BUG-O Girth Welders are automatic tank welding machines for field storage tank fabrication. They use self-propelled submerged arc welding to complete horizontal girth seams faster, more consistently and with less reliance on scaffolding or manual welding around the tank circumference.
With dual drive motors, integrated control panel, laser seam guide, ergonomic operator cabin, adjustable weld head, flux belt support, flux recovery system and modular single-sided or dual-sided configurations, BUG-O Girth Welders provide a high-productivity solution for top-down and bottom-up tank construction, internal and external welding, LNG tanks, cryogenic tanks and large industrial storage tank projects.
Overview
BUG-O Girth Welders are automatic welding machines designed for field storage tank fabrication. They are used to weld horizontal girth seams on large cylindrical tanks, helping contractors reduce welding time, improve arc-on time, lower weld defects and increase overall productivity during tank erection.
The BGW Series is built as a self-propelled submerged arc welding system that runs directly on the tank and carries the operator. This eliminates the need for scaffolding while improving operator comfort, safety and access to the weld joint. The machines are suitable for top-down or bottom-up tank construction and can be configured for internal or external welding.
Unlike basic tank welding carriages, BUG-O Girth Welders are supplied with a dual drive motor system, integrated control panel, efficient flux recovery system, laser sight guide, ergonomic operator cabin, adjustable weld head and flux belt support system. The modular design also allows the machines to be adapted for single-sided, dual-sided and custom-built tank fabrication applications.
The main technical advantage of BUG-O Girth Welders is the combination of mechanised submerged arc welding, operator-carrying tank travel and integrated flux management. Instead of relying on scaffolding and manual welding around the tank circumference, the machine travels on the tank shell and carries the operator, welding head, controls, flux support belt, flux recovery system and welding power supply support equipment.
The dual drive motor system is a key performance feature. BUG-O states that the dual AC motor design helps maintain constant travel around the tank circumference. When strake plate misalignment, uneven top edges or Tee joints create resistance, the drive system powers the machine across the irregularity while maintaining travel speed. This helps reduce horizontal weld seam defects and lowers overall tank erection costs.
The flux recovery system is also central to the machine’s efficiency. The adjustable rotating flux dam holds flux in the weld joint and carries it to the heavy-duty flux recovery vacuum system. This reduces flux waste, improves process cleanliness and supports reliable submerged arc welding in field tank fabrication.
The welding head is mounted on adjustable cross slides. The Tank Fabrication brochure lists 4″ / 102 mm vertical travel and 6″ / 152 mm horizontal travel, giving the operator practical control over wire placement and joint tracking. A laser pointer mounted on the welding head provides a visible reference to help keep the wire in the correct position during submerged arc welding.
The modular design is commercially important. BUG-O girth welders can be configured for single-sided or dual-sided welding, bottom-up or top-down construction, internal or external welding, and project-specific custom applications. This allows the same product family to support standard storage tanks, LNG / cryogenic tanks and more specialised tank construction requirements.
BUG-O Girth Welders are designed for field-erected storage tank construction and repair. Their primary application is horizontal girth seam welding, especially where mechanised submerged arc welding can reduce production time and improve weld consistency.
Typical applications include bulk storage tanks, oil and gas tanks, water tanks, petrochemical storage tanks, cryogenic storage tanks, LNG tanks, double-wall storage tanks, tank maintenance, partial strake replacement, wind tower construction, piling construction, chimney construction, power station absorbers and industrial field fabrication.
The wider tank fabrication family also includes vertical seam solutions. The BVW-1000 is designed for multi-pass vertical welding on field storage tanks, while the EGW-1000 is designed as a high-deposition electrogas vertical welding system using water-cooled copper backing bars and an automatic vertical travel carriage.
BUG-O Girth Welders are a strong choice for tank contractors that need to reduce welding time, improve operator safety and increase repeatability in field tank construction. By eliminating scaffolding and carrying the operator directly on the machine, the system improves both productivity and working conditions.
