High-vacuum Sealants | McMaster-Carr

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Krytox™ 240AB Type II

Krytox™ 240AZ Type I

Molykote High Vacuum Grease

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25 Products

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Vacuum Leak Sealants

Seal leaks on vacuum systems and components.

Epoxy resin sealants, also known as Torr Seals, form a rigid bond.

Bentonite/petrolatum sealants, also known as Apiezon sealants, form a flexible, non-hardening seal that’s easy to remove and reposition.

Sealants

Container
Size	Type	Begins to Harden	Reaches Full Strength	Vacuum Rating, torr	Maximum Vacuum @ Temperature	Tensile Strength, psi	Hardness	Mix Ratio	Temp. Range, °F	For Joining	Color		Each
Epoxy Resin
2 fl. oz.	Cartridge	60 min.	3 days	Ultra High	10 ^-9 torr @ 72° F	5,000	Extra Hard (Durometer 75D)	2:1	-45° to 245°	Metal, Glass, Masonry	Off-White	0000000	0000000
4.2 fl. oz.	Tube	60 min.	3 days	Ultra High	10 ^-9 torr @ 72° F	5,000	Extra Hard (Durometer 75D)	2:1	-45° to 245°	Metal, Glass, Masonry	Off-White	0000000	000000
Bentonite/Petrolatum
2.2 lbs.	Can	5 min.	1 hrs.	High	10 ^-4 torr @ 72° F	Not Rated	Not Rated	__	15° to 85°	Metal, Plastic, Glass	Gray	0000000	000000

Sealants with Dispensing Gun

Container
Size, fl. oz.	Type	Begins to Harden	Reaches Full Strength	Vacuum Rating, torr	Maximum Vacuum @ Temperature	Tensile Strength, psi	Hardness	Mix Ratio	Temp. Range, °F	For Joining	Color		Each
Epoxy Resin
2	Cartridge	60 min.	3 days	Ultra High	10 ^-9 torr @ 72° F	5,000	Extra Hard (Durometer 75D)	2:1	-45° to 245°	Metal, Glass, Masonry	Off-White	0000000	0000000

Dispensing Gun

Loading Method	For Cartridge Size	Material		Each
Cartridge	2 oz.	Plastic	0000000	0000000

Low-Outgassing Silicone Sealants

Compliant with ASTM E-595, these sealants produce almost no volatile materials in a vacuum. They’re made of silicone, so they’re RTV (room-temperature vulcanizing).

Elongation indicates flexibility—the higher the value is, the more a sealant can stretch.

Container
Size, fl. oz.	Type	Begins to Harden	Reaches Full Strength	Elongation	Joint Compression/ Expansion Tolerance	Tensile Strength, psi	Hardness	Temp. Range, °F	Specifications Met	For Joining	Color		Each
5.8	Cartridge	150 min.	7 days	420%	-25% to 25%	600	Durometer 36A (Medium Soft)	-200° to 500°	ASTM E595	Metal Plastic Rubber Composites Glass	White	0000000	0000000

High-Vacuum Seal and O-Ring Grease

A firm consistency and resistance to evaporation make this grease ideal for high-vacuum applications, such as flow meters, vacuum and pressure systems, and laboratory equipment. Apply directly to seals and O-rings to prevent drying and cracking.

NLGI viscosity grade is a rating of a grease's consistency. NLGI 1 is about the consistency of tomato paste. NLGI 2 is about the consistency of peanut butter. NLGI 3 is about the consistency of vegetable shortening and is comparable to Fomblin grease. NLGI 3.5 is between the consistency of vegetable shortening and frozen yogurt.

Grease with PTFE thickener resists aggressive acids, bases, and solvents. Chemours Krytox™ 240 grease is long lasting with an indefinite shelf life.

Grease lubricates most efficiently below the maximum temperature. Melting temperature is the point at which grease will fail and run out of equipment, leaving it to run dry. Nonmelting grease can be used at temperatures above the maximum temperature briefly, but then will break down more quickly.

Each

		Container
NLGI Viscosity Grade	Base Oil	Size, fl. oz.	Net Weight, lbs.	Type	Temp. Range, °F	Melting Temp., °F	Maximum Vacuum @ Temperature	Color	Specifications Met		Each
DuPont Molykote High Vacuum Grease—Silica Thickener
3.5	Synthetic	__	8	Pail	-40° to 400°	Nonmelting	10 ^-6 torr @ 72° F	White	__	0000000	0000000
3.5	Synthetic	5.3	__	Tube	-40° to 400°	Nonmelting	10 ^-6 torr @ 72° F	White	__	0000000	00000
Chemours Krytox™ 240AB Type II—PTFE Thickener
2	Synthetic	1/2	__	Tube	-40° to 450°	Not Rated	10 ^-6 torr @ 100° F	White	MIL-PRF-27617	00000000	00000
2	Synthetic	2	__	Tube	-40° to 450°	Not Rated	10 ^-6 torr @ 100° F	White	MIL-PRF-27617	00000000	000000
Chemours Krytox™ 240AZ Type I—PTFE Thickener
1	Synthetic	1/2	__	Tube	-70° to 300°	Nonmelting	10 ^-4 torr @ 100° F	White	MIL-PRF-27617	00000000	00000
1	Synthetic	2	__	Tube	-70° to 300°	Nonmelting	10 ^-4 torr @ 100° F	White	MIL-PRF-27617	00000000	000000
PTFE Thickener
3	Synthetic	3 1/2	__	Tube	0° to 480°	525°	10 ^-4 torr @ 72° F	White	__	0000000	000000

