Elastomeric Materials

The Gund Company fabricates and supplies elastomeric materials for demanding industrial applications, including foam, sponge, rubber, O-rings, EMI shielding, cork and rubber blends, and wool and polyester felt. Every elastomeric material is engineered and tested to ASTM and MIL specifications, giving engineers and procurement teams verified performance data before they commit to a design.

ELASTOMERIC MATERIAL SOLUTIONS

ELASTOMER MATERIALS IS ANY MATERIAL EXHIBITING ELASTIC OR RUBBER-LIKE PROPERTIES.

Elastomeric materials are measured in material type, compound, and durometer (the material’s hardness).

Since there is such a wide variety of elastomeric materials, the application is critical to understanding the job’s best material compound.

Types of Elastomeric Products:

Elastomeric Foam
Elastomeric Sponge
Molded Rubber Sheets
Extruded Rubber Sheet & Shapes
Liquid Cast Rubber Sheet & Shapes

Typical Product Names:

Microcellular Urethane Foam (Poron)
Silicone, Neoprene, EPDM Sponge
Fluorosilicone Sponge (Viton)
Cork/ Rubber Blend Sheet Material
SBR, Butyl, EPDM, Nitrile, Neoprene Sheet
Silicone Rubber Sheet

Explore The Gund Company’s other engineered material families alongside elastomerics: Thermoset Rigid Composites, Thermoplastic Materials, and Flexible Materials.

FOAM / SPONGE

RUBBER

O-RINGS

EMI SHIELDING / THERMAL MANAGEMENT

CORK / RUBBER

FELT / WOOL

FELT / POLYESTER

FOAM / SPONGE

Foam & Sponge Elastomer Properties

FOAM AND SPONGE ARE GENERALLY GROUPED AND REGARDED AS IN THE SAME PLASTIC/ELASTOMERIC MATERIALS FAMILY BECAUSE THEY EXHIBIT THE SAME CELLULAR STRUCTURE.

Additionally, they are commonly listed under similar industry specifications (ASTM, MIL, UL, FMVSS, and others).

Foam is a lightweight, open-cell product that is typically used for insulation, filtration, and cushioning. These low density cellular materials allow air movement through the cell structure. In addition to traditional foam’s legacy applications, high-density foams can be used for fluid-sealing applications. In contrast, higher-density foam products will have a higher concentration of cells. Medium and low-density foams will have a lower concentration of cells.

The sponge is an expanded, rubber-based material. The sponge can be processed in multiple material formulations (different compounds, densities, or open and closed cellular structures). The cells are not connected, which keeps the material from absorbing and retaining liquid. Compared to foams, sponges are considered to have superior mechanical properties.

Sponge and foam are available in sheets, rolls, and molded or extruded shapes, and The Gund Company can convert either material into finished, ready-to-install parts through its fabrication and converting capabilities. As needed, they can be ordered with or without ‘skin’ and PSAs (pressure-sensitive adhesive).

COMMON BRANDS:

Rogers®
Monmouth
Armacel®
K-Flex®
Rubatex®
Griswold

COMMON TRADE NAMES:

Poron®
Bisco®
EnsoLite®

USES:

Filtration
Thermal Insulation
Cushioning

Padding
Gaskets
Weather Stripping
Sound Barrier

To learn more about foam and sponge elastomeric materials from The Gund Company or request a quote for your application, Contact Us Today!

