Hardness Barcol

Barcol Indenter. The Barcol hardness tester is a hand-held, spring-loaded instmment with a steel indenter developed for use on hard plastics and soft metals (ASTM D2583) (2). In use the indenter is forced into the sample surface and a hardness number is read direcdy off the integral dial indicator caUbrated on a 0 to 100 scale. Barcol hardness numbers do not relate to nor can they be converted to other hardness scales. The Barcol instmment is caUbrated at each use by indenting an aluminum ahoy standard disk suppHed with it. The Barcol test is relatively insensitive to surface condition but may be affected by test sample size and thickness. 

Vickers and Knoop indentors, Barcol hardness, and Shore durometers (2) (b) to measure the resistance of a material to scratching by another material or by a sharp point, such as the Bierbaum hardness or scratch-resistance test and the Moh one for hardness and (c) to measure rebound efficiency or resilience, such as the various Rockwell hardness tests. The various tests provide different behavior characteristics for plastics, as described by different ASTM standards such as D 785. The ASTM and other sources provide different degrees of comparison for some of these tests. 

Barcol hardness Also called Barcol impresses It is a measure of the hardness of a plastic, that includes laminate or reinforced plastic, using a Barber Coleman spring loaded indenter. Gives a direct reading on a 0 to 100 scale higher number indicates greater hardness. This test is often used to measure the degree of cure for plastics, particularly TS plastics. 

Entry Watts DTSb (MPa) Barcol Hardness Visual... 

Series of runs were made to explore the effects of temperature, catalyst, and initiator on the cure rate (Figures 1 through 3). Taking a Barcol hardness of 63 as a reasonable level for comparison, standard formulations reached this level in 48 hours at 75°C, 24 hours at 85°C,... 

Indentation hardness by Barcol hardness tester for rigid plastics Creep relaxation of gasket materials... 

The physical properties of a typical room temperature-cured polyester concrete is as follows Barcol hardness (50), tensile strength (500 kg cm 2), elongation (0.45%), compressive strength (1400 kg cm 2) flexural strength (1050 kg cm ) and heat deflection (41"C). The latter may be Increased by 30 by the use of fumaric acid Instead of maleic acid. 

It is important when conducting expensive test programmes that the constituents be checked for quality prior to use and that the fabricated materials be checked after manufacture, or on receipt if already fabricated. The techniques used vary from the Barcol hardness test (see below) to the more rigorous DMA (dynamic mechanical analysis ISO 6721 (ten parts) [14]) or DSC [differential scanning calorimetry ISO 11,357 (7 parts) [15]) test methods. There is some concern that these tests do not give the same values due to subtle variations between different manufacturers equipment. 

The simple and nondestructive Barcol hardness test has the added advantage that it can be conducted in situ on the factory floor (see Section 6). The other techniques are more costly, require a greater degree of operator training, and are not practical for in situ factory use. However, they are suitable for checking incoming material as preimpregnates or laminates. 

The only specialist use of hardness testing for composite materials is related to the assessment of cure using the Barcol hardness test available as EN 59 [16], The test is frequently used as a low-cost quality check on the cure of laminates such as hand layup CSM materials used in marine and general purpose commercial moldings. Care should be taken to avoid cracking thin laminates. 

FIGURE 3.44 General construction of Barcol hardness tester. 

Barcol hardness See test, Barcol hardness, bare glass See fiberglass, bare. 

This decay rate is nearly equivalent to that exhibited by one g of radium in equilibrium with its disintegration products. A miUicurie (mCi) is 0.001 curie, curie point See magnetized curie point, curing See autoclave nitrogen atmosphere cure extruder wire and cable process, dry cure inhibitor prepreg volatile content reinforced plastic resin transfer molding test, Barcol hardness test, scorch Mooney thermoset plastic vulcanization welding, induction. 

All furan laminates must be postured to drive out the reaction condensate to achieve optimum properties. Curing for a fresh laminate should start with an initial temperature of SOT (66°C) for 4 h, which is slowly raised to 180°F (82°C) for 8 h of curing. Too fast a cure can result in a blistered or cracked laminate. A final Barcol hardness of 40-45 is necessary to develop optimum laminate properties. The structural formula for the resin is ... 

R.W. Mills, A. Uhl, G.B. Blackwell, K.D. Jandt, High power light emitting diode (LED) arrays versus halogen light polymerization of oral biomaterials Barcol hardness, compressive strength and radiometric properties. Biomaterials 23 (2002) 2955-2963. 

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