Solutions to Common Problems in the Removal of Coatings

The book covers a wide range of practical techniques for dealing with the problems encountered in the process of removing plating material, including chemical, mechanical, and electrolytic methods.The company provides detailed operating instructions to help users avoid mistakes and efficiently remove plating layers from different materials.

The most common problems.

Many friends encounter all sorts of headaches when dealing with the surface coating of metal products. For example, they might use the wrong method and end up damaging the base material, or spend ages trying to get the coating off and still not succeed.In fact, different metals (such as chromium, nickel and zinc) need different methods of treatment, and only by selecting the right method can one achieve the desired results.

Here's a look at three popular methods.

Chemical dissolving method.

Chemical methods are the most common way to remove the plating, but they require special attention to safety.Take nickel plating, for example. A solution of dilute nitric acid works well, but if the base metal is copper, the concentration must not be too high, otherwise the base metal will be corroded.Be sure to wear protective gloves, and make sure the ventilation is good.

The grinding method.

Sandpaper or sandblasting are more reliable for thicker coatings or for local treatment.My own experience is that first you should use a coarse sandpaper (80-120 mesh) to remove the surface layer, then switch to a fine sandpaper (400 mesh or more) to smooth the edges. In this way you can save effort and avoid scratches.

Electrolytic etching.

Electrolysis is suitable for precision parts, and involves the use of an electric current to gradually remove the plating.The best concentration of sodium carbonate solution is 8-12 %.You must maintain a steady voltage, and when the coating starts to bubble, that means you're getting results. Never get impatient and raise the voltage!

A guide to avoiding pitfalls.

The base materials can't be forgotten.

When processing soft metals such as aluminum, chemical methods can easily cause oxidation of the surface.It is suggested that you first do a small test in an inconspicuous place, to confirm the reaction time, and then do the whole area.

Waste water must be treated.

Don't pour chemical waste down the drain! Solutions containing heavy metals should be handed over to a professional recycling agency, while acidic solutions can be neutralized at home (for example, by adding baking soda).

The choice of tools is crucial.

When grinding, hard alloy tools are used, since ordinary steel tools wear out easily and can mix metal chips into the coating.If the coating is particularly stubborn, try using a heat gun to heat up the area before sanding it.

Special skills for dealing with special situations.

If the coating has multiple layers (such as copper and then chrome), it is recommended that you remove them layer by layer.First use hydrochloric acid to dissolve the chromium layer, then use ferric chloride to dissolve the copper layer. Don't mix them! Finally, before beginning, make sure to find out what the plating material is, and if you're really unsure, do a test on a scrap piece first.