Quality

A sealant is judged twice: on the data sheet before the order, and at the joint two years later. The first is what we can document here. The second is why the methods below matter.

The tests behind the table

PropertyMethodWhy it decides the outcome
Tensile strengthGB/T 528Whether the bead itself tears before the bond does
Elongation at breakGB/T 528How far the joint can move before the sealant fails
Tensile shear strengthGB/T 7124Load transfer between glass or metal and the bead
Shore A hardnessGB/T 531.1Soft enough to seal, hard enough not to sag
Skin timeGB/T 13477.5How long you can tool the bead before it skins
Sag resistanceGB/T 13477.6Whether the bead stays put on a vertical joint
Extrusion rateGB/T 13477.4Gun time per cartridge on a cold morning
DensityGB/T 13477.2Coverage per kilogram, and therefore cost per metre
Volatile contentGB/T 2793Shrinkage after cure; solvent content in the drum
Cure rateHG/T 4363Hours to handling strength at a given temperature and humidity
Elastic recoveryGB/T 13477.13Whether the joint closes again after movement

Typical value vs batch result

Every figure on a model page is a typical value from the printed catalogue. It tells you what the product is designed to do; it does not tell you what is in the drum you receive. For that you need the batch record, and you should ask for it before approving a shipment — tensile, elongation and skin time at minimum.

This distinction is not pedantry. Two batches of the same model can differ by several percent in tensile strength and still be in specification; a customer who specified the typical value as a minimum has bought a problem.

Documents

Certificate scans are supplied with the quotation package — business licence, ISO 9001 and the product certificate for the model you are buying. Ask for the current set and we will send the documents naming the same legal entity as the invoice.

Quality system

The company works to ISO 9001. The certificate and its scope are available on request — ask for them together with the batch record so both can be checked against the same legal entity.

What we will not do: publish a certificate number we cannot show, or quote a laboratory result without naming the laboratory. If a document is not in hand, the page says so. Write to ryan@pu-karmind.net for the current certificate set.