SECURITY & WARRANTY SEALS TYPES AND USAGE GUIDE

Security seals are one of the simplest, yet most underrated elements of a safety system in a facility. They allow for a quick determination of whether an adjustment screw, valve, guard, or housing has been tampered with – without the need for complicated access control systems. In industry, service, and maintenance, there is an increasing reliance on chemical lacquer seals and thread locking adhesives, which combine the function of mechanical security with a clear signal of manipulation.

To select the right seal, it is not enough to simply choose "red varnish." A different product will work on screws in electronics, another on machines washed with aggressive media, and yet another in applications involving contact with food. Below you will find a practical classification of security seals, based on solutions used in the industry and examples from the Melkib offer.

What is a security seal and when do you need it?

In technical terms, a security seal is an element or coating that:

blocks accidental or unauthorized changes to the position of an element (e.g., screw, knob, lever),
provides a legible trace of manipulation – once breached, it is impossible to restore the "factory" state without visible damage,
enables identification (color, number, company logo, code),
can serve as additional protection: anti-corrosion, against vibrations, or against thread loosening.

In practice, seals are used on, among others:

adjustment screws in machines and devices,
guards, doors, and covers of controllers,
valves, fittings, meters, and measuring apparatus,
devices subject to legalization, quality audits, and safety audits.

Types of security seals – mechanical and chemical

On the market, you will find two main groups of solutions: mechanical seals and chemical seals (lacquers and adhesives). They differ in construction, application method, and typical uses.

Mechanical seals (plastic, metal, labels)

This group includes, among others, plastic security seals, metal seals, and various types of security labels. They are mainly used for sealing doors, containers, bags, cabinets, cash boxes, or transport containers.

Plastic pull-tight seals – disposable, numbered, with a "tail" pulled through a hole and locked in a sealing chamber. Good for warehouse doors, containers, transport bags.
Metal and cable seals – used where very high mechanical resistance is required (transport, logistics, securing containers, wagons).
Sticker seals (VOID labels, leaf seals) – self-adhesive labels that leave a legible trace (e.g., the word VOID) when peeled off and prevent "traceless" re-sticking. They work well for sealing housings, rack cabinets, and service cases.

These solutions are ideal for securing housings and partitions, but they cope less well where small elements need to be sealed – individual screws, nuts, or retaining rings. In such situations, chemical seals work much better.

Chemical seals – warranty lacquers and thread lockers

Lacquer seals (warranty lacquers) and certain anaerobic thread lockers are typical chemical seals. After curing, they form a visible, colored dot or bridge on the screw, nut, or joint.

In a single application, you can achieve several key effects from the perspective of safety and maintenance:

Protection against self-loosening – the lacquer or adhesive acts as a wedge in the thread, increases friction, and limits the possibility of accidental loosening of the connection under the influence of vibrations.
Indication of manipulation – even a small attempt to loosen the screw (e.g., by a fraction of a turn) causes a characteristic crack or detachment of the seal. Thanks to this, the service technician immediately sees that someone has interfered with the setting.
Detection of spontaneous loosening – if the screw "comes out" on its own under load, the lacquer bridge between the screw head and the substrate breaks or ceases to align. This allows for the quick detection of a problem during an inspection before a failure occurs.
Marking the optimal screw position – the seal can simultaneously serve as a setting mark. A line or dot shows the position in which the element was calibrated (e.g., "factory setting", "position 0"), which speeds up adjustments and inspections.

They are applied directly to the screw head, thread, nut, or at the junction of two parts.
After curing, the coating is hard or slightly flexible, adheres to the substrate, and breaks or detaches in a characteristic way when an attempt is made to breach it.
A well-selected product can be simultaneously non-conductive (for electronics), resistant to process media, high temperature, and vibrations.

It is this group – chemical seals (lacquer seals and thread lockers) – that is key in the assortment of technical chemistry stores, such as Melkib.

Classification of BADER and WIKO lacquer seals – Standard, Fast Dry, Zero, Secure, Topsecure

In engineering practice, it is worth organizing lacquer security seals according to their chemical base, curing speed, and security level. A good reference point is the series of seals from the BADER brand and WIKO lacquers (in the Standard class), available in various variants in the Melkib store.

Standard Seals – universal protective lacquers

Standard Seals are classic, solvent-based protective lacquers intended for general industrial applications:

they ensure good adhesion to metals and many paint coatings,
they are clearly visible (high color intensity),
after curing, they form a hard but brittle coating – when an attempt is made to tighten or unscrew the screw, the seal cracks, leaving a legible trace.

They work well as basic security seals for screws in machines, switchgears, control cabinets, or measuring apparatus.

Fast Dry Seals – rapid curing and work on vertical surfaces

The Fast Dry series (e.g., BADER Fast Dry security seals) was designed for where very fast drying and the ability to work on vertical surfaces or overhead is key.

the lacquer has strong anti-sag properties – it does not "flow" off threads and edges,
it is non-conductive, so it can also be used in electronics and electrical engineering,
it is resistant to the action of many media (oils, fuels, coolants – according to the technical data sheet).

