases the strength of the joint. Lead free parts can be used with tin/lead solder. You should try ordering all parts, ICs, resistors, caps, proto boards, etc. lead free even if you are not using lead free solder yet. This will ease the conversion for you in the future. Consumables such as flux and tip cleaner should be certified for lead free soldering. Flux will need to withstand higher temperatures and longer dwell times, and some tip cleaners have tin/lead solder in them that could contaminate the lead free solder joints.

Not all fluxes are capable of sustaining high soldering temperatures. Flux charring, called “black tip syndrome”, occurs when thermally incapable fluxes turn the tip black and make re-tinning nearly impossible. Heat transfer is severely reduced when this happens. Buying compatible flux is key.

As we’ve said many times: you’ll need to set your solder iron slightly higher temperature than you are used to. You will also notice that slightly longer dwell times are needed because of higher melting points. Wetting or spread is also a little slower when compared to tin/lead. The resulting lead free solder joints will appear slightly grainy and dull compared to shiny tin/lead.

The iron must be kept clean and fully coated with the solder alloy, otherwise at the higher temps oxidation can occur. Solder tips will need to be cleaned and tinned more frequently. Use a wet sponge for cleaning and keep your tip tinned by adding a small amount of solder. In general, all tips will have a reduced life when using lead free alloys.

Lead free solder is more prone to solder bridges (shorts). Tin whisker growth is also possible with high tin alloys, but is poorly understood.

The temperatures required make lead free soldering a different experience, but not out of reach. If you can solder with tin/lead solder, you can solder lead free. If you are having problems soldering, maybe some of the tips here will help. Remember, soldering takes practice; solder, desolder, resolder some old circuit boards from computers or consumer electronics before attempting a project. Otherwise you can’t expect a perfect outcome. Knowledge, practice and experience will provide the consistency required for excellent hand soldering results. Please share any experiences you have working lead free.

Having the right tools and workspace are key to successful soldering. The actual technique is pretty simple. We will cover all the basic tools you need, the key to good soldering, and how to undo your mistakes or harvest components from old hardware.

The first thing you’ll need is a decent soldering iron. Weller makes a decent product, but RadioShack’s are dirt cheap if you’re in a hurry. My favorite iron was a temperature controlled Tenma with LED temp display (sadly lost from a crappy storage unit along with my oscilloscope).

Most soldering stations come with a sponge; they get lost and they tend to hold onto bits of solder. I actually prefer to use a paper towel instead. Either way, wet it down and give it a squeeze so it’s not sopping wet. If it dries out, it’ll burn when you wipe your iron on it.

Buying the right kind of solder is just as important. It comes in various thicknesses, metal alloys, and core types. I won’t get very deep into the alloys. Generally, you want 60/40 (60% tin, 40% lead). Most modern electronics are lead free, but for hobby work lead is fine. Just wash your hands when you’re done! The solder produced for plumbing work is usually very thick (left hand side) and has a solid metal core (or worse: acid core). For electronics work, you’ll definitely need rosin core. The rosin acts as flux for the solder, allowing it to flow onto and attach to the metal. You can certainly use liquid flux/rosin, but it’s usually not easy to find locally. For thickness, I always buy the thinnest rosin core I can find. To sum up: you want thin, rosin core, 60/40 solder.

Not all iron tips are created equal. For fine work, I always reach for my 15 watt Weller pencil iron. It has the smallest tip I could find, and I ground an even finer point on the tip with my rotary tool. The bigger iron is an inexpensive RadioShack station that I keep in my office to handle favors for coworkers.

Every so often, the tip of a soldering iron needs a little maintenance. If the end of the iron isn’t tinned, as in bright and shiny when you wipe it down, you’ll have a hard time getting solder to melt. Think of this stuff as a sort of pumice stone for your iron. Heat the iron up and rub the tip in the cleaner. The cleaner will melt a bit and your soldering iron should work better than ever.

