Whether you’re new to soldering or a veteran, there are going to be times when the soldering process is seamless, while other times problematic. The most common reason why a soldering session might not be successful is that the solder isn’t melting properly.
If your solder isn’t melting, then it is nearly impossible to get a proper flow for your project.
There are a few reasons why your solder isn’t melting, and it could be a very simple fix or it might be time to replace your soldering iron.
Below are 5 reasons why your solder isn’t melting:
1. Soldering Iron Isn’t Hot Enough
If the soldering iron isn’t hot enough, then the solder won’t melt as it should. Make sure to warm up your soldering iron before you start your stained glass project. It needs to be hot enough to help flow the molten solder through the seams.
The most successful soldering tip temperatures for stained glass are 700°-850°F for leaded solder and 800°-1,000°F for lead-free solder.
2. Using the right amount of flux
If you’re using the wrong flux or even too much or too little, it can inhibit the solder from melting. Try putting just enough flux that it wets the seams and allows the solder to melt and flow as it should. You want a flux that is strong enough will clean any remaining dirt or oxides without ruining the stained glass.
A gel flux can work really well with stained glass projects.
3. The tips are dirty or damaged
If your soldering iron tip is either dirty or damaged, it will stop the iron from transferring heat and therefore the solder won’t melt. If the tip is damaged, then it will need to be replaced.
If the soldering iron tip is still generating some heat, than the tip should be tinned or cleaned. Make sure to remove all the contaminants on the tip so the iron will heat up and your solder will then melt properly.
4. Make sure to use fresh high-quality solder
Not only is it important to choose the right solder, but make sure that it is one that is high-quality.
The best solder for stained glass is a 50/50 solder: 50% tin/50% lead which stays liquid the longest and generally has a melting point of 361° - 413° F. This solder tends to work best for copper foiled pieces.
You can also use 60/40 solder: 60% tin/40% lead which works well for stained glass. In general, the higher ratio that tin is to lead, the easier the solder can flow at a lower temperature.
If you’re worried about using lead, there are lead-free solder alloys that can work well with stained glass but will require a little more heat.
5. Soldering Iron is broken and needs to be replaced
If your soldering iron isn’t heating up to the right temperature to melt the solder, then it could be broken. If you have cleaned your iron thoroughly, including the tip of the iron and it still doesn’t heat, it might be time to replace your soldering iron.
If you have a more expensive soldering iron, you might just need a replacement part. However, if you are using a less expensive iron and the heat stops working, you will probably need to replace it.