Finished metal parts tarnish and corrode when humidity, salt and caustic vapours reach the bare surface. A thin, transparent lacquer seals the surface without hiding the finish. Micron 3501 Protektor MetaCoat is a fast-drying, single-component acrylic lacquer whose page says it protects metal surfaces from harsh environments, moisture, corrosion, dirt, dust, fungus and caustic vapours, dries transparent, and can be removed with Protektor thinner. For UV inspection or bulk brushing and dipping there is MetaCoat UV in 5 L (3508).
Why it happens
- Humidity and salinity. Coastal air and monsoon humidity speed up corrosion and tarnish on steel, brass and other metals.
- Caustic vapours. Process areas and some storage environments attack bare metal surfaces.
You will see tarnish, discolouration or corrosion spots on finished metal parts, often while they are in storage or on display.
How to fix it
Choose by application method and inspection needs:
- Aerosol, general use: Micron 3501 Protektor MetaCoat, 500 ml. Fast drying, transparent, with decent resistance to organic solvents, fungal growth, dust and dirt, per its page.
- Needs UV inspection, or bulk brush or dip (5 L): Micron 3508 Protektor MetaCoat UV, a UV-traceable acrylic lacquer that its page says can be brushed, sprayed or dipped.
- A UV lamp curing line is available for metal parts: Micron 3608 Protektor PolyCoat UV, a UV-cured coating listed for metal tools, fixtures, sheet metals and machined parts. It needs a medium-pressure mercury lamp.
The 3501 page directions are brief: cleaned metal parts are sprayed in line with the relevant process. Follow the instructions on the can and the TDS. General practice:
- Clean and degrease the parts; any fingerprint or oil will be sealed under the lacquer.
- Let them dry fully.
- Apply as the can and TDS direct, in a ventilated area.
- Let it dry before handling or packing.
What to avoid
- Clean parts first. Lacquer over oil, fingerprints or tarnish locks them in.
- Keep out of reach of children; do not spray in eyes or mouth (stated on the page).
- Do not use on surfaces that touch food; food contact is not stated.
- 3608 needs a UV lamp and operator UV shielding; it will not cure without them.
When to ask an expert
Hand off to Micron technical if:
- the part will touch food or drink;
- the part is for outdoor architectural use, which the pages do not cover;
- you need a specific salt-spray or corrosion test result.
Choosing between lacquer and a temporary rust preventive
A lacquer suits finished parts that should stay protected and look the same in service or on display. If parts are only waiting for the next process (welding, painting, machining), a temporary rust-preventive film that is easier to remove, such as 1201 Mould Saver, may suit better. Ask on Calchemi if you are not sure which you need.
FAQ
Will the lacquer change how the metal looks?
The 3501 page describes it as transparent. Apply thin, even coats so it does not run or pool.
Can I remove it later?
The page says it can be removed with Protektor thinner.
What is the difference between 3501 and 3508?
Both are Protektor MetaCoat acrylic lacquers for metal. 3501 is a 500 ml aerosol. 3508 is 5 L, UV-traceable, and its page says it can be brushed, sprayed or dipped.
Can I use MetaCoat on brass?
The page says it protects metal surfaces in general and does not list specific metals. Test on a sample part first, especially on polished brass or plated finishes.
See the product: Micron 3501 Protektor MetaCoat. Related: 3508 MetaCoat UV, 3608 PolyCoat UV. More fixes: general hub.