Dr. Fixit Feviseal Neutral Pro
A one-part neutral-cure silicone sealant for glass, aluminium and masonry joints that need to move with the building – without corroding metal frames, staining stone, or giving up in a Delhi summer.
What is it?
A one-part, moisture-curing neutral silicone sealant that cures into a flexible, medium-modulus rubber – unlike ordinary acetic (vinegar-smelling) silicones, it won’t corrode aluminium frames or discolour natural stone over time.
Where is it used?
Aluminium and UPVC window and door frame perimeters, glass and showroom glazing joints, metal cladding and ACP panel laps, ducting seams, and general interior sealing in homes, offices and commercial fit-outs.
Why use it?
Neutral-cure chemistry is safe on metals, mirror backing and natural stone where acetoxy silicones would eventually corrode or stain, and the cured sealant stays flexible from -40°C to +150°C – far past anything an Indian facade or window joint experiences.
How is it applied?
Gunned from a 280 ml cartridge into a masking-taped, backer-rod-supported joint, tooled within minutes before it skins over, then left to cure a minimum 7 days at above 50% relative humidity before full water exposure.
About Dr. Fixit Feviseal Neutral Pro
Feviseal Neutral Pro comes from Feviseal, the dedicated sealants range Pidilite Industries runs alongside its better-known Dr. Fixit waterproofing portfolio out of the same Construction Chemicals Division in Mumbai – which is why Space Arc, as an authorised Dr. Fixit distributor and applicator, stocks and installs it as part of the same building-envelope system. It is a one-part, moisture-curing RTV silicone that skins in 5 to 20 minutes and cures through atmospheric humidity into a medium-modulus rubber, rather than the harder, brittle-with-age film you get from cheap acetoxy tube sealants.
What earns it the word ‘neutral’ is the by-product released while it cures: neutral-cure systems give off alcohol or oxime vapour instead of the acetic acid that acetoxy silicones release, so it will not corrode aluminium window frames, blacken copper and brass fittings, or stain natural stone and marble the way a bathroom-grade acetoxy sealant eventually will. On Indian sites that matters most at aluminium and UPVC window perimeters, ACP cladding joints and glass storefronts, where the sealant sits in direct, permanent contact with the metal section for the life of the building – and where a corroded frame is a far costlier callback than a resealed joint.
The technical insight
The word ‘neutral’ in the name refers to the by-product of cure, and that single chemistry choice drives most of what this sealant is (and isn’t) good for. As Feviseal Neutral Pro cures via atmospheric moisture, it releases alcohol or oxime vapour; acetoxy silicones – the cheaper tube sealants sold for bathroom use – release acetic acid instead, which is mildly corrosive to aluminium, copper and brass and can etch or stain marble, limestone and mirror backing over months of contact. That’s why the datasheet rates it for primerless adhesion to glass, aluminium, brick, concrete, steel and ceramic without a corrosion caveat, and why it’s the specified choice for aluminium and UPVC frame perimeters rather than a generic acetoxy tube. The tested numbers back up a genuine “medium modulus” classification too: Shore A hardness of 22 on the clear variant (35 on white/black, since the pigment loading stiffens the cured gel slightly) sits well below high-modulus structural sealants, and elongation at break of up to 700% on ASTM D412 testing means the bead can absorb real thermal or structural movement rather than just filling a static gap. What it explicitly is not tested or rated for is equally instructive – the datasheet rules out structural glazing, continuous immersion and food/potable-water contact, so treat those exclusions as load-bearing facts rather than fine print.
Where it is used
- Perimeter sealing of aluminium and UPVC window and door frames against wind-driven monsoon rain
- General glazing and showroom/storefront glazing joints (non-structural glazing only)
- Metal cladding and ACP facade panel joint sealing
- HVAC ducting seam and joint sealing
- Interior gap sealing around door/window frames, exhaust fan housings and pipe penetrations in commercial fit-outs
- Sealing joints between dissimilar materials – glass to aluminium, metal to masonry, steel to concrete
- General weatherproofing of above-ground building envelope joints exposed to sun and rain but not submerged
Key advantages
- One-part, ready-to-use cartridge – no mixing or pot-life to manage on site, unlike two-part PU or polysulphide joint sealants
- Neutral cure chemistry is non-corrosive to aluminium, copper and brass, and won’t stain natural stone or mirror backing the way acetoxy silicones can
- Primerless adhesion to glass, aluminium, brick, concrete, steel and most plastics on a properly cleaned and degreased surface
- Cured sealant stays flexible across a very wide range, -40°C to +150°C, well beyond anything a Delhi NCR roof or facade joint will see
- Fast tack-free time (under 30 minutes) lets crews tool and strip masking tape the same day instead of waiting overnight
- High movement capability – up to 700% elongation at break on the clear variant – genuinely absorbs thermal and structural joint movement instead of just filling a gap
- Rated for outdoor exposure with good resistance to UV, ozone and weathering, so exposed glazing and cladding beads don’t chalk or crack prematurely
- Offered in Clear, White and Black in the same 280 ml cartridge format, so frame colour can be matched without switching products
Limitations & considerations
- Not rated for structural glazing applications – it seals the joint, it does not structurally hold glass panels in place
- Not recommended for continuous water immersion, below-ground joints, or trafficable joints exposed to abrasion
- Cannot be painted over once cured, so colour has to be chosen at purchase (Clear, White or Black)
- Should not be used where the sealant would contact food or drinking water
- Narrow application window – not to be applied below 4°C ambient or when the substrate surface exceeds 50°C
- Shelf life is 12 months from manufacture and it must be stored cool and dry, so site teams should check cartridge dates on bulk orders
Selection & best practice
Clean and fully degrease the joint faces before gunning – any dust, oil or curing-compound residue is the single biggest cause of adhesion failure with silicones. Mask both sides of the joint first for a straight, uniform bead, and size the joint properly: aim for roughly equal width and depth on narrow joints, and drop in a closed-cell backer rod on anything wider than about 10-12 mm so the sealant only bonds the two sides (not the base) and can flex with movement instead of tearing. Tool the bead immediately after gunning, before it skins, to press out air voids and get full contact on both faces – this is what actually delivers the adhesion, not just the bead sitting in the gap. Pull the masking tape while the sealant is touch-dry, not after it has fully cured, or you risk tearing the finished edge. Don’t apply below 4°C or when the surface itself is hotter than 50°C, keep it off wet or actively raining substrates, and hold off exposing the joint to sustained or pressurised water until the full 7-day cure (at above 50% RH) has passed. On unfamiliar or painted substrates, run a small test patch first rather than committing the whole elevation.
