Welding or Soldering: Which Is the Right Joining Method for Which Situation?
Both methods join metal, and both have their merits. The decision often depends on the specific application and the corresponding requirements. How much load must the joint withstand? Can a set stone withstand the heat? Will the joint be visible afterward? And what will the repair cost in the end?
Here, soldering is compared to micro-TIG welding—that is, pulsed precision welding on materials with a thickness of 0.1 mm or more, as used in jewelry workshops, dental laboratories, and in industry.
In short
- In soldering, only the solder melts; in welding, the component itself melts. This is the source of most of the differences described below.
- The main practical difference is the heat. Soldering heats the entire workpiece, while micro-TIG welding heats only a spot measuring 0.2 to 4 millimeters.
- Soldering remains the right choice when a gap needs to be filled, a surface needs to be joined, or a dissimilar pair of materials needs to be joined. Capillary joints, long seams, simple electronics (not high-temperature), and furnace soldering are typical applications here.
- Sometimes both methods are combined, for example, with brass. First, the parts are tack-welded, and then they are brazed.
Contents of this post
- In short
- What Happens During Soldering and What Happens During Welding
- A Comparison of Soldering and Micro-TIG Welding
- Heat: The Most Important Difference in Everyday Life
- Strength: What Really Holds the Joint Together
- Flux, Pickling Solutions, and the Workflow
- Appearance, Purity, Corrosion, and Biocompatibility
- When Soldering Is Still the Better Choice
- Combine the two: Pre-weld before soldering
- Decision-Making Guide by Use Case
- Costs: What You Actually Pay Per Connection
- An Overview of Lampert Devices
- Frequently Asked Questions About Welding and Soldering
- About This Post
- Conclusion: When to Use Welding, When to Use Soldering
What Happens During Soldering and What Happens During Welding
Both processes describe joining methods, although something fundamentally different happens within the workpiece. In brazing, the base material remains solid, and a filler metal with a lower melting point fills the joint. In welding, on the other hand, the base material itself melts locally—in the case of the micro-TIG process, in a short pulse lasting 0.1 to 34 ms at a spot size of 0.2 to 4.0 mm. The heat is thus introduced into the material in a targeted manner, and the process can be performed with or without filler material.
Soldering: Wetting Instead of Fusion
In soldering, a solder with a lower melting point than the base material is melted. It wets the joint surfaces, flows into the gap, and forms the joint as it solidifies. The parts being joined remain stationary during this process. The terminology standard DIN ISO 857-2 distinguishes between processes based on the liquidus temperature of the solder. Temperatures up to 450 degrees Celsius are classified as soft soldering; temperatures above that are classified as hard soldering. The third category, high-temperature brazing above 900 degrees, which was commonly used in the past, originates from the superseded DIN 8505 standard and continues to be used colloquially; in the current standard, it is classified as hard brazing.
Welding: of the same material as the workpiece
During welding, the base material is melted at the joint. The solidified weld consists of the same material as the component, so the joint is of the same material. In this process, either only the base material can be welded, or welding wire can also be incorporated into the joint. In micro-TIG welding, a short electrical pulse between a non-consumable tungsten electrode and the workpiece provides the energy, while argon shields the molten pool from the ambient air. Filler material is only necessary when material needs to be built up, and in that case, it is ideally of the same type as the welding wire.
A Comparison of Soldering and Micro-TIG Welding
The criteria that distinguish brazing and micro-TIG welding in everyday workshop operations, ranging from the temperature within the component to flux, post-weld finishing, and the detachability of the joint. The four criteria with the greatest impact on the workflow are discussed in detail below. The reference parameter on the welding side is the operating range of the Lampert devices: 9 to 630 A for the PUK 6.1 and 5 to 1,200 A for the Micro Arc Welder, with pulse durations ranging from 0.1 to 34 ms in each case.
