Good soldering is a skill that we master only by practice. Like welding and brazing, it is a process of creating a sound yet strong mechanical and electrical joint by using soft solder. The solder melts and flows evenly to create a sound mechanical and electrical joint at an equally high temperature.
However, many lack knowledge about soldering and aren’t familiar with it like welding and brazing. The task can become intimidating if you don’t know what solder to stick to use and at which temperature.
Without any further ado, let’s get to soldering FAQs so that you can clear any confusions you have about this metal-joining technique:
Do You Need Flux With Silver Solder?
Yes, you require flux when you are soldering. However, you should try using the minimum amount to prevent globs. I suggest you use a thin coating of flux because using a heavy layer might build up impurities within the joint. Moreover, it can weaken your joints. Using a thin flux coating prevents oxidization in certain places.
It is also possible to silver solder without flux. However, you have to use something to prevent oxidization on the metal surface. The modern silver solder is often manufactured with a rosin core which acts as a built-in flux.
If You Don’t Have Industry Flux, You Can Use The Following Alternatives:
- Petroleum jelly
- Pinecone flux
- Lemon juice flux
Can You Silver Solder With A Propane Torch?
Yes, you can use a household butane or propane torch to silver solder. However, the torches that work by burning MAPP gas are going to work better. Even though it is difficult to heat the propane torch for silver solder, you can manage if you are a hobbyist.
Generally, propane torches are designed for soft solders. Therefore, they have a neutral flame. When it comes to MAPP gas torches, they burn hotter as compared to propane torches and make soldering easier and faster.
When using a propane torch to solder, make sure to bend the parts a little to get a good fit.
4 Advantages Of Using A Propane Torch While Silver Soldering:
- Easily available on local hardware stores
- Lower temperature flames
- Available with different tank sizes
Can Silver Solder Be Used On Aluminum?
No, silver solder can’t be used on aluminum unless it is 100% pure. However, it is not an easy metal to solder. Many aluminum objects and materials that we see today are basically aluminum alloys. Most of the metals require the same soldering technique but a few of them are very hard to work with. You would have a problem soldering aluminum if you are not a professional.
You can’t remove aluminum oxide easily unless you use a strong flux such as an amine-based organic flux. Just because you are using a strong flux does not mean it will work easily on aluminum.
3 Fluxes To Solder Pure Aluminum:
- Chloride or fluoride (inorganic fluxes)
- Fluoroaluminate salts
- Amine-based organic flux
Can You Solder Aluminum To Steel?
Yes, you can solder aluminum to steel with the help of super alloy-1 multi-metal solder. Just a few years ago, joining steel with aluminum through soldering was considered impossible in the industry. However, super alloy-1 makes it seamlessly possible. It is a unique type of flux that joins the two metals when they have reached the temperature of 350 Fahrenheit.
You Can Solder The Following Metals In Combination:
- Zinc die-cast
- Stainless steel
- Pot metal
Before beginning the soldering process, you need to clean both the material, aluminum, and steel. If you don’t pre-clean both the materials, improper bonding might ruin your solder joint.
Can silver solder be used on gold?
We always use a low-temperature metal for soldering gold. Silver solder is a low temperature that is perfect to be used on gold. However, soldering gold requires a different yet difficult approach as compared to soldering with lead.
8 Steps To Use Silver Solder On Gold:
- Clean the gold to prevent improper bonding
- Sink the gold in a pickling solution and rinse with water to remove the contents of the acid
- Secure the gold piece above the soldering block by using a clamp or a tweezer
- Ensure that there’s a tiny gap or else, silver solder will fail
- Apply flux to the areas you wish to join together
- To prevent discoloration, ensure that all impurities are removed
- Grab the butane or propane torch and heat the flux until you see it boiling
- Add a small amount of silver solder and heat the surrounding area with your propane torch
Can Silver Solder Be Used On Brass?
Yes, silver solder is used to joint common metals including copper, brass, cast iron, stainless steel, mild steel, and other dissimilar metals.
