Soudal Fix ALL Flexi

Health & Safety Recommendations

Read the product label and Safety Data Sheet before use and follow all relevant site safety procedures. Wear suitable gloves, eye protection and workwear, and avoid prolonged skin contact. Keep the work area well ventilated during application and throughout curing, particularly in smaller rooms, bathrooms and enclosed spaces.

Do not smoke, eat or drink while using sealants and adhesives, and keep the product away from children and animals. Where masking tape, solvents or cleaning agents are used nearby, ensure compatibility with adjacent finishes and protect sensitive surfaces before starting. If the substrate is dusty from drilling, cutting or sanding, use appropriate dust control and a suitable mask to reduce inhalation of airborne particles.

Substrate Suitability

Soudal Fix ALL Flexi is designed for flexible sealing and bonding on a wide range of common construction materials and is suitable for internal and external use. It adheres well to many usual building substrates including concrete, brick, masonry, ceramic tiles, lacquered wood, metals, aluminium, acrylic baths, PVC, many plastics and natural stone, including porous stone where non staining performance is required. The product can be applied to surfaces that are dry or slightly moist, which is useful on refurbishment work where perfect dryness is difficult to achieve.

Fix ALL Flexi is not suitable for PE, PP, PTFE (Teflon®), bituminous substrates, copper, or copper containing materials such as bronze and brass. Bonding plastics such as PMMA (Plexi® glass) or polycarbonate (Makrolon® or Lexan®) in stress loaded applications can cause stress cracking and crazing within the substrate, so Fix ALL Flexi is not recommended for those situations. Adhesion and compatibility can vary between materials and coatings, so a small test area should always be completed before full application, especially on painted, powder coated, lacquered or unknown surfaces.

Surface Preparation

For best results the substrate must be rigid, clean and stable, free from dust, grease, release agents and loose material. Remove old sealant residues fully and ensure the joint edges are sound. Lightly damp surfaces can be acceptable, but visible water, standing moisture and contamination should be removed so the sealant can wet out the surface properly. On non porous substrates, clean and degrease with Soudal Cleaner & Degreaser and allow the surface to flash off fully before applying the product.

On porous substrates, improve consistency and reduce the risk of edge contamination by priming with Soudal Primer 150 where appropriate. Where additional surface activation is beneficial on difficult non porous materials, prepare with Soudal Surface Activator, following the product guidance and allowing adequate flash off time. Where the joint will be highly weather exposed, water loaded, or subject to regular movement, careful preparation becomes more important, and workmanship at this stage often determines long term performance.

Application Method (As A Sealant)

Apply Soudal Fix ALL Flexi using a suitable caulking gun. Mask the joint edges where a sharp finish is required, particularly on porous stone, decorative coatings or bright white sanitary surfaces. Cut the nozzle to suit the joint width and apply a continuous bead, ensuring the sealant is pressed into the joint and fully contacts both sides without air inclusions. Work steadily and avoid stretching the bead, which can introduce voids and weaken the seal.

Tool the joint before skin formation, smoothing with a suitable spatula and a minimal amount of soapy solution to achieve a neat, compact finish. Keep soapy solution away from the joint edges, as it can interfere with adhesion if it contacts the bonding surfaces. Only dip the finishing tool into the soapy solution rather than flooding the joint. Avoid finishing in full sunlight or hot, drying conditions where the solution can evaporate too quickly, making tooling more difficult and increasing the risk of surface defects.

Application Method (As An Adhesive)

For bonding applications, apply Fix ALL Flexi by caulking gun in beads or dots onto one substrate. For panels, always apply a continuous bead near the edges, plus additional beads across the field as required, to support uniform contact and reduce the chance of drumming or movement. Bring the parts together before skin formation and press firmly to wet out the adhesive and establish initial grab.

Where the item is heavy or under stress, provide temporary support while curing, using battens, packers or mechanical bracing as appropriate. A rubber mallet can be used to bed materials down evenly where this will not damage the finish. Bond strength is influenced more by the pressure applied during assembly than the duration of pressing, so ensure good initial contact and correct alignment before leaving the bond to cure.

Joint Dimensions

For sealing work, joint geometry is critical for movement accommodation and durability.

