Setting up an oxy-acetylene torch can feel tricky at first—get the pressures wrong and you’ll either end up with a noisy, unstable flame or a sooty mess that ruins your weld. That’s where an oxy-acetylene welding pressure settings chart becomes essential. By matching the right oxygen and acetylene pressures to your tip size, metal thickness, and welding application, you can achieve a stable flame, proper weld penetration, and cleaner results every time. These charts aren’t just about convenience—they’re critical for safety, fuel efficiency, and preventing flashbacks that can damage your equipment.
Whether you’re brazing thin sheet metal, fusing mild steel plate, or heating parts for bending and shaping, having the correct pressure settings dialed in makes all the difference. In this guide, we’ll break down the exact torch settings you need so you can weld with confidence and consistency.
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Oxy Acetylene Welding Basics
Oxy acetylene welding, or gas welding, mixes oxygen and acetylene to create a flame hot enough to melt metals—up to 6,300°F. It’s versatile for thin sheets, pipes, and repairs where electricity isn’t handy. The process works by heating the base metal to its melting point and adding filler rod if needed.
Use it when you need precise control, like on automotive bodywork or jewelry. Why? It’s portable, affordable for starters, and great for learning fundamentals before jumping to MIG or TIG.
Practical know-how: Always check your hoses for cracks— I once had a leaky acetylene hose that nearly turned a simple repair into a fireball. Fix? Replace hoses every few years and use flashback arrestors.
Why Pressure Settings Are Critical in Oxy Acetylene Welding
Pressure settings control the flame type—neutral, carburizing, or oxidizing—which affects weld quality. Too high acetylene? You get a sooty, weak weld. Too low oxygen? Slow progress and poor penetration.
In the real world, this matters for safety (preventing backfires) and efficiency (less gas waste). For US codes like AWS, proper settings ensure welds meet structural standards.
Anecdote: Early on, I cranked oxygen too high on a thin steel plate and burned right through it. Fix: Start low and adjust while watching the flame.
Tip: For prep, clean joints with a wire brush and bevel edges on thicker materials for better fusion.
Recommended Oxy Acetylene Pressure Settings for Different Materials
Settings vary by metal type—steel loves a neutral flame, while aluminum needs carburizing. Base it on thickness and tip size.
For mild steel, acetylene at 5-8 PSI and oxygen at 5-10 PSI is common for thin stuff. Brass or copper? Bump acetylene a bit for a softer flame.
Why use specific settings? Material compatibility—high oxygen on aluminum causes oxidation issues.
Know-how: Test on scrap first. I always keep scrap pieces handy to dial in settings without ruining the project.
Oxy Acetylene Welding Pressure Settings Chart for Steel
Here’s a chart I’ve compiled from years of shop work, aligned with common US equipment like Victor torches. It’s for welding mild steel—adjust for alloys.
| Metal Thickness (inches) | Tip Size | Oxygen PSI (Min-Max) | Acetylene PSI (Min-Max) | Flame Type | Notes |
|---|---|---|---|---|---|
| Up to 1/32 | 000 | 3-5 | 3-5 | Neutral | For fine work, low heat. |
| 1/32 – 1/16 | 00 | 3-5 | 3-5 | Neutral | Good for sheet metal. |
| 1/16 – 1/8 | 0-1 | 3-6 | 3-5 | Neutral | Common for auto repairs. |
| 1/8 – 1/4 | 2-3 | 4-10 | 4-7 | Neutral | Increase for penetration. |
| 1/4 – 1/2 | 4-5 | 6-12 | 5-8 | Neutral | Bevel joints first. |
| 1/2 – 1 | 6-7 | 7-16 | 6-10 | Neutral | Use filler rod. |
| 1 – 2 | 8-10 | 10-24 | 9-15 | Neutral | For heavy fabrication. |
This chart assumes standard tips—check your manufacturer. Never exceed 15 PSI on acetylene to avoid instability.
Step-by-Step Guide to Setting Up Oxy Acetylene Pressures
Let’s break it down like I’m showing a new trainee.
- Secure cylinders upright, chains on.
- Crack valves to blow out dust.
- Attach regulators—oxygen right-hand thread, acetylene left-hand.
- Connect hoses: green for oxygen, red for acetylene.
- Attach torch and tip.
- Open acetylene cylinder valve 1/2 turn, oxygen full.
- Set regulators: Acetylene 5-7 PSI, oxygen 7-10 PSI to start.
- Open torch valves, light acetylene with striker (never a lighter!).
- Adjust to neutral flame: sharp inner cone.
Common mistake: Lighting with both gases open—causes pop and soot. Fix: Light acetylene first, add oxygen slowly.
Safety: Wear leather gloves, shade 5 goggles, and have a fire extinguisher nearby.
Choosing the Right Tip Size for Oxy Acetylene Welding
Tip size matches metal thickness—too small, slow weld; too big, burn-through.
For 1/8” steel, use size 2 tip. How it works: Larger tips have bigger orifices for more gas flow.
When to use: Small tips for detail, large for heavy plate.
Anecdote: I used a too-large tip on thin tubing and warped it bad. Fix: Swap to smaller and use back-and-forth motion.
Prep tip: Clean tips with wire cleaners weekly to avoid clogged holes.
Flame Types and Their Pressure Adjustments
Neutral flame: Equal oxygen/acetylene, blue cone—standard for steel.
Carburizing: Extra acetylene, feathery cone— for aluminum, lower oxygen PSI.