SPONGE SPECIFICATION GUIDE

Polymer	NEO/EPDM/SBR				EPDM/BLEND			EPT BLEND

Specification
ASTM D1056-67	SCE41	SCE42	SCE43	SCE45	RE41E	RE42E	RE43E	RE41EPT
ASTM D1056-07	2A1	2A2	2A3	2A5	2A1	2A2	2A3	2A1
MIL-R-6130 TYP + ASTM D6576	II-A	II-A	II-A	II-A	II-B	II-B	II-B	—–
GRADE CONDITION	Soft	Soft-Med	Medium	Firm	Soft	Soft-Med	Medium	—–
MIL-C-3133C MIL STD 6708	SCE3 F2	SCE7 F2	SCE11 F2	SCE20 F2	RE3 F2	RE7 F2	RE11 F2	RE3
FLAMMABILITY SPECIFICATION
UL94 HF1	Listed	Listed	Listed	—–	—–	—–	—–	—–
UL94 HBF	Listed	Listed	Listed	—–	—–	—–	—–	—–
MIL-R-6130C	Pass	Pass	Pass	Pass	Pass	Pass	Pass	—–
FMVSS-302	Pass	Pass	Pass	Pass	Pass	Pass	Pass	—–
PHYSICAL PROPERTIES
25% Compression Deflection [psi]	2-5	5-9	9-13	17-25	2-5	5-9	9-13	2-5
Density Approximate [pcf]	6 +/-2	6 +/-2	9 +/-2	12 +/-2	6 +/-2	6 +/-2	9 +/-2	4 +/-1
Water Absorption Max. Weight %	5	5	5	5	5	5	5	5
Temperature Range ^oF	-40/+200	-40/+200	-40/+200	-40/+150	-70/+220	-70/+220	-70/+220	-40/+200
Temperature High Intermittent^oF	250	250	250	200	250	250	250	250
Ozone Resistance	Excellent	Excellent	Excellent	Fair	Excellent	Excellent	Excellent	Excellent
Tensile Strength [psi]	75	100	100	150	75	75	100	40
Fuel B Max. % Weight Change	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Elongation Typical Properties %	125	125	125	125	125	125	125	175
Durometer Shore 00 [Approx.]	40-50	45-55	55-65	65-75	40-50	45-55	55-65	37-47
Shrinkage 7 Days @ 158^o Max.	5%	5%	5%	5%	5%	5%	5%	5%
K Factor	0.30	0.30	0.38	—–	0.3	0.30	0.38	030

Polymer	100% NEOPRENE		EVA		PVC/NITRILE
Specification
ASTM D1056-67	SCE41NEO	SCE42NEO	2#EVA	4#EVA	IV1	IV2	IV3
ASTM D1056-07	2C1	2C2	2A1/2A2	2A2/2A3	2C1	2C2	2B3
MIL-R-6130 TYP + ASTM D6576	II-A	II-A	—–	—–	11-B	11-A/B	11-A/B
GRADE CONDITION	Soft	Soft-Med	—–	—–	Soft	Soft-Med	Medium
MIL-C-3133C MIL STD 6708	SCE3 F1	SCE7 F1	—–	—–	SCE3	SCE7	SCE11
FLAMMABILITY SPECIFICATION
UL94 HF1	Pass	Pass	—–	—–	Listed	Listed	Listed
UL94 HBF	Pass	Pass	—–	—–	Pass	Pass	Pass
MIL-R-6130C	Pass	Pass	—–	—–	Pass	Pass	Pass
FMVSS-302	Pass	Pass	Pass	Pass	Pass	Pass	Pass
PHYSICAL PROPERTIES
25% Compression Deflection [psi]	2-5	5-9	4-6	9-13	2-5	5-9	9-13
Density Approximate [pcf]	9 +/-2	9 +/-2	2 +/-5	3.0-4.0	3.0-5.0	5.5-7.5	7.0-9.5
Water Absorption Max. Weight %	5	5	10	10	7	5	5
Temperature Range ^oF	-40/+150	-40/+150	-110/+220	-110/+220	-40/+200	-40/+200	-40/+200
Temperature High Intermittent^oF	200	200	240	240	225	225	225
Ozone Resistance	Fair	Fair	Excellent	Excellent	Fair	Fair	Fair
Tensile Strength [psi]	80	90	60	100	50	75	100
Fuel B Max. % Weight Change	<250	<250	n/a	n/a	<250	<250	<100
Elongation Typical Properties %	150	150	275	310	100	100	100
Durometer Shore 00 [Approx.]	45-55	50-60	—–	—–	30-45	50-60	60-70
Shrinkage 7 Days @ 158^o Max.	5%	5%	5%	5%	3%	3%	3%
K Factor	0.38	0.38	0.25	0.30	0.25	0.23	0.30

