Blog posts of '2025' 'November'

Compressed gas cylinders are built to handle high internal pressure—but they don’t last forever. Over time, cylinders can develop stress cracks, corrosion, thread wear, or metal fatigue that make them unsafe to fill or use. That’s why federal DOT regulations require all high-pressure cylinders to be periodically inspected and recertified through hydrostatic testing. At Dupuy Oxygen, we supply and exchange certified cylinders across Central Texas—and we make sure every cylinder you receive meets all recertification requirements for safe, legal operation.

What Is Hydrostatic Testing?

Hydrostatic testing is a destructive-free method of testing cylinder integrity. During the test, a cylinder is filled with water (or another incompressible liquid) and pressurized to a level higher than its normal service pressure. The expansion of the cylinder is measured to determine whether it retains its structural integrity under stress. If the cylinder meets the required criteria, it is marked and certified for continued use. If not, it is condemned and permanently removed from circulation.

Who Regulates Cylinder Testing?

In the United States, cylinder testing and recertification is regulated by the Department of Transportation (DOT), specifically under Federal Regulation 49 CFR 180.205. Any cylinder that contains compressed gas—including welding gases, CO₂, nitrogen, oxygen, argon, or specialty gases—must comply. Cylinders must be tested at regular intervals depending on type, material, and service pressure.

Cylinder Testing Intervals

Different cylinder types have different recertification schedules. Here are the most common intervals used by Texas welders, industrial plants, and beverage facilities:

• Standard Steel Cylinders (e.g., oxygen, nitrogen, argon): Every 5 years
  
  

• Aluminum Cylinders: Every 5 years (unless marked with special exemptions)
  
  

• CO₂ Beverage Cylinders: Every 5 years
  
  

• SCBA or SCUBA Cylinders: 5 years (composite may be 3)
  
  

• DOT carbon fiber composite cylinders: 3-year cycle, 15-year lifespan
  Cylinders that miss their hydrostatic test due date cannot legally be refilled until recertified. DOT fines can apply to companies that transport or fill expired cylinders.
  
  

How to Read Cylinder Markings

Every cylinder has a stamped set of markings that indicate manufacturer, pressure rating, gas compatibility, and last test date. The hydrostatic test date appears as a month-year mark (e.g., "06 23" = June 2023). If a + or ★ symbol is present, it means the cylinder is authorized for bonus pressure rating or extended test interval. Cylinder markings must remain legible—otherwise, the cylinder may be condemned.

What Happens During Recertification

A full hydrostatic test and recertification includes:

1. External Visual Inspection – Checking for dents, gouges, rust, heat marks, fire damage, or thread issues
   
   

2. Internal Inspection (when required) – Detecting corrosion, pitting, or contamination
   
   

3. Hydrostatic Pressure Test – Measuring elastic expansion at 5/3 of service pressure
   
   

4. Stamping Test Date – Marking the cylinder with new expiration period
   
   

5. Repainting/Reconditioning – If needed, for safety labeling and corrosion resistance
   If a cylinder fails any part of the test, it is removed from service and must be destroyed according to DOT guidelines.
   
   

What Texas Shops Need to Know About Compliance

If your business owns cylinders, you are responsible for ensuring they are in test—even if you're not a refill facility. If you lease or exchange cylinders from Dupuy Oxygen, you’re covered. But if you own your own tanks, such as for bulk nitrogen or industrial oxygen, you must have a plan for ongoing recertification. Key rules include:

• No filling expired cylinders
  
  

• No transporting expired cylinders on public roads
  
  

• No sanding, painting over markings, or removing serial numbers
  
  

• No “homemade repairs” or valve swapping without certification
  Violation of these rules may result in OSHA citations, DOT penalties, and insurance liability exposure.
  