Oxidizing: Extra oxygen, hissing cone—for brass, higher oxygen.
Why adjust? Weld integrity—wrong flame adds carbon or oxides, weakening bonds.
Know-how: For neutral, set acetylene to sooty flame, add oxygen till cone sharpens.
Safety Considerations in Oxy Acetylene Pressure Settings
Safety first—acetylene is unstable above 15 PSI.
Use flashback arrestors on torch and regulators.
Inspect for leaks with soapy water.
In shop practice, store cylinders separately, oxygen away from flammables.
Anecdote: Forgot to close valves overnight, woke to low tanks. Fix: Always bleed lines and close valves post-use.
US codes: Follow OSHA for storage, ANSI for equipment.
Common Mistakes in Oxy Acetylene Pressure Settings and Fixes
Mistake: High acetylene causing carbon deposits.
Fix: Drop to 5-8 PSI, clean weld area.
Mistake: Low pressure, weak flame.
Fix: Check regulators, increase gradually.
Mistake: Mismatched pressures, popping torch.
Fix: Equalize around 5-7 PSI start, adjust.
From experience: Rushed settings lead to porosity. Take time to test.
Equipment Recommendations for Oxy Acetylene Welding
Go with Victor or Harris torches—reliable in US shops.
Regulators: Dual-gauge for accurate PSI.
Filler rods: RG45 for steel, match diameter to thickness.
Pros: Portable setup under $500.
Cons: Gas costs add up vs electric welding.
Tip: Invest in rosebud tips for heating large areas.
Oxy Acetylene vs Other Welding Processes: When to Choose Gas
Oxy acetylene shines for fieldwork without power.
Compare to MIG: Gas is slower but better for thin metal.
Pros: No electricity, versatile flames.
Cons: Slower, more skill needed.
Use when: Repairing exhausts or fencing on-site.
Anecdote: Switched to oxy for a remote job—saved the day when power failed.
Pressure Settings for Welding Aluminum with Oxy Acetylene
Aluminum needs carburizing flame, acetylene 5-10 PSI, oxygen 5-12 PSI.
Why? Prevents oxidation.
Use flux-coated rods, preheat gently.
Know-how: Clean with stainless brush, weld quickly to avoid warping.
Chart addition: For 1/16” aluminum, tip 1, acetylene 4-6 PSI, oxygen 4-7 PSI.
Pressure Settings for Brazing with Oxy Acetylene
Brazing uses lower heat, neutral or slightly carburizing flame.
Settings: Acetylene 3-5 PSI, oxygen 3-7 PSI.
For copper pipes, tip 2-3.
Pros: Strong joints without melting base.
Cons: Flux cleanup needed.
Tip: Use brass rods, heat evenly.
Real-World Applications of Oxy Acetylene Welding
In auto shops, for frame repairs—settings 5-8 PSI for 1/8” steel.
Farm work: Fixing implements, low pressures for thin parts.
Hobbyists: Art sculptures, precise control.
Industrial: Pipe welding, per ASME codes.
Story: Welded a trailer hitch at 10 PSI oxygen—held for years.
Pros and Cons of Oxy Acetylene Welding
Pros: Portable, cheap entry, versatile.
Cons: Gas hazards, slower than arc, skill-intensive.
When to choose: Learning or remote jobs.
Joint Preparation Tips for Optimal Welds
Bevel edges over 1/8” thick.
Clean oxides, oil.
Gap joints slightly for filler.
Prep work ensures penetration, reduces defects.
Filler Rod Selection and Compatibility
For steel: RG60, 1/16” diameter for thin.
Match rod to base—aluminum rods for aluminum.
Why? Compatibility avoids cracks.
Tip: Dip rod in puddle, don’t melt directly.
Maintaining Your Oxy Acetylene Equipment
Check regulators yearly.
Clean tips, replace O-rings.
Store cool, dry.
Anecdote: Neglected maintenance, had a stuck valve. Fix: Lubricate sparingly.
Troubleshooting Weak Welds Due to Pressure Issues
Weak bead? Increase oxygen slightly.
Porosity? Check for leaks, adjust to neutral.
Test pressures with gauge.
Conclusion
Wrapping this up, the key takeaways are simple: Use the oxy acetylene welding pressure settings chart as your go-to, start low and adjust for flame type, and always prioritize safety with proper equipment and checks. You’re now better prepared to pick the right settings, tips, and flames for any job—whether it’s steel repairs or aluminum fabrication. This knowledge builds strong, reliable welds that save time and money. Go ahead, grab your torch, set those pressures right, and weld with confidence.
FAQ
What are standard oxy acetylene pressure settings for welding steel?
For most steel welding, set acetylene to 5-8 PSI and oxygen to 5-10 PSI, adjusting based on thickness. Use a neutral flame for best results.
Why can’t I exceed 15 PSI on acetylene?
Acetylene becomes unstable above 15 PSI, risking explosions. Stick to manufacturer max for safety.
How do I light an oxy acetylene torch safely?
Open acetylene valve slightly, light with a striker, then add oxygen to adjust the flame. Never use a lighter.
What’s the difference between welding and cutting pressures in oxy acetylene?
Welding uses lower pressures (3-15 PSI) for controlled heat; cutting needs higher oxygen (20-40 PSI) for blow-through.
Can I use oxy acetylene for aluminum welding?
Yes, with a carburizing flame at 4-7 PSI each gas, flux, and aluminum rods. Clean thoroughly to avoid oxidation.
