Concrete Bonding Adhesive, Epoxy, or Silicone Tape? A Sika Chemicals Field Guide
Every few weeks I get asked the same question: which Sika Chemicals product do I actually need? I used to answer with one product. Then, in September 2022, I turned a small repair into a $3,100 problem by choosing the strongest-looking product instead of the right one. That failure changed how I select adhesives.
There is no universal adhesive. The right choice depends on what you are bonding, how thick or thin the layer is, whether the joint needs structural strength, and how long the repair has to last. So instead of giving you one generic recommendation, here are the scenario-by-scenario notes I now follow.
Which scenario are you actually in?
Before you order anything, run through this quick list. It will save you the kind of mistake that costs time and credibility.
- You are bonding fresh concrete to old concrete or repairing a shallow spall. That points to Sika Pro Select Concrete Bonding Adhesive.
- You are filling a deep void, setting an anchor, or mounting a specimen in a lab at room temperature. That points to a two-part cold mounting epoxy resin or a structural Sika epoxy adhesive.
- You need a temporary water-resistant seal or a protective wrap that can flex. That points to silicone adhesive tape transparent.
- You are putting paint on a canvas with acrylic paints. That is a completely different problem, and I will get to it.
Scenario A: Thin concrete repairs and cold joints
If the surface you are fixing is less than about 10 mm thick, or you are pouring fresh concrete against an old slab, the first product to know is Sika Pro Select Concrete Bonding Adhesive. It is a liquid bonding agent that you brush or roll onto a prepared, sound surface, then place your wet concrete or repair mortar before it dries. In the Sika Chemicals catalogue, this is grouped with concreting aids, not with structural epoxies, and that grouping matters.
I still kick myself for the 2022 failure. I was repairing a warehouse floor and I used a high-strength epoxy because I believed stronger equals better. It was a disaster. The epoxy created a hard, glossy film, and the 8 mm repair topping couldn't grip it. It delaminated in three sections. The cost of fixing that mistake: $3,100 in material and labor, plus the embarrassment of explaining to the client why the first 40 m² had to be broken up and redone.
What should have happened: a coat of Sika Pro Select Concrete Bonding Adhesive, then the repair mortar, then a proper cure according to the technical datasheet. The bonding agent is not for steel, and it won't fill a gap. But for thin concrete-to-concrete work, it is designed for that exact interface. (I know, it sounds too simple to be true. I learned the hard way.)
Scenario B: Deep gaps, anchors, and cold-cure epoxy
Now flip to the opposite situation. If you are setting a threaded rod into concrete, filling a 20 mm void, or mounting a metallographic sample for cutting and polishing, you want a two-part resin system. In the lab world, that is often a cold mounting epoxy resin, which cures at room temperature without a pressure press. In construction, the same cold-cure logic applies to Sika's structural epoxy adhesives.
The most frustrating part of this scenario is that people confuse the two because both have the word epoxy. A cold mounting epoxy resin is not designed to glue a rusty bracket to a wall. And a construction chemical anchor is not designed for specimen preparation. The products look similar, but the chemistry is optimized for completely different jobs.
Honestly, I didn't understand how different they were until a 2024 lab order. A customer asked for a cold mounting epoxy resin for what turned out to be an anchoring job. I caught it in time because the distributor asked a simple question: is the part going into a testing machine or into building? Always answer that question before ordering.
Scenario C: Temporary seals and protection
Sometimes you don't need a permanent bond at all. You need to seal a pipe joint, wrap a hose, cover a cable entry, or protect a repair while it cures. That's where silicone adhesive tape transparent earns its place in the kit.
The critical thing is to be honest about the word temporary. Silicone tape has good heat resistance and self-fuses if you overwrap it. But it is basically a flexible, water-resistant fix, not a structural epoxy and not a permanent concrete repair. I have watched a crew try to use it as the final fix on a coolant hose. It worked for a while, until the heat cycle broke the seal. Trust me on this one: use silicone tape for temporary, flexible, weather-resistant sealing, not for load-bearing connections.
Even after choosing tape for a temporary pipe seal, I kept second-guessing. What if the surface was too wet to bond? The 24 hours until the pressure test were stressful. The tape held, but I still had to come back with a proper repair once the replacement part arrived. That extra trip was my own fault; I should have inspected the surface first.
Scenario D: Wait, are you actually painting on canvas?
One of the strangest search referrals I see is the phrase what to paint on a canvas with acrylic paints. If that is you, stop reading construction chemical guides. You do not need Sika Pro Select, epoxy, or silicone tape on a canvas. You need artist-grade acrylic paint, a brush or palette knife, and a primed canvas.
For most beginners, a pre-primed cotton canvas is the easiest starting point. Acrylics can go directly on raw canvas, but primer (usually gesso) keeps the paint from soaking into the fibres and gives you a smoother surface. Raw canvas drinks paint like crazy; a primed canvas lets the paint sit where you put it.
As for what to paint: start with simple subjects, like fruit, a street scene, or an abstract block of shapes. Acrylics are forgiving enough for trial and error, so the bigger challenge is starting, not choosing the right subject. And if you were searching for a construction adhesive, this is your sign that the original query was an art-supply question, not a Sika Chemicals question.
How to tell which one you need
If you are still unsure, use the three-question check I now use before every order:
- What is the substrate? Concrete-to-concrete thin layer: Sika Pro Select Concrete Bonding Adhesive. Concrete-to-steel, deep void, or anchor: epoxy. Pipe, cable, or irregular temporary wrap: silicone adhesive tape transparent. Canvas: acrylic paint.
- How thick is the gap? Less than 10 mm and not load-bearing: bonding agent. More than 10 mm or load-bearing: structural epoxy. Any gap, but you expect to disassemble it later: tape.
- What is the timeline? Permanent repair: bonding agent or epoxy. Temporary fix until the replacement part arrives: silicone tape. Artwork meant to last decades: acrylic paint on gessoed canvas.
This sounds simple, but it's the checklist I wish I had before the 2022 floor failure and the 2024 lab mix-up. The products are not interchangeable. The full Sika Chemicals catalogue looks overwhelming, but you don't need twenty products. You need a small kit that matches the work you actually do.
And if you are a small contractor or a maker buying just one can of Sika Pro Select Concrete Bonding Adhesive, don't worry about being too small. The distributors I've worked with treat a $180 order seriously because they know today's small order is tomorrow's regular project. At least, that has been my experience since I stopped pretending one product fits everything.
Product names and availability vary by region. Verify the current technical datasheet and intended-use statement at sika.com for the exact product you are considering.