12 Caps | McMaster-Carr

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29 Products

About Pipe and Fittings

Measure your pipe and fittings to identify their pipe size, thread size, schedule, and thread type. Then, find compatible components.

Low-Pressure Stainless Steel Butt-Weld Pipe Fittings

Also known as Schedule 10 fittings, these are thin and lightweight. They have beveled ends that, when flush to pipe, create a trough for a strong weld that permits maximum flow.

Caps

Butt Weld

304/304L Stainless Steel—Fittings hold up in humid, damp, and washdown environments but will corrode if exposed to salt water or chemicals.

316/316L Stainless Steel—Fittings are the most corrosion resistant. They stand up to wet environments, just like 304 stainless steel fittings, but unlike 304 stainless steel, they will not corrode from salt water, chlorine solutions, and chemicals.

					304/304L Stainless Steel		316/316L Stainless Steel
	Pipe Size	Construction	OD	Pipe Schedule		Each		Each
Butt Weld



		12	Welded	12 3/4"	10	45735K621	0000000	43645K459	0000000

Stub-End Straight Adapters

Straight Adapter

Stub-end straight adapters are used with flanges. Slide a flange onto the stub end and weld the stub end to pipe (not the flange). Since the flange isn’t welded to the pipe, it can be disconnected easily, which creates an access point for frequent cleaning and inspecting.

				316/316L Stainless Steel
Pipe Size	Flange OD	Construction	Pipe Schedule		Each
12	15"	Welded	10	43645K462	0000000

Adhesive-Back Caps for Pipe Flanges

Stick these caps onto the raised face of flanges to prevent nicks and scratches during shipping and storage. They stay in place until you peel them off and leave no residue behind.

Polyethylene—These tough caps are hard and wear resistant to hold up against scrapes and gouges.

	Max. Temp., ° F	Color	Adhesive Material	Pkg. Qty.		Pkg.
Polyethylene







	For ANSI Flanges

	12	15"	Rigid	160	Black	Rubber	1	3445T26	000000

Drain, Waste, and Vent PVC Clamp-On Pipe Fittings for Water

To make installing and maintaining systems easy, these connectors come with clamps that form a strong seal on pipe and fittings once tightened.

Warning: Never use plastic pipe fittings, flanges, and pipe with compressed air or gas.

Caps

Clamp-On Pipe End

	For Pipe OD	Material	Max. Pressure @ Temp.	Clamp Material		Each
Clamp-On Pipe End



	12	12 3/4"	PVC	4 psi @ 72° F	300 Series Stainless Steel	4511K115	000000

Rubber Drain Pipe Plugs

Seal unthreaded pipe ends with these plugs. They come with a band that clamps over the outside wall of your pipe and tightens with a screwdriver.

Plugs

	For Pipe OD	Max. Water Back Pressure, ft. of head	Max. Air Back Pressure	Material		Each
Clamp-On Female



	12	12.20" to 12.80"	10	Not Rated	Neoprene	2394K22	0000000

Standard-Wall Plastic Pipe Fittings for Water

Connect these fittings to Schedule 40 plastic pipe–they are the industry standard for residential and commercial low-pressure plumbing and water supply applications. They are plastic for good corrosion resistance.

To prevent leaks in threaded connections, apply a sealant to the male threads. Threaded connections can be taken apart as needed for maintenance and repair. For metal threads, use PTFE tape. For plastic threads, apply a non-hardening, plastic-compatible sealant. Tape or sealants with PTFE are not recommended for plastic-to-plastic connections. When making a threaded connection be careful not to overtighten the threads. To prevent cracks and leaks, finger tighten the fitting, then wrench-tighten one to two turns.

Warning: Never use plastic pipe fittings, flanges, and pipe with compressed air or gas.

Note: For fittings that are not rated for pressure, you can use the pressure rating of the plastic pipe as a reference. Threaded fittings are limited to 50% of the rated pressure of the pipe.

Caps

Cement Socket

Female

Cement-Socket Fitting Connection—Attach socket-connect ends to unthreaded pipe or another socket-connect fitting with a PVC primer and cement (also known as solvent weld).

NSF/ANSI 61—To adhere to safety standards for drinking water systems, use pipe that meets NSF/ANSI 61.

