- 1 Why Oxyacetylene Welding
- 2 Knowing the Equipment Components
- 3 Top 5 Oxyacetylene Kits
- 4 Conclusion
Oxyacetylene welding is one of the oldest types of welding and demands special skill for getting the best result. In fact, the ancient popularity can be deduced from the fact that prior to the invention of electricity in rural areas, only this welding unit was performing the desired tasks in farming/ranching areas.
Although now faded in popularity for industrial uses, the technique is still preferred for several applications such as welding pipes, conducting brazing, performing repairs, and making sculptures and other artwork.
Also called Oxy-Fuel Welding (OFW), this kind of welding involves combustion with oxygen acting as a medium of heating. It includes acetylene and oxygen gases for welding metal quite quickly. A flame is generated at the tip of a torch by using these gases, while pure 100% oxygen boosts the flame’s heat for melting a filler rod (metal) and the metal in a workroom.
The combination of acetylene and pure oxygen gives an amazingly hot flame of 3,500 degrees Celsius or 6,330 degrees Fahrenheit. Both of them are mixed in suitable proportions inside the torch’s mixing chamber. The filler metal (optional) and molten metal from the edges of plate mix to form a molten pool and unite while cooling down.
Why Oxyacetylene Welding
Such a welding technique is ideal for welding thin steel sheets, plates, tubes, and pipes smaller in diameter. It is also preferable for repair welding, bronze welding, brazing, forging metal, and cutting metal.
Ideal materials for this kind of welding include mild steel, low alloy steels, carbon steels, and nonferrous ones, while brazing with this technique is perfect for brass, copper, stainless steel, and aluminum. The technique is also common in artisan welding, fabrication, and automotive repair stores. Here are the reasons why oxyacetylene welding is famous even today.
- Easier to use and learn than MIG/TIG
- Cheaper and more portable equipment than other welding techniques such as MIG/TIG
- Usage almost anywhere, even outside, unlike MIG using shielding gas
- Versatile use, even for cutting big pieces, preheating, straightening, bending, surfacing (due to least dilution with stuff to be welded), surface carburization (via reduce flame usage), braze welding, and post heating
- Versatile torch acting as a brazing torch, cutting torch, and a heating torch for shaping and bending
- More closely fulfillment of all requirements of aforementioned applications, than other fuel gases available commercially
- Assurance of precise control over heat input and flame temperature by adjusting the flow of gas, regardless of the presence of filler metal
- Variety of accessories such as multi-flame nozzles, cutting tools, and hoses; mechanized and manual cutting tasks with simple changes in them
While there are justifications for using oxyacetylene welding equipment, such models are also not free of limitations. They have low deposition rates, are not economical for welding thick stuff except for repair task, and okay weld properties as compared to those of arc welds. The okay quality of mechanical properties is perhaps due to the surrounding big zones affected by heat. Moreover, the weld lines produces are quite rougher in looks due to which more finishing is required, in case tidiness is essential.
Knowing the Equipment Components
Before you even start searching for oxyacetylene welding kits holding several components, it is essential for you to know them along with their way of working. This is because for welding, heating, or cutting almost any metal, it is necessary to have all the required components. Several components make up the kits, which include as cylinders, hoses, valves, and regulators. Let’s explore them now!
Usually, steel cylinders are used to store both the gases. The cylinders are sized by the cuft. of the gas they contain. An oxygen cylinder is usually in green color and range from below 20 to more than 300 cuft. It holds compressed gas with a pressure between 2000- 2640 Pounds Per Square Inch (PSI). Cylinders holding oxygen are forged from robust shield plate steel. None of its part shall be below ¼-inch thick. They employ a thin pressure safety disk of stainless steel, which aim to be cracked.
Those holding acetylene are usually black, gray, or red and have a size ranging from 10 to 400 cuft. These cylinders feature some porous filler for being wet with acetone for safe containment of acetylene at 250 PSI. It is essential to hold this cylinder in the upright manner to keep acetone intact in the tank.
