1. Intermediate Course (10) Soldering Karl Davies East Kent Radio Society EKRS 1

2. Soldering The accepted definition of soldering is:- The joining of metals using a filler material of a lower melting point than that of the parent metals to be joined. Note that some metals are easier to solder than others:- Tin, Copper and Brass are far easier to solder than Steel or Aluminium 2

3. Soldering Procedure The secret of a good solder joint is clean, clean and clean again. A solder joint is produced by:- 1) First thoroughly cleaning both surfaces to be joined. 2) Tin both surfaces. 3) Mechanical fix the components together. 4) Then apply heat to the joint and bring the solder to the joint. Ensure Soldering Iron tips are tinned or ‘wetted’ just beforehand to help transfer the heat 3

4. Solders Traditional Solder is an amalgam of Tin and Lead. The percentage of each of these materials defines the use for the solder %Tin %LeadUse 60 40Good for all electrical and mechanical work 45 55Very liquid used in plumbing 50 32Low melt solder for white-metal casings Plumbers solder is not suitable for electrical work Modern Lead Free solders need higher temperatures and greater care is needed 4

5. Solder Types Solder comes in many forms:- A solder stick with separate flux Solder Pastes good for joints outside, easy to use Multi-core solder is the usual form for electrical work Flux is present in many solders to remove surface Oxide layers and assist solder flow 5

6. Multicore Solder Flux Solder 6

7. Solder Joints BAD JOINT: TOO MUCH SOLDER BAD JOINT: TOO LITTLE SOLDER SOLDER TAG DIRT WIRE SOLDER TAG GOOD JOINT: OUTLINE OF WIRE SHOWING THROUGH SOLDER 7

8. Soldering Safety Remember:- Use soldering-iron stands to prevent accidental contact with the hot bit of the iron when not in use. Soldering work benches must be well ventilated to avoid inhalation of solder fumes. Always use eye protection when soldering to prevent solder or boiling flux from splashing into the eyes. 8