Plumbing Solder Melting Point, Composition And Its Flux

Plumbing solder is soft or hard fusing material with a melting point ranging from 90°C to 450°C. The soft solder tends to be on the lower side as it melts faster and flows smoothly, while the hard solder takes longer. From this, it is evident that pipe connection bonds made by hard solder last longer and are more efficient compared to soft solder. 

However, most plumbing solder lies at 183°C and 188°C depending on its composition. Therefore, it is important to understand the plumbing soldier’s composition to choose what is best based on the material to be soldered. Here you will learn various types of plumbing solder plus everything you need to make an informed decision. Read on!

What Are The Types Of Solder?

Plumbing solder differs from one another based on the material that creates their core. Their composition determines what materials they can be used on for strong bonding. Here are the various types of solder to consider:

Acid Core Solder

Acid core solder has high acidity content. This, therefore, means acid core solder should not be used with materials that can easily rust. 

Rosin Core Solder

This type of solder contains a mild flux with a metal tube surrounding a thin core of rosin. It is the best soldier type for binding electric devices due to its non-corrosive nature. 

Solid Core Solder 

This type of solder is a hard one since its core is made of a solid that takes more time to melt than the other two solder types. Therefore, solid core soldier tends to form string bond but needs flux to be separately applied when using it. 

What Is The Best Solder For Plumbing?

Safe solder is the best weld for plumbing, especially for home use. It is lead-free with 95% tin and 5% antimony. Safe solder is the best since it has viscosity lower than 50/50 and flows very fast through a joint. Due to its ability to flow very fast while being applied, it leaves a gap at the tip of the joint.

What Is The Most Robust Solder?

The most robust solder is one of tin and lead with 60/40 composition levels. This solder is also the most straightforward to work with since it has a melting point of 188°C. The tin and lead solder are used to create joints that last a long time without leakage or other mechanical issues.

What Is The Composition Of The Plumbing Solder?

Plumbing solder is lead-free due to the harmful effects of lead if it gets to drinking water. It comprises mainly metals like tin, copper, silver, bismuth, indium, zinc, and other traces. These metals are mixed in safe and effective proportions to ensure safe piped water. 

What Is The Difference Between Electric Solder And Plumbing Solder?

Flux used is the main differentiating factor between the electric solder and plumbing solder. Metal to be joined are cleaned using flux as it removes any present oxidation and prevents any other from forming. The two common types of flux are zinc chloride or zinc ammonium chloride. The electric solder flux has a rosin core, while the plumbing solder ones have the acid core.

Can Electric Solder Be Used For Plumbing?

Using electric solder for plumbing is mostly illegal and should not be done. Electric solder contains high lead levels, which is hazardous to the environment and unsafe for human consumption. If plumbing pipes are joined by electric solder use, the lead may dissolve into the water and cause harmful health effects. The electric solder is specially modified for electric purposes. This is because the components used are suitable for electronics but not for plumbing.

Can Plumbing Solder Be Used For Electronics?

In comparison, the plumbing solder has a larger gauge than the electric solder and does not virtually join electronics. Also, the acid core flux in the plumbing solder corrodes electronics if used. This corrosion makes it hard for the joints to form, and once they do, they don’t last long.

How Dangerous Is Lead Solder In Plumbing?

Using solder with high lead content may lead to the production of dust and fumes that are hazardous. For instance, using rosin core solder produces fumes that cause occupational asthma and worsen existing asthmatic conditions once inhaled. They also cause eye and upper respiratory tract irritation. 

How Can You Tell If Solder Contains Lead?

Taking a swab test is the best way to determine the presence of lead in solder. The following steps are taken to test:

Step 1: Take an activated lead check swab, ensuring other metals do not contaminate it.

Step 2: Rub the swab gently on the test area to collect a sample that needs the lead test.

Step 3: Observe the color change on the swab. If it turns red or pink, then there is the presence of lead. 

