How to Fix Black Marks on Plastic

It is a common problem for plastic to turn dark after laser marking, which can be a result of oxidation due to high temperatures or a chemical reaction in the material.This article provides three practical remedies, including rubbing with alcohol, polishing, and applying a protective coating, to help you quickly solve the problem of discoloration and restore the clarity of the marking.

Why does plastic turn black when it is branded?

Let's first talk about why it turns black.Plastic marking is usually done by laser or hot stamping, and under the action of high temperatures the surface of the material is easily carbonized or oxidized, especially plastics with high carbon content (such as ABS).Furthermore, if the temperature of the equipment is not adjusted properly, or if the material itself cannot withstand high temperatures, the label will turn black as soon as it is stamped.

Remedy 1: Alcohol wipes away black marks.

If the hair is not too dark, try this first.

Operation steps.

1. Dip a cotton swab in 75 % alcohol and gently wipe the darkened area.

2. Let the alcohol sit for 30 seconds to dissolve any carbonized material on the surface.

Use a dry paper towel to wipe in one direction only, and do not rub back and forth, to avoid scratching the surface.

This method is suitable for light discoloration. Remember to dry the area with a cold air fan after using.

Remedy 2: Finely polish.

If you have a stubborn stain, use a tool.

The tools are ready.

- 2000-grit sandpaper.

- Polishing paste (automobile grade is even finer).

- Soft cloth or a sponge.

Operating principles.

1. Dampen a sandpaper with water and rub lightly on the blackened areas.

2) After the spots have disappeared, use polishing cream to rub the area in circular motions.

3. Finally, use a damp cloth to wipe away any remaining paste.

Note: Be gentle when polishing. Overdoing it can deform the shape.

Repair technique 3. Coating.

It's a clever precaution against the black mold reappearing.

Recommendation letters.

UV varnish.

- Nano anti-oxidation spray.

The process.

1. The area to be marked after cleaning.

2. Apply a thin layer of UV lacquer and cure with a UV lamp (if no lamp is available, expose to sunlight for 15 minutes).

3. After the paint has dried completely, spray on an anti-oxidant to form a protective film.

This "invisible armor" can effectively block air, and is particularly suitable for plastic parts that will be used for a long time.

Finally, remember that different plastics react differently, so it's best to test a small piece first.If the stain is very large or the material is very special, it's probably better to find a professional.