For project managers, the value is operational efficiency. The machines increase arc-on time, support consistent travel speed, improve flux recovery and reduce manual variability. This can shorten tank erection schedules and reduce rework caused by weld defects.
For fabrication contractors, the modular design protects investment value. The machines can be configured for single-sided or dual-sided welding, top-down or bottom-up construction, internal or external welding and custom applications. This makes the product family adaptable across standard storage tanks, cryogenic tanks and specialised field projects.
| Product family | BUG-O Girth Welders |
|---|---|
| Product type | Automatic girth welding machines for field storage tank fabrication |
| Welding process | Submerged arc welding / SAW |
| Primary use | Horizontal girth seam welding on field-erected storage tanks |
| Construction methods supported | Top-down and bottom-up tank construction |
| Welding position / seam type | Horizontal girth welds, 3 o’clock welding position according to BGW manuals |
| Tank types | Single-wall and double-wall storage tanks; LNG and cryogenic tank configurations available |
| Welding location | Internal and external welding |
| Productivity claim | Can reduce field storage tank welding time by up to 40% |
| Operator access | Machine runs directly on the tank and carries the operator, eliminating the need for scaffolding |
| Drive system | Dual drive motor system / dual AC motor design controlled by a single frequency inverter |
| Flux system | Efficient flux recovery system with adjustable rotating flux dam and heavy-duty flux recovery vacuum |
| Weld head adjustment | 4" / 102 mm vertical travel and 6" / 152 mm horizontal travel according to the Tank Fabrication brochure |
| Seam tracking aid | Laser pointer / laser sight guide mounted on the welding head |
| Control panel features | Integrated control panel with power switch, auxiliary outlet control, flux recovery vacuum switch, interior lighting switch, input power indicator, travel ready indicator, LCD travel speed display, travel speed adjustment knob, weld speed indicator, maximum speed indicator and travel direction switch |
| Environmental / operator features | Weather-tight canvas covers, ergonomic operator cabin, interior lighting, spotlight for flux belt and under-seat storage |
| Standard welding equipment | Lincoln Electric® submerged arc welding equipment; DC-600 with NA-3 control box and feeder listed as standard in the Tank Fabrication brochure |
| Alternative power source note | All units are available with DC-1000 Power Source according to the Tank Fabrication brochure |
| Welding leads / control cable | 200 ft / 61 m of control cable and welding leads supplied with BGW series according to the Tank Fabrication brochure |
| Standard input power, BGW-1000 / BGW-2000 manual | 3 phase, 380 V ±10%; non-standard input available by consulting factory |
| Standard input power, BGW-5000 / BGW-6000 manual | 3 phase, 220 V / 380 V / 460 V ±10%; non-standard input available by consulting factory |
| Standard input frequency | 50 Hz ±5% / 60 Hz ±5% |
| Line power requirement | 40 kVA listed in BGW manuals and Tank Fabrication brochure |
| Operating temperature | -10°C to +50°C / 14°F to 122°F |
| Environmental protection | IP23 grade; F |
| Tank diameter operating range, BGW-1000 / BGW-2000 manual | Greater than 15 ft / 4.5 m |
| Tank diameter operating range, BGW-5000 / BGW-6000 manual | Greater than 15 ft / 4.5 m |
| Shell plate width, BGW-1000 / BGW-2000 manual | 6 ft - 10.5 ft / 1.8 - 3.2 m standard; maximum 15 ft / 4.5 m special |