All the cylinders come with valves (not those “R” tanks) affixed with a screw on cap made up of steel for defending the valve when not in use. You should handle a valve carefully, without oily or greasy hands.
Always check for stamp of last testing date atop the cylinder, as cylinders are tested regularly. Further, both cylinders should be upright and secured.
With high pressure rates in a full cylinder of either gas, something is required to lower the pressures such that it is suitable for the torch. This is where an adjustable pressure regulator comes in, which retains a stable pressure. It functions by accepting the pressure of the cylinder via a valve run by an adaptable diaphragm of stainless steel.
In simple words, a regulator in oxyacetylene welding controls pressure into the hoses and from the tanks/cylinders. The worker then needs to adjust the rate of flow via a group of needle valves residing on the torch. It is essential to set up a constant inner pressure into the hose for the needle valves to offer precise flow control for good quality welds.
A majority of regulators come with two gauges, of which one displays the inner pressure (high pressure) gauge and another displaying the pressure given from the regulator (low pressure or working pressure in hose) gauge. Many regulators are for rough or heavy-duty service and are without gauges but with a scale for having the desired pressure adjustments.
You will come across two regulator types namely, second stage and single stage. In the single stage, a fixed-pressure regulator retains the pressure freed from the cylinder at a constant load, even if cylinder pressure is falling. In the second stage that is adaptable, the first stage’s fixed pressure is alleviated to the low outlet pressure. While both render the same job, the second stage one give a more constant pressure once the pressure in the cylinder drops. Further, this type of regulator is more of heavy-duty kind as well as lasts longer with less maintenance despite heavy use. You can easily identify such a regulator with the presence of second pressure chamber, which single stage models lack.
It is also vital to note that the acetylene and oxygen regulators connect in a separate manner to their cylinders. The oxygen ones come with right hand threads, while acetylene ones possess left hand threads. All low pressure gauges on regulators for acetylene come with gauge scales showing a red mark at 15 psig, the maximum pressure limit for using acetylene.
3. Regulator Hoses
A double line rubber hose (type VD) connects the torch and regulator of cylinder. The green or blue line denotes oxygen, while the red line signifies fuel. You will see hoses usually in these sizes, 3/16, 3/8, 1/4, and 1/2 inch I.D. For Acetylene, various grades of type VD hoses are used, such as non-greasy resisting rubber cover and oil and flame resisting cover.
While oxygen hoses come with right hand thread, acetylenes one are red and have left hand thread. You can identify the left hand thread via a grove in the nut’s body along with an optional “ACET” stamp. Look for R & RM grades, as they are only for acetylene. Further, do look for service level marks such as standard, light, or heavy. Usually, you will also see hoses in common sizes, which are 5, 10, and 12mm ID.
4. Check Valves
The combustion resulting from the mixture of oxygen and acetylene needs to occur only in the torch tip or chamber. However, at times, improper handling can feed the gases into the regulators or hoses, where combustion can occur. Well, this is not good at all! This backflow is prevented by check valves lying between the torch and hoses. They do so by closing themselves when a reverse flow begins. Therefore, you should always have check valves for any of your torches.
5. Flash Back Arrestors
A flashback is a quick flame of high pressure, which occurs in the hose when there are no check valves or when they fail to run because of faulty installation. Check valves cannot stop a flashback once it triggers, but a flashback arrestor always does so! It works by connecting the hose at the regulator or torch and holds a spring-loaded trap for breaking the gas flow in case of flashbacks. Thus, you also should have flashback arrestors in the kit, as they act as economical insurance covers.
This is perhaps the main part of any oxyacetylene welding kit. Its main function is to adjust and control the flow of gas when you weld. It is actually an assembly of oxygen and fuel gas valves, mixing chamber, and handle. Both the oxygen and acetylene pass via the handle and combine at the tip to catch fire.
Such a torch assembly generates heat by burning acetylene, while inclusion of oxygen triggers the temperature of the flame at around 5,620 degrees. The assembly is highly versatile, as it is capable of producing its own portable source of heat for brazing, heating, and cutting a variety of metals.
