Dr. Fixit Pidiseal PS 43
A fuel-resistant, pouring-grade polysulphide sealant Space Arc specifies for highway, runway and forecourt joints that ordinary sealants can’t survive.
What is it?
A two-component, self-levelling polysulphide sealant that chemically cures into a tough, flexible rubber seal.
Where is it used?
Concrete highways, airport runways and aprons, aircraft hangar/workshop floors, fuel station forecourts, car parks, and general construction and expansion joints.
Why use it?
One of the few sealants genuinely rated for aviation-fuel and chemical exposure, with a high ±25% movement accommodation factor for joints under constant traffic cycling.
How is it applied?
Resin and curing agent are machine-mixed on site, the joint is primed with Dr. Fixit Pidiprime A, and the mixed sealant is poured directly into the primed, backer-rod-lined joint.
About Dr. Fixit Pidiseal PS 43
Dr. Fixit Pidiseal PS 43 sits in Dr. Fixit’s Joint Sealants range as the specialist choice for horizontal joints that see fuel, oil or solvent spillage alongside heavy movement — a combination most single-component PU or silicone sealants aren’t built to handle. It is a two-part, pouring-grade polysulphide: a grey resin and a curing agent that are machine-mixed on site and then poured, self-levelling, into a primed and backer-rod-lined joint, where they react chemically (not by moisture-cure) into a tough, rubber-like seal. That chemistry is the whole point of specifying it — polysulphide’s sulphur-linked backbone gives it genuine resistance to aviation fuel, diesel, and a range of chemicals that would soften or swell a standard sealant, which is why it turns up in Dr. Fixit’s literature against concrete highways, aircraft hangar and workshop floors, fuel station forecourts, car parks and airport runways rather than routine building expansion joints.
In practice this is a contractor’s product more than a homeowner’s — it is specified on NHAI/PWD highway packages, airport apron works, industrial fuel-handling facilities and multi-level parking structures where the joint design, priming schedule and mixing ratio all have to be followed precisely for the sealant to perform over its stated service life. Space Arc Engineering, as an authorised Dr. Fixit distributor and applicator across Delhi NCR and pan-India, typically supplies Pidiseal PS 43 alongside Dr. Fixit Pidiprime A primer and the backer rod/bond-breaker tape it’s designed to be installed with, and can put trained applicators on site for larger highway, airport or industrial floor packages where correct joint design (width-to-depth ratio) and mix consistency genuinely determine whether the seal lasts its intended decade-plus life or fails prematurely at the bond line.
The technical insight
The reason Pidiseal PS 43 gets specified over a cheaper PU or silicone sealant comes down to its polymer chemistry. Polysulphide sealants cure through a genuine chemical reaction between resin and curing agent — not by reacting with atmospheric moisture the way one-part PU or silicone sealants do — which is why the two components have to be machine-mixed before use and why the sealant has a hard pot-life cut-off rather than a gradual skin-over. That sulphur-linked backbone is also what gives polysulphide its distinctive resistance to hydrocarbons: aviation fuel, diesel and many solvents that would swell, soften or dissolve a standard sealant largely leave a cured polysulphide seal intact, which is exactly why Dr. Fixit’s own literature points this product at aircraft hangars, fuel stations and highway joints rather than general building work. The trade-off is a relatively low Shore A hardness (12–20 cured) paired with very high elongation (500–600%), a combination engineered specifically for a low-modulus, highly elastic seal that can absorb the constant thermal and traffic-load cycling of a pavement or runway joint without tearing at the bond line — hence the ±25% movement accommodation factor for butt joints, rising to 50% where the joint is detailed as a lap joint.
