Soldering is not only melting an alloy to connect different parts.
I'm not saying that I'm an expert but I spend a lot of time figuring out what good soldering procedure is.
I made horrable looking solderjoints before I study what I was doing wrong.
Many of us wrote good articles how to perform a good solderjoin.
There are some facts one have to take care of like close fitting, clean metal, good solder etc.
The best way to produce a clean workpiece is learn how to communicate with your torch and workpiece.
They give you signs how stupid this may look like but they do.
Whatch how your workpiece changes colors, when your flux is melting, when your flux is changing color from brown to clear. Start with a reduced flame, learn how to take benefit from gravity because melted metal will run to the lowest AND hottest point. Know the melting point of your solder and your flux. Know the temperature window where you have to work with. Stay within this window of approx 30 - 40°C depending on the solder you use.
Observe when you need to apply more flux because flux will evaporate leaving a gap for oxygen to access the silver.
Don't focus at your silversolder. When all basics are good it will flow You can't help it run better by looking at it. Don't tak you flame of your workpiece in order to reduce the temperature but move backwards holding the flame on your workpiece. This is called temperature controle. Taking i away from you workpiece is a free window for oxygen to access your workpiece.
It's all simple basic stuff, there are no secrets other then covering your piece with a coat made by borax and boric acid.
Check out the melting temperature of both an d compare it with the soldering melting temperature.
The very best advice I can give is P R A C T I C E, over and over again. Learn from you mistakes and never give up.
After a period of time it becomes second nature like breathing because you understand what is happening and how to overcome firestain.
Forget about electrostripping and learn what firestain is, how it's build, where it's build and how it evaluates in a next heating.
If you do, then you'll know that elctrostripping can't help you out for several reasons.
Silversmithing is a way more difficult then goldsmithing because copper and silver are both metals with an attitude.
Another advice I like to give is to use hard solder.
I don't use medium, easy or very easy except for repairs.
Yes I know, others have their opinion and swear by using them.
Know one thing. Lower solders have more yellow color due to the use of more brass talking about regular solder.
They will tarnish faster and you will see colorchange.
Sorry for this very long message.
Learning how to solder perfectly takes time, practice and lots of knowledge.
Wishing you al the best.