Teamac T-Wash Mordant Solution | Galvanised Steel Pre-Treatment for Paint Adhesion

• Pre-treat new galvanised steel within 7 days of galvanising before applying a primer or topcoat
• Improve paint adhesion on weathered galvanised steel or zinc surfaces
• Confirm full surface coverage visually — the blue solution turns grey on application
• Treat large galvanised steel areas cost-effectively — approximately 40 m² per litre
• Prepare galvanised roofing, cladding, structural steelwork, gates or railings for painting

• The galvanised surface is contaminated with oil or grease and has not been degreased first — degrease with Coo-Var Universal Degreaser before applying T-Wash
• The surface does not show a colour change on application — this indicates contamination; do not apply successive coats to overcome the lack of colour change

Teamac T-Wash Mordant Solution is a specialist acidic pre-treatment formulated for galvanised steel and zinc surfaces. Developed by Teamac — part of the Coo-Var group with over 115 years of British coatings heritage — it provides the chemical key that paint systems require to adhere properly to zinc surfaces, which are notoriously difficult to coat without pre-treatment.

The solution works by micro-etching the zinc surface through a controlled acid reaction, creating a mechanical and chemical bond for subsequent primer and topcoat systems. The built-in colour indicator makes the process straightforward to verify — the blue solution visibly turns grey on application, confirming that the surface has reacted correctly and is ready for priming. Areas that do not change colour should be treated as contaminated and cleaned before reapplication.

For best results, apply to new galvanising within 7 days of galvanising at works. It can also be applied to weathered galvanised surfaces, though reactivity diminishes as the age of the galvanising increases and may result in uneven colouration. Do not apply successive coats — a single application is all that is required.

Key Benefits

• Chemical key for galvanised steel — micro-etches zinc to provide the adhesion that paint systems require on galvanised surfaces
• Visible colour change indicator — blue solution turns grey on application, confirming full surface reactivity and coverage
• Exceptional coverage — approximately 40 m² per litre, making it highly cost-effective for large galvanised steel projects
• Suitable for new and weathered galvanising — apply to new galvanising within 7 days, or to weathered galvanised surfaces with appropriate preparation
• Single application — do not apply successive coats; one treatment is all that is required
• 115+ years of British expertise — trusted by fabricators, contractors and maintenance teams across the UK

Order before midday for next-day UK delivery.

Teamac T-Wash Mordant Solution is an essential pre-treatment for a wide range of galvanised steel and zinc surface coating projects:

• New Galvanised Steel Fabrications — Apply within 7 days of galvanising at works to provide the chemical key required for primer and topcoat adhesion. Suitable for galvanised steel gates, railings, fencing, structural fabrications and architectural metalwork before priming with Teamac Zinc Phosphate Primer.

• Galvanised Roofing & Cladding — Pre-treat galvanised steel roofing sheets, cladding panels and flashings before applying a primer and topcoat system. The exceptional coverage rate of approximately 40 m² per litre makes it highly cost-effective for large roof and cladding areas.

• Structural Steelwork & Fabrications — Apply to galvanised structural steelwork, beams, columns and fabrications before priming as part of a complete coating system. Suitable for both workshop application and on-site treatment of assembled steelwork.

• Weathered Galvanised Surfaces — Apply to weathered galvanised steel where paint adhesion has previously been a problem. Clean the surface thoroughly before application and monitor the colour change to confirm reactivity. Note that reactivity diminishes as the age of the galvanising increases.

• Metal Gates, Railings & Fencing — Pre-treat galvanised steel gates, railings and fencing before applying a decorative primer and topcoat system. The colour change indicator confirms full coverage across complex profiles and sections.

• Industrial & Commercial Maintenance — Use as part of a planned maintenance programme for galvanised steel assets including structural steelwork, plant equipment supports and external metalwork. Prevents adhesion failures and extends the life of the coating system.

If you need personalised advice on surface preparation, application methods, or compatible primer and topcoat systems, contact our experts via the live chat for tailored guidance.