	Pipe Schedule	Material	Color	Max. Pressure @ Temp.	Food Industry Std.		Each
Cement Socket Female



	12	40	PVC	White	Not Rated	NSF/ANSI 61	4880K299	0000000

Low-Pressure Iron and Steel Unthreaded Pipe Flanges

Bolt two flat-surface flanges or two raised-surface flanges of the same size together with a gasket (sold separately) to create an access point in a pipe line. Flanges are for use with low-pressure applications in noncorrosive environments.

Flanges

Stub-End Flange with Straight

Adapter: Front


Butt Weld: Front	Butt Weld: Raised Surface on Back	Slip-On Weld: Front	Slip-On Weld: Raised Surface on Back	Stub End: Flat Surface on Back

Butt-Weld Fitting Connection—Butt-weld flanges are also known as weld-neck flanges; the flange neck has a beveled end that, when flush to pipe, creates a trough for a strong weld.

Slip-on-Weld Fitting Connection—Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.

Stub-End Fitting Connection—Stub-end flanges are also known as lap-joint flanges. Use them with a stub-end straight adapter (not included). The stub-end straight adapter slides into the flange and welds to pipe (not the flange). Since the flange isn’t welded to the pipe, it can be disconnected easily for frequent cleaning and inspecting.

	Pipe Size					Bolt Hole
	(A)	(B)	Flanged Connection Surface (B)	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.		Each
Butt Weld



		12	12	Raised	19"	7/8"	1"	12	17"	150	Steel	285 psi @ 72° F	150 psi @ 300° F	68095K58	0000000


		Slip-On Weld Female



				12	12	Raised	19"	7/8"	1"	12	17"	150	Steel	285 psi @ 72° F	150 psi @ 300° F	68095K54	000000


				Stub-End Female



						12	12	Flat	19"	7/8"	1"	12	17"	150	Steel	285 psi @ 72° F	150 psi @ 300° F	68095K56	000000

Blind Flanges


Front	Raised Surface on Back

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

					Bolt Hole
	Pipe Size	Flanged Connection Surface	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.		Each
Flanged



		12	Raised	19"	7/8"	1"	12	17"	150	Steel	285 psi @ 72° F	150 psi @ 300° F	68095K61	0000000

Thick-Wall Plastic Pipe Fittings for Water

Connect these fittings to Schedule 80 pipe. With thicker, stronger walls than standard-wall fittings, they can handle heavy duty supply applications, such as water processing, wastewater treatment, and irrigation. Fittings are plastic for good corrosion resistance. They meet ASTM specifications and testing requirements for material quality.

Warning: Never use plastic pipe fittings, flanges, and pipe with compressed air or gas.

Note: For fittings that are not rated for pressure, you can use the pressure rating of the plastic pipe as a reference. Threaded fittings are limited to 50% of the rated pressure of the pipe.

Caps

Cement Socket

Female

Cement-Socket Fitting Connection—Attach socket-connect ends to unthreaded pipe or another socket-connect fitting with a PVC primer and cement (also known as solvent weld).

NSF/ANSI 61—To adhere to safety standards for drinking water systems, use pipe that meets NSF/ANSI 61.

	Pipe Schedule	Material	Color	Max. Pressure @ Temp.	Food Industry Std.		Each
Cement Socket Female



	12	80	PVC	Dark Gray	Not Rated	NSF/ANSI 61	4881K018	0000000

Low-Pressure Stainless Steel Unthreaded Pipe Flanges

Bolt two flat-surface flanges or two raised-surface flanges of the same size together with a gasket (sold separately) to create an access point in a pipe line.

Forged Flanges

Stub End with

Straight Adapter

(Front)


Front	Front

Forged flanges have better strength than cast flanges.

Butt-Weld Fitting Connection—Butt-weld flanges are also known as weld-neck flanges; the flange neck has a beveled end that, when flush to pipe, creates a trough for a strong weld.

Slip-on-Weld Fitting Connection—Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.

304/304L Stainless Steel—Flanges hold up in humid, damp, and washdown environments but will corrode if exposed to salt water or chemicals.

316/316L Stainless Steel—Flanges are the most corrosion resistant. They stand up to wet environments, just like 304 stainless steel flanges, but unlike 304 stainless steel, they will not corrode from salt water, chlorine solutions, and chemicals.