Once the lead has been detected, you should not use it for plumbing purposes, as it may bring about adverse effects to your health and the environment. 

Can Plumbing Solder Go Bad?

Plumbing solder prepared in a standard way should last a lifetime of the piping. If the plumbing solder looks clean on the purchase, it is good and is guaranteed to serve you for a long time. However, if the solder feels cold and doesn’t bond effectively, it may cause leaks and breakage in adverse cases after some time of use. It is mostly a result of lousy preparation from the factory level and cannot be blamed on the plumber.

Can You Re-Use Solder?

Absolutely solder can be re-used time and again. To extract it from old pipes for re-use, you need to locate the solder point and yank the wire out. Once it is cold, touch the new wire and iron to that solder point and stick it back inside to get a new solder joint. The solder works as well as new and lasts as long as the new solder.

How Can You Solder Copper Pipes With Water In Them?

Soldering copper pipes with water is nearly impossible since most of the heat goes into changing water to steam instead of melting the solder. However, a pipe plug can be used to stop the water flow as the pipes are fixed. A dissolvable pipe plug can be used for pipes that are being joined permanently instead of a manual one that requires to be pulled out.

What Is The Difference Between Soldering And Brazing?

The main between soldiering and brazing is the materials used and their melting points. Soldering requires a maximum of 840°C melting points, while brazing can go up to 1150°C before melting. The metals used in solderings like tin and antimony are way weaker than copper and silver used in brazing. Both, however, are used to join materials for long-lasting bonds.

Can I Solder Without Solder?

Yes. It is possible to solder without using solder itself. The purpose of solder is to create bonds and joints, and there are many other alternative tools. Tools like steel wire, screwdrivers, nails and Alan wrenches can be used instead of solder. Depending on the materials at hand, the mentioned tools can be used for a permanent or temporary solution. 

Is It Better To Crimp Or Use Electric Solder?

Crimping is known to create more substantial and more reliable connections compared to using electric solder. Soldering is weaker in this case since it requires a filler metal to hold the links in place. The filler metal degrades over time and gets weak, causing the connection to fail. It may result in leakages and breakages in the related materials. Electricians have also argued that crimping is more comfortable to accomplish compared to soldering with electric solder. By all means, crimping is a better solution when compared to soldering. 

What Precautions Should I Take While Soldering?

Soldering is a process that requires one to be careful, and it is best to take the following precautions:

Cut The Pipe Ends To Be Square

Use a pipe cutter to ensure all ends of the pipes to be soldered are square since they are to slide into various couplings. If even one end of a pipe is angled, the soldering process will be more rigid as there will be difficulty creating joints.

Clean And Debar The Pipe

Ensure the pipe is clean of all oxidation and protective coatings. Leave the pipe clean, bright and roughed up on the inside and outside and ready for soldering.

Apply The Right Amount Of Flux

Ensure you apply a light, thin and even coat of flux on the pipe using a brush. This ensures that the solder penetrates the joint evenly, making a good and long-lasting joint.

Heat The Joint

Use only the blue flame to heat the joints.  This is because blue flame has more heat and produces enough temperature to ensure the joints are heated evenly. Don’t heat the solder directly; instead, heat the metal and let it melt all around. The solder. Keep on heating until all the solder melts, and the seam of the joint looks full

Wipe Off Excess Product

After the joint has cooled off, use a damp rag or sponge to clean off excess product like flux. Cleaning prevents corrosion from taking place and destroying the newly made joint.

Final Word 

Plumbing solder has a relatively high melting point between 90°C and 450°C, making it suitable to join plumbing pipes. Besides, plumbing solder has various metal compositions but in the right proportions to serve its purpose effectively. The acid-based flux works perfectly to eliminate oxidation and other coatings to make it ready for joint formation. However, it would help if you always chose the right plumbing soldier with an ideal melting point based on the materials you are working on. 

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