A Technical Data Sheet TDS, in the shorthand everyone uses is the most underused document in the Indian construction chemicals industry. It sits in a WhatsApp forward, or a product box, or a website download section. Contractors glance at it. Purchase managers file it. Site supervisors stack it under something.
We’ve been distributing construction chemicals for over forty years. We can tell you with some confidence that roughly sixty percent of technical queries we’ve received would have been fully resolved if the person had read the TDS carefully before applying the product.
What a TDS Actually Is
A Technical Data Sheet is a manufacturer’s formal, legally accountable statement of what a product is, what it does, how it should be used, and what the conditions of its use are.
Every TDS has two kinds of content: the part that describes the product at its best, and the part that describes the conditions under which those best results are achievable. Most people read the first part. Almost nobody reads the second part carefully enough. The second part is where the real information is.
Coverage Rate, The Number Everyone Misreads
Coverage rate is typically given as theoretical coverage under ideal conditions on a smooth substrate. On a real site, actual consumption will be 10–30% higher due to substrate porosity, texture, and wastage. When ordering material, add at least 15% to the theoretical quantity.
Pot Life is Temperature Dependent, Always!
Pot life is the time after mixing during which the product remains usable. It is temperature dependent. A product with a 45-minute pot life at 20°C may have a 25-minute pot life at 35°C which is a typical Indian summer afternoon except some areas. Products applied beyond their pot life will have compromised performance, and the failure may not be visible for months.
DO NOT APPLY ANY LIQUID MEMBRANE IN HIGH HEAT , ABOVE 35 DEGREES ITS A RISK WITH SYSTEM PERFORMANCE. START EARLY MORNING or LATE EVENINGS in months of MAY - AUGUST
Substrate Preparation — The Most Ignored Section
This is the source of the majority of product failures we investigate. When a TDS says “substrate must be clean, dry, sound and free from oil, grease, dust, and loose material” — every word is doing work.
- Clean: Not just visually clean. Free from curing compounds, release agents, paint, laitance.
- Dry: Has a defined meaning. Surface moisture content within the specified range.
- Sound: No delamination, no hollow sections, no crumbling surface.
If substrate preparation is not done correctly, no product will perform to its data sheet specification. This is a categorical statement, not a probability.
Mixing Instructions, The Ratio i.e. A is to B always Matters!
For two-component products including most epoxy systems like BS Epoxy 611, Nitobod EP ofr SikaDur system and many polyurethane systems, and two-part cementitious coatings like SikaTop 107or 109, the ratio between components is determined by the chemistry, not by convenience. Mix times specified in TDS (typically 3–5 minutes with a mechanical mixer) are not conservative estimates. Under-mixing is a genuine failure mechanism.
The Three Questions to Answer Before You Open a Bag
- Is this the right product for this substrate in these conditions?
- What is the pot life at today’s site temperature?
- What does substrate preparation actually require here?
These three questions take about ten minutes to answer properly. They prevent most of the calls we get about product failures.
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For TDS interpretation or technical queries, chat with Divya on WhatsApp: wa.me/919256816832