Polymer	Closed Cell Silicone Sponge
Specification
AMS			3195		3196
MIL			MIL-R-46089		MIL-R-46089
DENSITY
PHYSICAL PROPERTIES	Soft		Medium		Firm		Extra-Firm
25% Compression Deflection [psi]	5-9		6-14		12-20		16-28
Density Approximate [pcf]	31		33		40		45
Water Absorption Max. Weight %	<1%		<1%		<1%		<1%
Temperature Range ^oF	-103 / +450		-103 / +450		-103 / +450		-103 / +450
Temperature High Intermittent^oF
Ozone Resistance	Excellent		Excellent		Excellent		Excellent
Tensile Strength [psi]	Good		Good		Very Good		Very Good
Elongation Typical Properties %	Good		Good		Very Good		Excellent
Thermal Conductivity BTU	0.75		0.75		0.80		0.85
in/hr/ft³/^oF	0.75		0.75		0.80		0.85
Dielectric Strength [approx]	150 volts/mil		150 volts/mil		150 volts/mil		150 volts/mil

RUBBER

Natural & Synthetic Rubber Compounds

Natural (gum) rubber is derived from the rubber tree. Conversely, rubber-like materials produced from sources other than the rubber tree are commonly referred to as synthetic rubber.

Though there are currently more than 36 synthetic rubber compounds available, not all are commonly used. Rubber compounds have been researched and engineered to meet many application requirements, including fluid, temperature, and pressure resistance. Many synthetic rubber elastomeric materials are also available with different degrees of reinforcement, such as cloth inserted (CI) of fabric reinforced (diaphragm).

COMMON TRADE NAMES:

Nitrile [Buna-N®]
Neoprene
Silicone
FKM [Viton®]
EPDM
SBR
Fluorosilicone
and many more.

COMMON USES:

Gaskets
Diaphragms
Seals
Chute Lining
Seats
Extrusions
Door Seals

Molded Seals [Shapes]
Tubing
Bumpers
Pads
Grommets
Washers

POLYMER CHARACTERISTICS
Polymers	Acrylonitrile Butadiene Rubber	Ethylene Propylene	Fluoroelastomer	Silicone
Common Names	Buna-N®, Nitrile, NBR	EPR, EPT, EP, EPDM	Viton®, FKM	VMQ
ASTM D1418 Designation	NBR	EPDM, EPM	FKM	Q, MQ, PMQ, PVMQ
ASTM D2000 Type/Class	BF, BG, BK, CH	AA, BA, CA, DA	HK	FC, FE, GE
Mil-R-3065 [Mil-Std-417 Class	SB	RS	TB	TA

General Characteristics
Durometer Range [Shore A]	20-95	30-90	50-95	10-85
Tensile Range [psi]	200-3500	500-2500	500-2000	500-2500
Elongation Range %	350-650	100-700	400-500	450-900
Compression Set Resistance	Good to Excellent	Good	Good to Excellent	Excellent
Resilience / Rebound	Good to Excellent	Fair to Good	Poor to Fair	Good
Abrasion Resistance	Good to Excellent	Good	Fair to Good	Good
Tear Strength	Good to Excellent	Fair to Good	Fair to Good	Good
Solvent Resistance	Good to Excellent	Poor	Excellent	Poor
Oil Resistance	Excellent	Poor	Excellent	Poor
Low Temperature oF	-70	-60	-30	-75
High Temperature oF	+250	+300	+572	+500
Ozone Resistance	Fair to Good	Good to Excellent	Excellent	Excellent

Polymers	Polychloroprene	Styrene Butadiene Rubber	Fluorosilicone	Polyisobutylene
Common Names	Neoprene	SBR	FVMQ	Butyl
ASTM D1418 Designation	CR	SBR	FVMQ	IIR, BIIR, CIIR
ASTM D200 Type/Class	BA, BC	AA, BA	FK	AA, BA
Mil-R-3065 [Mil-Std-417 Class	SE	RS	TA	RS

General Characteristics
Durometer Range [Shore A]	20-95	30-95	40-80	40-90
Tensile Range [psi]	500-3000	500-2900	500-1500	500-2900
Elongation Range %	100-800	300-450	150-600	300-850
Compression Set Resistance	Poor to Good	Good to Excellent	Very Good	Fair to Good
Resilience / Rebound	Fair to Good	Good	Good	Fair to Good
Abrasion Resistance	Good to Excellent	Excellent	Poor	Fair to Good
Tear Strength	Good to Excellent	Fair to Excellent	Poor	Good
Solvent Resistance	Fair	Poor	Excellent	Poor
Oil Resistance	Fair	Poor	Good	Poor
Low Temperature ^oF	-70	-60	-100	-70
High Temperature ^oF	+250	+250	+450	+300
Ozone Resistance	Good to Excellent	Poor to Good	Excellent	Excellent

Beyond raw sheet stock, The Gund Company converts rubber into finished gaskets, seals and molded parts. Talk to a specialist about custom rubber fabrication for your application.