Package

		Container
NLGI Viscosity Grade	Base Oil	Size, fl. oz.	Type	Temp. Range, °F	Melting Temp., °F	Maximum Vacuum @ Temperature	Color	Pkg. Qty.		Pkg.
DuPont Molykote High Vacuum Grease—Silica Thickener
3.5	Synthetic	5.3	Tube	-40° to 400°	Nonmelting	10 ^-6 torr @ 72° F	White	12	00000000	0000000

Low-Outgassing Sealing Tape

Tested to meet ASTM E595, a standard used by NASA, this tape seals gaps while releasing almost no volatile emissions that could damage sensitive electronics, even in a vacuum. The Tedlar backing resists chemicals and wear. And thanks to its acrylic adhesive, this tape will stay put—even when exposed to pulling forces and solvents.

Certificates with a traceable lot number and product shelf life are available for these products. Download certificates from ORDER HISTORY after your order ships.

3M 838
Wd.	Lg., ft.	Overall Thick.	Material	Adhesive Type	Temperature Range, °F	Tensile Strength, lbs./in. wd.	Adhesion to Steel, oz./in. wd.	Specifications Met	Color		Each
1"	216	0.004"	Tedlar PVF Plastic	Acrylic	-100° to 225°	24	47	ASTM E595	White	0000000	0000000

Glue-on-a-Roll

Apply this glue-like tape for a no-mess alternative to liquid adhesives, hot melts, and staples. Also known as adhesive transfer tape, these rolls have a thin film of pressure-sensitive glue on a peel-away liner. They are thinner and more conformable than tape with adhesive on both sides.

467MP and 468MP resist solvents and UV rays.

Rolls that meet ASTM E595, a standard set by NASA, will produce almost no volatile emissions, even in a high vacuum. They’re a great choice for use around sensitive electronics. They’ve even been used in space simulations.

3M Glue
Mfr. Model No.	Wd.	Lg., yd.	Thick.	Temp. Range, °F	Color	Specifications Met	For Joining		Each
467MP	1/2"	60	0.002"	Not Rated to 300°	Clear	ASTM E595	Metal, Plastic, Rubber	0000000	000000
467MP	3/4"	60	0.002"	Not Rated to 300°	Clear	ASTM E595	Metal, Plastic, Rubber	0000000	00000
467MP	1"	60	0.002"	Not Rated to 300°	Clear	ASTM E595	Metal, Plastic, Rubber	0000000	00000
467MP	2"	60	0.002"	Not Rated to 300°	Clear	ASTM E595	Metal, Plastic, Rubber	00000000	00000
467MP	3"	60	0.002"	Not Rated to 300°	Clear	ASTM E595	Metal, Plastic, Rubber	00000000	00000

High-Strength Glue-on-a-Roll

The 3M VHB adhesive on these rolls offers a strong hold that can replace rivets, spot welds, and other permanent fasteners. Also known as adhesive transfer tape, these rolls have a thin film of pressure-sensitive glue on a peel-away liner. They’re more conformable than tape with adhesive on both sides.

Rolls that meet ASTM E595, a standard used by NASA, release almost no volatile emissions that could damage sensitive electronics, even in a vacuum.

Certificates with a traceable lot number and product shelf life are available for these products. Download certificates from ORDER HISTORY after your order ships.

3M Glue
Mfr. Model No.	Wd.	Lg., yd.	Thick.	Max. Temp., °F	Color	Specifications Met	For Joining		Each
F9460PC	1/2"	60	0.002"	300°	Clear	ASTM E595	Ceramic, Composites, Glass, Metal	0000000	000000
F9460PC	3/4"	60	0.002"	300°	Clear	ASTM E595	Ceramic, Composites, Glass, Metal	0000000	00000
F9460PC	1"	60	0.002"	300°	Clear	ASTM E595	Ceramic, Composites, Glass, Metal	0000000	00000
F9460PC	1 1/4"	180	0.002"	300°	Clear	ASTM E595	Ceramic, Composites, Glass, Metal	0000000	000000

Low-Outgassing Optically Clear Two-Part Silicone Potting Compounds

Tested to meet ASTM E595, a standard used by NASA, these compounds produce almost no volatile emissions that could damage sensitive electronics, even in a vacuum. Light passes through them easily, so they’re ideal for protecting solar cells and fiber optics. Made of silicone, these compounds are softer and more flexible than epoxy and urethane compounds. That means they’re better at protecting against shocks and vibration. They also withstand a wider range of temperatures, so you can use them with electronics that heat and cool rapidly. These compounds are excellent electrical insulators, and they’ll shield your components from moisture and dust. However, they don’t hold up well to chemicals or scrapes. They’re also known as RTV (room-temperature vulcanizing).

These compounds are easy to apply in high volumes. Just mix the two parts together and pour them over components inside a container, such as a potting box.

		Dry Time
Container Size, oz.	Consistency	Touch, hrs.	Overall, hrs.	Hardness Rating	Dielectric Strength, V/mil	Thermal Conductivity, W/m-K	Temp. Range, °F	Specifications Met	For Use On	Color		Each
4.1	Thick Liquid	3	24	Medium Soft	475	0.2	-45° to 390°	ASTM E595	Aluminum, Brass, Bronze, Copper, Steel, Iron, Silver, Fiberglass, Glass	Clear	0000000	000000000