  

Industrial Users at Highest Risk of Noncompliance

We routinely see overdue cylinders in the following types of businesses:

• Small fabrication shops that own cylinders instead of swapping them
  
  

• HVAC or plumbing contractors storing cylinders for months or years
  
  

• Schools and trade programs using inherited or donated cylinders
  
  

• Beverage accounts using unlabeled or outdated CO₂ cylinders
  
  

• Companies with mixed ownership/rental cylinder inventory
  If you're unsure of your compliance status, Dupuy Oxygen can audit your cylinder fleet and manage retesting.
  
  

Benefits of Using an Exchange Program Instead of Owning Tanks

Owning cylinders means you are responsible for storage, valve care, hydrotesting, replacement, and DOT compliance. When you participate in a cylinder exchange program (such as Dupuy Oxygen’s), you eliminate:

• Recertification scheduling
  
  

• DOT documentation
  
  

• Failed cylinder replacement costs
  
  

• Tracking and test-date oversight
  When you return a cylinder to us, we take full responsibility for retesting, refurbishing, and legal compliance—so you never have an expired tank in circulation.
  
  

What Happens If a Cylinder Fails Hydrostatic Testing?

Failed cylinders must be:

• Condemned and visibly stamped “REJECTED” or “COND"
  
  

• Rendered permanently unusable—typically cut or drilled
  
  

• Recorded in the testing facility’s DOT log
  They may not be resold, reused, or repurposed (even as air tanks) unless repaired and retested by a DOT-authorized facility.
  
  

Why Shops in Central Texas Choose Dupuy Oxygen

As one of Texas’ most experienced industrial gas suppliers, Dupuy Oxygen offers:

• Fully DOT-certified cylinders in every exchange
  
  

• Automatic test date compliance for route customers
  
  

• Cylinder fleet audits for industrial operations
  
  

• Hydrotest outsourcing for customer-owned cylinders
  
  

• Delivery, pickup, and full-service tracking
  We ensure every cylinder you receive is safe, legal, and ready to fill—and we handle the paperwork, inspection, and liability so you don’t have to.
  
  

Need Help Staying Cylinder-Compliant?

Whether you’re running a welding shop, brewery, hospital, food plant, or industrial site, cylinder safety and recertification are non-negotiable.
Contact Dupuy Oxygen today for cylinder exchange plans, hydrostatic testing schedules, or a full gas compliance audit anywhere in Central Texas.

Whether you're running a fabrication shop, industrial plant, brewery, lab, or production line, your gas supply system affects everything—work efficiency, safety compliance, cost, and downtime. At Dupuy Oxygen, we supply welding gases, industrial gases, medical gases, and food-grade CO₂ across Central Texas, and one of the most common questions we get from businesses is: Should we switch to bulk or microbulk, or stick with cylinders? The answer depends on usage volume, storage space, delivery frequency, and operational priorities. Below, we’ll break down each option in detail so you can decide which system fits your shop best.

Traditional Cylinders: The Most Flexible Option

High-pressure cylinders have been the standard for decades because they’re versatile, mobile, and easy to swap out. A single shop may use cylinders for MIG welding gas, argon, CO₂, nitrogen, oxygen, helium, or specialty blends. Cylinders are ideal if your shop:

• Uses low to moderate gas volume
  
  

• Needs portability—ex: welding on multiple stations or jobsites
  
  

• Has limited storage or no tank pad
  
  

• Doesn’t want infrastructure installation
  For many shops using fewer than 700–800 cubic feet of gas per month, cylinders remain the most cost-effective option. However, downtime from cylinder changes, pressure variability, and gas waste at the bottom of the tank can add hidden costs—especially in multi-operator environments.
  
  

Microbulk Delivery: The Middle Ground for Growing Shops

Microbulk systems bridge the gap between cylinder delivery and full-scale bulk tanks. These small, permanent tanks are installed on-site and filled by Dupuy Oxygen via scheduled route truck. Microbulk advantages include:

• Less downtime—no cylinder swapping or purging
  
  

• Consistent pressure—ideal for automated welding or cutting
  
  

• Better cost-per-cubic-foot than cylinders
  
  

• Reduced floor space and improved safety
  
  

• Digital telemetry (optional) to monitor gas levels remotely
  Microbulk can store anywhere from 450 to 3,000 cubic feet depending on tank size and gas type. If your shop is frequently replacing cylinders or running short between deliveries, microbulk may be the most profitable upgrade.
  