O-RINGS

O-Ring Sealing Solutions

They are typically installed in a groove to hold them in place while squeezed between two opposite surfaces. In most cases, O-rings are sized using the inside diameter (ID) by Cross Section (CS). O-rings are particularly effective because they have memory and want to expand to their original size and shape. So compressing them between two opposing surfaces creates an air and/or fluid-tight seal. O-rings are available in a variety of natural and synthetic rubber compounds. Depending on the application, the material chosen can significantly impact the functionality of the O-ring.

Though they are a common commodity, choosing the proper O-ring for the application can be challenging when considering thermal resistance and degradation from fluid and gases. Additionally, there are several standards for O-rings worldwide. The most common standard for North America is AS568. We understand the various mechanical properties of O-ring materials for demanding oil and gas and aerospace environments. Contact one of our material specialists today to review your applications or request a quote

O-rings are available in most polymer compounds and sizes, including AS568B [chart below], metric sizes, both molded and vulcanized endless from the O-ring cord.

REQUEST A QUOTE

APPLICATIONS:

Hydraulics
Faucets
Gaskets
Setting Tools
Frac Plugs
Carburetors
Gas Valves
Helicopters

Cross Section					Cross Section						Cross Section
	1/16	3/32	1/8	3/16		1/16	3/32	1/8	3/16	1/4		3/32	1/8	3/16	1/4
ID	(.070)	(.103)	(.139)	(.210)	ID	(.070)	(.103)	(.139)	(.210)	(.275)	ID	(.103)	(.139)	(.210)	(.275)

1/32	001*				2 3/16		139				7	167	262	365	441
3/64	002*				2 1/4	053	140	228	331		7 1/4	168	263	366	442
1/16	003	102			2 5/16		141				7 1/2	169	264	367	443
5/64	004				2 3/8	036	142	229	332		7 3/4	170	265	368	444
3/32	005	103			2 7/16		143				8	171	266	369	445

1/8	006	104			2 1/2	037	144	230	333		8 1/4	172	267	370
5/32	007	105			2 9/16		145				8 1/2	173	268	371	446
3/16	008	106	201		2 5/8	038	146	231	334		8 3/4	174	269	372
7/32	009	107			2 11/16		147				9	175	270	373	447
1/4	010	108	202		2 3/4	039	148	232	335		9 1/4	175	271	374

5/16	011	109	203		2 13/16		149				9 1/2	177	272	375	448
3/8	012	110	204		2 7/8	040	150	233	336		9 3/4	178	273	376
7/16	013	111	205	309	3	041	151	234	337		10		274	377	449
1/2	014	112	206	310	3 1/8			235	338		10 1/2		275	378	450
9/16	015	113	207	311	3 1/4	042	152	236	339		11		276	379	451

5/8	016	114	208	312	3 3/8			237	340		11 1/2		277	380	452
11/16	017	115	209	313	3 1/2	043	153	238	341		12		278	381	453
3/4	018	116	210	314	3 5/8			239	342		12 1/2				454
13/16	019	117	211	315	3 3/4	044	154	240	343		13		279	382	455
7/8	020	118	212	316	3 7/8			241	344		13 1/2				456

15/16	021	119	213	317	4	045	155	242	345		14		280	383	457
1	022	120	214	318	4 1/8			243	346		14 1/2				458
11/16	023	121	215	319	4 1/4	046	156	244	347		15		281	384	459
11/8	024	122	216	320	4 3/8			245	348		15 1/2				460
13/16	025	123	217	321	4 1/2	047	157	246	349	425	16		282	385	461