This is a good choice when the production line must start shortly after the device is assembled or when the seal is to be applied to a large number of points in a short time.

[product id="4677,4674"]

Zero Seals – water-based, food safe

Zero Seals are modern protective lacquers based on water, without organic solvents. They are distinguished primarily by low emission of volatile organic compounds and the possibility of use in applications where high standards of food safety and environmental protection are required.

recommended for the food and pharmaceutical industries, production of packaging and devices having contact with food (upon meeting the requirements of the technical data sheet and sector regulations),
they work perfectly where it is important to limit odor and solvent emissions,
available in various colors, also in larger packaging (e.g., 1 kg) for production lines.

[product id="4676,4670"]

Secure and Topsecure – seals with an increased security level

For applications with particularly high risk (e.g., measuring apparatus covered by rigorous audits, devices with a ban on self-adjustment by the end user), Secure and Topsecure seals are used. As indicated by the manufacturer's materials and the video on the Melkib channel, these are versions with increased chemical and mechanical resistance, more difficult to remove without a legible trace.

Such seals are recommended where:

interference with settings may threaten a serious failure or accident,
it is necessary to maintain a full audit trail,
there is a risk of a deliberate attempt to forge or remove seals.

WIKO lacquers for thread marking

A separate, practical subgroup within the classic Standard seals are WIKO lacquers for thread marking. These are typical chemical seals that:

create a clear, durable marking of the screw or nut position,
allow for quick detection of attempts to loosen or spontaneous unscrewing of the connection,
work well when operating at elevated temperatures, typical for many industrial applications.

WIKO lacquers do not replace anti-corrosion coatings – their main function is signaling manipulation and controlling screw position, not protection against corrosion.

[product id="3799"]

Anaerobic adhesives as "Zero" seals

In many applications, the role of a security seal can be performed by an anaerobic thread adhesive (e.g., LOCTITE 222, 243, 2701), which simultaneously immobilizes the screw and constitutes a legible trace of connection breach. Such products are available, among others, in the category Zero Seals and in the group thread protection – thread adhesives.

When to choose a lacquer seal, and when a mechanical one?

In engineering practice, both solutions are often used in parallel – mechanical and chemical – but they perform a slightly different role:

Mechanical seals (plastic, metal, label) – choose when you are sealing access to the interior (doors, hatches, cassettes, packaging, containers) and you want to easily control if someone has opened the security.
Lacquer seals – choose when it is crucial to secure specific adjustment points (screws, valves, relays, connectors), when there is little space, or you are working with electronics.
Thread adhesives – use where, in addition to a trace of manipulation, you also need mechanical locking of the thread against self-loosening under the influence of vibrations.

How to select the appropriate security seal? – practical guide

When selecting a seal, it is worth going through a few simple steps.

Step 1: Determine exactly what you are sealing

a single adjustment screw, nut, locking ring,
a valve, fitting, meter, transducer,
a guard, cover, door, bolt, service cassette,
an electronic device, controller, communication module.

The smaller the element, the more it pays to use a lacquer seal instead of a plastic one.

Step 2: Examine the working conditions

The most important parameters include:

operating temperature – does the element heat up (e.g., near motors, power supplies, furnaces)? At high temperatures, choose high-temperature lacquers or appropriate anaerobic adhesives,
presence of media – oils, fuels, coolants, detergents, solvents; in demanding conditions, specialized lacquer seals resistant to media will be better, e.g., Fast Dry, Zero, selected LOCTITE adhesives,
humidity and washing – frequent washing of devices (CIP, pressure washers) requires chemically resistant products,
exposure to vibrations – with strong vibrations, a good solution is a combination of sealing lacquer with a thread adhesive.

Step 3: Consider hygienic and environmental requirements

In the food, pharmaceutical, and cosmetic industries and with devices having contact with food, choose water-based solutions, without solvents (e.g., Zero seals), in accordance with the requirements of the safety data sheet and plant standards.
In electrical and electronic zones, necessarily use non-conductive products, such as Fast Dry lacquers.

Step 4: Select the packaging form and application method

In the offer of lacquer seals, you will find, among others:

20–50 ml tubes – convenient for service work and small series,
30–50 ml cartridges – ideal for precise dosing using guns and dispensing systems,
1 kg packaging – for production lines and automatic dosing stations.

If you already work with guns and dispensers for adhesives, you can usually also plug in cartridges with sealing lacquer – this facilitates process standardization.

Step 5: Ensure correct surface preparation

Regardless of which product you choose, surface preparation is the foundation:

remove loose contaminants, dust, old coatings,
degrease threads and screw heads with an appropriate technical cleaner,
wait until the surface is completely dry, only then apply the seal.

Even the best security seal will not fulfill its role on a dirty, greasy surface.