The minimum joint width is 5mm and the maximum joint width is 30mm, with a minimum joint depth of 5mm. As a general rule for sealing, aim for joint width = 2x joint depth to support elastic movement without overstressing the sealant.

Where joints are deep, use a suitable PE backer rod to control depth and avoid three sided adhesion, which can restrict movement and increase the chance of joint failure.

Coverage

Coverage depends on joint width and depth, application method, substrate texture and wastage during finishing. For sealant work, use the Platinum Chemicals Sealant Estimate Calculator to calculate the number of cartridges required based on the joint dimensions and total linear metres, and allow a margin for tooling losses and uneven substrates.

For adhesive use, coverage depends on bead size, bead spacing and how much material is required to bridge minor irregularities, so practical site trials are recommended when bonding large panels or uneven backgrounds.

Curing Time

Fix ALL Flexi cures by moisture curing, forming a skin in around 10 minutes under typical conditions. Curing progresses at approximately 2–3mm/24h, but this can vary with temperature, humidity, airflow, bead thickness and substrate type. Cooler conditions and low humidity slow curing, while good ventilation supports cure. Avoid disturbing the joint during the early cure stage, and do not subject sealed joints to water loading, cleaning or movement until adequate cure has developed through the bead thickness.

If the product is being painted, allow sufficient curing first and use water based paints where possible. Because paint and varnish formulations vary widely, a compatibility test should be completed before full decoration to confirm adhesion, finish quality and flexibility. The paint film must be elastic enough to move with a plasto elastic sealant, otherwise cracking or edge splitting can occur.

Cleaning

Clean uncured product immediately after use. Remove excess material from tools and non porous surfaces with Soudal Swipex Wipes while the sealant is still fresh. Keep cleaning controlled around joint edges, particularly if a soapy solution has been used, to avoid contaminating adhesion areas.

Once cured, Fix ALL Flexi can only be removed mechanically, with support from Soudal Sealant Remover Spray where appropriate to aid residue removal. Protect delicate finishes before cleaning and test solvents or removers on a small inconspicuous area first.

Limitations

Fix ALL Flexi is not suitable for continuous water immersion and should not be specified where the joint will remain permanently submerged. It cannot be used as a glazing sealant, so for glazing and perimeter sealing of glass systems use Silirub 2 or Silirub LMN as appropriate. Do not use on polycarbonate, use Silirub PC. It is not suitable for bonding aquariums, use Silirub AQ. Avoid contact with bitumen, tar, or plasticiser releasing materials such as EPDM, neoprene and butyl, as these can cause discolouration and loss of adhesion; for EPDM interfaces use Silirub EPDM.

Discolouration can occur under extreme exposure to chemicals, high temperatures or prolonged UV radiation, and a total absence of UV can cause colour change in some situations. The sanitary mould resistant formulation improves resistance to mould growth, but it does not replace routine cleaning. Heavy contamination, soap residues and poor ventilation can still encourage fungal growth on the surface, so good hygiene and moisture management remain important in bathrooms and kitchens.

Other Information

For best long term results, ensure joints are correctly designed and do not bridge movement gaps with rigid fillers, paints or mortar. Masking the joint edges helps achieve a clean finish and reduces clean up, particularly on porous natural stone and textured substrates. When using different reactive sealants on the same detail, allow the first product to fully harden before applying the next, as incomplete curing can lead to compatibility issues and reduced performance.

Store cartridges in accordance with the packaging guidance and keep containers sealed when not in use. Application conditions influence performance, so apply within the recommended temperature range of +5°C to +35°C and protect fresh joints from early rain, heavy dust contamination, cleaning chemicals and mechanical disturbance. Skinning time and cure speed will vary with site conditions, so where programme is tight, test a small area first to confirm practical working time and finishing behaviour.

Q) What is Soudal Fix ALL Flexi and what type of product is it?

A) Soudal Fix ALL Flexi is a neutral curing, permanently elastic adhesive sealant based on SMX Hybrid Polymer. It is designed to bond, seal and fill in one product, so it covers many everyday site tasks without switching materials. After curing it forms a flexible rubber that copes with movement, vibration and thermal expansion, so joints stay intact instead of cracking like rigid fillers can. It is suitable for internal and external use, it is virtually odourless, and it is classed as very low emission which suits occupied buildings and refurbishment work. It also contains XS1 fungicides for mould resistance in humid areas.

