Two soldering questions?

Question

Hi, I have two questions about soldering components in a monitor:

1. I read that I should use very thin rosin-core solder. So I bought a roll of RadioShack solder, .022 dia (no unit of measurement specified), 62/36/2, Item # 64-013 E. But then I read that I need 22swg solder for this kind of work, which appears to be 0.7 mm in diameter. Is this the same thing? If not, which should I use?

2. Are all heatsinks the same? I read online that I could use a regular alligator clip because it is "just as good" as a "special tool." I have a regular RadioShack heatsink. Is this okay?

(Please, guys, do not post answers that warn me that I will drop dead if I try this. This is an LCD monitor, I know how to discharge the capacitors safely, and it's fine! I just need help with the soldering.)

1. Well, I'm using a 30-watt iron, which is hopefully okay, unless you guys tell me otherwise.
2. And: what capacity heatsink would you suggest?

Answer 1

You will not drop dead from an LCD. It is CRTs that are good for that. LCDs only hit about 1 KV on the backlight inverter, and then it is 300V to 600V while operating.

CRTs run 25kV to 30kV and the CRT itself is a capacitor capable of holding about 1 joule of energy.


Meanwhile, it depends on what you are soldering. If you are doing some surface mount stuff then that is all too big. On the other hand if you are doing some TO220 packages in the power supply you should be fine.

All heatsinks are not the same. Whoever told you to use an alligator clip needs a smack round the head. Why not use the heatsink of the part you are replacing? That was the one designed for the job. If you want something better, then pick a similar size and design from a better material, or a bigger one of similar design, or the same size but with more surface area. Watch out that it does not touch anything it should not the metal tabs on power transistors are a contact.

Careful soldering thin tracks, it is easy to lift a track from the heat of the iron. Also if you are removing components get a good solder sucker to get rid of the existing solder - it makes life a LOT easier.

Answer 2

The 0.022 diam solder is in inches; the metric equivalence is 0.56 mm. From that standpoint it is less than the 0.7 mm diameter recommendation. I would not worry about that.

The 22 swg solder is 60/40 ratio of tin / lead. Your solder is 62 / 36 and I am not sure the softening point is the same. It may work ok but it is not the same.

I would use 22 swg solder as specified.

No all heat sinks are not the same. They are rated in their heat transport capacity. If you do not carry away enough heat you will heat damage the components; if you carry away too much heat the solder won't melt.

Finally the soldering iron is another issue. To small and things will never get hot and the boards will be damaged; too big and you can burn things out.

Answer 3

The heat sink question answer depends on what you are
soldering- if passive components, just solder quickly and
move on...if transistors and the like, I used a hemostat clamp
to keep stuff cool. The alligator clamp should be fine.
Solder that you have and the iron both sound OK to me.
I presume that you know how to solder already.