About Dr. Fixit Tank Prime

{“name”:”Dr. Fixit Tank Prime”,”slug”:”drfixit-dr-fixit-tank-prime”,”brand”:”Dr. Fixit”,”realProduct”:”yes”,”officialSource”:”https://www.drfixit.co.in/resources/library/technical-data/large-projects/w046-dr-fixit-tank-prime”,”category”:”waterproofing”,”metaTitle”:”Dr. Fixit Tank Prime | PU Primer for Tanks | Space Arc”,”metaDescription”:”Dr. Fixit Tank Prime is a two-component polyurethane primer that keys concrete and masonry so PU waterproofing coats bond tight on tanks and sumps.”,”heroSubtitle”:”A two-component polyurethane primer that keys bare concrete so Dr. Fixit’s PU waterproofing coats actually stay put on the tank walls they’re meant to protect.”,”glance”:{“whatIsIt”:”A solvent-free, two-component (1:1 by volume) polyurethane-based primer built specifically as the bonding coat under Dr. Fixit’s polyurethane waterproofing range on concrete and masonry.”,”whereUsed”:”Underground and overhead RCC water tanks, sumps, STP/ETP chambers, basements and any concrete or masonry surface scheduled to receive a Dr. Fixit PU waterproofing topcoat.”,”whyUse”:”Bare concrete is porous and dusty; a PU membrane applied straight onto it can pinhole, blister or peel off in patches. Tank Prime penetrates the surface, seals it, and gives the topcoat a mechanically keyed film to bond into instead of a fighting chance.”,”howApplied”:”Stir resin (Part A) and hardener (Part B) separately, pour Part B fully into Part A and mix 4-5 minutes with a slow-speed drill, then roller or brush it on in one or two thin coats totalling 200 gm/m². Recoat once tack-free — typically 6 to 24 hours depending on site temperature.”},”technicalInsight”:”What makes Tank Prime worth specifying over a generic bonding coat is the combination of low viscosity and moisture tolerance. The resin runs 150-1650 mPas depending on batch and the hardener 100-400 mPas — thin enough to travel into the capillary pores of concrete rather than sit as a skin on top, which is why the sheet still bonds to damp or freshly cast (\”green\”) concrete instead of demanding the usual 28-day dry-cure wait. Pidilite tests adhesion to ASTM D7234 and reports a pull-off value of 2 MPa with concrete failure — meaning the primer bond itself doesn’t let go; the parent concrete tears first. That’s the number a site engineer actually wants to see, because it confirms the primer isn’t the weak link in the waterproofing build-up. The trade-off is a short 30-minute pot life at 25°C, so it behaves more like a fast two-pack epoxy than a forgiving cementitious slurry, and mixing needs to be batched to what a crew can actually roll out before it kicks.”,”applications”:[“Priming underground and overhead RCC water tanks ahead of a Dr. Fixit PU waterproofing coat”,”Bond coat for sumps and basement water-retaining structures before tanking”,”Sealing/priming coat on bare concrete in STP and ETP chambers before PU lining”,”Humidity-barrier priming where a vapour-drive problem is expected under the topcoat”,”Substrate priming on damp or green (recently cast) concrete that can’t wait for full cure”,”Re-priming old, leaking tanks during retrofit waterproofing before a fresh PU recoat”,”Priming construction-joint and masonry-to-concrete transitions inside tank walls”,”Prep coat ahead of PU-based terrace and roof waterproofing where humidity resistance matters”],”advantages”:[“Zero-VOC, low-odour, non-flammable formulation — usable inside enclosed, poorly ventilated tank chambers without the fumes of a solvent-based primer”,”Bonds to damp or green concrete, so priming doesn’t have to wait for a full 28-day cure on new tanks”,”Low viscosity gives genuine mechanical penetration into concrete pores, not just a surface film”,”Simple 1:1 by-volume mix ratio is easy for site crews to measure and reduces dosing errors”,”Documented adhesion (2 MPa, ASTM D7234) shows concrete failure, meaning the primer bond outperforms the substrate itself”,”Purpose-built as the primer for Dr. Fixit’s PU range, removing guesswork on primer-topcoat compatibility”,”Recoat window can be as short as a few hours in warm weather, keeping tight tank-lining schedules on track”,”Compact 1.6 kg kit sizing suits small tank jobs without large leftover quantities”],”limitations”:[“Pot life is only 30 minutes at 25°C — batches must be sized to what a crew can roll out before it starts to gel, especially in Delhi summer heat”,”It is a primer, not a standalone waterproofing product; it must always be followed by a compatible PU topcoat within the recoat window”,”Performance is temperature-sensitive: cold weather retards cure and can stretch recoat time to 24 hours, while heat accelerates it and shortens working time”,”Needs proper surface preparation — laitance, oil, curing compounds and algae removed, and a substrate compressive strength of at least 15 MPa — or the bond figures on the datasheet won’t hold on site”,”Once a kit is opened it should be used promptly; there’s no practical way to store a part-used pack”,”Two-pack site mixing demands discipline — under-mixing or eyeballing the ratio can leave tacky, under-cured patches that show up only after the topcoat goes on”],”bestPractice”:”Confirm the concrete