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How To Fix Copper Foil Soldering Mistakes

How To Fix Copper Foil Soldering Mistakes

When you are working on a stained glass piece or design, it is a very precise and it can be a time-consuming process.  It takes practice to master.  And it is always exciting to see how the final project turned out. 

Sometimes it’s perfect and other times, it isn’t quite what you envisioned and there are a few soldering issues that need to be fixed.  While it can be disappointing, there are some ways to fix these mistakes without starting the whole project from scratch.

Below are some common copper foil soldering mistakes and a few suggestions to help fix these mistakes:

The Solder is Leaking Through to the Other Side of the Copper Foil Piece

Below are a few reasons why the solder might leak through:

1. If the soldering iron is too hot, it could cause the solder to melt too quickly, and you should check that your iron isn’t set too high. The iron should run anywhere from 700 to 1,000 degrees 700- 850°F for leaded solder and 800°-1,000°F for lead-free solder.

2. If you cut the pieces too wide, the solder will invariably leak through.  Try to make the pieces just wide enough to fit a thin layer of solder.

3. If you put too much liquid flux in between the gaps, it will leak through as well.

4. When you are soldering, if you move too slowly, all the solder could melt in one place and then leak.

5. Having the right solder and flux can prevent leaking. 60/40 solder flows more easily than 50/50 solder. A gel flux can work well with stained glass and prevent less leaking.

Some recommendations to help when the solder has leaked through:

Try to tack solder (or place a small amount of solder) each joint and check that your pieces are held together in one place.  Lift the entire piece carefully and place a damp towel underneath the piece while you are soldering.  This can help cool the solder and prevent it from leaking to the other side.

The Solder Lines Are Too Thick

Another common soldering mistake is when the solder lines are too thick, and you want to be able to smooth it out to correct it.

Some recommendations to help:

While some people try to use sandpaper to help with thick solder lines, it really isn’t strong enough to smooth out the solder.  The best thing you can do is to slow down when you are soldering so that the solder can melt.  If your iron can’t get hot enough even when you slow down the pace, a larger tip can help.  This can allow more heat to spread evenly throughout the piece.    Also, check that the tip is clean before doing so.

Corroded Copper Foil Issues

If you are working on a piece and must stop half-way through the project, there is a chance your copper foil will become corroded.

The best way to fix this is easy.  Only start a project when you have the time to complete the soldering all the way through. If you do have to stop, make sure to wipe the flux off with a towel. Then wash down the seams with soap and water to help remove all the flux so it doesn’t corrode the copper foil.

While these are only a few of the issues that might occur when soldering stained glass, the best thing you can do is practice.  The more you practice, the better your piece and soon enough soldering stained glass will become second nature to you!

And, of course, having the right stained glass soldering equipment, solder and flux can make the whole process even smoother.


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