So I assume "sweating" simply means soldering? Isn't there something inside a sweat type valve that can't handle the heat of my torch like plastic or something that actually makes the seal inside the valve? I'd love to hear any and all advice. Thanks in advance.

As a rule we either try to use as little heat as possible to melt the solder, e4ith that or we take the valve apart and protect the washer or "O" rings while we solder. Good luck Tom

Use the ball valves they are made to sweat without having to take them apart to remove material that could melt like washers. They have a very durable heat resistant ball. Remember this when you use female threaded valves also, all sweating must be done prior to applying teflon or sealent to threads.