You only need to wait about 30 seconds after soldering before turning the water back on. Letting the solder joint cool completely, like a minute or two, is recommended but not totally necessary. The key is to allow the solder to harden enough that the water pressure won’t damage or crack the joint.
How Long Should You Wait to Turn Water on After Soldering?
Doing your own plumbing repairs can be daunting, especially for beginners. One of the most common concerns is knowing when it’s safe to turn the water back on after soldering a pipe joint. Turn it on too soon, and you risk the joint failing and springing a leak. Wait too long, and you’re needlessly inconvenienced.
So how long should you wait to turn water on after soldering? Let’s take a detailed look.
Why Waiting is Important After Soldering
Soldering pipes requires heating up the joint to very high temperatures. The solder melts and flows into the seam, creating a watertight bond once cooled and hardened.
But if water flows through the pipe before the solder has sufficiently hardened, it can cause thermal shock. This rapid temperature change can weaken or even crack the joint.
The key is allowing enough time for the solder to fully harden and gain its strength back after being heated up. Then it will be able to withstand the water pressure without failing.
So waiting at least a little while after soldering is crucial. But you don’t need to wait long.
The Minimum Wait Time After Soldering Pipes
The absolute minimum time to wait before turning water on after soldering is 30 seconds. This gives the solder enough time to harden and become strong enough to withstand water flow.
While 30 seconds is sufficient, it leaves little margin for error. If the joint didn’t heat evenly or you used too little solder, it may need longer to fully harden.
So for most do-it-yourselfers, waiting 1-2 minutes is recommended for assurance that the joint is ready for water pressure.
Letting the Joint Cool Completely
While you only need to wait 30 seconds – 1 minute for the solder to harden, letting the joint cool completely is ideal.
This means waiting until the joint is the same temperature as the surrounding air. For copper pipes, there will no longer be any sign of discoloration from the heat.
Letting the joint cool for 2-3 minutes before turning the water on is a good rule of thumb. This gives you assurance that the solder has fully hardened and the joint has normalized to room temperature.
The cool down time depends on the size of the pipe – larger joints may take longer to cool. Inspect the joint and feel that it’s no longer hot before turning on the water.
Pro Tips for Ensuring the Solder Joint is Ready
- Visually inspect the solder joint before turning on the water. Make sure the solder has evenly flowed into the seam and hardened. Tap the joint gently – it shouldn’t move or feel soft.
- feel along the joint with your fingertip to check that it’s cooled to room temperature. Any remaining heat is a sign it needs longer to normalize.
- If in doubt, wait longer. There’s no harm in allowing a few extra minutes. Rushing the process risks damaging the joint and requiring repairs.
- Turn on the water slowly at first. Gradually increase flow while checking for leaks. This prevents excessive pressure on the joint before you’re sure it’s watertight.
Follow these steps for safe water turn-on after soldering:
- Allow 30 seconds for the solder to initially harden. One minute is even better.
- Let the joint cool completely for 2-3 minutes, ensuring it’s normalized to room temperature.
- Visually inspect the joint – solder should have evenly flowed into a smooth seam.
- Gently tap the joint and feel along it – you shouldn’t detect any soft spots or movement.
- Open the main valve slowly to allow water to flow. Check for leaks before increasing flow.
- Once you’ve verified no leaks after a few minutes, open the valve fully to restore normal water pressure.
Following this process ensures you don’t turn on the water prematurely, while not making you wait unnecessarily long after soldering is finished.
Helpful Tips to Get Pro-Quality Soldered Joints
Beyond knowing when to turn the water back on, proper technique is key to creating lasting, leak-free soldered pipe joints. Here are some helpful tips:
- Thoroughly clean and sand pipe ends to remove oxidation and provide a smooth surface for soldering.
- Apply flux generously to pipe ends to aid solder flow. Ensure joint areas are completely coated.
- Heat joints slowly and evenly until flux bubbles and melts. Hot enough for solder to melt shows proper temperature.
- Let solder flow into joint seam without applying too much. Feed additional solder as needed until seam is filled.
- Allow joint to cool undisturbed once solder has hardened. Avoid blowing on it or moving the pipe.
- Use lead-free solder for all potable water applications. Avoid lead solder for health reasons.
- Practice technique on scrap pipes before working on installed plumbing to hone skills.
Safety Tips for DIY Soldering
Soldering pipes itself comes with safety hazards to be aware of:
- Protect yourself with safety glasses, gloves, and flame-resistant clothes when soldering.
- Work in a well-ventilated area to avoid inhaling toxic solder/flux fumes.
- Keep a fire extinguisher handy in case of accidental igniting of flammable materials.
- Be sure to turn off the main water supply valve before soldering to avoid scalding water.
- Make sure no flammable products like paint thinners are nearby when using a torch.
- Allow torches to fully cool after use before storage to prevent fire hazard.
Common Soldering Problems and Solutions
Even when waiting the proper time after soldering, leaks may still occur if the joint wasn’t created properly:
Problem: Solder didn’t fully fill joint seam
Solution: Reheat joint and apply more solder to fill completely
Problem: Joint leaks immediately upon water turn-on
Solution: Joint heated improperly – re-sand and re-solder carefully
Problem: Dripping leak even after time waiting
Solution: Apply more flux and solder to strengthen seal
Problem: Soldered joint appears burnt or crystallized
Solution: Overheating – avoid excess torch heat on one area
Being prepared to re-do a faulty solder joint and following best practices will ensure you get watertight, professional joints.
Doing your own plumbing soldering takes skill, patience, and attention to detail. But the satisfaction of fixing or installing pipes yourself makes the effort worthwhile. Following the right soldering and cooling procedures will prevent frustration and costly callbacks down the road.
The necessary wait time after soldering before turning water on is quite short – just 30 seconds to 1 minute for the solder to initially harden.
Allowing 2-3 minutes for the joint to fully cool and normalize is recommended, but not absolutely required.
Visually inspecting joints and gradually increasing water flow provides assurance leaks are avoided.
Combined with proper soldering technique, this brief waiting period will result in strong, lasting plumbing repairs.
Carefully soldering pipes and allowing proper cool-down shows patience and discipline that lead to professional-quality results.
So don’t rush the process – a few short minutes could save you from a burst joint and water damage down the road.
Q: Can I speed up the solder cool down process?
A: It’s best not to attempt to accelerate cooling as this risks weakening the joint. Let the solder harden and cool naturally.
Q: What if I can still see a small gap in the solder joint?
A: Reheat and apply additional solder to fill any gaps fully. The joint should be smooth with solder completely sealing the seam.
Q: Do different pipe materials like PEX or copper require different wait times?
A: The same 30 second to 2-3 minute recommendations generally apply to any soldered pipe material. Inspect to ensure full hardness.
Q: Could turning on water too soon cause a joint leak to spring up later?
A: Yes, if water pressure stresses the joint before the solder has fully strengthened, it could eventually fail down the road.
Q: Should I retouch the joint with solder if I see moisture on the pipes?
A: Yes, any moisture indicates the joint is still too hot and needs more solder applied once fully dried out.