has reached at least 15 MPa compressive strength and mechanically roughen it (wire brush or light grit blast) before vacuum-cleaning off dust — Tank Prime bonds to a keyed, clean surface, not a dusty one. Mix full Part A and Part B quantities together (not partial pours) with a slow-speed drill for the full 4-5 minutes specified, and only mix what your crew can apply within the 30-minute pot life — in Delhi’s summer that often means working early morning or evening and batching smaller quantities more often. Apply thin — two light coats beat one heavy one — and keep total consumption at 200 gm/m². Don’t dilute with solvent even if it looks thick on a hot day. Once it’s tack-free, get the PU topcoat on within the recoat window; leaving primed concrete exposed too long, or under monsoon dust, undoes the prep work.”,”specs”:[{“property”:”Chemistry”,”value”:”Two-component, solvent-free, flexible polyurethane primer”},{“property”:”Mix Ratio (Part A : Part B)”,”value”:”1:1 by volume”},{“property”:”Specific Gravity of Mix”,”value”:”1.1 (ASTM D1475 @ 25°C)”},{“property”:”Pot Life”,”value”:”30 minutes @ 25°C”},{“property”:”Recoat Time”,”value”:”6-24 hours (weather dependent)”},{“property”:”Adhesion to Concrete”,”value”:”2 MPa, concrete failure (ASTM D7234)”},{“property”:”Theoretical Coverage”,”value”:”200 gm/m² total, in one or two thin coats”},{“property”:”Pack Size”,”value”:”1.6 kg kit (Part A: 0.7 kg + Part B: 0.9 kg)”},{“property”:”Shelf Life”,”value”:”12 months, unopened, 5-25°C dry storage”}],”useCases”:[{“sector”:”Residential (Delhi NCR apartments & villas)”,”detail”:”Priming overhead RCC water tanks before applying Dr. Fixit’s PU waterproofing coat during new-construction handover.”},{“sector”:”Commercial & institutional buildings”,”detail”:”Priming basement sumps and fire-fighting water reservoirs ahead of a PU topcoat in office and mall developments.”},{“sector”:”Industrial (ETP/STP)”,”detail”:”Priming concrete effluent and sewage treatment chambers before a PU lining is applied for chemical and moisture resistance.”},{“sector”:”Retrofit & renovation”,”detail”:”Re-priming old, leaking underground tanks as part of a Space Arc retrofit waterproofing scope before recoating with PU.”},{“sector”:”Institutional (schools, hospitals)”,”detail”:”Priming new underground water-storage tanks as part of the base-build waterproofing package.”}],”faq”:[{“q”:”Is Dr. Fixit Tank Prime certified safe for drinking-water (potable) tanks?”,”a”:”The manufacturer’s datasheet for Tank Prime itself doesn’t carry a potable-water certification the way some other Dr. Fixit products do (Pidifin 2K, for instance, is CFTRI-certified for drinking water contact). If the tank will store potable water, confirm with Space Arc which specific PU topcoat in the system is certified for that use before finalising the build-up.”},{“q”:”Can Tank Prime go onto damp concrete, or does the tank have to be bone dry first?”,”a”:”Yes — the datasheet specifically states it bonds even to damp or green (freshly cast) concrete, which is useful on new tanks where you can’t always wait out a full dry cure.”},{“q”:”How much area does one 1.6 kg kit cover?”,”a”:”At the stated 200 gm/m² total consumption, a 1.6 kg kit covers roughly 8 m² whether applied as one coat or split into two thin coats.”},{“q”:”What topcoat do I apply over Tank Prime?”,”a”:”It’s formulated as the primer for Dr. Fixit’s polyurethane waterproofing range, but the datasheet doesn’t name one specific topcoat SKU. Space Arc will confirm the exact PU topcoat to pair it with based on whether the tank is overhead, underground, or holds potable water.”},{“q”:”Why is the pot life so short compared to other Dr. Fixit primers?”,”a”:”At 30 minutes at 25°C, it’s shorter than cementitious primers because it’s a reactive two-component polyurethane, not a water-based slurry. Mix only what your crew can roll out in that window, and expect it to go even faster on a hot Delhi afternoon.”},{“q”:”How soon can we apply the waterproofing coat after priming?”,”a”:”Recoat time is weather-dependent — as fast as a few hours in summer heat, up to 24 hours in cold winter conditions, per the technical datasheet.”}],”positioning”:”Tank Prime isn’t sold as a stand-alone waterproofing product — it’s the bonding layer that makes the rest of Dr. Fixit’s system work, so it’s normally quoted alongside a compatible PU topcoat rather than on its own. Within the Dr. Fixit range it sits close to products like Pidiproof LW+ (an integral waterproofing admix dosed into the tank’s concrete mix itself) and Pidifin 2K (a CFTRI-certified elastomeric coating for potable water tanks) — the three address different layers of the same tank: admix in the concrete, primer on the surface, and a certified topcoat for water contact. For teams comparing suppliers, Fosroc’s below-grade PU membrane Nitoproof 600 covers similar underground/tank waterproofing territory, though it’s a single-component, moisture-cured system with its own primer requirements rather than a direct swap for Tank Prime’s two-component build-up — worth asking Space Arc to walk through both systems side by side if you’re choosing between the two brands for a tank-lining scope.”}

