Paste solder has enjoyed a love-hate relationship with many. Jewelers form strong impressions of its worth, or as some feel, worthlessness mostly because of the way it’s used and viewed.
First, let’s dispel a few myths about paste solder:
MYTH: Paste solder melts at lower temperatures than regular solder.
FACT: Not necessarily, it is available in different hardnesses just like other solders.
MYTH: Paste solder is the ultimate solution for all soldering woes and can replace sheet or mire solders.
FACT: Again, not so. Paste solder has its purpose and place, and in these applications it works very well; however, take it out of its proper environment, and you may set yourself up for some disappointment.
Tell Me About It
Paste solder is intended to join small surfaces or surfaces that fit together with extremely close tolerances. The vehicle in which the powdered solder is embedded (most notably flux) makes up a large portion of the volume of paste solder. Using too little causes much of the trouble experienced with paste solder.
When the solder melts and begins to flow, it also begins to alloy into the surface of the metal (solder erosion) when you overheat it. The typical reaction is to add more heat to make the solder flow. Unfortunately, there is no solder left to flow and the surface of the piece begins to oxidize. At this point, you tend to add more solder, and it refuses to flow as well due to the oxidized surface. The trick to using paste solder is to use a little extra and heat it with a neutral to slightly reducing flame, never an oxidizing flame.
- Paste solder works well when you need to join earring posts to the earring.
- You can also use it to close jump rings that have a lap joint.
- Paste solder works best along joints that do not require the solder to flow and draw.
- We do not suggest using past solder for sizing and retipping. There is no advantage in that application.
- Paste solder is not the best choice for repairs that require a butt joint. Do not expect to draw paste solder along a seam as the solder particles are too small to flow any distance.
BONUS! Rose gold's on the rise. Learn how to solder the blush medal in this video.