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Universal Impact Tester Model #172

Model No. IM-172

Basic Tester

The basic tester is made up of two major assemblies, the base and the guide tube. The black oxide aluminum base is 1 .5" thick, 10" wide, 12" deep and has a sturdy arm for holding the guide tube. It is also fitted with leveling screws, die cavity, circular level, tube clamp & two test panel magnets.

The aluminum gravity guide tube is 48" high, 1.25" I.D. and fitted with height
scale (inches/centimeters) & height clamp.

See Accessories for required Indenter, Receiving Die and Dropping Weight.

Specification References

ASTM D 6905-03
ASTM D 2794 "Resistance of Organic Coatings to the Effects of Rapid Deformation - Impact." MIL-P-85582A; MIL-P-23377C; MIL-C-85285A; MIL-E-24763A (SH); NCAA 11-10 (11-6, 11-16, AND X-1); ECCA
ASTM D 4226 "Impact Resistance of PVC Building Products."
Meets ASTM G 14 with optional accessories - Call for details.
General Electric Company PLI-100 "Modified Gardner Impact Strength," 1975.
Federal Highway Administration FP-74 "Standard Specifications for the Construction of Roads and Bridges on Federal Projects," Section 633.06, Traffic Control Signs- Impact Resistance.
Model 172 meets Proposed Revision at TT-P-2756A, Polyurethane coating: Self-Priming Topcoat, Low Volatile Organic Compounds (VOC).

Impact Testers

The experience of many years has taught that the bending and stretching of the metal base on which a coating was applied provided valuable information on the elastic and adhesive characteristics of the coating. Numerous types of instruments have been used: powered elongation testers, cylindrical or conical mandrels, manual or powered indenters and falling weight indenters. The falling weight indenters are normally most severe due to the "shock" nature of the test. Many different falling weight indenters are now in use and it is the design purpose of the new UNIVERSAL IMPACT TESTER, MODEL 172, to provide a range of operating capability that matches or exceeds most of these existing instruments. In addition, MODEL 172, with selected auxiliaries, exceeds specification ASTM D 2794.

Method Of Use

Coatings to be tested are applied to cleaned thin metal panels (suitable panels are available from the Paul N. Gardner Company.) After the coating to be tested is properly cured and ready for test, the test panel is placed on the selected supporting die and magnets, or for the GE evaluation, on the flexible anvil. The selected indenter with associated weight or the combined indenter weight is placed in the tube so that it rests on the test panel. The guide tube is then adjusted in the base so that the scale registers zero at the lifting handle or mark and/or the position of such lifting member while at rest. The weight or combined weight indenter is then raised to the desired height, noted and released. The test panel is inspected, and depending on results, the test may be repeated by releasing the weight or the combined weight indenter at a higher or lower elevation. (When using the GE FLEXIBILITY TEST IMPACTER the usual practice is to use a fixed height drop, as is covered under "Procedure" below). Coating failure is determined when cracks first appear in the coating with the minimum inch-pounds of falling weight. Such failure cracks may be made more visible by the application to the test area of a copper sulfate solution (CuSO4).

ASTM Method D 2794, which is now also used in place of FEDERAL TEST METHOD STANDARD NO. 141C, 6226 calls for a 0.64" diameter die which may be used with either a separate 0.500" or a 0.625" hemispherical head indenter.

The ASTM method specifies that a separate weight (IM-172-60) be used to impact against the indenter punch. Normally, a two pound weight will satisfy most test conditions.

Range of the test equipment may be greatly extended by the use of an auxiliary drop weight. The two pound auxiliary weight may be secured to and used with the two pound separate drop weight.

Many operators have found it more convenient to replace the separate weight and indenter punch with a combined single unit. The two pound combined units are available with hemispherical tip diameters of .500" and 0.625". The one kilogram combined unit has a tip diameter of 20 mm.

The combined weight indenter punch units have been found to provide a somewhat more severe test condition than the separate weight and indenter punch. This is due to the separate stationary indenter absorbing a small amount of the drop weight energy

GE Flexibility Tester

Some of the Specifications That Call For the Use of the GE Impact-Flexibility Test are
MIL-P-85582A, MIL-P-23377C, MIL C 85285A and

ASTM D 6905-03

The Universal lmpact Tester, Model 172, also accommodates the GE Impact Flexibilily test method. The GE impacter weights 3.6 pounds and has formed on each end four convex spherical segments which are of different radii and extensions.

Operating procedure is essentially the same for all die, indenter punch and weight or combined ball weight-indenter punch combinations except for the GE impacter.