Coverage: Approximately 40 m² per litre

Coverage per size

• 2.5L bottle: Covers approximately 100 m² per application

Important: Do not apply successive coats. A single application of T-Wash is all that is required. Applying additional coats will not improve adhesion and is not recommended.

Example calculations

• For a set of galvanised steel gates (approximately 5 m²), a 2.5L bottle will treat approximately 20 sets of gates
• For galvanised roofing or cladding of 50 m², a 2.5L bottle will provide 2 full treatments
• For structural steelwork of 100 m², a single 2.5L bottle will provide one full treatment

Practical coverage may be lower depending on surface texture, porosity and application method. For accurate project planning, we recommend ordering 10–15% extra.

Note: If no colour change takes place on application, the area should be treated as contaminated. Clean the surface thoroughly and allow to dry before reapplying. Do not apply successive coats to overcome a lack of colour change.

Surface Preparation

New Galvanising (within 7 days of galvanising at works)
• The surface must be clean, dry and free from contamination
• If contaminated with oil or grease, wipe over with Coo-Var Universal Degreaser before proceeding
• Do not apply to contaminated or unclean surfaces

Weathered Galvanising
• Clean down using an abrasive pad, water and a cleaning agent, followed by rinsing and allowing to dry fully
• If contaminated with oil or grease, wipe over with Coo-Var Universal Degreaser before the cleaning down procedure
• Note: reactivity of the treatment diminishes as the age of the galvanising increases and may result in uneven colouration from light grey to dark grey

Application

1. Apply by brush, roller or dip to the clean, dry galvanised surface
2. The blue solution will turn grey on application — this colour change confirms that the surface has reacted correctly
3. If no colour change takes place, treat the area as contaminated — clean thoroughly and allow to dry before reapplying
4. Do not apply successive coats to overcome a lack of colour change
5. Allow to dry for 1.5–2 hours at 20°C before applying primer
6. Wash all equipment thoroughly with fresh water immediately after use — Mordant Solution attacks many metallic surfaces including spray equipment

Drying Times (at 20°C)

• Touch dry: 1.5–2 hours

After drying, apply Teamac Zinc Phosphate Primer or another suitable primer within the recommended overcoating window.

Important Notes

• Apply to new galvanising within 7 days of galvanising at works for best results
• Do not apply successive coats — a single application is all that is required
• Areas showing no colour change should be treated as contaminated and cleaned before reapplication
• Mordant Solution attacks many metallic surfaces — wash all equipment with fresh water immediately after use
• If using spray equipment, take particular care — guns and equipment may be damaged if not washed immediately

Recommended System Products

Free delivery on orders over £75 — stock up on everything you need in one go and complete the job properly.

Coo-Var Universal Degreaser: Degrease galvanised steel surfaces contaminated with oil or grease before applying T-Wash. Essential first step on contaminated surfaces to ensure proper reactivity and adhesion.

Teamac Zinc Phosphate Primer: Apply over T-Wash once dry as the anti-corrosive primer coat before topcoating. The recommended primer for use on galvanised steel after T-Wash pre-treatment.

Paint Brushes, Rollers & Frames: Use suitable brushes or rollers for T-Wash application. Wash all equipment thoroughly with fresh water immediately after use.

These products are commonly combined for best long-term results.

What is Teamac T-Wash Mordant Solution used for?
It is used to pre-treat clean zinc and galvanised steel surfaces before painting, providing a chemical key that allows paint systems to adhere properly. Without pre-treatment, paints typically show poor adhesion on galvanised steel.

How do I know if it has worked?
The solution is blue and visibly turns grey on application. This colour change confirms that the surface has reacted correctly and is ready for priming. Areas that do not change colour should be treated as contaminated and cleaned before reapplication.

Can I apply it to weathered galvanising?
Yes, but reactivity diminishes as the age of the galvanising increases and may result in uneven colouration from light grey to dark grey. For best results, apply to new galvanising within 7 days of galvanising at works.

Can I apply more than one coat?
No. Do not apply successive coats. A single application is all that is required. Applying additional coats will not improve adhesion and is not recommended.

