MC-Bauchemie MC-BondAid Plast
A ready-to-use polymer bonding coat that replaces hacking with a permanent bond between old and new concrete or plaster.
What is it?
MC-BondAid Plast is a ready-to-use, non-ionic polymer liquid from MC-Bauchemie that acts as a bonding agent and plastering aid. Brushed or sprayed neat onto a prepared surface, it forms a polymer membrane that grips both the old substrate and the fresh concrete, mortar or plaster placed over it, replacing mechanical hacking.
Where is it used?
On RCC repair of beams, columns and slabs, at construction joints between old and new concrete, on brick and block masonry ahead of plastering, as a bond coat before guniting or shotcrete, and on smooth or glazed concrete where plaster would otherwise struggle to key.
Why use it?
It removes labour-heavy hacking and the micro-cracking hacking causes, costs less than an epoxy bonding system, is non-toxic enough for potable-water structures, and improves bond and tensile strength while cutting permeability and chloride ingress at the joint.
How is it applied?
Apply undiluted by brush or spray in one full coat onto a clean, sound, pre-wetted-then-surface-dried substrate. Bring on fresh concrete, mortar or plaster wet-in-wet, ideally within 60-90 minutes and never beyond 1.5 hours, at roughly 8-10 m²/kg on fairly non-absorbent surfaces.
About MC-Bauchemie MC-BondAid Plast
On most repair sites in Delhi NCR, the default way to get new concrete to stick to old concrete is still a labourer with a chisel, hacking the surface for mechanical key. It works, but it is slow, noisy on occupied sites, and it routinely over-stresses the surrounding concrete, seeding the kind of micro-cracks that show up as fresh delamination a year or two later. MC-BondAid Plast is MC-Bauchemie’s answer: a milky-white, non-ionic polymer liquid supplied ready to use, brushed or sprayed straight onto a cleaned, sound surface. As it sets it forms a thin polymer membrane that keys into both the old substrate and whatever fresh cementitious material follows, whether that is a repair mortar, a plaster coat, or fresh concrete at a construction joint.
What makes it practically useful is less the chemistry itself and more the trade-offs it removes. Because no hacking is needed, repair work on occupied buildings, water tanks and older masonry can proceed without the dust and vibration of chipping, and being non-toxic it is cleared for use inside potable-water structures where an epoxy bonding agent would draw extra scrutiny. It also costs meaningfully less than two-part epoxy systems, which matters when bonding coat is a small line item against a larger repair-mortar quantity. The one discipline it demands back is timing: the wet-in-wet window is short, and a site coating one area while mixing mortar in another needs to sequence the two carefully so the film is never left to skin over before the mortar goes on.
The technical insight
MC-BondAid Plast works on film formation, not on chemical bonding the way an epoxy resin does. The polymer dispersion coalesces as it loses water into a continuous membrane that mechanically interlocks with both surfaces it touches — which is why the manufacturer’s own lab notes cite it holding plaster onto smooth, glazed tile, a substrate where a hacked key would fail outright. This is also why the 60-90 minute window matters more than it looks: once that film has fully coalesced and skinned over before fresh material arrives, it stops being a shared interface and starts acting as a bond-breaking layer — the most common reason bonding-agent failures get reported on site. Because it is a standalone coating rather than an admixture dosed into the mortar, the joint’s entire performance rides on uniform, full-coverage application in one pass; a missed patch is a weak point the mortar layer cannot compensate for afterwards.