11/4	026	124	218	322	4 5/8			247	350	426	16 1/2				462
15/16	027	125	219	323	4 3/4	048	158	248	351	427	17		283	386	463
13/8	028	126	220	324	4 7/8			249	352	428	17 1/2				464
17/16		127	221		5	049	159	250	353	429	18		284	387	465
11/2	029	128	222	325	5 1/8			251	354	430	18 1/2				466

19/16		129			5 1/4	050	160	252	355	431	19			388	467
15/8	030	130	223	326	5 3/8			253	356	432	19 1/2				468
1 11/16		131			5 1/2		161	254	357	433	20			389	469
13/4	031	132	224	327	5 5/8			255	358	434	21			390	470
1 13/16		133			5 3/4		162	256	359	435	22			391	471

17/8	032	134	225	328	5 7/8			257	360	436	23			392	472
1 15/16		135			6		163	258	361	437	24			393	473
2	033	136	226	329	6 1/4		164	259	362	438	25			394	474
2 1/16		137			6 1/2		165	260	363	439	26			395	475
2 1/8	034	138	227	330	6 3/4		166	261	364	440

*Section Diameter of AS568-001 is 1/32
* Sectional Diameter of AS568-002 is 3/64

To learn more about O-Ring materials from The Gund Company or request a quote for your application, Contact Us Today!

Visit our material datasheets Section for more information.

EMI SHIELDING / THERMAL MANAGEMENT

EMI Shielding & Thermal Management Materials

EMI Shielding: Electromagnetic Interference has become far more significant in recent years as the use of electronic devices continues to increase. As the utilization of these devices continues to grow, so does the exposure to a wide range of frequencies. Through years of research and development, manufacturers have determined that electrical insulation, enclosures, and cables have proven to be effective ways to contain these frequencies.

Organizations such as the CE & FCC have provided guidelines in the form of legal requirements to prevent electromagnetic interference (noise). Because of that, EMI Shielding has become a necessity in the electronics industry. Since there is a wide variety of application designs and frequency requirements, various materials have been manufactured to provide adequate shielding.

Thermal Management: Historically, thermal grease was used to create continuity between power sources and heat sinks. Unfortunately, this grease was not ideal in applications where ease of installation and cleanliness were paramount. These days, many applications utilize thermally-conductive materials or thermal management in place of this grease.

Thermally-conductive compounds contain fillers that maintain flexibility in service while providing continuity between the mating surfaces. In electronic equipment, air acts as an insulator and must be eliminated for optimum performance. Manufacturers of electronic devices want to establish an anaerobic environment to allow continuity between the power source and heat sink for proper performance. Such thermal management products create continuity within the component to optimize the heat dissipation from the power source.

Thermal management products are used in an expansive list of applications, including generators and motors where consistent heat dissipation protects sensitive components. And so, there is an equally wide variety of thermal management options available.

The Gund Company is well versed in both EMI Shielding and Thermal Management Contact one of our material specialists today to review your applications or request a quote.

CORK / RUBBER

CORK & RUBBER PRODUCTS ARE INSTRUMENTAL IN METAL-TO-METAL JOINTS.

No allowance needs to be made for the side flow if a proper firmness material is selected. The compressibility of cork/rubber can be used in place of more expensive non-compressible rubber seals. Some of the friction of cork is retained in these products and helps to reduce extrusion and slippage.

Cork/rubber products can contain sponged materials that conform to and compensate for minor flange irregularities more easily. This characteristic is especially useful in stamped or other lightweight assemblies where the available bolt spacing and bolt load are usually low.

Cork/rubber products have an unusual resilience which helps resist compression set and other effects of fatigue. Cork-rubber seals are more resistant to aging than traditional rubber compounds.

Cork/rubber compounds are used to establish and maintain intimate contact between the flanges, a common requirement in transformer and switchgear gasketing. The most common synthetic rubber compounds are Neoprene® and Nitrile. However, special applications may use cork material blended with Hypalon®, Silicone, Fluoroelastomer, SBR, or Vamac.