| Criterion | Brazing | Micro-TIG welding |
| Joining Mechanism | The filler material melts and wets the parts to be joined, which remain firmly bonded | The base material itself melts and solidifies to form a homogeneous joint |
| Temperature in the component | The entire component must be brought to operating temperature | Heat remains localized; the component generally remains lukewarm to the touch |
| Filler material | Solder, i.e., a foreign alloy in the joint | No filler material required when using a welding wire of the same material composition |
| Flux | Required, except when soldering under an inert gas or in a vacuum | Not required; argon provides protection for the molten metal |
| Refinishing | Staining, neutralizing, re-polishing | Largely not applicable |
| Hardness | Determined by the filler metal, usually below the base material | Can reach the strength of the base material |
| Appearance | The solder joint has a different color and tarnishes differently | Same material; virtually invisible after polishing |
| Corrosion | Foreign metal in the joint and solder gap promotes contact and crevice corrosion | No foreign alloy, no structural gap |
| Gap Bridging | Strength of the process; capillary gaps typically range from 0.05 to 0.2 mm | Limited; the joint surfaces should be in contact |
| Heat-sensitive parts | Brick, plastic, springs, and electronics are at risk | Can generally remain in the component |
| Multiple joints on the part | Requires staggered soldering sequences; otherwise, the previous joint will come loose | Can usually be repeated as often as desired |
| Detachability | Soft-soldered joints can be disassembled by heating | Cannot be disassembled without causing damage |
Heat: The Most Important Difference in Everyday Life
Heat Propagation During Soldering
Soldering works through capillary action and wetting, which requires the entire joint area to reach the working temperature. In practice, the entire component heats up. As a result, set stones often have to be removed from their settings; plastic parts and gaskets are at risk and may melt; adjacent solder joints may come loose; and, in the case of sterling silver, for example, a widespread fire-like glow may appear.
What a pulse lasting just a few milliseconds changes
In micro-TIG welding, the pulse duration ranges from 0.1 to 34 ms. During this time, the material melts locally, and the heat is immediately dissipated into the surrounding material. The component remains lukewarm; often, it can still be held in the hand while working.
This results in projects that simply can’t be done with the torch.
- Ring sizes can be adjusted while the stone remains set.
- Weld clasps onto the finished, polished chains.
- Seal sensors and enclosures that contain temperature-sensitive electronics.
Real-world examples can be found under “Jewelry and Industrial Applications.”
Strength: What Really Holds the Joint Together
A solder joint is as strong as the solder, not as strong as the component. Silver solders and gold solders have lower strength values than their corresponding base materials, while soft solders are significantly weaker. This is compensated for by the surface area. A capillary gap of typically 0.05 to 0.2 mm and a generous overlap result in a strong joint, even though the solder itself is softer.
A weld, on the other hand, consists of the base material itself (and often of a wire of the same type) and can achieve the same strength as the base material. There is no foreign alloy to act as a weak point and no structural gap in the joint.
Flux, Pickling Solutions, and the Workflow
Soldering requires flux so that the solder wets the surface and the surface remains free of oxidation. After soldering, the residues must be removed—usually by pickling and neutralizing—otherwise they will cause corrosion. Afterward, the polish is restored. In micro-TIG welding, this entire process is eliminated because the inert gas takes over the role of the flux: argon 4.6 with a purity of 99.996%.
The argon displaces the oxygen from the weld zone as long as the area is hot, at a flow rate of approximately 2 l/min, with automatic pre- and post-flow. No flux means no residues, no pickling, and no neutralization.
The real advantage lies in the sequence of the work steps. A workpiece can be fully finished and set, then welded, and finally polished. With brazing, the process is reversed: first join, then etch, then restore the surface. When repairing finished parts, this difference is where the real time savings come from—not the seconds per pulse.
If dark spots remain after welding, this may be due to the gas shield or residue on the workpiece. The weld area should therefore always be cleaned beforehand (just as with soldering).
Appearance, Purity, Corrosion, and Biocompatibility
You either see the seam or you don’t
A brazed seam is made of a different alloy than the workpiece. It has a slightly different shade, polishes differently, and tarnishes differently over time than the surrounding material. This is particularly noticeable with white gold, rhodium-plated surfaces, and intensely colored alloys. A welded seam is made of the same material as the workpiece and is almost invisible after polishing.
Fineness
Due to their design, solders used in precious metal fabrication have a lower fineness than the workpiece. Anyone working with fineness specifications and hallmarks must keep the solder content in mind. This issue does not arise when welding materials of the same type.