Where it is used
- Bonding coat before patch-repair mortar on RCC beams, columns and slabs
- Adhesion coat at construction joints between old and new concrete pours
- Bond coat for fresh plaster onto brick and block masonry, without hacking
- Bonding coat ahead of guniting or shotcrete repair work
- Bond coat before commencement of structural concrete repair
- Adhesion primer for plastering over smooth, dense or glazed concrete
- Bonding coat inside potable-water tanks and STP structures
- Surface treatment to reduce permeability and chloride ingress at repair joints
Key advantages
- Removes hacking entirely, along with its labour, time and dust
- Avoids the micro-cracking mechanical hacking induces in sound concrete
- Ready to use out of the pail — no on-site mixing or dilution to get wrong
- Non-toxic formulation, usable in potable-water-contact structures
- Meaningfully cheaper than two-part epoxy bonding systems
- Improves interfacial bond and tensile strength versus an untreated joint
- Lowers permeability and chloride ingress at the bonded interface
- Single-coat brush or spray application, suited to patch and large repairs alike
Limitations & considerations
- Short, non-negotiable wet-in-wet window (60-90 minutes, hard cap 1.5 hours) — miss it and the coat must be redone
- Data sheet publishes only density; no adhesion (MPa), open-time-vs-temperature or chloride-migration figures are quoted, so treat durability claims as qualitative
- Not a substitute for a structural epoxy bonding agent where very high load-transfer or rapid strength gain is specified at the joint
- Coverage is substrate-dependent — 8-10 m²/kg holds for fairly non-absorbent surfaces only; porous substrates consume noticeably more
- Water-based, so freshly coated surfaces need protection from rain before the overlay goes on
- The technical data sheet on file is dated January 2013 — Space Arc confirms the current edition and packaging with MC-Bauchemie before quoting a job
Selection & best practice
Chip out unsound concrete and get to a genuinely sound, dust-free, coating-free surface first — this is a bonding coat, not a substitute for substrate preparation. Wash the cleaned surface and let it go touch-dry before coating. Apply undiluted, by brush or spray, in one full coat with no skipped patches, since gaps in coverage are gaps in the bond. Before opening the pail, stage the repair mortar or plaster crew and material, because fresh work must go on wet-in-wet, ideally inside 60-90 minutes and never beyond 1.5 hours — coating a large area and mixing mortar afterwards is the most common way this product gets blamed for what was really a sequencing problem. Store unopened pails away from sun, rain and frost.
Specifications
| Type of Product | Polymer Bonding Agent |
| Form | Liquid |
| Colour | Milky White |
| Density | ≈1.01 ± 0.02 g/cm³ |
| Shelf Life | 9 months from date of manufacture |
| Pack Sizes | 5 kg and 30 kg pails |
| Coverage | 8-10 m²/kg (fairly non-absorbent surfaces; substrate-dependent) |
| Application | Brush or spray, single undiluted coat |
| Wet-in-wet Overcoating Window | 60-90 minutes (maximum 1.5 hours) |
Industry use cases
Residential & Commercial Repair (Delhi NCR)
Bond coat on RCC beams and columns ahead of patch-repair mortar on an occupied site, avoiding hacking-related dust and disruption.
Heritage & Masonry Restoration
Plaster bonding onto old brick masonry facades where mechanical hacking would damage the original fabric.
Retaining Walls & Tunnelling
Bond coat ahead of guniting or shotcrete repair on retaining walls and tunnel linings.
Water & Wastewater Infrastructure
Non-toxic bonding coat for potable water tank and STP refurbishment, where an epoxy system would need extra clearance.
New-build RCC Construction Joints
Bonding coat at construction joints between concrete lifts poured at different times.
Frequently asked questions
Does MC-BondAid Plast need diluting with water before use?
How long do we have between coating and plastering or concreting over it?
Can it really make plaster stick to a smooth or glazed surface?
Is it safe inside a drinking-water tank or sewage structure?
How far does one kg go?
What pack sizes and shelf life does Space Arc supply?
How we position MC-Bauchemie MC-BondAid Plast
Within MC-Bauchemie’s own range, MC-BondAid Plast sits alongside Nafufill BBR and Nafufill SBR — both bonding-type products, but formulated as additives gauged into repair mortar rather than a standalone brush/spray membrane — so a specifier is really choosing between “coat the substrate, then mortar” and “dose the bonding polymer into the mortar itself,” and the two are sometimes combined for belt-and-braces adhesion. It is typically specified upstream of MC-Bauchemie’s Nafufill KM-series repair mortars, which need exactly this kind of bond coat before placement. Where a project has standardised on an epoxy-based repair system, or an engineer has called for higher load-transfer at the joint, Fosroc’s Nitobond SBR is the credible cross-brand alternative — an SBR-latex bonding agent covering the same “bond old to new concrete without hacking” role, worth discussing where a client’s approved-vendor list already runs Fosroc for other repair work.
Fosroc Nitobond SBR — Where a project has standardised on Fosroc for its other repair works, or where the specifier is already running an SBR-latex repair system, Nitobond SBR covers the same bond-old-to-new-concrete role as a direct cross-brand alternative.
Related Concrete Repair products
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