BS EN 3847:2019 pdf download

BS EN 3847:2019 pdf download

BS EN 3847:2019 pdf download.Aerospace series – Paints and varnishes – Determination of sedimentation rating
1 Scope
This document specifies the method of test for evaluating the tendency of paints and varnishes towards sedimentation of their pigments.
The procedure describes a method where the pigmented paint is allowed to settle at a specified temperature and for a specified time.
The procedure is not applicable to products which possess a pot life inferior to the specified measuring time.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 2431, Paints and varnishes一Determination oflow time by use of flow cups
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
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4 Principle
Leave the paints to settle (at their consistency for use in the case of a mixture) at a specified temperature and for a specified time.
5 Apparatus
apparatus specified in ISO 2431;
一100 ml measuring cylinder. The distance between the reference lines 0 ml and 100 ml shall be approximately 18 cm;
一enclosure regulated at (23土2) °C.
6 Preparation of the test material
6.1 Sampling
The paint containers, base, activator and thinners, shall be thoroughly homogenised prior to any samples being extracted for testing.
After homogenisation the paint material shall be allowed to settle for 30 min in a closed container to enable entrapped air to escape and any thixotropic properties to be regained. Take a 200 ml sample of each of the paint components.
If the mixture is prepared in an open receptacle, only a stainless steel smooth edged spatula shall be used to scrape the bottom carefully in order to set any solid deposits in suspension.
6.2 Preparation of the paint
Allow the samples to attain (23+2) °C and then the component parts of the paint shall be rehomogenised.ln the case of 2 (two) component products this shall be a base/activator mixture according to the activation ratio specified by the manufacturer.
Measure the flow time of the paint in accordance with ISO 2431 and adjust the viscosity using appropriate thinners to the flow time which is required by the product standard or in the manufacturer’s instructions.
7 Procedure
lmmediately on completion of preparation, the paint mixture shall be decanted into a measuring cylinder until the upper surface of the meniscus shall be level with the 70 ml reference line.
Close the measuring cylinder using a cork or stopper and allow it to stand upright for 4h in the temperature regulated enclosure.
On completion, shall be noted the volume V occupied by the supernatant fluid above the sediment.