	Pipe Size					Bolt Hole					304/304L Stainless Steel		316/316L Stainless Steel
	(A)	(B)	Flanged Connection Surface (B)	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Max. Pressure @ Temp.		Each		Each
Butt Weld



		12	12	Raised	19"	7/8"	1"	12	17"	150	230 psi @ 72° F	44685K325	0000000	———	0


		Slip-On Weld Female



				12	12	Raised	19"	7/8"	1"	12	17"	150	230 psi @ 72° F	44685K323	000000	44695K252	0000000


				Stub End



						12	12	Flat	19"	7/8"	1"	12	17"	150	230 psi @ 72° F	44685K327	000000	44695K256	000000

Forged Blind Flanges


Front	Raised Surface on Back

Forged flanges have better strength than cast flanges.

304/304L Stainless Steel—Flanges hold up in humid, damp, and washdown environments but will corrode if exposed to salt water or chemicals.

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

					Bolt Hole					304/304L Stainless Steel		316/316L Stainless Steel
	Pipe Size	Flanged Connection Surface	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Max. Pressure @ Temp.		Each		Each
Flanged



		12	Raised	19"	7/8"	1"	12	17"	150	230 psi @ 72° F	44685K329	0000000	44695K258	0000000

Stub-End Straight Adapters

Straight Adapter

					304/304L Stainless Steel		316/316L Stainless Steel
Pipe Size	Wall Thk.	Flange OD	Construction	Pipe Schedule		Each		Each
12	—	15"	Welded	10	———	0	43645K462	0000000
12	0.156"	15"	Welded	10	45735K623	0000000	———	0

High-Pressure Iron and Steel Unthreaded Pipe Flanges

Forged for extra strength, these heavy duty flanges can withstand high-pressure applications. Bolt two flat-surface flanges or two raised-surface flanges of the same size together with a gasket (sold separately) to create an access point in a pipe line.

Forged Flanges


Slip-On Weld (Front)	Slip-On Weld (Raised Surface on Back)

Forged flanges have better strength than cast flanges.

Slip-on-Weld Fitting Connection—Slip-on weld flanges have no internal stop; slide a pipe through the flange and weld on both sides.

	Pipe Size					Bolt Hole
	(A)	(B)	Flanged Connection Surface (B)	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.		Each
Slip-On Weld Female



		12	12	Raised	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300	Steel	600 psi @ 72° F	300 psi @ 300° F	6806K414	0000000

Forged Blind Flanges


Front	Raised Surface on Back

Forged flanges have better strength than cast flanges.

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

					Bolt Hole
	Pipe Size	Flanged Connection Surface	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Max. Pressure @ Temp.	Max. Steam Pressure @ Temp.		Each
Flanged



		12	Raised	20 1/2"	1 1/4"	1 1/4"	16	17 3/4"	300	Steel	600 psi @ 72° F	300 psi @ 300° F	6806K421	0000000

Thick-Wall Plastic Pipe Flanges for Water

Also known as Pressure Class 150 flanges, these flanges have thick, strong walls to handle heavy duty industrial plumbing and water supply applications, such as water processing, waste water treatment, and irrigation. They meet NSF/ANSI 61 for drinking water. Bolt two same-size flanges together with a gasket (sold separately) to create an access point within a line. All are PVC, which has good corrosion resistance. Some are also glass filled for extra durability. They meet ASTM D1784 specifications and testing requirements for material quality.

Warning: Never use plastic pipe fittings, flanges, and pipe with compressed air or gas.

Flanges

NSF/ANSI 61—To adhere to safety standards for drinking water systems, use pipe that meets NSF/ANSI 61.

	Pipe Size					Bolt Hole
	(A)	(B)	Flanged Connection Surface (B)	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Color	Food Industry Std.		Each
Cement Socket Female



		12	12	Raised	19"	7/8"	1"	12	17"	150	PVC	Dark Gray	NSF/ANSI 61	4881K103	0000000

Pipe Cement

		Each
Pipe Cement for Pipe SIze Greater Than 6 (8-fl. oz. Can)	74605A921	000000

Rotating Flanges

Rotating flanges are also known as Van Stone flanges; they swivel for easy bolt hole alignment.

NSF/ANSI 61—To adhere to safety standards for drinking water systems, use pipe that meets NSF/ANSI 61.