Silver Solder Is Usually Available In 3 Forms:
- Bare wire
- Flux impregnated
- Flux coated
I prefer using bare wire to silver solder brass along with a powder flux. When it comes to flux-coated silver solder, they are expensive and the flux often falls off if you bend the wires a little. Flux impregnated silver solder works well with bass. The only downside is the cost of the solder.
Can Silver Solder Be Chrome-plated?
No, silver solder would not bond to chrome plating. The chrome plating is a thin layer over steel. The silver solder does not adhere to the thin coating but if you grind or file the chrome plating, the silver solder will work well.
Even though removing the plating will allow silver solder to adhere, the strength of the material will be reduced significantly.
Can You Use Silver Solder For Electronics?
Yes, you can use silver solder for electronics as they are great for repairing multi-stranded wires. Silver solder is available in various diameters. The silver solders with large diameters are used for big applications such as tinning. However, they are not suitable for precise work such as surface mounting.
Solders Used For Electronics Fall Into The Following Category:
- Lead-free solders
- Lead alloy solders
- Silver solders
Silver solder is usually lead-free. However, some manufacturers prefer combining it with lead. Silver solder is used for electronics to prevent a harmful effect, known as migration.
If you use typical lead solders, the solder will produce silver plating leaches. This causes the joint to become rough and prone to breaking easily.
I suggest using a rosin-core silver solder as it helps to eliminate oxidization on the surface of the metals in different electronic appliances.
What Is The Difference Between Silver Solder And Regular Solder?
Standard solder is a typical metal alloy that has a low melting point. For instance, welders use nickel or tin for regular soldering. While silver soldering occurs when you utilize a solder that is made up of more than 45% silver.
A stand solder too contains silver but it is less than 15%. If there is a high percentage of silver in a solder, it will have a higher melting point. Therefore, you will get a strong joint. The magic material in the standard solder is silver. However, the concentration is low and you will end up redoing your joints.
On the other hand, silver solder is quite useful when you want to create joints with steel, stainless steel, and copper. Silver solder is also known as a hard solder in the welding community. That being said, it is a line between soft soldering and brazing.
3 Reasons Why You Should Choose Silver Solder Over Regular Solder:
- Great adhesion
- Higher tensile strength
- Corrosion resistance is high
- The electrical conductivity is better
Is Silver Solder Actually Silver?
Even though the percentage of silver is high in silver solder, other metals are also alloyed into it. It means that the solder is primarily silver but the additional metals provide excellent characteristics for strong bonding.
For instance, silver solder often includes tin, zinc, or copper. While tin and zinc provide low melting points, copper is prone to corrosion and enhances the electrical conductivity.
The Majority Of Silver Solders Have The Following Combination:
Moreover, the percentage of each metal in the silver solder depends on the flow point.
Can You Silver Solder Over Soft Solder?
No, you can’t silver solder over soft solder because it contains lead. If you have to silver, remove all the traces of soft solder. Silver soldering is done at a high temperature which can turn the lead in the soft solder into a corrosive compound. As a result, it will eat within the brass and oxide will form on the surface. The oxidization will prevent the silver solder from making a joint. In short, silver solder does not work well with the lead.
Can You Silver Solder Without Flux?
Yes, you can silver solder without flux but it’s a very difficult task. The flux is used to break down the layers of oxide on the surface of the metal. This way, the solder wets the metal surface and makes a strong joint.
If the solder does not make a connection with the metal, you would have to redo the joint. As for soldering without flux, you can file the metal to its bright part and solder it immediately. However, I don’t suggest it as it is an unreliable method. Moreover, this technique is impossible for electronics.
3 Advantages Of Using Flux:
- Better joints
- Good and even flow of solder
- It is used to desolder the joints
What Can I Use Instead Of Flux For Soldering?
- Petroleum jelly
- Lemon juice
- Homemade pine tar flux
- Rosin flux
All the options are available on hand, cheap, and as effective as flux. Whatever flux you use, ensure that you use enough so that you can create a strong joint.