Specifications
| Chemistry | One-part, moisture-curing neutral-cure RTV silicone sealant |
| Density, uncured paste | 1.000 g/cm³ (Clear); 1.300 g/cm³ (White & Black) |
| Skin formation / tack-free time | 5-20 min skin; <30 min tack-free (ASTM C679) @ 25±1°C, 50±5% RH |
| Cure rate | 1-2 mm per 24 hr @ 25±1°C, 50±5% RH; full cure in 7 days minimum |
| Hardness (7-day cure) | Shore A 22 (Clear); Shore A 35 (White & Black) – ASTM C661 |
| Elongation at break | 700% (Clear); 500% (White & Black) – ASTM D412 |
| Tensile strength | ≥0.8 N/mm² (Clear); 1.1 N/mm² (White); 1.4 N/mm² (Black) – ASTM D412 |
| Service temperature range (cured) | -40°C to +150°C |
| Pack size & coverage | 280 ml cartridge (Clear/White/Black); ~7.7 linear m for a 6mm x 6mm joint per cartridge |
Industry use cases
Residential high-rise / apartment fit-out
Perimeter sealing of aluminium and UPVC window frames against wind-driven monsoon rain, without long-term risk of frame corrosion at the sealant line
Commercial retail / showroom
Storefront and showroom glazing joints where a clean, near-invisible clear bead is needed between large glass panels and aluminium mullions
Industrial sheds and warehousing
Metal cladding sheet laps and HVAC ducting seam sealing on factory and warehouse envelopes
Office and commercial interiors
General interior gap sealing around door/window frames, AC ducts, vents and exhaust housings during fit-out
Facade and ACP cladding (non-structural)
Weatherproofing of above-ground perimeter joints on ACP and metal cladding panels, outside of structural glazing scope
Frequently asked questions
Is this the same as the silicone I’d use to reseal a bathroom sink or shower cubicle?
Can I use it for structural glazing, where the sealant is holding the glass panel in place?
How soon can the joint get rained on after we apply it?
Will it corrode our aluminium window frames like some cheap tube sealants do over time?
Can it be painted over to match the wall or frame colour?
Does Space Arc just supply the cartridges, or can you apply it on our project?
How we position Dr. Fixit Feviseal Neutral Pro
Within the Feviseal family this sits above Feviseal GP/GP Pro (economy, acetoxy-cure general-purpose silicones better suited to non-critical interior joints where the acetic-acid odour and mild corrosion risk don’t matter) and alongside Feviseal Weatherproof Pro, a higher weathering-grade sibling for the most exposed facade elevations. For paintable interior trim and moulding gaps, Feviseal Multipurpose (a water-based acrylic) is the correct sister product, and for sanitary wet areas Feviseal Bathroom & Kitchen’s anti-fungal glossy white is purpose-built rather than Neutral Pro. Against Fosroc, the honest comparison isn’t a like-for-like silicone – Fosroc’s Nitoseal range leans toward MS polymer and polysulphide chemistries (Nitoseal MS600, Thioflex 600) for heavier-movement or immersed joints, so a specifier reaches for Fosroc specifically when the joint will see water immersion, potable-water contact, or fuel/chemical exposure that sits outside what a silicone sealant is designed to tolerate.
Fosroc Nitoseal MS600 — Where a joint will actually sit under continuous water immersion or needs potable-water approval – a water tank or sewage-works joint, say – Feviseal Neutral Pro is explicitly ruled out by its own datasheet, and Fosroc’s Nitoseal MS600 (a one-part, isocyanate-free MS polymer sealant built for immersed structures) is the more honest specification, even though it’s a different chemistry rather than a like-for-like silicone swap.
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