The technical insight

What makes Tank Prime worth specifying over a generic bonding coat is the combination of low viscosity and moisture tolerance. The resin runs 150-1650 mPas depending on batch and the hardener 100-400 mPas — thin enough to travel into the capillary pores of concrete rather than sit as a skin on top, which is why it still bonds to damp or freshly cast (“green”) concrete instead of demanding the usual 28-day dry-cure wait. Pidilite tests adhesion to ASTM D7234 and reports a pull-off value of 2 MPa with concrete failure — meaning the primer bond itself doesn’t let go; the parent concrete tears first. That’s the number a site engineer actually wants to see, because it confirms the primer isn’t the weak link in the waterproofing build-up. The trade-off is a short 30-minute pot life at 25°C, so it behaves more like a fast two-pack epoxy than a forgiving cementitious slurry, and mixing needs to be batched to what a crew can actually roll out before it kicks.

Where it is used

• Priming underground and overhead RCC water tanks ahead of a Dr. Fixit PU waterproofing coat
• Bond coat for sumps and basement water-retaining structures before tanking
• Sealing/priming coat on bare concrete in STP and ETP chambers before PU lining
• Humidity-barrier priming where a vapour-drive problem is expected under the topcoat
• Substrate priming on damp or green (recently cast) concrete that can’t wait for full cure
• Re-priming old, leaking tanks during retrofit waterproofing before a fresh PU recoat
• Priming construction-joint and masonry-to-concrete transitions inside tank walls
• Prep coat ahead of PU-based terrace and roof waterproofing where humidity resistance matters

Key advantages

• Zero-VOC, low-odour, non-flammable formulation — usable inside enclosed, poorly ventilated tank chambers without the fumes of a solvent-based primer
• Bonds to damp or green concrete, so priming doesn’t have to wait for a full 28-day cure on new tanks
• Low viscosity gives genuine mechanical penetration into concrete pores, not just a surface film
• Simple 1:1 by-volume mix ratio is easy for site crews to measure and reduces dosing errors
• Documented adhesion (2 MPa, ASTM D7234) shows concrete failure, meaning the primer bond outperforms the substrate itself
• Purpose-built as the primer for Dr. Fixit’s PU range, removing guesswork on primer-topcoat compatibility
• Recoat window can be as short as a few hours in warm weather, keeping tight tank-lining schedules on track
• Compact 1.6 kg kit sizing suits small tank jobs without large leftover quantities

Limitations & considerations

• Pot life is only 30 minutes at 25°C — batches must be sized to what a crew can roll out before it starts to gel, especially in Delhi summer heat
• It is a primer, not a standalone waterproofing product; it must always be followed by a compatible PU topcoat within the recoat window
• Performance is temperature-sensitive: cold weather retards cure and can stretch recoat time to 24 hours, while heat accelerates it and shortens working time
• Needs proper surface preparation — laitance, oil, curing compounds and algae removed, and a substrate compressive strength of at least 15 MPa — or the bond figures on the datasheet won’t hold on site
• Once a kit is opened it should be used promptly; there’s no practical way to store a part-used pack
• Two-pack site mixing demands discipline — under-mixing or eyeballing the ratio can leave tacky, under-cured patches that show up only after the topcoat goes on

Selection & best practice

Specifications

Industry use cases

How we position Dr. Fixit Tank Prime

Tank Prime isn’t sold as a stand-alone waterproofing product — it’s the bonding layer that makes the rest of Dr. Fixit’s system work, so it’s normally quoted alongside a compatible PU topcoat rather than on its own. Within the Dr. Fixit range it sits close to products like Pidiproof LW+ (an integral waterproofing admix dosed into the tank’s concrete mix itself) and Pidifin 2K (a CFTRI-certified elastomeric coating for potable water tanks) — the three address different layers of the same tank: admix in the concrete, primer on the surface, and a certified topcoat for water contact. For teams comparing suppliers, Fosroc’s below-grade PU membrane Nitoproof 600 covers similar underground/tank waterproofing territory, though it’s a single-component, moisture-cured system with its own primer requirements rather than a direct swap for Tank Prime’s two-component build-up — worth asking Space Arc to walk through both systems side by side if you’re choosing between the two brands for a tank-lining scope.

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