Where it is used
- Concrete highway and expressway pavement joints
- Airport runway and apron expansion joints
- Aircraft hangar and workshop floor joints
- Fuel station forecourts and tank-farm bund joints
- Multi-level and open car park deck expansion joints
- Heavy-duty industrial and warehouse floor slab joints
- Precast concrete panel joints exposed to fuel or chemical spillage
- General construction and structural expansion joints needing high movement capacity
Key advantages
- Genuine aviation-fuel and chemical resistance — a real differentiator versus generic PU or silicone joint sealants
- High movement accommodation: ±25% on butt joints and up to 50% on lap joints, suited to constantly trafficked pavement
- Self-levelling, pouring-grade formulation — pours directly from the mix container with no gunning or tooling needed on horizontal joints
- Very high elongation at break (500–600% per ASTM D412) so it stretches and recovers with cyclic slab movement instead of tearing
- Non-shrink chemical cure gives a consistent, tough rubber seal rather than a skinned-over surface with a soft core
- UV resistant, so exposed runway, highway and open car-park joints don’t need a topping or protective coat
- Backed by internationally recognised sealant standards — BS 5212, BS 4254 and ASTM D412
- Nil VOC content, relevant where indoor air quality or enclosed hangar/workshop ventilation is a concern
Limitations & considerations
- Pouring/self-levelling grade only — designed for horizontal joints, not suitable for vertical or overhead applications
- Two-component system with a short pot life (about 2 hours at 25°C, roughly 1 hour above 35°C), so it needs a trained crew and correct mechanical mixing, not casual DIY application
- Priming is mandatory on porous substrates, adding a preparation step and a time window (apply sealant within 8 hours of priming) that must be planned into the schedule
- Not compatible with pitch- or bitumen-based materials in direct contact
- Must be fully cured before permanent water immersion, so it isn’t the right choice where a joint needs to be watertight immediately after installation
- Maximum joint width of 50 mm — wider movement joints need a different detail or product
Selection & best practice
Joint width should sit between 5 mm and 50 mm, with a minimum sealant depth of 10 mm on porous substrates and 20 mm on trafficked or hydrostatically loaded joints — Dr. Fixit’s own guidance gives a 1:1 width-to-depth ratio for 6–12 mm joints, 2:1 for 12–25 mm, and half-or-less for 25–50 mm joints, all packed with a tightly fitted closed-cell backer rod (or a bond-breaker tape where a rod can’t be used) so the sealant only bonds on its two sides, not the base. Prime porous surfaces with Dr. Fixit Pidiprime A — twice on very porous concrete, applying the second coat within 3 hours of the first going tack-free — and pour the mixed sealant while the primer is touch-dry and within 8 hours of priming, or re-prime. Mix resin and curing agent with a slow-speed drill (300–450 rpm) for 2–3 minutes to a uniform grey with no streaks; working time is only around 2 hours at 25°C and drops to roughly 1 hour above 35°C, which matters on an Indian summer site, so mix only what one crew can place in that window. Keep the joint dry for at least 24 hours after pouring and away from chemical exposure for 7 days, and don’t bring the product into contact with pitch- or bitumen-based materials, which it isn’t compatible with.
Specifications
| Chemistry / System | Two-component, pouring-grade polysulphide elastomeric sealant |
| Colour | Grey |
| Density | 1.48–1.54 kg/litre |
| Hardness (cured, Shore A) | 12–20 (ASTM D412) |
| Elongation at break | 500–600% (ASTM D412) |
| Movement Accommodation Factor | ±25% (butt joints), 50% (lap joints) |
| Service temperature range | −15°C to +80°C |
| Standards compliance | BS 5212, BS 4254, ASTM D412 |
| Pack size | 4-litre kit |
Industry use cases
Highways & Roads
Sealing expansion and construction joints in concrete highway and expressway pavements where continuous vehicle loading demands high cyclic movement capacity.
Aviation & Airports
Runway, apron and hangar floor joints where aviation fuel resistance and UV stability under open-sky exposure are both non-negotiable.
Fuel Retail & Industrial
Fuel station forecourts, tank-farm bunds and workshop floors where diesel/petrol spillage would degrade an ordinary sealant over time.
Parking Structures
Multi-level and open-deck car park expansion joints subject to vehicle traffic, temperature-driven slab movement, and occasional oil drips.
Industrial Flooring
Heavy-duty warehouse and factory floor slab joints needing a tough, non-shrink, chemically resistant seal under repeated forklift and pallet-truck traffic.
Frequently asked questions
Can Pidiseal PS 43 be used on vertical joints?
Do I really need to prime the joint first?
How much sealant do I need per running metre of joint?
Will it actually stand up to diesel or aviation fuel spillage?
How long before the joint can be trafficked or exposed to water?
What’s the working (pot) life once the two parts are mixed?
How we position Dr. Fixit Pidiseal PS 43
Within Dr. Fixit’s own Joint Sealants line-up, Pidiseal PS 43 is the fuel- and chemical-resistant, pouring-grade polysulphide option — it’s normally specified alongside Dr. Fixit Pidiprime A (the primer it requires on porous substrates) and used with standard backer rod or bond-breaker tape rather than as a stand-alone product. For vertical joints, or projects wanting a gun-grade rather than self-levelling consistency, buyers typically move to a gun-grade polysulphide or a modern hybrid/PU sealant elsewhere in the Dr. Fixit or wider Pidilite range. Outside the Dr. Fixit brand, the closest genuine equivalent most specifiers weigh up is Fosroc Thioflex 600, a comparable two-part polysulphide sealant — the choice between the two usually comes down to which brand a contractor is already standardised on for a given highway, airport or industrial project, since both are internationally recognised, standards-compliant polysulphide systems. Space Arc stocks and applies both families, so the practical decision can be made on availability, project specification, or existing site brand preference rather than any meaningful performance gap.
Fosroc Thioflex 600 — A specifier already standardised on Fosroc systems, or one who needs a gun-grade rather than pouring-grade polysulphide detail, might choose Thioflex 600 as a comparable two-part polysulphide sealant instead.
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