Insure that the apparatus is level and that the desired die, indenter punch and weight or combined weight-indenter punch are in place. It may be convenient to set the guide tube clamp at a specified height if a particular test series is to receive the same impact energy. Normal procedure is to place the test panel between the indenter punch and the die with the coating facing downward against the die. (Some investigators have gained important information on coating properties by placing the panel in the apparatus with the coating facing upward and in contact with the indenter punch). With the test panel in place, raise the weight or combined weight indenter punch to a predetermined level and release. Remove the test panel and inspect the condition of the coating. The test may then be repeated at the same drop level to confirm the initial reading or repeated at a different drop level.

Following each test, the coating condition should be recorded along with the inch-pounds or meter-kilograms of the drop. It is also recommended that coating thickness be measured and recorded as well as the curing schedule and other possible influencing factors. Inch-pounds of drop is determined by subtracting the height reading, if not zero, by adjustment of the guide tube in the base arm, of the lifting rod or other index mark when the drop member is at rest on the test specimen from the drop height at the same reference point and multiplying this value by the pound weight of the drop element.

Proceed as follows to use the GE Impacter: Remove the die from its cavity in the base unit and install between the magnets, the aluminum plate with the top rubber anvil held in place with two strong rubber bands, insuring that the bands are in the grooves of the plate so that the plate seats firmly on the base. This rubber anvil has a 60 Shore hardness and should be replaced if worn or damaged. Install the GE impacter in the guide tube.

With an uncoated panel in place on the rubber anvil, determine the height of drop for each end of the impacter to show on the panel slight evenly spaced segment marks of the impacter circumference. The heights so determined will always be used. Place the coated panel to be tested face down against the rubber anvil and drop the impacter from the above determined height. Remove the panel from the tester and inspect the coating. Record the maximum percent area increase accommodated by the coating without cracking or other failure, from the table above.

¹WARNING: Damage will result if receiving die or blank plate such as IM-172-GE/2 (RUBBER ANVIL PAD) is not in place while the instrument is in use.

CAUTION: The operation of this instrument involves high energy impact. Eyes should be protected with safety glasses. Fingers and hands should be kept clear of the impact area.

Spherical Segment	End	Base Diameter	Segment Radius	Segment Evaluation	% Area Increase
1	A	0.375	0.194	0.146	60
2	A	0.375	0.208	0.119	40
3	A	0.375	0.252	0.084	20
4	A	0.375	0.326	0.059	10
5	B	0.375	0.440	0.042	5
6	B	0.375	0.676	0.027	2
7	B	0.375	0.947	0.019	1
8	B	0.375	1.332	0.013	.5


Item Number	Item
IM-172	Model 172 Basic Tester
Accessories
IM-172-0	Blind Plug 40MM Radius X 1" Deep
IM-172-1	Combination 1/2" Ball & 2 Lbs Weight Indenter
IM-172-11	ASTM 1/2" Ball Indenter Punch
IM-1 72-12	ASTM 0.125" Radius 20° Indenter Punch
IM-172-2	Accompanying Die, ASTM 0.640" For 1/2" Indenter
IM-172-3	Combined 5/8" Ball& 2 Lb Weight Indenter
IM-172-31	ASTM 5/8" Ball Indenter Punch
IM-172-4	Accompanying Die For 5/8" Indenter
IM-172-45	Proportional Die 14.5MM
IM-172-5	20MM Ball
IM-172-6	Accompanying Die For 20MM
IM-172-60	ASTM 2 Lb Dropping Weight For Indenter Punch
IM-172-71	Extension Weight, 2 Lbs., Male/Female
IM-172-8	Addtional Screw-On Weight, 1 KG
IM-172-9	Die Original For 5/8" 0.685"
IM-172-R00	172 Base Replacement Only
IM-172-R01	Gravity tube Replacement Only
IM-172-GE	GE Impact Test Adapter Complete
IM-172-GE/1	GE Indenter Only
IM-172-GE/2	GE Fixture Plate Only
IM-172-GE/3¹	GE Rubber Anvil Pad Replacment¹
IM-172-911	1-1/2" Elevation Block
IM-172-912	3" Elevation Block
IM-172-G14	ASTM G 14 Adapter, Complete
IM-172-G14/1	ASTM G 14 Combined 3 Lb Weight, 5/8" Diameter Ball
IM-172-G14/2	ASTM G 14 V-Block Attachment w/Hardware
IM-172-G14/3	Clamps, High Torque Stainless (Pair)
Special dies, weights & indenters made upon request to your specifications