Resources
Six guides, each with the notes underneath it. Every note answers one question a buyer has actually asked, with the numbers from the data sheet rather than adjectives.
9 pages · 8 notes
Windscreen adhesive
Bead geometry, modulus, primerless systems and the failures that come back.
Windscreen adhesive: the specification guide — the guide
- KA518 vs KA520 vs KA530F: choosing a windscreen adhesive — Three PU windscreen grades compared on tensile strength, elongation and skin time — and the four questions that decide which one your bay actually needs.
- Why a windscreen adhesive cures too slowly — Why a bead is still soft the next morning: cold glass, dry air, thick sections and the four reasons a cure runs late, with the arithmetic that predicts it.
- How much windscreen adhesive a car actually takes — Bead cross-section, cartridge maths and why an 8×10 mm triangle is 40 mm² — the calculation that turns 'one cartridge per car' into a number.
- Primerless windscreen adhesive: what it covers — Primerless PU adhesives cut a process step, not the preparation. What the claim covers on glass, paint and metal, and where it stops being true.
- Installing windscreen adhesive below 10 °C — Cold glass, slow cure and the two-hour promise that quietly stops being true: what changes below 10 °C and how to keep the bay moving without guessing.
- Bus and coach glazing needs a different windscreen adhesive — Larger glass, more body flex and higher wind load: why a passenger-car adhesive is the wrong specification for a coach, and what the numbers look like.
- Diagnosing a failed windscreen bond — Peel test, frit reading and bead cross-section: a three-step diagnosis that separates a product failure from a preparation failure, in ten minutes.
- Windscreen adhesive shelf life and storage — Why a cartridge skins over in the nozzle, what heat does to a moisture-curing adhesive, and how to store it so the last cartridge behaves like the first.
6 pages · 5 notes
Body seam sealing
Sealing versus bonding, sanding and paint compatibility, corrosion at lapped joints.
Body seam sealing: sealer, adhesive or both — the guide
- Seam sealer vs structural adhesive: which seam gets which — One fills a gap, one carries load. Mixing them up is the most expensive mistake in body repair — how to tell which seam is which before the gun comes out.
- Painting over seam sealer without a comeback — Cure window, primer compatibility and the waterborne basecoat trap: why a sealer that passed the thumb test can still ruin a paint job on the car.
- Seam sealer and corrosion at lapped joints — Where rust actually starts on a repaired panel, why a bead over a wet seam makes it worse, and the two preparation steps that prevent most comebacks.
- Sealing container and trailer seams: STP or PU — Mixed substrates, exterior UV and joints that flex at 80 km/h: why the roof seam and the floor seam of a trailer often need different products.
- Cartridge, sausage or barrel: pack economics — Gun time, waste and changeover: why the cheapest cartridge is rarely the cheapest metre, and which pack format fits which workshop size and throughput.
7 pages · 6 notes
Construction joints
Movement class, joint geometry, backer rod, wet concrete and pressure joints.
Construction joint sealant: movement, geometry and failure — the guide
- Joint design decides whether the sealant works — Width-to-depth ratio, backer rod, three-sided adhesion and movement class — the four joint decisions that matter more than the sealant brand.
- Joint movement class: the number that decides the sealant — How movement is calculated as a percentage of joint width, what ISO 11600 and ASTM C920 classes mean in practice, and why elongation is not the same thing.
- Backer rod sizing and three-sided adhesion — Why a bead bonded on three faces cannot stretch, how to size a backer rod by joint width, and the cheap detail that prevents most joint failures.
- Sealing green and damp concrete: why it fails later — Moisture-curing does not mean you can seal wet concrete. What happens at the interface, how long to wait, and the primer that decides the bond.
- Sealing tunnel and drainage joints under water pressure — Where a surface bead stops working and a waterstop starts: pressure, movement and the joint details that keep a tunnel or culvert dry under pressure.
- Cold-weather joint sealing: the double problem — Low temperature slows the cure and opens the joint at the same time — why winter installation needs a different plan, not a different product.
6 pages · 5 notes
STP and industrial bonding
Where silyl-terminated polymer wins, where PU still does, and what primerless really covers.
STP sealant: where it beats PU and where it does not — the guide
- PU sealant vs silicone: which one for which joint — PU and silicone compared on adhesion, movement, paintability and UV — with the four joints where the wrong choice usually ends in a comeback.
- MS polymer vs PU for windscreen bonding — Why the primerless, solvent-free appeal of MS polymer does not replace polyurethane in direct glazing — and the two cases where it genuinely does.
- Primerless STP claims, tested by substrate — Which substrates genuinely bond without a primer, which need an activator, and the ten-minute coupon test that settles it before a production run.
- Overcoating STP sealant: paint systems and cure windows — STP is paintable, but not at any time with any paint. How cure state, coating chemistry and film build decide whether the topcoat stays put.
- STP sealant outdoors: UV, colour and chalk — Why STP survives sunlight better than PU, what still changes on a roof seam after five years, and when a topcoat is still worth the extra step.
5 pages · 4 notes
PUR wood adhesive
Moisture content, clamp time, treated timber and the alternatives.
PUR adhesive for glulam and engineered timber — the guide
- Moisture content is the PUR adhesive process variable — Why 8–12% is the working window, how to measure moisture on the shop floor, and what wet or frozen timber does to a glue line that looks fine.
- Clamp time and press scheduling for PUR — How temperature, moisture and section thickness move the 1–4 hour catalogue range, and how to schedule a press without gambling on the release time.
- Bonding treated and dense timber with PUR — Preservative treatment, extractives and density change how PUR wets and cures. What to test before a structural run, and which species to watch.
- PUR vs PVAc, MUF and EPI: choosing a wood adhesive — Four adhesive families compared on water resistance, creep, gap filling and handling — and the applications where each one actually wins in a plant.
8 pages · 7 notes
Buying and importing
Specification, certificates, MOQ and the documents that decide whether a container clears.
Buying PU sealant from China: the eight checks — the guide
- How to read a sealant data sheet — Standard, typical value, method and the difference between a catalogue figure and a batch result — a buyer's guide to the table on every model page.
- Importing PU sealant from China: the eight checks — Dangerous goods, shelf life, heat in transit and the documents a customs broker asks for — a checklist for a first sealant order from China.
- Why PU sealant costs more than silicone per cartridge — The cost difference is real but it is not where buyers think: raw material, coverage, rework and the hidden cost of a bead that has to be painted twice.
- Batch certificate vs catalogue value — A certificate of analysis is useful only if it names the batch, the method and the measured result. What to ask for, and what a bare certificate is worth.
- MOQ and pack economics: why the number changes per format — Why a cartridge MOQ, a sausage MOQ and a barrel MOQ are different questions, and how to structure a first order that does not leave you with dead stock.
- Ten questions for a sealant factory visit — What to look at, what to ask, and what the answers reveal: ten questions for a sealant factory visit that separate a plant from a trading company.
- Running a sealant sample trial that means something — Substrate, cure conditions, failure mode and a control: how to test a sample cartridge so the result predicts the production batch you receive.
Have a question the catalogue does not answer? Write to ryan@pu-karmind.net — the answer may end up here.