About electric soldering iron purchase skills
Is it better to heat the soldering iron internally or externally?
Internal heat soldering irons are smaller and less expensive. The internal heating type electric soldering iron has higher heating efficiency, and it is more convenient to replace the soldering iron tip. The heating core is installed inside the tip of the soldering iron, so the heat loss is small. Common internal heat and lead-free long-life internal thermoelectric soldering irons on the market have powers of 20W, 25W, 35W, 50W, etc., of which 35W and 50W are the most commonly used.
The external heat type is as the name says, "external heat" means "heating outside", so named because the heating core is outside the electric soldering iron. It is suitable for welding both large components and small components. Since the heating resistance wire is outside the tip of the soldering iron, most of the heat is dissipated to the external space, so the heating efficiency is low and the heating speed is slow. Generally, it takes 2 to 5 minutes to preheat before welding. Its volume is large, and it is inconvenient when soldering small devices. However, it has the advantages of longer use time and higher power of the soldering iron tip. There are various specifications such as 25W, 30W, 40W, 50W, 60W, 75W, 100W, 150W, 300W and so on. High-power electric soldering irons are usually externally heated.
How to use a soldering iron, how to use a soldering iron?
1. Select suitable solder, low melting point solder wire for welding electronic components should be selected.
2. Flux, use 25% rosin dissolved in 75% alcohol (weight ratio) as flux.
3. The electric soldering iron should be tinned before use. The specific method is: heat the electric soldering iron, and when it can melt the solder, apply flux, and then apply solder evenly on the soldering iron tip, so that the soldering iron tip can be eaten evenly A layer of tin.
4. Soldering method, polish the pads and component pins with fine sandpaper, and apply flux. Dip an appropriate amount of solder with the tip of the soldering iron and touch the solder joint. After the solder on the solder joint is completely melted and immersed in the component lead, the soldering iron tip is gently lifted away from the solder joint along the lead of the component.
5. The welding time should not be too long, otherwise it is easy to burn the components. If necessary, use tweezers to clamp the pins to help heat dissipation.
6. The solder joints should be in the shape of sine wave peaks, the surface should be bright and smooth, without tin thorns, and the amount of tin should be moderate.
7. After the soldering is completed, use alcohol to clean the residual flux on the circuit board to prevent the carbonized flux from affecting the normal operation of the circuit.
8. The integrated circuit should be soldered last, and the electric soldering iron should be reliably grounded, or use residual heat for soldering after power failure. Or use a special socket for integrated circuits, and then plug the integrated circuit after soldering the socket.
9. The electric soldering iron should be placed on the soldering iron stand.
