How to solder stainless steel to stainless steel using tin and rosin? This is a very time-consuming process, for which you need to know all the subtleties and tricks of soldering. If you follow the instructions discussed in this article, you will be able to make a reliable connection of stainless steel products.
Process Features
Only lead-free solders (for example, tin and alloys based on it) can be used for work with food containers. Soldering stainless steel products is a complex process that requires some knowledge and skills. The best solder for working with the mentioned metal is tin. Thanks to this material, it will be possible to make a high-quality connection. However, tin is more often used for soldering when you need to attach small parts or repair small cracks. Solder is sold in spools or bars 2-4 mm thick.
Tin soldering is rarely used in industry. And at home, to repair household items (for example, a stainless steel kettle), they use a soldering iron or a gas burner, as well asmentioned solder. In this case, the main thing is to prepare the necessary consumables (consumables). But we should not forget: in the course of soldering work, hot objects and toxic substances will be used, so safety rules must be observed.
Why do you need flux?
This substance will ensure uniform spreading of the solder over the surface of the soldering zone and create conditions for high-quality adhesion of the material to the metal coating. Fluxes are currently classified according to their impact on the following varieties:
- Inactive (neutral), containing no acids. In addition, they are almost non-conductive.
- Active (acidic) fluxes.
- Protective (anti-corrosion), the purpose of which is to protect the soldering area of the finished joint from corrosion and destruction.
If the question arises, why do we need a flux for soldering, then the answer can be this: this substance is necessary to comply with the technology, since it will definitely be needed during soldering. However, the method of applying the composition depends on its initial state:
- if the flux is in a solid state, the soldering iron tip must first be dipped into the reagent, and then grab a little solder with it;
- the finished liquid mixture will have to be applied to the soldering area with a brush;
- paste-like substance should be treated with a regular stick.
Also, flux is sometimes sold in special tubes.
Required Tools
Before proceeding with the repair of the product, you need to prepare the following tools and materials:
- A simple soldering iron (minimum power - 100 W) or a propane torch.
- Organic solvent (such as white spirit or acetone).
- Tin solder.
- Rosin or phosphoric acid.
- Steel cable.
- Metal brush, file or sandpaper.
- A clean cloth to wipe.
However, before soldering stainless steel to stainless steel and, accordingly, repairing the part, you should purchase protective equipment: polyurethane gloves, goggles and a respirator. In addition, to connect large products, a more powerful soldering iron, the tip of which must be fireproof, may be required: this will not only increase the service life, but also increase the technical parameters of the tool. As for solder, it should also be said that tin bars are suitable for soldering food utensils or other containers, since they contain less harmful impurities.
How to solder with a soldering iron with rosin and tin: technology
When the materials and tools are prepared, you can proceed to this operation. To solder stainless steel at home, you need to follow this step-by-step instruction:
- Clean the metal surface from oxide film and other contaminants with sandpaper or a brush.
- Degrease the repaired part with solvent.
- Apply flux to the surface to be treated -rosin or soldering acid. This step does not need to be performed if a combined tin solder is used, which already contains the mentioned substance. Flux must be applied immediately before soldering, as a film forms on the surface of the stainless steel after about 10 seconds.
- Heat the soldering area, which is applied flux, tinned tip of the soldering iron.
- Add solder if needed, but most likely won't tin the entire surface the first time.
- Re-apply the flux and heat it again with a soldering iron. Repeat this process until the surface of the metal is covered with a uniform layer of tin. The main thing is that the solder does not melt from the tip of the soldering iron, but from the heat stored by the part. In addition, to make the soldering of stainless steel with tin better, you need to add rosin to the joints, due to which oxides from the solder will be removed.
- Wash the product from flux residues. To complete this step, you need to prepare a solution consisting of water and detergent, and buy metal scrapers. The remains of rosin, according to the masters, are well cleaned with cold water, since the substance becomes brittle in it.
Soldering is considered to be of high quality if the result is a uniform surface. But in any case, at the end, the coating must be sanded with sandpaper or a file.
