MC-Bauchemie MC-DUR Putty
A two-component, moisture-insensitive epoxy putty that seals cracks and rebuilds concrete-to-steel interfaces on structures that can’t be dried out first — wet, damp or fully submerged.
What is it?
A solvent-free, two-component epoxy putty mixed 1:1 by weight, with a moisture-insensitive resin system that cures and bonds on damp or underwater substrates — something ordinary epoxy putties can’t do without a dry surface.
Where is it used?
Crack sealing in concrete and steel; pointing ahead of waterproofing or coating work; protective epoxy layering on structures in marine or submerged exposure — water tanks, reservoirs, silos, breweries, dairies and food-processing units.
Why use it?
It bonds where cementitious putties and standard epoxies can’t — on wet or underwater substrates — with high early compressive and bond strength, so crack-sealing on live structures like sumps, STPs or tank interiors doesn’t have to wait for a dry site.
How is it applied?
Mix resin and hardener 1:1 by weight for 3–5 minutes with a slow paddle mixer (max. 600 rpm), then hand-apply with gloves, spatula or trowel within the roughly 50-minute pot life, finishing with a light wet-glove rub.
About MC-Bauchemie MC-DUR Putty
MC-DUR Putty is MC-Bauchemie’s two-component, solvent-free epoxy putty for sealing cracks in concrete and metal, built around one specialist trait: it works on substrates that aren’t bone dry. Most epoxy putties need clean, fully cured, moisture-free concrete — fine on a new building, unrealistic on a live water tank, an underground sump, a jetty pile cap, or anything sitting through India’s monsoon. Its moisture-insensitive resin chemistry is designed to tolerate surface moisture and cure reliably in dry, moist and fully underwater conditions, which is why the manufacturer’s own literature lists underwater crack sealing as a stated application, not a stretch use case.
For Space Arc’s Delhi NCR and Pan-India project base, that property matters more than the raw strength numbers, though those are respectable too — over 20 N/mm² compressive strength within a day, and bond strength high enough that pull-off tests fail in the parent concrete, not the epoxy bondline. In practice, it earns its place not as a bulk repair mortar (the 8 kg putty pack isn’t built for that) but as the crack-sealing, pointing and protective-layer specialist for water-retaining structures, marine substructures and hygienic industrial floors where there’s no time to dry out the substrate before repair.
The technical insight
The distinction is in curing chemistry, not resin family. Standard epoxies rely on a clean, dry substrate because surface moisture interferes with wetting at the interface — apply them to a damp crack and the bondline is typically weak. MC-DUR Putty’s moisture-insensitive hardener is engineered to tolerate that surface film, which is what lets the manufacturer certify underwater use. The bond data backs it: EN 1542 testing at 3 days returns above 2.5 N/mm², with failure reported in the concrete substrate, not the adhesive layer — the bondline outperforms the concrete around it. The roughly 50-minute pot life at 30°C (FIP 5.1) is worth noting too: it’s fast-reacting, so batch sizes should match what a crew can place in that window, especially in Indian summer heat.
Where it is used
- Sealing structural and non-structural cracks in concrete and steel, dry, moist or fully underwater
- Crack and joint sealing in sumps, water-retaining structures and marine or submerged substructures
- Pointing and surface preparation ahead of waterproofing or protective coating on marine-exposed concrete
- Protective epoxy layering on concrete exposed to chemical attack, corrosion or abrasive wear
- Repair and crack sealing inside potable water tanks, reservoirs and water-treatment structures
- Crack and joint sealing in breweries, dairies and food-processing plants needing hygiene and chemical resistance
Key advantages
- Moisture-insensitive formulation bonds to damp and underwater substrates, no drying-out needed
- Solvent-free, simple 1:1 by-weight mix ratio for consistent site batching
- High early strength — over 20 N/mm² compressive at 1 day, over 25 N/mm² at 3 days (ASTM C579)
- Bond strength above 2.5 N/mm² (EN 1542), with failure occurring in the concrete, not the bondline
- Good resistance to water, corrosion, chemical attack and abrasion for marine/industrial exposure
- Hand-workable putty consistency — gloves, spatula or trowel, no pumping equipment needed
Limitations & considerations
- Pot life only around 50 minutes at 30°C — mix small batches, especially in Indian summer heat
- Application must stop below +5°C substrate/ambient temperature — mainly relevant in hill-station winters
- A putty, not a bulk-fill mortar — the 8 kg pack suits cracks and pointing, not large-volume recasting
- Cleaning agent is MC-Thinner EP only; water and water-based cleaners are explicitly ruled out
- Unmixed hardener is alkaline and a skin/eye irritant, so gloves and eye protection are essential
Selection & best practice
Prepare concrete to a sound, laitance-free profile — pressure-water-jet honeycombing and strip old paint — and blast-clean steel to Sa 2½ per DIN 55928 part 4. Batch only what the crew can mix, place and finish inside the roughly 50-minute pot life, staying conservative through pre-monsoon and peak-summer months. Mix with a slow paddle mixer (max. 600 rpm) to limit air entrainment, and finish with a light wet-glove rub.
Specifications
| Chemistry / System | Two-component, solvent-free, moisture-insensitive epoxy resin putty |
| Mixing Ratio | 1:1 by weight (resin : hardener) |
| Mixed Density | 1.55 kg/l at 27°C |
| Pot Life | ~50 minutes (100 g at 30°C, per FIP 5.1) |
| Compressive Strength | >20 N/mm² at 1 day, >25 N/mm² at 3 days (ASTM C579) |
| Bond Strength | >2.5 N/mm² at 3 days (EN 1542), concrete failure per FIP 5.14 |
| Slant Shear Strength | >10 N/mm² at 3 days (ASTM C882) |
| Application Temperature Range | +5°C to +40°C substrate/ambient; +10°C to +40°C material |
| Pack Size / Shelf Life | 8 kg pack; 12 months in sealed packaging, stored +5°C to +30°C |
Industry use cases
Water & Wastewater Infrastructure
Sealing construction joints and hairline cracks in sumps, STPs and water tanks where the surface can’t always be fully dried before repair.
Marine & Coastal Structures
Pointing and crack-sealing on jetties, wharves and coastal RCC elements sitting in tidal or splash-zone moisture.
Food & Beverage Plants
Crack and joint sealing in breweries, dairies and food-processing floors and tanks needing chemical resistance and a hygienic finish.
Industrial & Process Plants
Protective epoxy layering and crack repair on plant floors and equipment plinths exposed to chemical attack and impact loading.
Frequently asked questions
What makes MC-DUR Putty different from an ordinary epoxy putty?
Can it actually be applied underwater?
How much working time do I get once it’s mixed?
What pack size does it come in, and how do I estimate quantity?
Does the surface need special preparation first?
Is this for large structural repairs, or only cracks and patching?
How we position MC-Bauchemie MC-DUR Putty
MC-DUR Putty sits at the crack-sealing and pointing end of MC-Bauchemie’s Concrete Repair range — for larger structural sections it’s typically specified alongside the brand’s Nafufill polymer-modified repair mortars, with MC-DUR Putty reserved for cracks, joints and pointing where a wet or underwater bond is the deciding factor. Buyers comparing brands also look at Fosroc’s epoxy range (Nitobond EP as a bonding agent, Renderoc HS Xtra for repair mortar) or Sika’s epoxy putty systems, but few carry the same explicit underwater-application backing — so the choice usually comes down to whether the substrate can be guaranteed dry. Space Arc stocks and applies both MC-Bauchemie and Fosroc lines and recommends on technical fit rather than brand alone.
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