| Shell plate width, BGW-5000 / BGW-6000 manual | Bottom-to-top: 6 ft - 10.5 ft / 1.8 - 3.2 m standard; top-to-bottom: 6 ft - 8.7 ft / 1.8 - 2.6 m |
| Travel speed, BGW-5000 / BGW-6000 manual | 100 - 2900 mm/min / 3.94 - 114 in/min |
| Travel speed, Tank Fabrication brochure table | 4 - 144 ipm / 100 - 2900 mm/min listed for BGW-6000 |
| Typical welding travel speed, manuals | Approximately 18 in/min / 450 mm/min listed as a typical procedure guide |
| Typical welding parameters, manuals | Approximately 400 A, 28-30 V, WFS 91" / 2300 mm listed as a guide for 3.2 mm wire |
| Single torch deposition rate, manuals | Approximately 11 lb/hr / 5 kg/hr listed as a typical guide |
| BGW-1000 configuration | Single-sided girth welder; commonly used due to light weight and simplicity; requires one operator |
| BGW-2000 configuration | Double-sided girth welder with A-frame and weld head on each side; requires two welding power supplies and normally two operators |
| BGW-5000 configuration | Universal single-sided girth welder for top-down or bottom-up constructed tanks |
| BGW-6000 configuration | Dual-sided girth welder for cryogenic storage tanks; can be used as two single-sided units |
| BGW-5000-LNG configuration | Single-sided girth welder for cryogenic storage tanks; dual-sided model also referenced |
| CGW-5000 configuration | Compact single-sided girth welder for top-down or bottom-up construction, repair and applications where space is limited |
| BGW-5000-LNG tank diameter application | 7 ft - 13 ft / 2 - 4 m listed in the Tank Fabrication brochure table |
| BGW-6000 tank diameter application | Minimum 15 ft / 4.5 m listed in the Tank Fabrication brochure table |
| CGW-5000 tank diameter application | 15 ft / 4.5 m inside listed in the Tank Fabrication brochure table; brochure also notes minimum 10 ft O.D. / 15 ft I.D. work for CGW-5000 |
| BGW-6000 shell plate thickness | 5/16" - 1 9/16" / 8 - 40 mm listed in the Tank Fabrication brochure table |
| CGW-5000 shell plate thickness | 7/32" - 1 3/4" / 5 - 45 mm listed in the Tank Fabrication brochure table |
| BGW-5000 / BGW-6000 shell plate height | 6 ft - 10 ft / 1.8 - 3.0 m listed in the Tank Fabrication brochure table |
| Wire diameter, BGW-5000-LNG | 2 x 1/16" / 2 x 1.6 mm listed in the Tank Fabrication brochure table |
| Wire diameter, BGW-6000 | 1/8" / 3.2 mm listed in the Tank Fabrication brochure table |
| Wire diameter, BGW-5000 | 3/32" / 2.4 mm listed in the Tank Fabrication brochure table |
| Wire diameter, CGW-5000 | 1/8" / 3.2 mm listed in the Tank Fabrication brochure table |
| Approximate weight, BGW-5000-LNG | 1,984 lb / 900 kg listed in the Tank Fabrication brochure table |
| Approximate weight, BGW-6000 | 3,968 lb / 1,800 kg listed in the Tank Fabrication brochure table |
| Approximate weight, BGW-5000 | 2,094 lb / 950 kg listed in the Tank Fabrication brochure table |
| Approximate weight, CGW-5000 | 770 lb / 350 kg listed in the Tank Fabrication brochure table |
| Frame load capability, BGW-1000 / BGW-2000 manual | 550 lb / 250 kg; enough for two operators according to manual description |
| Maximum load capability, BGW-5000 / BGW-6000 manual | 250 kg / 551.16 lb |
| BVW-1000 use | Multi-pass vertical welding on field storage tank vertical seams in an enclosed environment |
| EGW-1000 use | High-deposition single-pass electrogas welding of vertical tank joints using water-cooled copper backing bars and automatic vertical travel carriage |
| Spare parts kit | SPK-BGW-1000; brochure notes it must be ordered with every BGW and CGW unit and can be ordered separately |
| Custom configurations | Custom-built units available for special applications, including LNG solutions |
| Country of manufacture | USA |
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