The exact definitions of an internally heated soldering iron and an externally heated soldering iron are described below:
(1) Endothermic soldering iron:
As the name says, "internal heat" means "heat from the inside", then the relative position of the heating element and the copper head should be "the heating element in the inside of the copper head of the solder", or explained as "its iron head over the outside of the heat generator", so that the heat is transferred to the iron head from the inside, which has the advantage of fast heat up and high heating efficiency. For "its iron head set in the external heat generator", so that the heat from the inside to the iron head, with fast heat, high heating efficiency, small size, light weight, power consumption, use of dexterity and other advantages. Suitable for welding small components. But due to the high temperature of the soldering iron head is easy to oxidise black, the iron core is easy to be broken, and the power is small, only 20W, 35W, 50W and so on several specifications.
From the above explanation, then in the end what kind of soldering iron is endothermic soldering iron is very obvious, here and then on the map:
Endothermic soldering iron used in the shape of the iron head is hollow cylinder, the heating element is the iron head set, so that its heat is not easy to disseminate to the air, so the heat utilisation efficiency is higher, shorter preheating time, and the power generally do not have to do too much to meet the requirements of the general endothermic power of 50W or less, common 20W ~ 30W or so of the endothermic soldering iron.
(2) Externally heated soldering iron:
As the name says, "external heat" means "heat outside", because the heating resistance in the outside of the soldering iron and so named. It is suitable for soldering both large components and small ones. Due to the heating resistor wire in the outside of the iron head, most of the heat is emitted to the external space, so the heating efficiency is low and the heating speed is slow. Generally it takes 6 to 7 minutes to preheat before soldering. Its volume is large, welding small devices appear to be inconvenient. But it has the advantages of longer use of the soldering iron head and higher power, with 25W, 30W, 50W, 75W, 100W, 150W, 300W and other specifications.