Can You Use Vaseline As Flux?
Yes, petroleum jelly or Vaseline is a good alternative to flux. Vaseline is a household product used for various purposes. Vaseline is made of mineral oils and waxes, making the texture anti-corrosive. Due to its nature, you won’t have to worry about the object or the soldering stick.
Moreover, it is as good as flux when it comes to removing grime and dirt. Experts suggest that it eliminates all the oxides from the surface that weakens your solder joint.
3 Alternatives To Flux:
- Homemade rosin
- Lemon juice
- Pine tar flux
What Kind Of Solder Should I Use For Electronics?
The most common solder used for electronics is rosin core, lead-free solder. This type of solder is made of copper or tin alloy. You can use the leaded solder as well. The leaded rosin core solder is 40% lead and 60% tin. However, it is becoming less and less popular due to respiratory illnesses.
Even if you use leaded rosin-core solder, make sure to use it in a properly-ventilated area and wash your hand after the work.
3 Tips To Buy Solder For Electronics:
- Do not invest in an acid-core solder as it ruins your components and the circuitry
- Acid-core solder is only used for metalworking and plumbing
- Use a thick-diameter solder for joining metals with large surfaces
What Type Of Solder Is Used For Electrical Wiring?
The best solder to use for electrical wiring or tinning is rosin-core solder in electrical grade. It is an acid-free solder with a built-in flux in the solder’s core. When it comes to repairing electrical wiring, you should never use solder that contains acid. Otherwise, you will damage the wire’s insulation and the wire itself.
Acid-core solder is only manufactured for metalworking and plumbing. Even if you use a non-rosin, acid-free solder, don’t forget to apply flux to eliminate oxides from the surface.
How To Solder Electrical Wiring:
- Prepare the solder wire
- Heat the soldering iron and wipe off the grime on the tip with a dry sponge
- Apply solder to the tip of the soldering iron
- Melt the solder as you work on the electrical wiring
- Cool the solder and inspect the results
Is There A Difference Between Plumbing Solder And Electrical Solder?
Yes, we use acid-core solder for plumbing and acid-free rosin core solder for electrical work. Both the solders differ from each other because electrical grade solder contains rosin flux. The acid we find in the plumbing solder is quite corrosive and is only meant to scrape off the oxidization from the surface.
However, the same acid can damage the electrical wires and their insulation property. If the wires get damaged, the joint might fail. You might also face a fire or electrical shorts.
Why Does My Solder Not Stick?
- Not providing enough heat to the solder
- Using a soldering tip that has oxidized
- Not sanding the oxidized or dirty parts
Other reasons account for solder not sticking on the metal. The first reason is using the bad technique while applying solder to the tip of the iron. If you let the solder sit on the tip, it will boil, fall off or turn into fumes.
The second reason is soldering without flux. It removes all the oxide layers from the metal as solder does not stay on oxidized surfaces. Due to high soldering temperatures, oxides form and prevent the solder from adhering to the metal.
Why Does My Solder Ball Up?
- Excessive fire scale
- Dirt, grime, and oil on the metal surface
- Your flame size or torch’s tip is too big for the task
- Dirty solder
- Heat sink
Solder balls are formed by spitting and gassing the commercial flux on the metal surface. Technically, the solder bounces back from the solder wave. However, there’s a solid reason why your solder balls up on a PCB. It occurs when there’s a high drop in nitrogen or extensive backflow in the environmental air.
Will Solder Flow Upwards?
Yes, the solder flows upwards to some extent. If you burn the flux before soldering the joint, the solder will flow in the opposite direction because the metal surface will oxidize. Now, solder does not cooperate well with oxidized metals. Instead of flowing downwards, it will ball-up and flow upwards.
Can You Solder Copper Without Flux?
Yes, flux is a vital component when it comes to soldering copper. Flux does not only attract the flame but deoxidizes the metal surface as well, thanks to its acidic nature. The solder will wet the alloy and will create a strong, water-proof joint.
