VLF-3 Rev #1C Assembly Instructions
9
IMPORTANT Note for New Soldering Irons:
A new soldering iron must be “tinned” in order to work well. Follow these steps:
1. Plug in the iron.
2. When it first heats up, apply solder liberally to the tip.
3. Wipe off the excess solder onto a damp sponge and you are ready to go!
When done soldering a joint, the solder should be shinny and appear to wick onto the
component lead and onto the copper pad on the PCB (a concave shape). If the solder
curves inward away from either, a convex shape, then that might be a cold solder joint
where there is not a good electrical connection between the parts. Too much solder will
be bulbous at the joint. Insufficient heat to the wire or PCB will result in solder not
flowing onto the metal to make good contact. Solder is used to make that good
electrical connection; it is not good for making a strong mechanical connection. If
necessary, briefly reheat the component lead and copper pad to try to flow the solder.
If necessary had a very small additional amount of solder, but avoid prolonged contact
with the soldering iron or you may damage the component or PCB copper pad. You will
likely see an amber colored brittle material near joints you have soldered. That is rosin
that is inside the solder to begin with. It helps the solder to wick onto the lead and
copper pad. It can be scraped away gently if you want to clean up the job after
finished. The solder you use should be for PCB use, not plumbing on copper pipes.
The PCB variety has a very small diameter, perhaps a millimeter. The plumbing kind
might be 3mm in diameter. Don’t go to a plumbing supply place to get solder. Also, do
not use a soldering gun for this work; it gets too hot. Use a 15-25 Watt soldering iron.
It takes little heat to do this, though more than enough to burn yourself. If you happen
to splash liquid solder onto yourself, fear not. It will hurt, but only briefly and not with
much consequence to your skin usually. This isn’t like having hot glue wick onto your
finger. Trust me, you do not want to experience that. Learn from my mistakes young
Padawan.