Q) What jobs is Fix ALL Flexi best suited to in everyday building work?

A) It suits jobs where you need dependable adhesion plus a flexible joint line. Typical uses include sealing around trims, frames, junctions and service penetrations, filling gaps during refurbishment, and bonding items where a slightly elastic bond line helps prevent future cracking. It performs well in kitchens and bathrooms because it contains XS1 fungicides for mould resistance, and it also holds up outdoors thanks to excellent UV resistance and ageing stability. It is particularly useful on remedial repairs where surfaces may not be perfectly dry, because it can be applied to slightly damp and humid backgrounds, provided they are stable and not carrying visible water.

Q) Can Soudal Fix ALL Flexi be used as both a sealant and an adhesive?

A) Yes, that is a core benefit. As a sealant it creates a watertight, elastic seal in connection joints and movement gaps, and as an adhesive it bonds many common building materials with a resilient, shock absorbing bond line. The method changes with the task. For sealing, apply a continuous bead, compact it properly and tool it to a smooth profile that sheds water. For bonding, apply beads or dots that allow bedding down and contact, then press firmly before skinning. Heavy or stress loaded items still need sensible temporary support until curing has progressed through the bead thickness.

Q) Which surfaces does Fix ALL Flexi stick to without primer?

A) Fix ALL Flexi offers primerless adhesion on most common construction substrates, across both porous and non porous materials. In practice it often bonds to masonry, concrete, brick, ceramic tiles, lacquered wood, many metals, aluminium, PVC, acrylic sanitaryware and a wide range of plastics used in fit out work. It is also suitable for natural stone, which is a major advantage where staining would be unacceptable. Primerless does not mean prep free. Dust, grease, old sealant residue, soap film and loose paint can all reduce adhesion and create edge lift, so clean, stable joint faces still matter.

Q) Is Soudal Fix ALL Flexi suitable for natural stone like marble and limestone?

A) Yes. Fix ALL Flexi is non staining and specifically suitable for natural stone, including porous stones where many sealants can leave dark edges or permanent halos. This makes it a safe choice for thresholds, vanity tops, wall cladding details and decorative stone trims where appearance matters. Mask edges for a crisp line, keep tooling controlled, and remove any squeeze out immediately. The product has been assessed for natural stone staining behaviour to ISO16938 1, which adds reassurance when working on visible finishes. As with any sealant, do a small test first on unfamiliar stones, because porosity and surface treatments can vary.

Q) Can Fix ALL Flexi be used in bathrooms and kitchens without going mouldy?

A) It includes XS1 fungicides, giving strong resistance to mould growth in humid environments. That makes it well suited to sealing and bonding around sinks, baths, shower trays, tiled junctions and worktops where condensation and cleaning cycles are routine. The practical reality is that mould resistance helps joints stay cleaner for longer, but it does not replace hygiene. If joints are constantly wet, poorly ventilated or coated in soap residues, staining can still develop on the surface over time. Apply to clean, dry joint edges, tool neatly, and allow proper curing before heavy water exposure, so the seal reaches full performance and remains easy to clean.

Q) Can you apply Soudal Fix ALL Flexi on slightly damp surfaces or in bad weather?

A) Yes, within sensible limits. Fix ALL Flexi is designed for all weather application and can be applied onto slightly damp or humid surfaces, which is useful on refurbishment work and external repairs where perfect dryness is hard to achieve. Slightly damp means the surface is stable and not carrying visible water. Standing water, active leaks or saturated edges will reduce adhesion and can trap moisture in the joint. Wipe down and remove contamination, improve drainage where possible, then seal once the joint faces are stable. Outdoors, protect fresh joints from immediate wash off, and avoid applying where rain is likely to hit the bead before skin formation.

Q) How much movement can Soudal Fix ALL Flexi accommodate in a joint?