How to connect stainless parts: the best technique
First you need to equip the workplace. The table must be steel or have a non-combustible surface. The main thing is that it be even. In addition, you need to make high-quality exhaust ventilation. In turn, in order to solder several products into one at home, it is necessary to cover their parts with tin and fix them together. The next step is to simultaneously heat the parts so that the hot solder connects. Probably, tin will have to be added to the soldering area, bringing it on the tip of the soldering iron.
After that, you need to warm up the entire surface and, if the solder is of good quality, you need to put the parts on a flat surface. A stainless steel product assembled from two or more parts must not be moved until the joints have completely hardened. It is better to secure the soldered parts with fasteners (for example, clamps or a vice).
Gas torch soldering: kettle repair
First, you need to carefully clean the soldering area with sandpaper and remove scale near the damaged area. To solder a stainless steel kettle with a gas burner, you need to follow this instruction:
- Heat the connection with a flame, smoothly moving the device. The heat will be sufficient when the solder begins to melt from touching the metal.
- Apply flux (rosin or phosphoric acid) to the area to be soldered.
- Apply tin over the damaged area, while continuing to heat the area with a burner so that the substance, melting, fills the entire defective area.
- Sand the seam with a metal brush.
- Wipe the soldered area with alcohol to clean its surface from scale andoxides.
In the course of soldering work, you need to monitor the level of oxygen. To determine this parameter, you need to look at the flame, the normal hue of which is blue. In a supersaturated composition, the color will be pale, which indicates an excess of oxygen. If you ignore this requirement, it is likely that the stainless steel will begin to oxidize.
Benefits of tin soldering stainless steel
The advantages of this method include the following properties:
- consumables are inexpensive;
- no lengthy part preparation required;
- easy soldering work for small products;
- tin solder reduces fluidity of stainless steel when soldering;
- good connection quality.
Flaws
In addition to the undeniable advantages, soldering stainless steel with tin solder has some disadvantages:
- difficulty when sealing seams on inclined and vertical planes due to the high fluidity of tin;
- Insufficient permanent connection strength for large structures;
- reduction in the allowable temperature range of soldered parts due to the fact that tin will simply melt if the material is exposed to temperatures above 231.9 °C.
Recommendations
Of course, without a good soldering iron and flux, it will not be possible to make a reliable connection. However, before soldering stainless steel, you need to consider other points:
- It is advisable to buy a soldering iron with a tip that does notburns: the service life of such a tool is longer than that of a conventional fixture. However, it must be constantly cleaned of scale and sharpened. In addition, it is recommended to use a soldering iron with constant heating: this will save energy.
- Soldering stainless steel without flux is a bad idea, as an oxide film will constantly appear.
- Inexperienced craftsmen should practice a little on unnecessary details and scraps. It must be remembered: a reliable connection is difficult to tear off, and you can check its quality with a screwdriver or an awl.
- The part treated with solvent should only be touched with gloves, as a small stain left on the surface can spoil the whole work.
- Before you solder stainless steel to stainless steel, you need to provide the room with good ventilation. In addition, do not touch heated metal or solder with your hands, or inhale toxic fumes.
- Containers with substances after use must be immediately closed with a tight lid.
- The finished part must be cleaned of flux and soldering composition. Food containers are treated with soapy water and boiled to neutralize aggressive acids.
Basic mistakes
If, taking into account the recommendations, it still failed to make a high-quality connection, then such a failure may occur due to:
- poor metal stripping and poor degreasing;
- insufficient heating of stainless steel;
- wrong solder or flux;
- what is solderedthe part was mechanically stressed too early because the product did not have time to harden.
Conclusion
The article discussed how to solder stainless steel to stainless steel. To perform the described work, you need to purchase the necessary equipment and fixtures. During soldering, the main thing is to make high-quality seams that will provide parts with a reliable connection. Also, with the information in this article, anyone can repair small stainless steel items on their own with a soldering iron, tin solder, and flux.
