Order now! Operators are standing by! I'm sure you have seen the TV spots for the latest and greatest products that we just can't live without. Recently there was one that caught my eye and as an engineer, might have caught your eye as well. It's advertising the Cold Heat cordless soldering tool.
The commercials promise that you can solder wires together and then immediately tuck the tool, tip first, in your pocket without burning you and your shirt. As an engineer, a good soldering iron is an essential tool in my kit. A really good bench set is critical to making solid repairs and connections. So when I first saw the commercials for Cold Heat, I have to say I was skeptical of its capabilities.
When I was offered a chance to demo the soldering tool without the chance of feeling taken for my money, it was too good to pass up. First, I'll lay out a few observations and details on the soldering tool. It operates on four AA batteries. It also comes in a small carrying case that protects it from being damaged in your tool kit. It also has a plastic cover that goes over the tip to protect it, and a bright blue LED below the tip provides light directly on your work. A red LED on top of the tool shows when the tip is hot. I found the tool to be easy to hold on to but had some difficulty controlling it when using it in a tight area on a circuit board.
Eager to figure out how it works, I picked up the directions that came with it. It's actually a simple process. Heat is generated when the two electrically insulated electrodes make contact with metal. It's a controlled short circuit. That is the simplest explanation. The electrodes cause a short circuit across the surface of the material being soldered. This is how the tool claims to cool so fast. Once the short circuit is removed, the current has stopped and the heat is gone.
Performance at a glance
Heats and cools quickly
Operates on four AA batteries
Averages more than 700 joints per battery pack
Tip heats only during soldering
Includes plastic case
The tip is made of a material called Athalite, which is covered by patents and pending patents for the manufacturer. The tip is two pieces of Athalite with an insulator between them. This split tip is where the action occurs. According to coldheat.com, the tip temperature reaches about 800 degrees Fahrenheit within 1.2 seconds and cools to room temperature in less than three seconds.
It was easy to confirm the rapid heating. Once a short was in place, the solder would melt. Testing the cooling aspect took some time; I had to overcome the instinct to avoid being burned. It took several attempts before I could bring myself to grab the tip three seconds after making a connection. Once I did, I was surprised and relieved to find that the tip was cool.
You might wonder what Athalite is and where it comes from. After reading about it and searching the Internet, all I can say is that it's a patented, resistive material that supposedly is fairly malleable and the Cold Heat people are keeping its real composition pretty quiet. From what I was able to learn, they are talking to several companies on how to apply it to more applications. Keep your eyes open for the name in the future.
The demo model came with a small piece of project board and a few attached resistors. I quickly read through the instructions and found that the first thing I needed to remember is to not press hard. The tips are fragile and pressing down doesn't make the heat transfer faster because even though the tool is on, there is no heat until you make a connection between the split tips.
The directions state clearly that “the tool is intended for hobby or light professional use in electrical projects with medium-sized components.”
I tried the tool on an XLR connector and had little luck at first. It took some practice but after a while I was able to make connectors as fast as with my bench soldering iron. Instead of laying the tip inside the connector's soldier cup and then getting soldier to flow, I used the edge of the cup to create the short and allowed the whole cup to heat to get the solder to flow. Once I figured it out, it wasn't too bad. However, do not make an XLR connector and then touch the tip. It gets hot and stays hot for several minutes because of the amount of heat needed to solder a connector this size.
I also tried Cold Heat on several types of circuit boards I had lying around the back room. One problem I found was that due to the amount of heat needed at times to get a component to release from the board, I lifted more than one solder trace. After some practice I got better at it but I would recommend practicing before trying to repair the only board in your transmitter that you don't have a spare for. The small piece of project board was an easy victim when it came to lifting the copper traces on it. Something else to remember, because of the heat involved, is that connections stay hot a lot longer. So when soldering on temperature sensitive material, heat sinks are a must. It's also difficult getting into tight areas on boards when you need to work between components. It is a bit bulky at the end.
Cold Heat comes with a bevel tip but also has chisel and conical tips available. Each tip has a unique shape for various uses, and can be changed by simply pulling the current tip out and sliding the next tip in. The manufacturer also states that the tips work best on 18 to 20 AWG wire. Battery life is rated at about 700 to 750 joints, although this will likely be a lot less if you are making XLR connectors.
Overall, it's a nice package and I can see its uses in broadcast engineering, especially in a portable kit for on-the-spot repairs. It's not going to replace the soldering iron in your regular kit. If it saves you a little time every time you use it by not having to wait for your corded iron to heat and cool, it will pay for itself after a while.
Kramer is director of radio engineering for Radiovisa, Sherman Oaks, CA.
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