Since stainless steel is mostly used where it is exposed to heavy stress, you should also rely on a permanent solution for fastening it. You can, instead of soldering stainless steel, choose a screwed joint - but for that you have to drill through the sheet, making it vulnerable to corrosion. Screws can also loosen over time, and the once-firm connection is history.
You probably also think immediately of the familiar screw when you want to fasten something. That is presumably because you have no experience with soldering stainless steel. But it is actually not that difficult. In a few steps, we explain how to approach this task and how to ensure an optimum result - regardless of whether you want to use smooth or brushed stainless steel.
Solder or weld stainless steel? A good question
For most people, soldering is familiar only in connection with electrical engineering. When metal is to be fastened somewhere, welding automatically comes to mind. Yet soldering is an option not only for fine work - although it is of course far better suited to that, since it allows much finer working. Stainless steel jewellery, for example, is usually soldered.
In any case, a soldered joint is preferable to gluing stainless steel. Gluing appears at first glance to be the quickest and easiest way to create a connection between stainless steel workpieces - but it is not truly resilient and will not last. It must also be noted that soldering and gluing are not suitable for joining heavy stainless steel parts such as a trailer floor plate. Here, welding remains the only option. To decide on one of the methods, ask yourself the following questions:
- What load must the seam withstand?
- Is the joint in a visible area?
- Can I weld or solder on site?
Usually, the answer to whether you should solder or weld stainless steel then emerges by itself.
A tip from practice: should your dishwasher ever spring a leak, you can simply solder it. We know that sounds unbelievable, but very small holes can be closed quickly and easily this way. When soldering your dishwasher, just make sure the solder is food-safe.
What equipment do you need for soldering stainless steel?
If you are now thinking of major expenses, we can reassure you. A soldering iron, which you need for this, is far cheaper to buy than a welding machine. For the soldering iron to be suitable for stainless steel, it must have a copper tip. To solder stainless steel, you also need solder and flux as consumables - likewise not very expensive to purchase.
The flux performs an important function when soldering stainless steel: it has a cleaning effect and ensures that the area to be joined is free of contaminants. The solder is melted by the soldering iron and spreads evenly. As it cools, it solidifies, creating a permanent connection between the two stainless steel workpieces.
Temperature determines the process
In soldering stainless steel, a distinction is made between brazing (hard soldering) and soft soldering. The distinction lies in the different temperatures: brazing requires a temperature of more than 450° Celsius. When solder is processed at such a high temperature, the resulting molecular bond is stronger and a harder soldered seam is created - but the effort for this process is also considerably greater.
That is also why soft soldering is the usual process for stainless steel. Here, the solder only needs to reach a temperature between 180° and 250° Celsius. If you want to work with coated stainless steel sheet, this is the optimum process. Even though it does not quite achieve the strength of welding and brazing, you still obtain a very resilient joint.
Soldering stainless steel yourself, step by step
As with many other manual tasks, good preparation is half the battle - and so it is with soldering stainless steel sheets. The best approach is as follows.
Step 1: Cleaning
A clean working environment is essential. If you have not cleaned the area where you want to create a soldered joint thoroughly, contaminants can become trapped in the seam - in the worst case, you will have to redo it. Brake cleaner has proven to be a good cleaning agent that completely removes grease and other residues. Simply spray a piece of kitchen paper with it and wipe the area to be soldered thoroughly.
Step 2: Applying flux
For a good result, you must now apply the flux. Spread it generously over the surface so that all the spots to be soldered are covered. For stainless steel, use a flux based on phosphoric acid - it is preferable to agents based on hydrochloric acid or chloride.
Step 3: Soldering
Soldering stainless steel requires two work steps. First, you must preheat the area: simply hold the soldering iron against the spot you want to solder for about 10 seconds.
The second step is melting the solder with the soldering iron. Try to let the liquid tin drip evenly onto where the soldered seam is to form, aiming for as smooth a surface as possible.
If you want to be on the safe side, you can apply a second layer of solder to the seam - but it must first have cooled completely. A seam gains particular stability when applied in a zigzag pattern. Either way, you may only move the soldered workpieces once the seam has cooled down fully.
Where do you get the material?
Every DIY store carries soldering irons and consumables. It will be more difficult to get stainless steel sheets in the right size. This is where we can help, because we have specialised in cutting sheets and processing stainless steel.
Our sales colleagues can be reached by telephone and can quote you a price for your desired sheet immediately. The advice is always non-binding and free of charge. If you commission us, we produce your individual sheet within two days and hand it over for dispatch. So you never have to wait more than a few days - and can then get started with soldering your stainless steel right away.
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