- Never touch the soldering iron, past the handle. It will melt your skin.
- Always put the soldering iron back into its holster when not in use. Do not ever leave it lying out in the open.
- Always turn off your soldering iron when unattended, no matter for how short a time. Want to go to the bathroom? Turn off your station. Your mom called you? Turn off your station. An armored truck crashed outside and cash and gold is spilling into the street? Turn off your station.
- Always make sure your soldering station is free of clutter and especially flammable materials.
- Do not touch your eyes, nose, or mouth when soldering. Solder and components can contain lead and other toxic compounds.
- Do not breathe in soldering fumes. Rosin fumes are toxic and can cause extreme irritation of the eyes and throat. Prolonged exposure is a serious health risk.
- Always wash your hands with soap after handling solder, flux, or electrical components.
Identifying Good Solder Joints
A solder joint is where the component and the soldering pad join. This is where solder bonds the components and pad together. There are two types of solder joints, a good one and a bad one.
Fixing Bad Solder Joints
- Too Much Solder: Usually this is not a problem, for us if it is not causing a short leave it be. But if you want to wick some solder away, what you do is use your soldering iron to reflow the joint, and either use a solder sucker to suck up the excess solder, or quickly whisk your iron away and it will pull much of the excess solder.
- Not Enough Solder: To fix this simply re solder the joint.
- Cold Joint: To fix a cold joint, simply reflow / resolder the joint, and make sure enough heat is applied that the solder physically bonds with he component and pad.
- Too Much Heat: This happens when your iron is too hot or has spent too long touching the component / pad. Not really a fix I know of for this, leave it be and try to be quicker next time.
- Short: Very common problem and simple fix. Using your wet iron, place it in the middle of the connected (short) joints. The solder will reflow between the components, if using a solder sucker suck away the excess solder now, if not using a solder sucker you simply need to quickly remove your iron once the solder has reflowed, and your iron should pull off much of the excess solder and the short should be fixed.
- BIGGER IS BETTER: When soldering make sure as much of the soldering iron contacts the pads and component as possible. The more surface area the iron is touching the more quickly and evenly the component and pad can heat up and flow solder. Make sure you are using a tip that is large enough to heat the components used.
- DON’T USE THE TIP: Heat is transferred via surface area contact. The more of the iron making contact, the better. The soldering iron tip has very little surface area and will not effectively heat and flow solder to components.
- WET YOUR IRON: Wetting an iron is making sure there is always some solder covering the irontip. Keeping melted solder on your irontip increases the surface area it can touch and helps melt and flow solder. Dry irons are incredibly difficult to melt solder with, and are bad at transferring heat. Keep a small coating / blob of solder on your iron.
- CLEANING YOUR IRON: Before you solder, wipe your hot iron on a damp sponge or brass wire, and then immediately melt some solder back on the irontip. During soldering you may wipe excess solder from your tip on the sponge/brass wire as often as you like, just make sure to always re apply solder. Never leave your iron without a coating of solder.
Through Hole Soldering Procedure
- Wipe down your work area to ensure it is free of dust and debris.
- Ensure that your PCB is free of any contaminants. To do this wipe your board down using 90% isopropyl alcohol and a microfiber cloth. This is not necessary for us, as long as the board is not visibly dirty or contaminated no cleaning is required.
- Place through hole components onto the board. Make sure the components are orientated correctly and are the correct value.
- Bend the leads against the board so that the components are firmly in place.
- Solder through hole components by holding the soldering iron to the component lead and the pad simultaneously, then feed solder into the joint.
- When the board is complete, if needed, wipe away excess flux using a microfiber cloth dipped in a small amount of 90% isopropyl alcohol.