COMMON BRANDS:

ECORE Intl
Amorim Cork Solutions

COMMON TYPES:

Composition Cork
Cork & Neoprene
Cork & Nitrile
Cork & Sponged Rubber

Property	Test Method	Typical Result	Typical Result	Typical Result	Typical Result
Cork & Rubber Composition
Polymer		Neoprene	Neoprene	Nitrile	EPDM – Sponge
Density [ibs/ft³]	ASTM D3676	35.7	37.5	39.9	31.5
Tensile Strength [lbs/in²]	ASTM F152	240	355	253	135
Compression @ 100 psi	ASTM F36	—-	—-	—-	35%
Compression @ 400 psi	ASTM F36	45%	29%	40%	—-
Recovery		80%	80%	82%	90%
Shore A Hardness	ASTM D2240	63	60 to 80	60 to 70	54
Flexibility	ASTM F147	3 max	3 max	3 max	3 max
Fluid Immersion	ASTM F146
Oil 1 [70 hrs @ 212^oF]		-5 to +15%	-10 to +8%	-5 to +10%	-10 to +10%
Oil 3 {70 hrs @ 212^oF]		+5 to +50%	+5 o 15%	—-	+15 to +50%
Fuel A [22 hrs @ 75^oF]		0 to +35%	0 to +15%	—-	0 to +25%
Compression Set B	ASTM D395
25% deflection, 22 hrs @ 158^oF		55% max	65% max	60% max	90% max
Temperature Range ^oF		-140 to +250	-140 to +250	-140 to +250	-140 to +250
Specification	ASTM F104	F227000 M1 T	F226000 M2 T	F227000 M2 T	F226000 M1 T
Specification	MIL-G-12803	P2255B	P2245A	P2256A	P2265A
Shelf Life		5 Years	5 Years	5 Years	5 Years

Property	Test Method	Typical Result	Typical Result	Typical Result	Typical Result
Cork & Nitrile Composition
Polymer		Nitrile	Nitrile	Nitrile	Nitrile
Density [ibs/ft³]	ASTM D3676	40.1	45.9	52.6	30.5
Tensile Strength [lbs/in²]	ASTM F152	295	325	422	120
Compression @ 100 psi	ASTM F36	25%	—–	—–	38%
Compression @ 400 psi	ASTM F36	39%	33%	24%
Recovery		81%	82%	81%	90%
Shore A Hardness	ASTM D2240	60 to 75	60 to 75	60 to 80	50
Flexibility	ASTM F147	3 max	3 max	3 max	3 max
Fluid Immersion	ASTM F146
Oil 1 [70 hrs @ 212^oF]		-5 to +10%	-5 to +10%	-5 to +10%	0 to +15%
Oil 3 {70 hrs @ 212^oF]		-2 to +15%	-2 to +20%	-2 to +15%	+10 to +30%
Fuel A [22 hrs @ 75^oF]		-2 to +10%	-2 to +10%	-2 to +10%	0 to +15%
Compression Set B	ASTM D395

Property	Test Method	Typical Result	Typical Result	Typical Result	Typical Result
Cork & Neoprene Composition
Polymer		Neoprene	Neoprene	Neoprene	Neoprene
Density [ibs/ft³]	ASTM D3676	35.6	48.4	53.1	48.4
Tensile Strength [lbs/in²]	ASTM F152	218	336	400	336
Compression @ 100 psi	ASTM F36	—–	—–	—–
Compression @ 400 psi	ASTM F36	47%	25%	26%	32%
Recovery		81%	83%	80%	83%
Shore A Hardness	ASTM D2240	61	65 to 75	60 to 80	65 to 75
Flexibility	ASTM F147	3 max	3 max	3 max	2 max
Fluid Immersion	ASTM F146
Oil 1 [70 hrs @ 212^oF]		-2 to +10%	-2 to +20%	-2 to +20%	+2 to +10%
Oil 3 {70 hrs @ 212^oF]		+5 to +30%	+15 to +50%	+15 to +50%	+10 to +50%
Fuel A [22 hrs @ 75^oF]		0 to +15%	0 to +15%	0 to +15%	0 to +15%
Compression Set B	ASTM D395
25% deflection, 22 hrs @ 158^oF		60% max	60% max	55% max	60% max
Temperature Range ^oF		-40 to +250	-40 to +250	-40 to +250	-40 to +250
Specification	ASTM F104	—–	F226000 M2 T	F224000 M2 T	F226000 M2 T
Specification	MIL-G-12803	—–	P2255A	P2254A	P2255A
Specification	AMS-C-6183	TYP 1 CL 2 GR A	TYP 1 CL 2 GR B	TYP 1 CL 2 GR C	TYP 1 CL 2 GR B
Shelf Life		5 Tears	5 Tears	5 Tears	5 Tears