If you don’t use a flux paste, soldering copper will become a disaster because the solder will stick to the tip instead of the alloy.
Where Do You Put Flux When Soldering?
When soldering, you should always put the flux close. As you have to apply flux with a pen, it has to be near so you can solder immediately.
Can I Solder Without Flux?
Yes, you can solder without flux but it will compromise the quality of your joints. Many applications demand the use of flux. The purpose of flux is to eliminate the oxidized layer on the metal and clean all the impurities to create a better solder joint.
If you create weak solder joints due to impurity built-up, you will have to deal with the damage and redo the joints. For instance, weaker electrical joints result in poor conductivity. Moreover, flux enables the flow of the solder.
If You Solder Without Flux, You Will Face Two Major Consequences:
- You will be using more solder
- Weaker bonds
What Is Flux In Soldering?
Flux is a solution made of a wetting agent, water, activator, and cleaning agent. Its purpose is to clean the surface of the metal as well as the soldering iron’s tip. To make solder spread better on the metal surface, we use flux as it eliminates impurities and the oxidized layers. This ensures that you get strong solder joints.
Can I Glue Instead Of Solder?
No, superglue is not a substitute for soldering. There is no comparison of the bond’s tensile strength created through soldering. The materials will crack open after a few days if you use glue. Whereas, the solder melts evenly between the gap and joins two surfaces permanently.
Soldering Flux Alternative?
The best soldering flux alternative is petroleum jelly. It is available for half the price and is as effective as commercial flux. You might have a container of Vaseline sitting in a corner or somewhere. If you are out of commercial flux, you can always use Vaseline as it is made of mineral oils and waxes.
Moreover, its non-corrosive nature won’t damage the soldering iron as well as the subject you are soldering. Apart from removing grime and dirt, it cleans the metal oxides on the surface that might weaken the solder joint.
8 Steps On How You Can Solder By Using Petroleum Jelly:
- Clean the surface by removing all the dirt and dust particles
- Make sure that the surface is dry before soldering
- If you are using Vaseline, apply it on the surface and wipe it off using a kitchen towel paper
- If you are using Vaseline as a flux, do not reapply it
- If you are using rosin or lemon juice, dab the liquid on the Q-tip or use a small brush to apply evenly
- Use the soldering iron to apply molten silver solder
- If you are having trouble applying the solder, you might need to reapply the homemade flux
- After the solder has cooled down, ensure that the solder bond is strong
Flux Vs. Solder?
While flux helps you through the soldering process, solder is used to repair or join two components. The metal surface can become impure from contaminants, impurities, dirt, dust, and grime. The contaminants on the metal surface can prevent you from achieving good joints.
To remove contamination, we use flux before the soldering process. It does not only remove the impurities but also promotes even flow to make a strong connection.
On the other hand, solder is an alloy with low melting points. It is used for joining metal that is less fusible. The solder is always heated and melted to connect the two metal pieces.
What Is Soldering Flux Made Of?
Commercial soldering flux is made of resin acids or ammonium chloride for tin and copper. To solder galvanized iron, the flux is made of zin chloride or hydrochloric acid. If you wish to braze or weld, you need to use flux made of borax.
The Soldering Flux Is Made Up Of:
- High-temperature tolerant chemicals
The physical properties of a flux include conductivity, flammability, corrosivity, viscosity, volatility, cleanability, and residue tack.
Soft Soldering Advantages And Disadvantages
Advantages of Soft Soldering
- The parent metal will not melt
- It can be done at a low temperature
- Any metal can be joined
- Less time to solder
Disadvantages Of Soft Soldering
- Low strength joints
- You can’t solder heavy metals
- Toxic fumes might affect your health
How Strong Is Soft Solder?
A soft solder has a pressure rating of 100 psi. It is used for many years to repair copper pipes in water and plumbing systems.
How Much Pressure Can Solder Hold?
A solder joint can withstand a pressure of 440 psi.