Differences in Solder
So you’ve taken up soldering, eh? Or maybe you're just thinking about it… Perhaps you’ve seen the blog about the components of a soldering iron and even purchased one. Without going into the WHYs of soldering, let’s navigate the myriad of solder types.
Types of Core:
- Acid core: This has a wire form but is filled with an acid-based flux (flux being a chemical cleaning or adhesion agent- think “prepping the surface”). Don’t use this unless you’re a plumber or working with sheet metal.
- Rosin core: Also a wire form but filled with a material based on resin. You will want to use this in your electronics applications. (Tip: look for RMA, mildly-activated, rosin.) Note, though, that you will have to clean up the residue unless you buy the “no-clean” kind. If you have asthma or are doing an application in a place for youth, however, you may want to do more research to find a more appropriate core.
Types of Materials:
- Lead: Although its benefit is a lower melting temperature, you might not want to use it. If you don’t know why, search “lead side effects” in your preferred browser. If you still decide to use it because of its ease to work with (like many pros still do), just have common sense, follow all precautions, and don’t sell your product to anyone in Europe.
- Platinum, Gold, or Silver: For jewelers. Silver has some benefits in electronic applications but those are not usually worth the added cost.
- Indium: Low melting point and high resistance to temperature swings. Often used to solder to gold or for cryogenic applications; somewhat expensive.
- Copper: Copper plus tin equals bronze, copper plus zinc equals brass. Copper improves the wetting properties and resistance to thermal cycle fatigue. (Wetting or wettability refers to the ability to stay on a solid surface, versus kind of rolling off.)
- Nickel: Increases melt fluidity, has a prettier shinier finish- a very good addition.
- Antimony: Increases strength and prevents “tin pest” (aka deterioration). Do not use on zinc, cadmium, or galvanized metals unless you want brittle joints. Does not affect wettability.
- Bismuth: Lowers the melting point and improves wettability but not worth using because of expense and its proneness to cracking.
- Tin: very widely used but best when in an alloy; no good on its own unless you like “tin whiskers”.
- Zinc: Low cost and low melting point but pretty corrosive and susceptible to oxidation.
- There are a few more, less known additives but that’s enough to get you started.
Basically you can get any diameter wire you want but here’s a guideline: buy two thicknesses, 0.8mm (0.032”) and 1.0mm (0.039”). The 0.8 will be for surface mount components, and 1.0 will be for wires and leads.
If you want to worry the least about environmental implications and clean-up, search “lead free” and “no clean” then filter by type, etc. M many sites provide reviews you can read and filter by. Kester is a reputable brand that will give you more options than you can shake a stick at, so give that a whirl we highly recommend their products!