What if there is no colour change?
If no colour change takes place, treat the area as contaminated. Clean the surface thoroughly and allow to dry before reapplying. Do not apply successive coats to overcome a lack of colour change.

What surfaces can it be used on?
It is specifically formulated for zinc and galvanised steel surfaces. It is not intended for use on other substrates.

How much does a 2.5L bottle cover?
Approximately 40 m² per litre — a 2.5L bottle covers approximately 100 m² per application.

What pack size is available?
Teamac T-Wash Mordant Solution is available in a 2.5L polythene bottle.

How long before I can apply primer?
Allow 1.5–2 hours drying time at 20°C before applying primer. Drying times will be longer in cold or humid conditions.

What primer should I use after T-Wash?
Teamac Zinc Phosphate Primer is the recommended primer for use on galvanised steel after T-Wash pre-treatment.

Can I use spray equipment to apply it?
Mordant Solution attacks many metallic surfaces including spray equipment. If using spray equipment, wash guns and all equipment thoroughly with fresh water immediately after each work period to prevent damage.

Is it flammable?
Yes. This product has a flash point of 31°C. Keep away from heat, sparks and naked flames during application and drying. Ensure adequate ventilation at all times.

How should I prepare a contaminated galvanised surface?
If contaminated with oil or grease, wipe over with Coo-Var Universal Degreaser before applying T-Wash. For weathered galvanising, clean down using an abrasive pad, water and a cleaning agent, rinse thoroughly and allow to dry before applying.

Do you offer next-day delivery?
Yes. Order before midday for next-day delivery to mainland UK addresses. Contact us for delivery options to Scottish Highlands, Northern Ireland and other remote areas.

Technical Data Sheet

Safety Data Sheet

We recommend these system products to achieve the best results with Teamac T-Wash Mordant Solution. Free delivery on orders over £75

Coo-Var Universal Degreaser — degrease galvanised steel surfaces contaminated with oil or grease before applying T-Wash; essential first step on contaminated surfaces

Teamac Zinc Phosphate Primer — apply over T-Wash once dry as the anti-corrosive primer coat; the recommended primer for galvanised steel after T-Wash pre-treatment

Paint Brushes, Rollers & Frames — suitable brushes and rollers for T-Wash application; wash all equipment thoroughly with fresh water immediately after use

Not sure which primer or topcoat system is right for your galvanised steel project? Contact our experts via live chat for free, tailored advice — we will help you choose the right products and get the best result.

Fast, Reliable & Fully Tracked UK Delivery

Every order is dispatched from our warehouse using a fully tracked DX or FedEx service, so you always know when your paint will arrive.

Delivery Options

• FREE Standard Delivery (orders over £75) Arrives in 2–3 working days
• Standard Delivery – £7.95 Arrives in 2–3 working days
• Express Delivery – £13.95 Next working day delivery when you order before 12:00 noon (Mon–Thu)
• Spending £75+? Select Express Upgrade at checkout and only pay the difference

Dispatch & Delivery Times (What Happens After You Order)

• Express delivery (order before 12:00 Mon–Thu) Dispatched same day, delivered next working day
• Standard delivery (Mon–Wed orders) Dispatched next working day, delivered 2–3 working days later
• Orders placed Thursday (standard delivery) Dispatched Friday for Monday delivery
• We do not dispatch or deliver on weekends or UK bank holidays

What to Expect on Delivery

Please provide a contact telephone number at checkout. This allows the courier to share tracking updates or contact you if there are any delivery issues.

Most orders require a signature on delivery. If you may not be available during the day, we recommend delivery to a workplace, business address, or another location where someone can sign.

Outside the UK Mainland?

Delivery prices shown apply to UK Mainland only.

For the Highlands, Islands, Northern Ireland, or non-mainland addresses, please contact us for a quick personalised quote via live chat, by calling 01482 222 421, or emailing info@specialistpaintsonline.co.uk.

Bottom Line

Order today, get fast and reliable delivery, track every step, and get painting without delays.