  

Bulk Supply: The Right Choice for High-Volume Users

Bulk tanks are permanently installed systems designed for large-volume users—typically 4,000 cubic feet/month or more. Ideal for manufacturers, metal fabricators, food processors, laser-cutting operations, and breweries, bulk offers unmatched convenience and cost savings. Benefits include:

• Lowest price per cubic foot
  
  

• Zero cylinder handling or storage
  
  

• Fewer deliveries and guaranteed uninterrupted supply
  
  

• Custom tank sizes based on consumption
  
  

• Available for nitrogen, oxygen, argon, CO₂, and blends
  Bulk customers also eliminate safety risks tied to cylinder transport, handling, or stacking. If your company relies on constant gas availability—without tolerance for supply interruptions—bulk is the strategic long-term solution.
  
  

Usage Thresholds: When It’s Time to Upgrade

Still unsure which category you’re in? Use this general rule of thumb:

• Cylinders: 0–600 cubic ft/month per gas type
  
  

• Microbulk: 700–3,000 cubic ft/month per gas type
  
  

• Bulk: 4,000+ cubic ft/month or mission-critical uptime
  If you're refilling cylinders more than once a week—or paying for cylinder rental, hazmat, and delivery fees regularly—it’s time to evaluate your ROI on a larger format.
  
  

Additional Factors to Consider

Space Requirements: Cylinders take up floor space and require indoor storage compliance. Bulk/microbulk require outdoor placement and pad installation.
Delivery Frequency: Cylinder delivery may happen weekly. Bulk may only need filling monthly—or less.
Labor Costs: Cylinder changeouts and manifold switching eat into paid labor time. Microbulk and bulk eliminate this entirely.
Flow & Pressure Stability: Automated welders, lasers, CNC tables, and beverage systems perform better on steady pressure—not cylinder-by-cylinder fluctuation.
Safety & Compliance: Reduces fall, leak, and handling risks, and improves OSHA recordability.

Real-World Example — Welding Shop in Waco

A structural steel fabrication shop using 80 cylinders of C25 per month switched to a 1,000-liter microbulk tank from Dupuy Oxygen. Results:

• Reduced cylinder handling by 100%
  
  

• Lowered gas cost by 18%
  
  

• Gained 30+ hours of labor back per month
  
  

• Eliminated cylinder rental and hazmat fees
  
  

• Improved weld bead consistency on robotic cells
  The upgrade paid for itself in under 5 months.
  
  

Gas Types Available in Cylinders, Microbulk, and Bulk

• Argon (welding, laser, specialty)
  
  

• CO₂ (beverage, MIG mix, industrial)
  
  

• Nitrogen (purging, HVAC, food packaging)
  
  

• Oxygen (cutting, medical, industrial)
  
  

• Argon/CO₂ Mixes (75/25, 90/10, custom blends)
  
  

• Specialty/Calibration Gases (available for industrial cylinders only)
  
  

Why Central Texas Shops Trust Dupuy Oxygen

As one of the most experienced gas suppliers in Waco and surrounding counties, we provide turnkey gas delivery systems designed to grow with your business. Our services include:

• Site evaluations and usage analysis
  
  

• Cylinder, microbulk, and bulk program setup
  
  

• On-site tank installation and telemetry
  
  

• Scheduled route delivery and emergency supply
  
  

• Local support for welding, beverage, industrial, and specialty gas users
  Whether you're a single-station weld shop or a multi-plant manufacturer, we match your gas supply to your production needs—not the other way around.
  
  

Ready to Size Your Gas System?

Choosing the right supply format can reduce downtime, cut operational costs, improve safety, and scale with your business for years.
Contact Dupuy Oxygen today for a usage analysis, cost comparison, or on-site consultation anywhere in Central Texas. We'll help you determine whether cylinders, microbulk, or bulk is the smarter long-term solution for your shop.

