HT S25 All-Purpose Silicone Sealant Singapore — Quick Facts

The HT S25 All-Purpose Silicone Sealant is a one-part neutral cure silicone from T2960. Plus, it seals and weatherproofs joints for years. It gives off no acetic acid as it sets. So it stays low in odour. Also, it is safe on bare metal. In short, this is an all-purpose silicone sealant Singapore trades reach for first.

• Type — One-part neutral cure, high modulus
• Joint movement — ±25% (ASTM C719)
• Sound — STC ≥40 in wall systems (ASTM E90; C919)
• Tack-free — Under 30 minutes at 23 °C (ASTM C679)
• Full cure — 24 hours at 2 mm bead
• Hardness — Shore A 43 (ASTM D2240)
• Elongation — Over 350% (ASTM D412)
• Joint size — 6 to 50 mm wide, 6 to 25 mm deep
• In service — Minus 48 °C up to 149 °C
• Standard — ASTM C920, Type S, Grade NS, Class 25
• Sticks to — Glass, metal, ceramic, wood, PVC and ACP
• Pack — 300 ml tubes, 25 per carton
• Colours — Clear, White, Grey, Dark Grey, Black; custom on request
• Shelf life — 12 months, unopened

Product Description

First, HT S25 seals out wind and water. Acid-cure types can stain or rust some surfaces. But this one will not. Plus, it bonds well to glass, metal, ceramic, wood, PVC and ACP panels. So one tube covers glazing, build work and wet areas. It also cuts sound through wall systems. Do you need a different type? Then browse our full range of sealants.

Key Benefits of the HT S25 All-Purpose Silicone Sealant

• Neutral cure — Safe on metal and low in odour. So you can use it indoors.
• Keeps water out — Also, it stands up well to rain and sun.
• Stays flexible — Moves with the joint as heat rises and falls.
• Cuts noise — Holds STC ≥40 in wall systems (ASTM E90; C919).
• Handles movement — Takes ±25% joint movement (ASTM C719).
• Easy to gun — Smooth to tool. Plus, it is tack-free in under 30 minutes.

Neutral Cure Versus Acetoxy Silicone Sealant

First, silicones split into two camps. Acetoxy types give off acetic acid as they set. So that brings a sharp vinegar smell. It can also rust bare metal and mark some surfaces. Neutral cure types, such as HT S25, give off much milder by-products. So they are the safer bet on aluminium, zinc-coated steel, mirrors and coated panels. For more on how these products work, see this guide to sealant types and uses.

Applications for the All-Purpose Silicone Sealant

Next, HT S25 sticks to a wide range of surfaces. So it suits many jobs:

• Joints in metal, glass, concrete, ceramic, wood and PVC.
• Glass-to-glass and glass-to-metal sashing.
• Pre-built homes, freight containers and cold rooms.
• Duct work and ACP panels.
• Wall seals that cut sound.

Also, this tube is part of our wider silicone sealant range. So we can match a grade to your joint detail.

Packaging, Colours and Storage

• Tubes: 300 ml, 25 per carton.
• Colours: Clear, White, Grey, Dark Grey and Black. Custom colours on request.
• Storage: First, keep tubes at 15 to 27 °C. Also, keep them dry. Do not let them sit above 50 °C for long.
• Keep it sealed: The sealant reacts to air. So close part-used tubes tight.
• Keep it clean: Water and alcohol spoil it. So guard the tube from both.
• Shelf life: 12 months in the sealed tube. Still, check the “Use Before Date” on the pack.
• Stock rule: Use the oldest stock first.

Technical Data for HT S25 All-Purpose Silicone Sealant

First, these figures come from the HT S25 All-Purpose Silicone Sealant data sheet (Rev. 09.23). So you can match this all-purpose silicone sealant in Singapore to your spec.

• Form — Paste. So it holds its shape in the joint.
• Specific gravity — 1.50
• Flow rate — Over 10 ml per minute (ASTM C1183)
• Cure type — Moisture cure. It sets on damp in the air.
• Slump — 0 mm (ASTM C639)
• Tooling time — Under 8 minutes
• Tack-free time — Under 30 minutes at 23 °C (ASTM C679)
• Cure time — Up to 24 hours for a 2 mm bead
• Hardness — Shore A 43 (ASTM D2240)
• Tensile strength — 1.4 MPa (ASTM D412)
• Elongation — Over 350% (ASTM D412)
• Joint movement — Plus or minus 25% (ASTM C719)
• Peel bond — 117.0 N mean (ASTM C719)
• Ageing — No cracks after UV and bend tests
• Apply at — 4 °C to 43 °C
• In service — Minus 48 °C up to 149 °C

Standards This All-Purpose Silicone Sealant Meets

The HT S25 All-Purpose Silicone Sealant meets or beats these test rules:

• ASTM C920 — Type S, Grade NS, Class 25. Use NT, A, M and O.
• ASTM E90 and C919 — Holds STC 40 or more in a wall system.

Thus you can name this all-purpose silicone sealant in Singapore specs with ease.

Joint Design for the All-Purpose Silicone Sealant

First, size the joint right. Then the bead can do its job. Also, we size joints for all-purpose silicone sealant in Singapore work every day.

