ProStar™ Seam Welders

Built with Valuable Features for Faster Changeovers and Superior Quality

ProStar™ longitudinal seamers are available in either external or internal/flat sheet models. They are specifically designed for 100 percent penetration, single-pass welds on cylinders and flat sheets while minimizing or eliminating heat distortion to the material. ProStar seamers are typically used for butt welds. With slight modifications certain corner joints, such as cones, bowed shapes and lap welds can be welded efficiently.

Innovative Features

  • Buildup of magnetism is minimized through a unique design that can reduce or even eliminate arc blow
  • Cantilevered design at one end allows loading and unloading of cylinders or other closed sections that require a longitudinal seam
  • ProStar seamers provide exceptional visibility around the weld head and work area

Available Options

  • Replaceable copper tipped fingers
  • Replaceable stainless steel tipped fingers
  • Stainless steel backup bar
  • Water cooler
  • Powered elevation
  • Side beam track extension
  • Power cable support track
  • Powered end latch
  • Automatic pneumatic seam alignment gauges
  • Vertical seamers
  • Cars and conveyors
  • Computerized controls
  • Rotating mandrels
  • Oscillation
  • Automatic voltage control
  • Wire feeding
  • Video
  • Seam tracking
  • Slides
  • Carriages
  • Remote mounting of reels or flux delivery and recovery systems
  • Torch lead/lag brackets
  • Weld head mountings
  • Gas backup bars
  • Fume exhaust mounting
  • Solid strip fingers
  • Adjustable mandrels
  • Pneumatic torch lift
  • Patented rocking backup bar
Praxair ProStar Seam Welders

Quick-Change Rocking Backup Bar

  • Patented design minimizes downtime when changing back-up bars. Ideal for situations where seamers are run continuously, or for welding different materials and materials of different thicknesses.

Standard Equipment

  • Copper back-up bar with backup groove machined to customer specifications
  • Water-cooled mandrel
  • Two seam alignment gauges
  • Variable pressure aluminum finger clamping system
  • Safety air-interlock on mandrel latch
  • Machined side beam track
  • Rack and pinion carriage travel

External Seamers 


Weld Length Clamping LengthWorkpiece Dimensions (ID - OD)Material ThicknessFootprint Mandrel Height Approx. Shipping Weight 
PRS24E3530
24 in. 30 in. 3.5 in. - 30 in. .020 in. - 3/8 in. 73 in. x 335/16 in. x 651/16 in. 37 in. 2,400 lbs. 
PRS36E353036 in. 42 in. 3.5 in. - 30 in. .020 in. - 3/8 in. 86 in. x 335/16 in. x 651/16 in. 37 in. 2,500 lbs.
PRS48E423048 in. 54 in. 4.2 in. - 30 in. .020 in. - 3/8 in.98 in. x 345/16 in. x 657/16 in. 37 in.2,800 lbs.
PRS60E523060 in. 66 in. 5.2 in. - 30 in. .020 in. - 3/8 in.110 in. x 345/16 in. x 657/16 in. 37 in. 3,600 lbs.
PRS72E63672 in. 78 in. 6 in. - 36 in. .020 in. - 3/8 in.122 in. x 347/16 in. x 717/16 in. 43 in. 4,000 lbs.
PRS96E83696 in. 102 in. 8 in. - 36 in. .020 in. - 3/8 in.149 in. x 347/16 in. x 717/16 in. 43 in. 5,500 lbs.
PRS120E936120 in. 126 in. 9 in. - 36 in. .020 in. - 3/8 in.168-1/4 in. x 347/16 in. x 373/16 in. 45 in. 6,500 lbs.
PRS144E636 144 in. 150 in. 11 in. - 36 in. .020 in. - 3/8 in.192-1/4 in. x 347/16 in. x 737/16 in. 45 in. 8,500 lbs.
PRS168E1436168 in. 174 in. 14 in. - 36 in. .020 in. - 3/8 in.266 in. x 347/16 in. x 737/16 in. 45 in. 9,750 lbs.
PRS192E1436192 in. 198 in. 14 in. - 36 in. .020 in. - 3/8 in.270-1/2 in. x 453/8 in. x 81 in. 473/8 in. 11,000 lbs.

Internal Seamers 


Weld Length Clamping LengthWorkpiece Dimensions (ID - OD)Material ThicknessFootprint Mandrel Height Approx. Shipping Weight 
PRS120I50-FS
120 in. 126 in. min. 50 in. ID.020 in. - 3/8 in. 17 ft. 7-1/4 in. x 43 in. x 599/16 in. 2115/16 in. 9,450 lbs. 
PRS14450FS144 in. 150 in. min. 50 in. ID .020 in. - 3/8 in. 19 ft. 7-1/4 in. x 43 in. x 599/16 in. 2115/16 in. 10,490 lbs.
PRS168I50FS168 in. 174 in.min. 50 in. ID .020 in. - 3/8 in.14 ft. 6 in. x 43 in. x 599/16 in. 2115/16 in.11,780 lbs.
PRS192I50FS192 in. 198 in. min. 50 in. ID
.020 in. - 3/8 in.23 ft. 9-3/4 in. x 43 in. x 601/16 in. 2315/16 in. 13,865 lbs.
PRS216I50FS216 in. 222 in. min. 50 in. ID .020 in. - 3/8 in.26 ft. 1-1/4 in. x 43 in. x 601/16 in. 2315/16 in. 15,950 lbs.
PRS240I50FS240 in. 246 in. min. 50 in. ID .020 in. - 3/8 in.28 ft. 1-1/4 in. x 43 in. x 601/16 in. 2315/16 in. 17,520 lbs.