Carbon dioxide (CO₂) is a crucial asset in beverage carbonation, draft systems, and production processes. Whether it’s served through kegs, craft taps, or fountain dispensers, CO₂ plays a key role in quality and consistency. But it also brings serious safety risks if not handled properly. In enclosed spaces like restaurants, bars, walk-in coolers, and breweries, even a minor leak can cause oxygen displacement and create an invisible—and deadly—hazard. At Dupuy Oxygen, we supply beverage-grade CO₂ throughout Central Texas and help local businesses stay compliant, protected, and CO₂-aware.

How CO₂ Behaves in the Workplace

CO₂ is an odorless, colorless gas that is heavier than air. When it leaks, it sinks and accumulates in low-lying spaces like basements, keg coolers, and storage rooms. At low concentrations, it can cause headaches, dizziness, or fatigue. At higher levels, it can lead to suffocation without warning. This makes CO₂ one of the most dangerous “silent hazards” in the food and beverage industry—and one that OSHA, TABC, TDSHS, and city inspectors take seriously.

Common Places CO₂ Leaks Occur

Leak points are often found in places where CO₂ is stored, distributed, or dispensed. These include:

• Beverage gas cylinders and manifolds
  
  

• Keg coolers and walk-ins
  
  

• Soda fountain systems
  
  

• Brewery fermentation tanks and brite tanks
  
  

• Damaged or aging distribution lines
  
  

• Improper fittings, valves, or regulators
  Leaks are especially dangerous when unnoticed—for example, overnight or in rarely accessed storage areas. Regular checks, inspections, and monitoring systems are necessary for safe operations.
  
  

OSHA & TABC CO₂ Safety Requirements in Texas

Businesses handling CO₂ must comply with OSHA’s permissible exposure limits (PEL), which cap workplace CO₂ levels at 5,000 ppm over an 8-hour period. Higher levels require corrective action, reporting, and mitigation systems. Additionally, food and beverage businesses must comply with rules governing high-pressure cylinder storage, ventilation, hazard communication, and employee training. Failure to comply can result in fines, shutdowns, or liability in case of injury.

CO₂ Monitoring Systems: Your First Line of Defense

Installing a fixed CO₂ monitoring system is no longer optional—it's a best practice and often a code requirement. These devices automatically measure ambient CO₂ levels and sound alarms when concentrations exceed safe limits. Alarms should trigger at:

• 5,000 ppm: First alert—evacuate non-essential staff
  
  

• 15,000 ppm: Emergency alarm—full evacuation required
  Modern monitors are wall-mounted and hardwired for accuracy, with sensor placement near floor level to detect CO₂ buildup early. When paired with automatic gas shutoff valves, they create an intelligent safety system that protects both staff and customers.
  
  

Best Practices for Beverage CO₂ Storage

Proper storage reduces risk and ensures regulatory compliance. Key requirements include:

• Cylinders stored upright, chained, or cart-secured
  
  

• No storage in unventilated basements, boiler rooms, or employee restrooms
  
  

• Valve caps in place when not connected to a system
  
  

• Nitrogen and CO₂ cylinders separated from flammable gases
  
  

• Clear hazard signage posted in storage and fill areas
  Staff should never store cylinders near heat sources, ignition points, or tight spaces without ventilation. Dupuy Oxygen offers delivery, installation, and certified gas handling training to help businesses meet safety standards.
  
  

Delivery Options for Restaurants & Breweries in Waco

Dupuy Oxygen offers three delivery formats for beverage CO₂ customers in Central Texas:

• Standard Cylinders: 20–50 lb cylinders for restaurants and taprooms
  
  

• Microbulk Tanks: Small refillable vessels for high-volume CO₂ users
  
  

• Bulk Systems: On-site CO₂ tanks with remote fill access—ideal for breweries, stadiums, or refineries
  Each format has unique safety needs and compliance requirements. We work with customers to size their system properly and prevent over-ordering, wasted gas, or unsafe storage conditions.
  
