How to Use a Solder Iron

Soldering irons come in micro (12 watts) to large (100-plus watts). The super small, low wattage soldering irons are used for soldering very small work. The average consumer soldering iron is 25 watts. To solder, two or more pieces of metal are heated up quickly. A flux and solder are applied and they flow into the joint, bonding the metal pieces together to form a strong joint. Flux is a chemical cleaner which cleans oxides from metal surfaces to prepare them to accept the solder. Solder is a low melting point (soft) alloy often composed of tin and lead. Flux-cored solder is a solder with the flux included in the center.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Soldering iron
• Solder
• Flux
• Distilled water
• Sponge
• Bowl of water
• Emery cloth
• Gloves
• Large tweezers
• Mechanical hands, metal brush, steel wool are optional

Using A Soldering Iron

1. 
    
   Typical soldering iron.

   Assemble the soldering iron. Many irons come with a variety of tips such as a chisel, conical, rope, smoothing, foam cutter and score. They also have different size tips. Insert the smallest tip you can use for the project. You can rest the hot iron in a stand so it won't contact anything accidentally.

2. Place the soldering iron on its stand before plugging it in. The tip will get hot immediately and careless handling can cause burns. If the tip contacts material other than solder it will have to be cleaned and tinned (have solder applied to it) again before it will wet properly.

3. Clean the metal surfaces of the objects to be soldered. Flux will remove oxidation, not dirt, oil, grime, grease or other contaminants. Sometimes cleaning means just a quick scrub with a metal brush or steel wool.

4. 
    
   Mechanical arms and clamps with magnifying glass for close work.

   Insert very small items to be soldered, such as jewelry, into mechanical clamps, which have two or more small, easily positioned alligator clamps on a stand. These hold the metal pieces in place for soldering so that you can hold the soldering iron with one hand and the the solder spool with your other hand. Sometimes only tiny pieces of solder are used; these can be melted into balls, then picked up and placed precisely.

5. Use a brush to apply flux to the pieces of metal where solder will be applied.

6. Plug in the iron. The tip should heat quickly. There should be a glistening drop on the end of the iron. This solder is left on the tip intentionally to keep stored tips from oxidizing.

7. 
    
   Solder on a spool.

   Apply solder on pipes by feeding the solder wire along the seam between two pipes. For other solder projects, bits of solder are snipped off and applied to the clean and fluxed surface with tweezers. Be careful not to handle the solder; skin oils can cause the solder to lose adhesion.

8. Return the soldering iron to the stand. While it is hot, wipe it clean with a sponge dipped in distilled water; minerals in tap water can degrade the tip. After wiping it clean, the tip should be tinned with a small amount of solder. If the tip becomes oxidized, Use an emery cloth and, when the tip is hot, wipe away the oxidation. The iron should be immediately tinned again to protect it from further oxidation while stored.

Tips & Warnings

• Use the right size tip for the project. Heat in the iron tip will diminish as heat transfers from the tip to the metal pieces. Properly applied solder will have a shiny appearance. Use long tweezers to move metal pieces if they are still hot. Wear a glove if you need to touch any metal.
• Soldering irons can easily burn the skin or other objects.

References

• Action Electronics