• Width — 6 mm to 50 mm.
• Depth — 6 mm to 25 mm.
• Moving joints — Aim for a width to depth ratio of 2 to 1. Or follow our advice on site.
• Backer foam — Use foam that suits silicone. It holds the bead up as you gun it.
• Bond break — The foam also stops the bead sticking at the base. So the joint can move on both faces.

How to Apply All-Purpose Silicone Sealant

These steps follow the HT S25 All-Purpose Silicone Sealant data sheet.

1. Clean the joint. First, strip off all dirt. Also, take out form release oil, water repellents, laitance, old sealant and old coatings. Then blow the joint out with oil-free air. Or vacuum it.
2. Wipe metal, glass and plastic. Next, use a proper solvent. But do not use soap or detergent. Then wipe the face dry with a clean cloth. Also, clean two to three hours before you gun the bead.
3. Prime if you must. HT S25 grips most surfaces with no primer. Still, concrete, mill finish alloy and zinc-coated steel may need one. So run a small bond test first.
4. Mask the edges. Then tape both sides. So this gives a clean line on show work.
5. Fit the backer. Now push in the backer foam or joint filler as specified.
6. Gun the bead. First, work in one pass. Then go one way on flat joints. Also, go bottom to top on upright joints. Press hard enough to fill the whole joint width.
7. Tool it. Next, use light pressure. So the bead spreads onto both faces and the backer. The paste is light, so it tools with ease and leaves no voids.
8. Peel and clean up. Last, pull the tape before the bead starts to set. Then wipe spare sealant off metal and plastic with a solvent while it is still soft.

Where Not to Use the All-Purpose Silicone Sealant

The HT S25 All-Purpose Silicone Sealant is not the right choice in a few spots. So please avoid:

• Flat joints that take foot or wheel traffic.
• Flat joints that sit under water for long spells.
• Concrete that still holds form oil or other bond breakers.
• Stuff that bleeds oil or solvent. That means oiled wood, some rubber gaskets and old failed sealant.
• Fully closed gaps. The bead needs damp air to set.
• Wet or raw faces. Also, do not tool the bead with water.
• Marble, limestone and such. They soak up oils, so they may stain.
• Faces where no site bond test has been done.
• Jobs that call for FDA or USDA sign-off.

One more note on looks. Silicone sheds chalk and grime poorly, so dirt can cling to it. Thus a darker shade hides this best in dusty spots.

Care and Repair

The HT S25 All-Purpose Silicone Sealant needs no upkeep. But if a bead gets torn, cut out that part. Then clean the gap and gun in fresh sealant. So dispose of waste as the local rules ask. Also, keep it out of drains and waterways. Plus, we back each all-purpose silicone sealant in Singapore that we supply.

Frequently Asked Questions

What is a neutral cure silicone sealant?

It is a silicone that gives off mild by-products as it sets. Acid-cure types give off acetic acid instead. So neutral cure is safe on metal and low in odour. Overall, HT S25 is a one-part, high modulus neutral cure silicone.

Can HT S25 be used on aluminium composite panels?

Yes. It bonds well to ACP. It also bonds to glass, metal, ceramic, wood and PVC. The cure is neutral. So it will not harm the panel coating.

How much joint movement can this silicone sealant take?

It takes ±25% joint movement, tested to ASTM C719. So design the joint wide enough. Thus the movement must stay in that range.

Is HT S25 good for acoustic wall systems?

Yes. It holds STC ≥40 in wall systems, tested to ASTM E90 and C919. So it suits wall edge joints. It also suits gaps where pipes and ducts pass through.

What colours and pack sizes are there?

It comes in 300 ml tubes, 25 per carton. Stock colours are Clear, White, Grey, Dark Grey and Black. Plus, we can mix custom colours.

How fast does HT S25 go tack-free?

Tack-free time is under 30 minutes. But full cure takes much longer. It hinges on joint depth, heat and damp. So check the data sheet for cure times.

How should the tubes be stored?

First, keep them at 15–27 °C and keep them dry. Also, do not let them go above 50 °C. Stored that way, shelf life is 12 months in the sealed tube.

Does HT S25 need a primer?

Not on most surfaces. Plus, it grips glass, metal, ceramic, wood and PVC on its own. But concrete, mill finish alloy and zinc-coated steel can need a primer. So run a small bond test first.

What joint size suits this sealant?

First, gun it into joints 6 mm to 50 mm wide. Then keep the depth from 6 mm to 25 mm. For joints that move a lot, aim for a width to depth ratio of 2 to 1.

How hot or cold can the joint get?

First, apply the bead at 4 °C to 43 °C. Once set, it copes from minus 48 °C up to 149 °C. So it suits sun-baked facades and cold rooms alike.

Can I use HT S25 on a floor joint?

No. Keep it off flat joints that take foot or wheel traffic. Also keep it out of joints that stay under water. So ask us for a floor grade instead.

Where can I buy all-purpose silicone sealant in Singapore?

T2960 stocks HT S25 at our Tuas West base. Also, we can check that it suits your surface first. So call or email our team for a price and data sheets.

Specify HT S25 All-Purpose Silicone Sealant for Your Singapore Project

Do you need a price, data sheets or advice on a surface? Plus, our team can help with joint design and colour. Email contact@t2960.com.sg or call +(65) 6267 1300.