Most common mistakes when using security seals

Application on a non-degreased substrate – low adhesion, the seal comes off easily and does not give a reliable trace of manipulation.
Applying a layer that is too thick – longer drying time, greater susceptibility to chipping during vibrations.
Selection of lacquer without considering temperature and media – in an aggressive environment, the seal may soften, discolor, or be partially dissolved.
Using conductive products in electronics – risk of short circuits and damage to SMD elements.
Lack of documentation – during audits and complaints, the lack of information on which seal was used, at which station, and since when becomes a problem.

Security seals in practice – example applications

Machines and production lines – Standard and Fast Dry seals on adjustment screws, limit stops, valve settings, pressure transducers.
Electronics and automation – non-conductive, quick-drying Fast Dry seals for securing potentiometers, switches, plugs, connectors, and communication modules.
Food industry and pharmacy – water-based Zero seals on valves, regulators, operator panels, and device covers in zones where low VOC emission and hygiene requirements are important.

If you want to see what the application of seals looks like live, check out the video on the Melkib channel: "How do warranty seals for screws work? How to secure a device against unwanted interference?", where, among other things, the differences between Standard, Zero, and Fast Dry seals and practical tips are shown.

TAGGR Industrial Markers – a supplement to security seals

In addition to typical lacquer seals and thread adhesives, TAGGR industrial markers are also used in many plants. These are not seals in the strict sense (they do not "block" the screw), but they constitute an ideal supplement to the security system – they allow for durable marking of an element, describing the setting position, media path, machine number, or service point.

On what surfaces do TAGGR markers work?

Markers in the TAGGR Rough Surface Marker tube have been developed specifically for difficult industrial conditions. According to the manufacturer's data, they are suitable for marking practically all types of substrates, including:

smooth and very rough metals,
greasy, oily, and dirty surfaces,
wet elements, and even marking underwater,
concrete, stone, rust, wood, plastics, glass, and neoprene.

Unlike classic markers, the TAGGR lacquer system maintains adhesion and coverage even where oil or grease is present on the surface.

Most important technical properties of TAGGR markers

permanent, highly covering lacquer – legible markings even on dark and rusty substrates,
resistance to weather conditions in accordance with DIN EN ISO 2810, which enables use outdoors as well,
wide range of operating temperatures – from approx. −80 °C to +160 °C (depending on the color), thanks to which markings do not disappear under typical thermal loads in industry,
good resistance to media (water, fuels, oils, selected solvents – details in the manufacturer's TDS),
electrical insulation – possibility of use also in the vicinity of electrical installations, if they require lacquer markings,
practically "indestructible" writing head with a 2.5 mm steel ball (Rough Surface) and a clip that enables constant, repeatable pressure on the tube and convenient use of the product to the end.

Where a marker, and where a seal?

In practice, it is worth combining security seals with TAGGR markers:

lacquer seal or thread adhesive – when you must secure a screw, valve, or setting against unauthorized adjustment and a legible trace of manipulation is needed,
TAGGR marker – when you need a durable marking (arrow, scale, number, socket description, line code) on a difficult substrate: greasy, wet, rusty, or very rough.

As a result, the user sees both whether the connection has been tampered with (seal) and has clear, abrasion-resistant operational markings made with the marker.

FAQ – most frequently asked questions about security seals

Does a lacquer seal make unscrewing the screw difficult?

Classic lacquer seals primarily signal manipulation – upon unscrewing the screw, they crack and clearly show that the connection was tampered with. Additional resistance to self-loosening is provided by anaerobic thread adhesives, which can simultaneously perform the role of a seal and a thread lock.

How to choose the color of the security seal?

Choose the color in terms of readability and plant standard:

red – the most frequently used "alarm" color, clearly visible in inspections,
yellow, green, blue – often used to distinguish lines, shifts, functions (e.g., service settings vs factory settings),
in applications with audits, you can use different colors for subsequent inspections, which facilitates later identification.

Are Zero seals really food safe?

Seals from the Zero series are water-based and do not contain organic solvents, which makes them the preferred solution in applications requiring special care for the environment and food safety. However, one must always check the safety data sheet and internal plant requirements (HACCP, IFS, BRC, etc.).

Can a lacquer seal be removed and reapplied without a trace?

No. By definition, a security seal must be destroyed when an attempt is made to remove it. An attempt to "repair" a sealed dot usually leaves visible traces: differences in texture, discoloration, lack of coating continuity. It is thanks to this that seals are a credible element of the security system.

How long does a Fast Dry seal take to dry?

Seals from the Fast Dry series were designed as quick-drying lacquers, allowing for the rapid startup of the device after assembly. However, the drying time depends on the layer thickness, temperature, and ventilation – therefore, one should always follow the data from the manufacturer's technical data sheet and perform a short test in the target conditions.

Can I combine a lacquer seal with a thread adhesive?

Yes – in many applications this is the safest solution. The thread adhesive is responsible for the mechanical lock and sealing, and the visible dot of sealing lacquer performs the function of a manipulation signal and setting marking. Such an approach is particularly popular in machines exposed to strong vibrations.

If you need help in selecting specific security seals for your application (machine, production line, measuring devices, electronics), contact the Melkib team – we will select the product and application method for your working conditions and audit requirements.