Corrosion and Cadmium Contamination Sites
Two different metals joined in a conductive connection form an electrochemical cell that promotes contact corrosion. Added to this is the solder joint itself, where moisture and residues can accumulate. A weld made of the same material contains neither foreign metal nor a structural gap. Cadmium-containing brazes have been banned in the EU since 2011, according to Entry 23 of Annex XVII of the REACH Regulation, for brazes containing 0.01% or more cadmium. They may still be present in repair parts that were placed on the market before December 10, 2011.
Dental and Medical Technology
This is precisely why precision welding has become the standard in dental technology and orthodontics. Solder joints in the oral environment are a weak point—both in terms of corrosion and as a niche for plaque—and any additional foreign metal is an additional factor to consider in material evaluation. Examples of applications can be found under Orthodontics and Dental Technology.
When Soldering Is Still the Better Choice
A precision brazing machine does not completely replace the brazing station. Whenever a gap is intentionally left in the design, when a large area needs to be joined in a single operation, or when two very different metals are joined, brazing remains the appropriate method. The capillary gaps for which a brazing design is intended typically range from 0.05 to 0.2 mm; for welding, however, the joint surfaces must be in full contact.
- The gap as a design principle: In pipe-in-socket, socket, and push-fit connections, the solder flows into the gap and creates a broad-area bond.
- Large areas: When joining large areas, soldering is done in a single step, whereas fine welding is done point by point.
- Improper fit: If the parts to be joined do not fit together snugly, solder can fill the gap. For welding, the surfaces must be in contact.
- Very different materials: For material combinations that form brittle intermetallic phases when melted, brazing is the safer option from a metallurgical standpoint.
- Electronics: Solder joints provide a reliable electrical connection, are gentle on the material, and are reversible. Soldering is the standard method for printed circuit boards.
- Mass production: Furnace and induction brazing join multiple joints simultaneously and reproducibly through precise temperature control.
- Detachable joints: Soft-soldered joints can be separated again by heating, whereas a welded joint cannot.
Combine the two: Pre-weld before soldering
These processes are not mutually exclusive; they complement each other. The most common combination is position welding: The parts are tacked into their exact positions using short, high-energy pulses and then brazed using conventional methods. This eliminates the need for binding wire, clamps, and positioning compounds; the parts can no longer shift during heating, and the fit is precise in the end.
The PUK features its own spot welding mode with 80 to 700 A at 1.5 ms, while the PUK D has a spot welding connection. Other useful combinations based on practical experience:
- Weld over any pores or cavities in the casting using material of the same type, then continue working as usual and solder in another location.
- Mechanically remove an old solder joint and weld the repair using the same method so that the seam matches the workpiece in color and tarnishing characteristics.
- First, weld the heat-sensitive assembly, then solder the non-critical rough joint.
Decision-Making Guide by Use Case
A concise guide for everyday workshop use, organized by task rather than by process. For each task, the guide provides a recommendation and the rationale behind it, ensuring that the decision remains transparent and can be applied to similar components. In borderline cases, a test piece determines the outcome, not the table, because at material thicknesses of 0.1 mm or greater, both options are usually technically feasible, and wall thickness, alloy, and accessibility then influence the result.
| Assignment | Recommendation | Rationale |
| Changing the Ring Size for a Set Stone | Welding | The stone can remain in the piece; no need to remove and re-set it |
| Add fins and claws | Welding | Material deposition on the smallest structures without heating the setting |
| Filling Pores and Cavities in Castings | Welding | Localized application of material of the same type; no alloy in the defect |
| Orthodontic Wires and Appliances | Welding | No foreign metal and no solder joint in the oral environment; the wire retains its properties |
| Repairing Surgical Instruments | Welding | A seamless joint of the same material, with no gap where residue can accumulate |
| Hermetically Seal the Sensor Housing | Welding | Tight, homogeneous seam, verifiable via leak test |
| Tube in Sleeve, Capillary Connection | Soldering | The capillary gap is the basis of the design; solder flows into it |
| Long seam or large area | Soldering | Flat joint in a single operation instead of point by point |
| Joining Very Different Materials | Soldering | The solder wets both surfaces without creating brittle intermetallic phases |
| Electronic Components | Soldering | Precise electrical contact, reversible, gentle on components |
Costs: What You Actually Pay Per Connection
The cost comparison depends less on the initial purchase and more on ongoing maintenance. Soldering requires materials for each joint—solder, flux, etchant, and fuel gas—while fine welding requires almost exclusively argon at about 2 l/min and the electrode. The decisive factor, however, is labor time, since pickling, neutralization, and post-polishing are no longer necessary. Complete systems start at around 4,400 EUR net, ex works.
