A sealant is a small purchase that causes big problems when it is wrong. Put an acrylic in a wet, moving joint and it cracks within a season. Put an acetoxy silicone on marble and it can stain the stone. Paint over a silicone and the paint simply beads off. Every one of these is a job that has to be cut out and redone.
The good news is that sealants come down to three families, and once you know which does what, choosing is quick. This guide explains silicone, polyurethane (PU), and acrylic sealants in plain terms, tells you which sealant to use for common jobs around the Tricity, and points to the Feviseal and Dr. Fixit products we stock at Khandelwal Trading Co. in Panchkula. For the wider view of adhesives and sealants together, see our guide to choosing the right bond.
The Three Sealant Families at a Glance
Before the detail, here is the short version of what separates them.
- Silicone: the most flexible and water-resistant, best for wet areas, glass, and glazing. Long service life, but it cannot be painted over.
- Polyurethane (PU): the toughest and most adhesive, best for concrete, masonry, and structural or moving joints. It can be painted.
- Acrylic: the economical, paintable option for interior gap-filling in dry areas. Easy to use, but low flexibility and low moisture resistance.
The two things that decide between them are almost always the same: how much water the joint sees, and how much it moves.
Silicone Sealants: For Wet Areas, Glass and Glazing
Silicone is the go-to sealant for anywhere water is a constant. It stays flexible for many years, resists UV and moisture well, and repels water rather than absorbing it, which is why it dominates bathrooms, kitchens, and glazing work. Its one real limitation is that paint will not stick to it, so it is used where the seal is meant to be seen or clear.
Within silicone there are two cure types, and mixing them up is a common and costly mistake.
Acetoxy vs neutral cure
- Acetoxy silicone (such as Feviseal Acetoxy) cures fast and grips strongly on glass and glazed tiles. As it cures it releases acetic acid, which is the vinegar smell, and that acid can corrode some metals and stain natural stone. Keep it to glass and glazed surfaces.
- Neutral silicone (such as Feviseal Neutral Pro) is low-odour and safe on metals, mirrors, concrete, and natural stone. It is the right choice for sensitive surfaces and for sealing window and door frames, ACP joints, and mirror bonding.
For exposed exterior joints, a weatherproof grade built for sun and rain (such as Feviseal Weatherproof Pro) is the correct pick, available in clear, white, and black. And if you are sealing around marble or granite, always use a neutral silicone. Our AKEMI stone and marble care guide covers protecting stone in more depth.
Polyurethane (PU) Sealants: For Concrete, Masonry and Moving Joints
Where a joint has to take real movement, abrasion, or structural load, polyurethane steps up. PU bonds aggressively to porous surfaces like concrete, wood, brick, and masonry, handles the movement of construction and expansion joints, and can be painted over once cured, which silicone cannot.
Dr. Fixit PU Sealant is a one-part polyurethane joint sealant for horizontal and vertical use, with strong adhesion to concrete, brickwork, wood, glass, aluminium, and steel. It is the right choice for expansion joints, floor joints, and heavier-duty sealing that silicone is not designed for.
Keep in mind: PU can attract dust on its surface over time and, unlike silicone, is not ideal for glass-to-glass bonding or constantly submerged glazing. For those, silicone still wins.
Acrylic Sealants: For Interior Gap-Filling and Painting
Acrylic sealants are the economical, water-based option for interior work in dry areas. They are easy to apply, smooth out cleanly, clean up with water before curing, and, crucially, they take paint well. That makes them ideal for filling cracks and gaps in walls, trim, and skirting before painting.
Use them for: interior gap-filling, cracks around trim and beading, and low-movement joints that will be painted over.
Do not use them for: constant water exposure or joints that flex a lot. Acrylics handle far less movement than silicone or PU and have lower moisture resistance, so a wet or moving joint will fail. Reach for silicone or PU there instead.
Which Sealant to Use: Quick Decision Guide
Standing at the counter and want the fast answer? Match the job to the family.