  

Employee Training & Hazard Communication

All staff working near CO₂ should understand:

• How to identify CO₂ hazards
  
  

• What to do in case of a leak or alarm
  
  

• Where emergency shutoff valves are located
  
  

• Why they should never enter a confined space with suspected CO₂ exposure
  Training is not only smart—it helps satisfy OSHA’s Hazard Communication Standard (29 CFR 1910.1200), which requires CO₂ to be treated as a hazardous substance.
  
  

Signs Your Business Needs a CO₂ Safety Assessment

You may be overdue for a safety check if:

• You’ve expanded your draft system or added more kegs
  
  

• Your cylinders are stored in a walk-in cooler
  
  

• You don’t have CO₂ monitors installed
  
  

• Employees have reported dizziness or odor complaints
  
  

• You’ve never received CO₂ compliance training
  Dupuy Oxygen’s field specialists can perform on-site assessments to locate risks, recommend mitigation, and update your storage and monitoring systems.
  
  

Why Waco Businesses Trust Dupuy Oxygen

As the top beverage gas supplier in Central Texas, Dupuy Oxygen brings:

• Beverage-grade, food-safe CO₂ delivery
  
  

• Local route service and emergency dispatch
  
  

• CO₂ monitoring equipment, installation, and training
  
  

• Cylinder exchange and microbulk supply programs
  
  

• Expertise serving breweries, bars, restaurants, cafeterias, and venues
  We’re not just a gas provider—we’re a safety partner for the food and beverage industry.
  
  

Keep Your Business CO₂ Safe with Dupuy Oxygen

Protect your employees, comply with OSHA standards, and ensure uninterrupted beverage service with professional CO₂ delivery and safety solutions.
Contact Dupuy Oxygen today for beverage CO₂, monitoring equipment, or a complete safety audit for your Waco-area restaurant or brewery.

When it comes to MIG welding, your choice of shielding gas directly affects weld quality, spatter levels, penetration, arc stability, and ultimately—project cost. In Central Texas, where industries rely on reliable welding performance in manufacturing, production, repair, and energy sectors, selecting the right gas is a critical decision. At Dupuy Oxygen, we supply the full range of shielding gases—including pure argon, CO₂, and custom mixes—and guide welders and shop owners in choosing the best solution based on material, budget, and application.

Argon: The Inert Gas of Choice for Non-Ferrous Welding

Argon is a fully inert gas, meaning it does not react with molten metal. This makes it ideal for welding non-ferrous metals such as aluminum, magnesium, titanium, and copper alloys. For MIG welding aluminum, 100% argon is the industry standard, offering a stable arc, low spatter, and smooth bead appearance. Steel applications are limited with pure argon, as the gas does not promote adequate penetration. For stainless steel, argon can be used but is typically blended with CO₂ or O₂ for improved results. Argon’s low ionization potential also contributes to a smooth, controlled arc, making it suitable for precision welding, thinner materials, and high-detail work.

CO₂: High Penetration at a Low Cost

100% CO₂ is the most cost-effective shielding gas in MIG welding—and the only active gas commonly used alone. It offers deep penetration, making it ideal for structural steel, heavy plate, farm equipment repair, and applications requiring strong root fusion. However, the trade-off is higher spatter, a harsher arc, and more post-weld cleanup. Many Central Texas fabrication and agricultural shops choose CO₂ for its price point and penetration on mild steel, especially where appearance is less critical than durability. For semi-automatic applications, CO₂ requires additional cleanup time and can increase wear on consumables due to arc instability.

Argon/CO₂ Blends: The MIG Welding Workhorse

The most common MIG shielding gas is a blend of argon and CO₂—typically in ratios such as 75/25 (C25), 85/15, or 90/10. These blends combine the arc stability and low spatter of argon with the penetration benefits of CO₂. A 75/25 blend (75% argon, 25% CO₂) is widely used for carbon steel welding and provides smooth metal transfer, good bead appearance, and reduced cleanup. Higher-argon blends (90/10 or 95/5) are suited for robotic welding, spray transfer, and high-production environments, minimizing downtime and rework. Shops working with both thin and medium-gauge steel often standardize on C25 for versatility and predictable performance.

