Heat’s a solid trick, especially if you’re worried about fumes or have to work indoors. I’ve had good luck with a heat gun on stubborn plumbing parts—just gotta be careful not to scorch anything plastic nearby. Vinegar’s slow but it does creep in over time. Ever tried tapping the stem gently with a hammer after heating? Sometimes that vibration helps break the bond. Don’t get discouraged if it takes a couple rounds—old plumbing can be stubborn.
I get the appeal of heat, but honestly, I’ve seen more folks get into trouble with a heat gun than actually solve the problem—especially in tight spaces where you can’t see what’s behind the wall or under the sink. Melted seals, scorched paint, even a warped valve body if you’re not careful. I’m more of a “penetrating oil and patience” type. PB Blaster or Liquid Wrench, let it soak overnight if you can swing it. Sometimes I’ll even wrap a rag soaked in the stuff around the stem and cover it with plastic to keep it from evaporating too quick.
Tapping with a hammer does help, but I’d go easy—old brass can crack if you get carried away. If it’s really stuck, I’ll use a strap wrench for extra leverage instead of risking damage with pliers or channel locks. Heat’s got its place, but for old plumbing, slow and steady usually wins the race in my book.
I hear you on the risks with heat, but honestly, there are times when patience just isn’t enough—especially if you’re dealing with decades of mineral buildup or corrosion. I’ve had jobs where even after soaking overnight, that stem wouldn’t budge until I hit it with a little controlled heat. The trick is to use a small butane torch, not a heat gun, and keep it moving. Quick bursts, watch your surroundings, and have a wet rag handy to cool things down fast. Sometimes that’s the only way to break the bond without rounding off or snapping something. Just gotta know when to call it quits before you do more harm than good.
I get what you’re saying about heat being a last resort, but I always worry about damaging the finish or accidentally melting something plastic nearby. Here’s how I usually approach it, especially when I’m trying not to spend more than I have to on repairs:
- Penetrating oil first—Kroil or PB Blaster if I’ve got it, WD-40 in a pinch. Let it sit as long as possible (overnight if you can).
- Use a proper stem wrench, not pliers. Less chance of rounding things off.
- If that doesn’t work, I’ll sometimes tap the handle gently with a rubber mallet to try and break up the corrosion—just enough to jostle it, not bend anything.
- Only after all else fails will I reach for heat. Even then, I’m super cautious—like you said, quick bursts with a mini torch and always with a wet rag right there.
One thing that’s tripped me up before: sometimes the stem is stuck because there’s hidden mineral buildup inside the valve body itself. No amount of external soaking or heat will help if that’s the case. In those situations, have you ever tried using vinegar or CLR to dissolve some of that gunk? It’s messy and slow but has saved me from replacing parts before.
Also curious—when you do use heat, do you ever worry about weakening solder joints nearby? I’ve had one leak on me after getting too aggressive with the torch. Maybe just bad luck or old plumbing... but now I’m extra paranoid.
Wondering if anyone’s had success with those freeze-and-release sprays instead of heat? They’re supposed to shrink the metal enough to break the bond but I haven’t tried them myself yet. Might be worth a shot before breaking out the torch again...
Also curious—when you do use heat, do you ever worry about weakening solder joints nearby? I’ve had one leak on me after getting too aggressive with the torch.
Man, I’ve been there. Once tried to “just nudge” a stuck stem with a little heat and ended up chasing a pinhole leak for hours. Now I’m paranoid too—if there’s solder anywhere close, I’ll try everything else first. Haven’t tried the freeze sprays yet, but I’m tempted. Anything to avoid another plumbing “adventure” under the sink at midnight...
