ColdHeat

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ColdHeat is an American company founded to develop and market products using the proprietary graphite-like compound it has named Athalite. The composite material is claimed by the manufacturer to have the unusual ability to conduct large amounts of heat and return to room temperature in a short amount of time.

Detail of a Cold Heat soldering iron showing the split tip. The US nickel is for scale reference.

[edit] Soldering iron

The first two products are soldering irons. The manufacturer claims this soldering iron is unique in that its "Athalite" tip undergoes a temperature change from ambient temperature to approximately 800°F and back to ambient within three seconds when the tip is removed from the work.

The tip of this apparatus is split into two sections that completes an electrical circuit when something of low resistance is placed across the tip; e.g. solder. With a current flowing, the resistance of both the solder and the tip produces heat and causes the solder to heat up and flow. For light duty work it was designed for, the "Athalite" tip barely warms at all and can thus cool very rapidly; however if the user attempts to solder things beyond the ability of the iron, this absorbed heat can make the tip very hot and it can take over a minute to cool in some cases.

The original iron is powered by 4 ordinary AA (LR6) alkaline batteries for portability and is capable of melting solder up to 18–20 gauge. The second iron is powered by 5 AA alkaline batteries, to give it more wattage.

The soldering iron has a built-in light. The direct marketing campaigns are geared toward occasional users who may lack soldering experience and to whom safety is important.

A Cold Heat soldering iron viewed from the side. The US nickel is for scale reference.

The device works by running a high current (by electronic standards) through the tip. Running a high electric current through sensitive parts inadvertently may not be a good idea in certain instances. It is a great tool for hobbyists and people repairing metallic items, but if it is to be used on electronics, one should be well aware of how the device works and the sensitivity of components being soldered. When not in contact with a joint the split tip has 6 volts (7.5 volts for the second iron) across it, easily enough to destroy semiconductor p-n junctions on contact if the iron accidentally touches multiple closely spaced pads . This has nothing to do with static-electricity damage; a forward-biased p-n junction may be destroyed by less than 1V applied across it unless the current is limited to only a few tens of milliamperes, which ColdHeat does not do and could not operate if it did (also note that if the iron limited the voltage at the tip to less than 0.1V at all times and had circuitry to increase the current to maintain the wattage delivered, it could work without risking component damage because it could not accidentally forward bias p-n junctions).

Some people debate whether the heat actually comes from the resistance of the tip or from the resistance in the solder. As one ColdHeat engineer said,

It’s a common misunderstanding that high current in the joint causes the heat. The heat is generated by resistance within the tip. Heat is then conducted to the joint just as in traditional solder tools. Also, current in the joint is limited to the small region between the two tip halves and doesn’t pass through the part being soldered. There is a tiny transient voltage when the tool is applied or removed, but it is orders of magnitude below the levels that cause static-electricity damage.^{[citation needed]}

This statement is incorrect in that electro-static damage can occur at as little as 20V, and 6V is less than one order of magnitude smaller than 20V.

[edit] Criticism

Common criticisms include that the tip is very fragile and therefore easily damaged (and almost as expensive as the entire unit), that the unit doesn't have enough wattage for effective desoldering of many board-mounted and chassis-mounted components, and that the design of the tip is incompatible with some unusual soldering techniques such as continuous flow soldering (a popular technique for hand-soldering high-pin-count SMT packages, based on the principles of wave soldering). ^[1]

Another issue is that the ColdHeat device causes damage to electronic components due to the high current that flows through the tip as mentioned earlier.

The device also does not work with rechargeable AA batteries. When directly shorted, as they are in this iron, such rechargeable batteries may explode, causing injury to the user.

Alkaline batteries are specified for use, but in rare instances, these too have been known to explode.

[edit] Other Products

Currently ColdHeat features products other than the soldering tool that use the same technology, including a cordless hot-melt glue gun called Freestyle. It heats up much more quickly than others (but not instantly like the solder tool.) It comes with a built-in stand, a pack of mini glue sticks, rechargeable battery, AC adapter, and an instructional manual and a book with different project ideas.

ColdHeat has recently released a cordless heated seat, as well as a selection of heated pet beds.