A) It can accommodate joint movement up to ±20% when the joint is correctly designed and backed. This allows the cured seal to stretch and recover as materials expand, contract and flex through temperature changes, vibration and normal building settlement. Correct geometry is what unlocks that performance. Avoid thin feathered edges, avoid three sided adhesion, and control depth with a PE backer rod where needed. Tool the bead so it is compacted against both sides and finished to a smooth, slightly concave profile. If the joint is too wide, too shallow, or poorly backed, movement stresses concentrate at the edges and long term durability suffers.

Q) What is the typical skinning and curing time for Fix ALL Flexi?

A) Skin formation is typically around 10 minutes, giving a workable window for neat tooling without leaving the surface exposed for too long. Curing then progresses at roughly 2 to 3mm per 24 hours, so deeper joints and thicker adhesive beads take longer to cure through. Temperature, humidity and airflow all influence cure speed. Cold conditions and limited ventilation slow it down, while warm, well ventilated conditions help it along. Avoid loading bonded items or exposing sealed joints to heavy water, aggressive cleaning or movement until adequate curing has developed through the thickness. If painting is planned, allow full cure first for best results.

Q) How do I prepare surfaces properly before using Soudal Fix ALL Flexi?

A) Preparation is simple but non negotiable. The joint edges must be rigid, sound and free from dust, grease, release agents, soap residues and loose paint. Remove old sealant fully, because residues can act as a bond breaker even when they look clean. On non porous materials, clean and degrease using Soudal Cleaner & Degreaser, then allow it to flash off fully before applying product. Slightly moist surfaces can be acceptable, but visible water should be removed. On porous or chalky masonry, stabilise weak areas and remove friable material so the sealant bonds to something load bearing. A quick test bead on an inconspicuous area is smart on unknown coatings.

Q) When should I use Soudal Primer 150 with Fix ALL Flexi?

A) Use Soudal Primer 150 when the substrate is porous and you want more predictable adhesion. It is particularly helpful on dusty masonry, friable plaster, very absorbent concrete, weathered edges and surfaces that tend to pull binder out of sealants. Priming stabilises the surface so the sealant bonds to something strong, rather than to weak surface dust. Apply Primer 150 neatly to the bonding faces only, allow it to dry as instructed, then apply Fix ALL Flexi. Primer is not a substitute for cleaning. Remove contaminants first, then prime if needed. On sound, clean, stable substrates you may not need primer, but on critical exterior joints it can improve consistency.

Q) What is the best application method when using Fix ALL Flexi as a sealant?

A) Mask both sides if appearance matters, then gun a continuous bead into the joint with the nozzle cut to match the width. Push the bead into the joint so it contacts both sides fully and avoids air pockets. Tool immediately before skinning, compacting the sealant and shaping it to a smooth profile that sheds water and resists dirt pick up. If you use a light soapy solution for finishing, keep it off the joint edges, only wet the tool, because contamination on the bond faces can cause local loss of adhesion. Remove masking tape straight after tooling, while the sealant is still workable, then leave the joint undisturbed to cure.

Q) How should I apply Fix ALL Flexi when I am using it as an adhesive?

A) Apply Fix ALL Flexi in beads or dots on one substrate, then bring the parts together before skinning and press firmly to establish contact. For panels and boards, apply beads near edges and corners, then additional beads across the field to support the surface and reduce drumming. The bond strength depends on compression and contact, so bed the part down properly and check alignment before leaving it. Provide temporary support for heavy items, vertical work or anything that could move under its own weight. Where appropriate, gentle bedding with a rubber mallet and a block helps achieve full contact without damaging finishes. Keep in mind that thick beads cure more slowly.

Q) Can Soudal Fix ALL Flexi be painted over, and when should you paint it?

A) Yes. Once cured it can be painted with many water based paint systems, which is useful where you want a flexible joint line that blends into the finish. Timing matters. Do not paint over uncured sealant, because it can trap moisture, extend cure time and cause paint cracking as the sealant continues to cure and move. Allow sufficient curing based on bead thickness, temperature and ventilation, then do a small compatibility test with your chosen paint. The paint film must be elastic enough to move with the joint, otherwise it can split at the edges even if the sealant underneath remains sound. For best appearance, tool smoothly and keep bead size controlled.