Choosing Based on Transfer Mode

Your shielding gas must match your transfer mode.

• Short Circuit Transfer: Works with 100% CO₂ or 75/25 blends. Good for thin materials, out-of-position welding, and lower heat input.
  
  

• Globular Transfer: Possible with pure CO₂, but not preferred due to high spatter and poor aesthetic.
  
  

• Spray Transfer: Requires at least 80% argon, giving high deposition rates, low spatter, and deep penetration on thicker steel in flat or horizontal positions.
  
  

• Pulsed MIG: Ideal for aluminum and stainless steel using high-argon blends. Offers low heat input without sacrificing weld quality.
  Knowing your transfer mode helps narrow down the right gas long before you buy.
  
  

Cost vs. Performance in Central Texas Shops

Shielding gas cost varies significantly—pure CO₂ is the most affordable, while argon-based blends cost more per cubic foot. However, the cheapest gas is not always the most cost-efficient. High-spatter CO₂ means more time spent grinding, cleaning, and reworking. In contrast, 75/25 or 85/15 blends reduce cleanup, improve bead quality, and shorten production time. For high-volume welding operations in Waco, Temple, Killeen, and surrounding areas, the labor savings often outweigh the slightly higher gas cost—especially when producing visible welds or working with automated equipment.

Material Matters

Your material type should always guide gas selection:

• Mild Steel: 100% CO₂ or 75/25 argon mix
  
  

• Stainless Steel: Argon/CO₂/O₂ blend (e.g., 90/7.5/2.5)
  
  

• Aluminum: 100% argon (or Ar/He mix for thicker sections)
  
  

• Galvanized Steel: 75/25 with anti-spatter techniques
  Dupuy Oxygen can provide custom blends if your application has unique wetting, penetration, or bead profile requirements.
  
  

Cylinder, Microbulk, or Bulk Supply Options

Whether you're running a single-shop setup or a multi-bay production line, we offer various supply configurations:

• Individual Cylinders: Ideal for small welding operations or mobile work
  
  

• Microbulk Tanks: Cost-effective for medium-volume shops using 750–3,000 cubic feet/month
  
  

• Bulk Tanks: Designed for large manufacturers or ongoing high-volume MIG welding
  Central Texas welders can choose the right size, pressure, and delivery frequency for their business—without overpaying for unused capacity.
  
  

Weld Troubleshooting: Shielding Gas Issues

Common signs you’re using the wrong gas:

• Excessive spatter
  
  

• Porosity or wormholes in the bead
  
  

• Poor penetration or cold lap
  
  

• Unstable or sputtering arc
  
  

• Burn-through on thin sheet metal
  Gas selection isn’t the only variable, but it’s one of the most common root causes of weld inconsistency. Dupuy Oxygen’s team can help diagnose issues and recommend the right gas adjustment.
  
  

Why Central Texas Welders Trust Dupuy Oxygen

Dupuy Oxygen has supplied welding gases, cylinders, and custom mixes across Central Texas for decades. We work directly with fabrication shops, metalworking businesses, manufacturers, trade schools, and pipeline contractors to deliver:

• Top-grade gas purity
  
  

• Fast cylinder swapouts and delivery routes
  
  

• Competitive pricing for bulk and microbulk
  
  

• Technical support from experienced welding gas specialists
  We’re not just a supplier—we’re a long-term industrial partner.
  
  

Ready to Select the Best Gas for Your MIG Setup?

Whether you're welding steel, aluminum, or stainless—and whether you run one torch or 50—Dupuy Oxygen has the right gas, supply format, and expertise for the job. Our team can help you compare cost, weld quality, and delivery options so you get the best long-term value.
Contact Dupuy Oxygen today for MIG gas pricing, shop evaluations, or on-site delivery anywhere in Central Texas.