Tinning of metal can be used in various cases - when soldering, to increase the protective properties of the metal, to hide flaws in its surface. Most often, soft solders are used for this - with a melting point of no higher than 300 ° C. The technology of their use is quite simple and does not cause serious difficulties even for those who took up this work for the first time.
Necessary
- - solder;
- - flux;
- - electric soldering iron;
- - blowtorch or hair dryer;
- - soldering paste;
- - sandpaper;
- - a brush with stiff bristles;
- - clean napkins.
Instructions
Step 1
Select the materials for tinning that are best suited to the material of the product that you are going to tin. If contact with food is possible, the solder should be free of lead. There are many lead-free solders - tin alloys with indium, beryllium, zinc, silver. Pure tin can also be used. It should be borne in mind that lead-free solders are inferior to tin-lead (POS) in adhesion and wettability. Therefore, if the manufactured product will not have direct contact with a person, it is better to use tin-lead solders for tinning.
Step 2
The choice of flux is determined by the type of material to be processed. For tinning ferrous metals, zinc chloride (ZnCl2 - zinc chloride, soldering acid) and ammonium chloride (NH4Cl - ammonium chloride) are best suited. For stainless steel, fluoric acid is used. A good remedy is unispa-3, which is a 20% solution of phosphoric acid in water. It is able to remove not only the oxide film from the metal surface, but also rust.
Step 3
A very convenient means for tinning are solder pastes, which contain solder and flux in their composition, which eliminates the need to separately process the product with flux and solder. In particular, Wurth's S-Sn97Cu3 paste is lead-free and has good wettability.
Step 4
Use an electric soldering iron as a heating element with a small size and small thickness of the product. For larger sizes, use a blowtorch, gas torch or hair dryer. The heating device must provide heating of the metal up to 250-300 ° C.
Step 5
Before tinning, thoroughly clean the product from traces of the old coating and rust using a metal brush and sandpaper. The metal surface must be cleaned to the base metal. Blow the surface with air to remove fine dust and stones and degrease it.
Step 6
After cleaning, treat the surface with a suitable flux - using a brush or cloth - and warm it up to the desired temperature with one of the devices listed in step 4. Then proceed with applying the solder.
Step 7
Tin small items using a soldering iron with solder applied to it, rubbing the surface with it. In this case, the solder from the soldering iron will go to the material being plated.
Step 8
If the size of the product is significant, place the solder on the surface of the heated metal, wait for it to melt and rub it over the surface with a wooden spatula or a brush with stiff bristles.
Step 9
You can preheat the solder in a container until it melts and stir with a stick - so that it takes the form of very small pebbles. Then distribute these stones over the surface of the part, warm it up and rub the solder with a brush.
Step 10
When using solder paste, after cleaning and degreasing the surface, apply a thin layer of the compound to the surface to be treated and heat it up with a hair dryer or blowtorch. At the same time, try not to overheat - the start of boiling of the paste should serve as a signal to the end of heating the zone. After heating, remove the remaining paste from the surface with a clean cloth.
