OUTLINE
This procedure covers the general guidelines for soldering through hole components using a point to point soldering method. There is basically only one style of through hole component. Whether there are a few leads or many or whether the component is large or small the soldering principles are the same.

  

PROCEDURE REFERENCES
CTC 7721	1.0	Foreword
CTC 7721	2.1	Handling Electronic Assemblies
CTC 7721	2.2	Cleaning
CTC 7721	2.5	Baking and Preheating
CTC 7711	7.1.1	Soldering Basics
CTC 7711	7.1.2	Preparation For Soldering And Component Removal
CTC 7711	7.1.3	Solder Joint Acceptability Criteria
IPC 7711	7.2.1	Soldering Through Hole Components, Point To Point Method

TOOLS & MATERIALS
Cleaner
Flux
Microscope
Soldering Iron with Tips
Solder
Wipes

PROCEDURE

1. If needed, form the component and clean the area.



2. Insert the component into the plated hole. If needed, secure in place by bending leads or other mechanical means.



3. If needed, apply liquid flux to the plated holes and pads.



4. Place the soldering iron tip at the junction between the pad and component lead. Apply a small amount of solder at the junction of soldering iron tip and lead to make a solder bridge. (See Figure 1).

   NOTE
   The size of the solder is important when soldering small components. If the solder is too large, it is easy to melt too much solder into the joint. If the solder is too small, it can take too long to melt the optimum amount into the joint.
   
   

   CAUTION


Avoid exerting any pressure on the pad.


5. Immediately feed solder into the joint from the side opposite from the soldering iron tip until the proper fillet is achieved. Remove the solder then remove the iron. The iron may be swept over the end of the component lead to cover it with solder. (See Figure 2).

   NOTE
   Apply the solder to the side opposite from the soldering iron tip so that the work surfaces and not the iron will melt the solder.
   
   

6. On multiple lead components solder the opposite corners first to stabilize the component. Follow by soldering the remaining leads in a random pattern to reduce excessive heat buildup in one area.



7. Clean the flux residue, if required and inspect.