Q) What cleaning products should I use for uncured and cured Fix ALL Flexi?

A) Clean up immediately for the easiest result. While uncured, wipe smears from tools and non porous surfaces using Soudal Swipex Wipes, changing wipes regularly to avoid spreading residue. Remove masking tape promptly and tidy the bead line before skinning. Once cured, Fix ALL Flexi usually needs mechanical trimming, because cured hybrid polymers do not wipe off. For residue removal support, use Soudal Sealant Remover Spray according to its instructions, then clean again before re sealing. Always test cleaners and removers on sensitive finishes first, especially on plastics, painted surfaces and natural stone, because aggressive rubbing can mark coatings even if the cleaner itself is compatible.

Q) What are the main limitations and do not use cases for Fix ALL Flexi?

A) Do not use Fix ALL Flexi on PE, PP, PTFE or bituminous substrates, as adhesion will be unreliable. Avoid copper and copper containing materials such as brass and bronze. It is not a glazing sealant, so for glazing and façade perimeter sealing use Silirub 2 or Silirub LMN as appropriate. It is not suitable for aquarium bonding, use Silirub AQ, and it is not suitable for polycarbonate, use Silirub PC. Avoid contact with plasticiser releasing materials such as EPDM, neoprene and butyl, because this can cause discolouration and loss of adhesion. Where you must seal EPDM, use Silirub EPDM.

Q) How does Fix ALL Flexi compare to silicones like Silirub 2 or Silirub A?

A) Fix ALL Flexi is a hybrid polymer adhesive sealant, so it is chosen when you want both sealing and bonding and the option to paint the finished joint. Silirub 2 and Silirub LMN are neutral cure silicone sealants designed for high movement glazing and exterior weather sealing, with very strong UV and ageing resistance, but they are not paintable. Silirub A is an acetoxy sanitary silicone with mould resistance for wet areas, but it is not suitable for natural stone and it is also not paintable. Fix ALL Flexi sits between these, giving a flexible, durable joint line on many substrates, including natural stone, while still offering practical adhesion for bonding tasks.

Q) Is Fix ALL Flexi safe to use outdoors and on exposed joints?

A) Yes. It is suitable for internal and external use and it offers excellent UV resistance and ageing stability, so it is a strong option for exterior sealing and repairs where a flexible, durable joint is needed. It also helps on changeable weather days because it can be applied in all weather conditions, including on slightly damp surfaces. That said, good detailing still matters outdoors. Ensure joint edges are stable, avoid sealing over active water ingress, and protect the fresh bead from heavy rain until it has skinned. If the joint is a true glazing perimeter or a high movement façade detail, choose a specialist silicone such as Silirub 2 or Silirub LMN, because those are built specifically for long term exposure in those applications.

Q) What tips help you get the best finish and avoid joint failure with Fix ALL Flexi?

A) Most failures come from poor preparation or poor joint design, not from the product. Clean non porous surfaces with Soudal Cleaner & Degreaser, remove old sealant residues fully, and use Soudal Primer 150 on porous, dusty edges where consistency matters. Control depth with a PE backer rod so the sealant bonds to two sides only, then gun a continuous bead and tool before skinning. Keep any soapy finishing solution away from the joint edges, only wet the tool. Allow realistic curing time, especially in cold or low airflow areas, and avoid painting or loading too early. For bonding, bed parts down properly and support anything heavy until cure has developed through the bead thickness.

Q) How should Soudal Fix ALL Flexi be stored, and what causes problems on site?

A) Store cartridges sealed, protected from extreme heat and frost, and use stock sensibly so extrusion and curing remain consistent. On site, most issues are caused by the background. Dusty plaster, chalky masonry, oily residues, old silicone traces and unstable paint layers lead to edge de bonding that looks like adhesive failure but is really surface failure. Another common mistake is applying excessively thick sections, then sealing over them too soon with paint or trim. Thick beads cure more slowly and can remain soft beneath the surface for longer than expected. If the job is critical, do a small adhesion test first, keep joints properly backed, and allow curing time that matches the bead size and conditions.

Technical Data Sheet

Fix-All Product Selector

Safety Data Sheet