What Happens During Soldering
Per connection: solder (which is itself a valuable material when used with precious metals), flux, etching solution, fuel gas, and, above all, labor time for etching, neutralizing, and final polishing. Added to this is the risk of scrap on valuable parts if stones, springs, or plastics cannot withstand the heat.
What Is Involved in Precision Welding
Purchase of the equipment, followed by argon at approximately 2 l/min, electrodes that can be reground multiple times, and welding wire for building up material. Consumption per joint is minimal, and rework is largely eliminated.
Factors That Determine Payback Period
It depends on reduced rework, avoided scrap, and orders that previously went to outside contractors. Fully functional complete setups, including eye protection and a gas supply, start at around 4,400 EUR net ex-factory for the PUK, 5,100 EUR for the PUK D, and 7,000 EUR for the Micro Arc Welder. Leasing is available. For more information on what to look for when purchasing equipment, see the article “How to Recognize a High-Quality Welding Machine.”
An Overview of Lampert Devices
All three professional devices operate on the same micro-TIG principle and differ in power, programs, and intended applications. The PUK, with a range of 9 to 630 A, is designed for gold and silver smiths; the PUK D offers the same power range plus a micro mode for wires under 0.2 mm used in orthodontics; and the Micro Arc Welder, with a range of 5 to 1,200 A, is designed for industrial, laboratory, and repair applications. If you’d like to try out a unit in person, use the “Find a Dealer” feature to locate your nearest contact.
| Feature | Micro Arc Welder | PUK | PUK D |
| Applications | Industry, Laboratory, Research, Repair | Goldsmiths, silversmiths, jewelers, watchmakers | Dental technology, dental laboratories, orthodontics |
| Peak Current (TIG) | 5 to 1,200 A | 9 to 630 A | 9 to 630 A |
| Pulse duration | 0.1 to 34 ms | 0.1 to 34 ms | 0.1 to 34 ms |
| Minimum workpiece thickness | 0.1 mm or more | 0.1 mm or more | Micro mode below 0.2 mm for orthodontic wires |
| Secure before soldering | using short pulses | Dedicated spot welding mode, 80 to 700 A at 1.5 ms | Fixing welding connection |
| Material Lines | 12 (Universal, Gold, Silver, Platinum, Palladium, Bronze, Stainless Steel, Titanium, Aluminum, Tin, Brass, Copper) | 11 | 10 Dental Alloys |
| inert gas | Argon 4.6, approx. 2 L/min, automatic pre- and post-flow, no flux | ||
| Interface | Modbus TCP/IP via LAN, 21 documented registers | without | none |
| Certification | EN 60974-6, EN 61000-6-2/-6-4, EN 63000 (RoHS), CE, and UKCA | ||
| Warranty | 1 year | 3 years | 3 years |
| Investment (Full Starter Package) | Starting at approx. 7,000 EUR net | Starting at approx. 4,400 EUR net | Starting at approx. 5,100 EUR net |
Frequently Asked Questions About Welding and Soldering
In principle, yes, because the weld consists of the base material itself and can achieve the same strength as that material, whereas a brazed joint has the strength of the brazing material, which is generally lower. In practice, however, it depends on the execution: A large-area brazed joint with a properly designed gap can be stronger than a poorly welded seam. The advantage of welding is that the joint is made of the same material and no foreign alloy acts as a weak point in the joint.
The limit is 450 degrees Celsius, which corresponds to the liquidus temperature of the solder. According to DIN ISO 857-2, the process is called soft soldering if the solder becomes liquid below 450 degrees, and hard soldering if it becomes liquid above that temperature. Soft solders are usually tin-based and produce comparatively soft joints, while hard solders based on silver, brass, or gold produce significantly stronger joints. The third category, high-temperature brazing above 900 degrees, which was commonly used in the past, originates from the superseded DIN 8505 standard; the current terminology standard recognizes only the two categories, even though the term continues to be used in practice.
