PQ-19 - Acid cleaner for exterior surfaces (descaling and rust-removing agent)

PQ-19 External Cleaning Acid for limescale, rust and stubborn grime

PQ-19 exterior cleaning acid is formulated for jobs requiring a genuine descaler. Furthermore, it combines mineral acids with wetting agents and corrosion inhibitors, thereby improving its ability to penetrate limescale, surface rust and adhered environmental grime.

This product is used on surfaces exposed to the elements, including metal, limestone and granite. Consequently, it is very useful on façades, walls, plinths and areas where dirt becomes ingrained over time.

What it removes and where it is recommended

PQ-19 exterior cleaning acid helps remove limescale and rust. Furthermore, it is particularly effective on granite walls, as their porosity allows a large amount of dirt to accumulate. It is also used to remove cement residues from hard-wearing surfaces.

• External limescale: limescale films and deposits caused by water or rain.
• Surface rust: stains and marks on exposed areas.
• Environmental pollution: dirt embedded in walls, particularly granite.
• Cement residues: splashes and residues after construction work (depending on the surface).

Surfaces and compatibility

PQ-19 can be used on metal, limestone and granite surfaces. However, it has a slight corrosive effect on copper and its alloys. Furthermore, it may attack steel, aluminium, zinc and magnesium if left in contact for too long. Therefore, monitor the time and always rinse.

• Never use undiluted.
• Before application, carry out a test to check whether it blackens or attacks the surface.
• Use non-metallic, low-pressure spraying equipment.

Instructions for use (step by step)

First, prepare the dilution. Then, apply by low-pressure spraying. Leave it to work for the specified time and do not exceed this. Finally, rinse with pressurised water to remove residue and dirt.

1. Dilute to between 2% and 5% depending on the level of limescale or build-up.
2. Spray using non-metallic, low-pressure equipment.
3. Leave to work for 5 to 10 minutes.
4. If the soiling is heavy, scrub manually with a brush.
5. Rinse with pressurised water.

Neutralisation on granite and limestone (for best results)

On granite and limestone surfaces, after applying PQ-19, it is recommended to neutralise with an alkaline degreaser. For example, you can use MARDHES H1 or TARSPRAY 8 at 5% to 10% and then rinse with water. This stabilises the surface and improves the final finish.

Internal link: See alkaline degreasers for neutralisation

External link: CLP reference (chemical safety)

Professional use

CAUTION: product for professional use only. Use appropriate PPE and always follow the label instructions and workplace procedures.