Property		Typical Result
Composition Cork
Density [ibs/ft³]	ASTM D3676	15.8
Tensile Strength [lbs/in²]	ASTM F152	125
Compression @ 100 psi	ASTM F36	36%
Recovery		83%
Flexibility	ASTM F147	5 max
Specification	ASTM F104	F217000RT
Specification	MIL-G-12803	P2128A
Specification	HH-C-576B	Cl 1 TY II

To learn more about cork/rubber elastomeric materials from The Gund Company or request a quote for your application, Contact Us Today!

FELT / WOOL

NATURAL WOOL FELT IS ONE OF THE OLDEST MAN-MADE TEXTILES. MANY CULTURES HAVE LEGENDS AS TO HOW THE FELTING PROCESS WAS DISCOVERED.

One of the earliest accounts of felting details how nomads fleeing persecution packed their sandals with wool to prevent blisters while crossing the desert. At the end of their journey, the movement and sweat had turned the wool into felt socks.

Felt is a textile material that is produced by matting, condensing, and pressing fibers together. Felt can be made of natural fibers such as wool or animal fur or synthetic fibers such as petroleum-based acrylic or acrylonitrile, or wood-based rayon. Blended fibers are also common. Felt has special properties that allow it to be used for a wide variety of purposes. It is fire-retardant and self-extinguishing; it dampens vibration and absorbs sound, and it can hold large amounts of fluid without feeling wet.

Felt from wool is considered to be the oldest known textile. Many cultures have legends as to the origins of felt making. Sumerian legend claims that Urnamman of Lagash discovered the secret of felt making. The stories of Saint Clement and Saint Christopher relate that the men packed their sandals with wool to prevent blisters while fleeing from persecution. At the end of their journeys, the movement and sweat had turned the wool into felt socks.

Today’s pressed wool felt is made via an intricate process often referred to as “wet processing.” Fibers are worked together by applying pressure, moisture, and vibration, then carded and cross-lapped to make multiple material layers. The material’s ultimate thickness and density determine the number of layers that are then steamed, wetted, pressed, and hardened.

In the wet felting process, hot water is applied to layers of animal hairs. Repeated agitation and compression cause the fibers to hook together or weave together into a single fabric piece. Wrapping the properly-arranged fiber in sturdy, textured material such as a bamboo mat or burlap will speed up the felting process. The felted material may be finished by fulling.

Specifications: SAE/C-F-206G

Most fiber used in pressed felt is wool. Wool fibers have small barbs on them, which aid in the natural locking or felting process. The manufacturing of pressed wool felt is primarily mandated by SAE standards. These standards determine the wool content, density, and other physical and mechanical properties of the felt. Pressed wool felt is identified by the SAE standards F-1 thru F-26.

The lower the SAE numbers will be more machinable, have better vibration absorption, and have better abrasion resistance. Wool felt has excellent wicking properties. It can absorb its weight in oil several times, and when used as a lubrication wick, it will supply small amounts of oil at a uniform rate in motor and generator bearing applications. Pressed wool felt has excellent solvent resistance and stability in oil. SAE wool felt is unaffected by sunlight and maintains its original form after long periods of stress.

COMMON TYPES:

Wool
Polyester
High Temperature

COMMON TRADE NAMES:

NOMEX®

APPLICATIONS:

Gaskets
Wicking
Dust Shields
Grease Retainer

Sound Reduction
Wipers
Weather Stripping
Pads

US Federal Specification C-F-206G

Type 1 Roll Felt SAE No.	F-1	F-2	F-3	F-5	F-7	F-10	F-11
Classification No.	16R1	16R2	16R3	12R1	12R3	9R1	9R2
Wool Content %	95	90	85	95	80	95	87
Chlorothene Solubles %	2.5	2.5	2.5	2.5	4.0	2.5	3.0
Water Solubles %	2.5	2.5	3.0	2.5	4.0	2.5	2.5
Total Solubles %	3.0	4.0	4.5	3.0	7.0	3.0	4.5
Ash Content %	1.5	2.0	2.5	2.0	3.0	2.5	3.0
Tensile Strength psi	500	500	400	250	225	200	75
Slit Resistance psi	33	28	22	18	12	8	6
Width (inch)	60	60	60/72	60	72	72	72
Color	White	Pink	Gray	White	Gray	White	Gray