- Bathroom, sink, shower, kitchen wet joints: silicone (neutral on stone and metal, acetoxy on glass and glazed tile).
- Glass, glazing, aluminium window frames: silicone.
- Marble, granite, and mirror edges: neutral-cure silicone only.
- Exterior joints in sun and rain: weatherproof silicone, or PU where movement and adhesion matter.
- Concrete, masonry, and expansion or floor joints: PU sealant.
- Door and window frames that will be painted: PU (paintable) or acrylic for lighter interior work.
- Interior wall cracks and gaps before painting: acrylic.
The Paintable Question
This single point clears up most confusion. If the joint has to be painted over, you cannot use pure silicone, because paint will not adhere to it. Choose PU or acrylic instead, both of which take paint once cured. If the joint will stay clear or be left as it is, silicone is usually the better performer, especially in wet or exterior conditions. So before you buy, ask one question: does this seal need to be painted? The answer rules silicone in or out immediately.
Application Tips for a Clean, Lasting Seal
The product is only half the job. These habits give a professional finish with any sealant.
- Clean and dry the joint. Remove old sealant, dust, and grease completely. A new bead over a dirty joint will not last.
- Use a backing rod for deep or wide joints. A closed-cell backer rod fills the base of the joint so the sealant bonds to the two sides, not the bottom, which lets it flex properly.
- Mask both edges. Run masking tape along both sides for a neat line, and peel it away while the sealant is still wet.
- Tool the bead. Smooth the bead firmly with a tool or a wetted finger to press it into full contact and remove air pockets.
- Mind the joint width. For wider joints, a sensible width-to-depth ratio keeps the seal working as the joint moves. When in doubt, ask us or check the product datasheet.
Common Mistakes to Avoid
- Acetoxy silicone on stone or metal. The acid can stain stone and corrode metal. Use neutral cure there.
- Acrylic in a wet or moving joint. It has low flexibility and low water resistance and will crack. Use silicone or PU.
- Trying to paint over silicone. Paint will not hold. Choose PU or acrylic if the seal must be painted.
- No backing rod in a deep joint. The sealant bonds on three sides and tears as the joint moves. Use a backer rod.
- Sealing over a dirty or wet joint. Prep first, every time.
Frequently Asked Questions
Which sealant should I use in a bathroom?
Silicone. It stays flexible and repels water, which suits bathroom and wet-area joints. Use a neutral-cure silicone on natural stone, metal, and mirrors, and an acetoxy grade on glass and glazed tiles.
What is the difference between acetoxy and neutral silicone?
Acetoxy silicone cures fast and grips glass and glazed tile well but releases acetic acid, which can stain stone and corrode metal. Neutral silicone is low-odour and safe on stone, metal, and mirrors. Choose neutral for sensitive surfaces.
Can I paint over silicone sealant?
No. Paint does not adhere to silicone. If the joint has to be painted, use a polyurethane or acrylic sealant, both of which accept paint once cured.
Which sealant is best for concrete and expansion joints?
Polyurethane. A one-part PU sealant like Dr. Fixit PU Sealant bonds strongly to concrete and masonry, handles joint movement, and can be painted, which makes it ideal for expansion and floor joints.
Where can I buy silicone, PU and acrylic sealants in Panchkula?
KTC Tools stocks the Feviseal and Dr. Fixit sealant ranges in Panchkula and serves the Tricity. Tell us the surface and conditions and we will match you to the right sealant.
Not Sure Which Sealant? We Will Match It
Bring the surface and the conditions to us, wet or dry, moving or fixed, paint or no paint, and we will hand you the right sealant, from Feviseal silicones to Dr. Fixit PU. KTC Tools stocks the range in Panchkula and serves the Tricity. Browse our wider construction chemicals and sealants range too.
Visit: Shop No. 4, Street No. 2, Maheshpur, Sector 21, Budanpur, Panchkula, Haryana 134117
Call: 94175 65977 | WhatsApp: wa.me/919417565977
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