Securely holding the work piece is important, but your hands will be busy with the iron and solder. My current favorite tool is this Panavise Jr. which runs about $25. Props to Ladyada for unknowingly turning me onto Panavise products. If you need something cheaper, you can score a set of helping hands – it’s set of alligator clips connected to a weighted base. They work great and I still use them for smaller soldering projects.

Some projects require extra fine attention to detail. A giant magnifying glass lamp comes in handy when visually inspecting for shorts and dealing with surface mount problems (I inherited this one one from my grandmother). You’ll be fine without one, but they’re great when you need to work on really small components or when your eyes are getting tired.

For one-off projects, prototyping boards from RadioShack are handy. They’re cheap, easy to get, and making a connection is as simple as bridging your solder across the copper pads.

Before investing your time soldering parts together, it’s a good idea to prototype your circuit. Breadboards like these are great for preventing frustration later on. When I tried to buy my first one, I was about 10 years old. Nobody knew what the hell I was talking about and the local RadioShack apparently didn’t keep them in stock. People at RadioShack kept trying to sell me kitchen cutting boards. After about a year of wondering if [Forrest Mims] was insane, I finally visited another RadioShack that actually had them.

Don’t bake your bits. Passive components like resistors or small ceramic capacitors don’t usually suffer any problems from being heated up, but you should still pay attention to how long you’ve been cooking them with your soldering iron. If you’re having problems getting a solder joint just right, let the parts rest for a few minutes so they have a chance to cool off between soldering rounds.

Integrated circuits like this logic chip are usually far more sensitive to heat and static than passive components. Sockets are cheap insurance against blowing a chip.

RadioShack sells the small red handled clip as a heat sink. It’s okay, but a generic hemostat like the one above works and holds on even better. They’re also great for saving your finger tips from burns by holding wires in place while you solder them.

To successfully solder a component, don’t melt the solder on the iron. Put the iron against the copper on the board (solder pad) and the component you want to attach. Give the iron a moment to heat up both of them. Then melt the solder on the component and, if needed the copper pad.

Do not melt the solder on the tip of the iron. Sometimes it’s necessary to melt a small amount on the iron to facilitate heat transfer, but to achieve a good connection, you want the solder to melt and flow onto the component leads.

Heat up the component with the iron just before applying solder!

Once the joint is good, the soldering iron can be used to remove small amou
nts of excess solder from the joint.

Wipe the solder and burn rosin off by pulling the tip across your wet sponge or paper towel.

The joint should be good if the solder flowed onto both the copper pad and the wire lead of the component.

Now you’ll need to trim down the excess wire lead of the component. If you use diagonal cutters, the piece you cut off will probably fly through the air. These flat cutters are my favorite: the metal wire stays still and the resulting edge isn’t nearly as sharp.

Nobody’s perfect. Sometimes we need to remove a bad component or undo a mistake. Desoldering braid works sort of like a sponge for excess solder.

To desolder something, just place the braid over the target and apply your soldering iron over the top. The heat should transfer through the braid and the melted solder will flow onto the the copper like oil though a wick. For larger amounts of solder, I normally pull out my bigger iron. For small amounts, even the pencil iron does the trick.

For larger desoldering jobs, like recovering components, a desoldering iron works wonders. The hotter the better, so let it warm up for a while before using it.

Compress the bulb with your thumb before you touch the board with the iron.

Once it’s in position, give it a moment the heat the solder and release the bulb. The bulb with suck up the solder through the hollow tip. Larger components might take a few hits, but smaller ones usually only take a single pull.

We’ve covered all the basics: the tools, soldering and desoldering. If you’re looking for a good starter project, I highly suggest taking a shot at making your own headphone amplifier. I built this one from RadioShack parts (I had some high end opamps in my parts bin). It’s a rewarding, low cost project. If you want an even more illustrated guide, check out these basic videos from NASA or even this collection of videos from Solder.net.