Yes, that is one of the main reasons for using this process in the jewelry industry. The pulse lasts only fractions of a millisecond to a few milliseconds; the heat remains localized, and the component barely heats up at all. This makes it possible to resize rings, add prongs, or weld clasps without removing the stone. With soldering, the workpiece would have to be heated over a large area to soldering temperature, which many stones cannot withstand.
In most repair and installation cases, yes. There are two advantages: no foreign metal in the joint—meaning no visible solder seam and no difference in tarnishing behavior—and no widespread heat input, meaning no chipped stones and less fire glow. For capillary joints, gap bridging, and large surfaces, brazing remains the best approach.
No. Micro-TIG welding does not use flux; argon performs that function and keeps oxygen away from the molten metal. In terms of the workflow, this means that a workpiece can be fully machined, finished, and polished before being welded. With brazing, the surface must be rebuilt afterward.
No, that almost always leads to pores and inclusions. Soft solders contain tin and, in some cases, lead; hard solders contain zinc; and older silver solders also contain cadmium. These elements boil well below the welding temperature, vaporize suddenly, and contaminate the molten pool. Solder residues must be mechanically removed beforehand until the bare base material is exposed.
No. According to Entry 23 of Annex XVII of the REACH Regulation, as amended by Regulation (EU) No. 494/2011, brazing alloys and metal parts of jewelry with a cadmium content of 0.01 percent by weight or higher may no longer be used or placed on the market. Exceptions include, among other things, jewelry that was already on the market before December 10, 2011, or that was more than 50 years old at that time—and it is precisely this older stock that ends up in repair shops. If the origin of an old solder joint is unclear, the solder should be removed mechanically and the work area effectively ventilated, as toxic cadmium oxide fumes are produced when it vaporizes.
Positioning welding joins two parts in a precise position using short, high-energy pulses before they are conventionally soldered or further processed. It replaces binding wire, clamps, and positioning compounds, making it the most common combination of the two methods. Parameters and additional use cases are listed above in the section “Combining Both.”
To some extent. Related materials, such as different types of stainless steel or gold alloys of varying fineness, can generally be joined well. With metals that are very different, however, brittle intermetallic phases form; in such cases, brazing is often the better option because the brazing material wets the two materials without melting them. For specific material combinations, it’s worth performing a test weld before moving to mass production.
It’s not about the unit price per connection, but rather the rework saved, the scrap avoided, and the orders that remain in-house as a result. The individual items are listed above in the section on costs. Fully functional complete setups start at around 4,400 EUR net, ex works, for the PUK; leasing is available.
About This Post
This article is provided by Lampert Werktechnik, the manufacturer of the PUK, PUK D, and Micro Arc Welder micro-TIG precision welding machines. The company was founded in 2001 in Werneck, Lower Franconia, and has been developing, manufacturing, and servicing its products there for more than 20 years. The devices are in use in over 100 countries, and the dealer network spans more than 60 countries. The information in this article is taken from the operating manuals, declarations of conformity, and daily application advice.
Do you have a specific question about one of your own components? Our application team will weld it free of charge and document the parameters in a written welding report. Submit your request via our contact form; details on the process can be found on the On-Site Test Welding page. If you’d like to see a unit in person, use the “Find a Dealer” feature to locate your nearest contact.
Conclusion: When to Use Welding, When to Use Soldering
Brazing joins parts using a filler material and requires heat throughout the entire component, flux, and post-processing. Fine welding fuses the component itself, selectively in 0.1 to 34 ms over a depth of 0.2 to 4.0 mm, without flux or pickling. When it comes to heat-sensitive parts, a uniform appearance, corrosion-free joints, or repairs to finished parts, welding has the advantage. When gaps need to be bridged, surfaces joined, or dissimilar materials joined, brazing remains the appropriate process.
Most workshops therefore take a two-pronged approach and use fixation welding as a bridge between the two. If you want to know how your own component will react, simply submit the material, wall thickness, and requirements via our contact form, and you’ll receive a free sample weld along with a written welding report. For more information: An Overview of Micro-Welding and Precision Welding and the Glossary.
Do you have a question about a specific component?
Our application engineers will review your joining task and provide reliable information on materials, parameters, and feasibility. A sample weld with a written welding report is provided free of charge and is available for material thicknesses of 0.1 mm or greater. The result is returned along with the parameters used so that you can replicate it on your component.