	Pipe Size					Bolt Hole
	(A)	(B)	Flanged Connection Surface (B)	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Color	Food Industry Std.		Each
Cement Socket Female



		12	12	Raised	19"	7/8"	1"	12	17"	150	PVC	Dark Gray	NSF/ANSI 61	4881K106	0000000

Pipe Cement

		Each
Pipe Cement for Pipe SIze Greater Than 6 (8-fl. oz. Can)	74605A921	000000

Blind Flanges

NSF/ANSI 61—To adhere to safety standards for drinking water systems, use pipe that meets NSF/ANSI 61.

					Bolt Hole
	Pipe Size	Flanged Connection Surface	Flange OD	For Bolt Dia.	Dia.	No. Of	Bolt Circle Dia.	Pressure Class	Material	Color	Food Industry Std.		Each
Flanged



		12	Raised	19"	7/8"	1"	12	17"	150	PVC	Light Gray	NSF/ANSI 61	4881K109	0000000

Air-Inflatable Plugs

Conform to wide and out-of-round pipes with these inflatable plugs. Also known as pneumatic plugs, they're designed for temporary seals since they can lose pressure over time. They’re better for lower-pressure applications than water-inflatable plugs. Inflate them with a hand pump; an air compressor may overinflate the plug and cause damage.

Plugs with a chain or eyebolt can be tethered through either so they don't get lost or stuck in your pipes during installation. For easy removal once testing is complete, pull on your tether.

With Zinc-Plated Steel Eyebolt

Ribbed

Body

Ribbed Body—Plugs with a ribbed texture have better traction against pipe walls than plugs with a smooth texture. When sealing oily or polished walls, they’ll resist slipping.

Maximum Air Back Pressure—Maximum air back pressure is the amount of pressure a plug can withstand without moving.

Maximum Water Back Pressure—Maximum water back pressure refers to the pressure resulting from the height of the water above the plug.

For Pipe		Deflated		Max. Back Pressure
Size	ID	Dia.	Ht.	Air, psi	Water, ft. of head	Req. Inflation Pressure, psi	Temp. Range, ° F	Seal Material	Body Texture		Each
12	10.50" to 12.25"	10 1/4"	13 3/4"	17	40	25	-20 to 125	Natural Rubber	Ribbed	3058K9	0000000

Air-Inflatable Plugs with Bypass

Conform to wide and out-of-round pipes with these inflatable plugs. Also known as pneumatic plugs, they're designed for temporary seals since they can lose pressure over time. Use the bypass tube on these plugs to add air, water, and other fluid to your pipeline or to relieve pressure while testing.

Inflate with a hand pump (sold separately); an air compressor may overinflate the plug and cause damage. Tether the plugs using either the eyebolt or chain/ring so they don't get lost or stuck in your pipes during installation. Pull on the tether for quick and easy removal once testing is complete.

With Zinc-Plated Steel Eyebolt

Maximum Air Back Pressure—Maximum air back pressure is the amount of pressure a plug can withstand without moving.

Maximum Water Back Pressure—Maximum water back pressure refers to the pressure resulting from the height of the water above the plug.

For Pipe		Deflated		Max. Back Pressure			Bypass
Size	ID	Dia.	Ht.	Air, psi	Water, ft. of head	Req. Inflation Pressure, psi	Pipe Size	Thread Type	Gender	Temp. Range, ° F	Seal Material		Each
12	10.50" to 12.25"	10 1/4"	13 3/4"	13	30	35	3	NPT	Female	-20 to 125	Natural Rubber	2580K14	0000000

Expansion Plugs with Bypass

Style C

Use the bypass tube on these plugs to add air, water, and other fluid to your pipeline or to relieve pressure while testing. The seal expands to temporarily close off pipe openings.

Style C—For Style C, twist the wing nut to expand the seal. They have an NPT threaded bypass for making leak-tight connections.

Maximum Air Back Pressure—Maximum air back pressure is the amount of pressure a plug can withstand without moving.

Maximum Water Back Pressure—Maximum water back pressure refers to the pressure resulting from the height of the water above the plug.

	For Pipe		Max. Back Pressure				Material		Bypass
	Size	ID	Air	Water, ft. of head	Overall Ht.	Temp. Range, ° F	Seal	Bypass Cap	Pipe Size	Thread Type	Gender		Each
Style C







				Iron Stem

				12	11.50" to 12.00"	Not Rated	4	14 5/8"	30 to 150	Natural Rubber	Metal	1	NPT	Male	2644K32	0000000