Type 1 Roll Felt SAE No.	F-13	F-15N	F-26N	F-50	F-51	F-55
Classification No.	9R4	9R5	8R5	16R1X	16R3X	12R3X
Wool Content %	75	55	45	95	92	75
Chlorothene Solubles %	4.0	4.0	8.0	2.5	2.5	4.0
Water Solubles %	4.0	5.0	6.0	2.5	2.5	4.0
Total Solubles %	8.0	9.0	14.0	3.0	4.5	8.0
Ash Content %	3.5	4.0	5.0	1.5	2.5	3.0
Tensile Strength psi	75	75	75	500	300	200
Slit Resistance psi	2	2	2	33	22	12
72	72	72	72	60	60/72	72
Color	Gray	Gray	Gray	White	Gray	Gray or Black

FELT / POLYESTER

POLYESTER FELT IS A SYNTHETIC, NEEDLE-PUNCHED FELT MADE FROM POLYESTER FIBERS.

Material is normally supplied in either black or white. This general-purpose felt is made in various densities with thicknesses ranging from .019” to 2”.

Polyester felt is fairly inexpensive and often made in comparable density and thickness to SAE-pressed wool felt. The maximum temperature of polyester felt is 300°F, compared to 200°F for SAE-pressed felts. This material is commonly used for filtration applications, gaskets, wipers, and padding in various industries. The density of polyester felt is commonly measured in ounces per sq. yd.

Polyester felt is normally supplied in either black or white, in various densities and thicknesses ranging from .019” to 2.0”.

APPLICATIONS:

Filtration
Gaskets
Weatherstripping
Wipers
Crate lining
Padding

The Gund Company holds ISO 9001:2015 and AS9100D quality certifications across its manufacturing locations, and every elastomeric material family on this page, from foam and sponge to felt, is backed by the same specification and quality documentation available on request.

Need help specifying the right elastomeric material? Contact our material specialists or request a quote to get started.

Visit our material datasheets Section for more information.

FAQs

What is an elastomeric material?

An elastomeric material is any material that exhibits elastic, rubber-like properties, meaning it can be stretched or compressed and return to its original shape. The Gund Company fabricates elastomeric materials in foam, sponge, solid rubber, O-ring, EMI shielding, cork and rubber blend, and felt forms.

What is the difference between elastomeric foam and sponge?

Foam is a lightweight, open-cell material where air moves through connected cells, making it well suited to insulation, filtration and cushioning. Sponge is an expanded rubber-based material with closed, unconnected cells, which keeps it from absorbing liquid and gives it superior mechanical properties compared to foam.

How do I choose the right elastomeric material for my application?

Selection comes down to material type, compound and durometer (hardness), matched against your application’s temperature range, chemical exposure, compression and sealing requirements. The Gund Company’s material specialists can review your application and recommend a compound backed by ASTM and MIL specification data.

What industries use elastomeric materials from The Gund Company?

Elastomeric materials from The Gund Company are used across aerospace, power electronics, generators, motors, transformers, metals processing, electric vehicles, oil and gas, and medical applications, wherever sealing, cushioning, EMI shielding or thermal management is required.

Do you offer custom elastomeric material fabrication?

Yes. Beyond material selection, The Gund Company converts and fabricates elastomeric materials into finished parts, including die-cut gaskets, molded seals, O-rings and custom shapes, through its in-house fabrication and converting capabilities.

What specifications do The Gund Company's elastomeric materials meet?

Depending on the material and compound, elastomeric products are manufactured and tested to specifications including ASTM D1056, ASTM D2000, ASTM D1418, MIL-R-6130, MIL-C-3133C and SAE felt standards F-1 through F-26. Request a quote to confirm the specification for your specific application.