A basic assembly usually has two cylinders of high pressure and corresponding regulators. There is also a dual line hose for transferring both the gas from regulators to the handle. The handle of welding torch is capable of containing a welding tip, cutting attachment, or heating tip (not included in all basic torch kits).
For cutting with torch, a cutting tip associated with the cutting attachment’s end is indispensable. This tip regulates the thickness of material under operation along with the pressures established at the regulators.
Two basic types of mixer exist, wherein the gases unite. These are injector and medium pressure type also known as positive, equal, or balance pressure type. Of the two, the latter one is more common and is preferred for pressures over 1 PSI. In such a mixer chamber, both the gases enter at approximately equal pressures. On the other hand, the injector type is preferable for pressures below 1 PSI and for facilitating high-pressured oxygen to pull acetylene into the chamber.
Regardless of the torch kit you consider, you are ensured of 5,620 degrees as the working temperature. Further, the cylinder’s size does not influence the flame temperature but affects the duration for which the flame shall burn.
A welding torch is rated as per thickness of metal under welding consideration. This rating ranges from light duty to heavy duty, the former being ideal for sheet steel of up to 2mm and heavy duty for steel plate over 25mm.
Well, the nozzles that you select need to be the right one. A torch that you select should accept a variety of nozzles featuring a diameter as per the material thickness. The pressure of gas should be such that it contributes in offering the precise flow rate for the nozzle’s diameter.
8. Flame Type
In the mixture, oxygen and acetylene proportions can be controlled to have a carburizing, oxidizing, or neutral flame. For welding, a neutral flame is essential, featuring equal amount of both gases. However, in most cases, little more oxygen results in a vivid whitish cone flanked by a clear blue envelope. Neutral flame is essential for welding cast iron, copper, aluminium, and steels.
For having an oxidizing flame, some more oxygen should be added, which makes the cone darker and sharper with shorter and more intense envelope. This flame boasts the highest temperature and is useful for brazing tasks and welding brass.
In case of a carburizing flame, the flame appears to be a long internal white section flanked by a clear blue envelope and has the least temperature of all flame types.
In oxyacetylene welding, the flame has two parts inner or chief combustion area and outer or secondary combustion area. The inner one is the hottest area. While welding, the inner area’s point has to be over the joint edges. On the other hand, the outer area preheats the edges of the joint and averts oxidation by utilizing the flanking oxygen from pool and emitting water vapor and carbon dioxide.
9. Welding & Cutting Tips
Designed for letting the gas mixture contribute to flame, the welding tip resides on the handle’s end. You can find tips in a myriad of sizes and shapes for facilitating any welding job. They are identified through a number. The higher the number, the bigger the tip’s hole and thicker the metal it can cut or weld.
A welding tip possesses a single hole, while a cutting tip has a mid hole surrounded by several smaller holes in a spherical pattern. While oxygen comes from the mid hole, preheat flame emits from the surrounding holes.
Well, there are several factors to decide the tip size but it is chiefly the metal’s thickness that makes you determine the size.
10. Welding Goggles & Gloves
These two safety gears need to be tough and durable for ensuring protection while using the oxyacetylene kit. Choose gloves that are designed specifically for welding use for safeguarding your hands, while face shield or goggles on eyes should be such that the harm from hot metal and sparks stay way, particularly while cutting.
Minimum shade #5 safety goggles are required for protection from torch. The right lens shade is essential for maximum protection. Shade #5 is recommended for light and medium cutting, welding up to 12mm, as well as brazing, #6 for heavy cutting, and #8 for heavy welding (13mm+).
There is also a need of hand-held striker for securely sparking as well as a cylinder cart for safely containing the cylinders as well as accessories.
Top 5 Oxyacetylene Kits
This one is a lightweight kit that is portable enough to be carried around almost anywhere. It is a medium duty kit designed for welding and brazing for commercial applications related to plumbing, ventilation, air conditioning, and heating. With this kit, you can weld steel of up to .125 inches and braze copper tube that is of an inch by using the supplied tips. The kit contains 10 items, including the two regulators, handle with front valve, weld/braze tips, safety goggles, twin hose set, tank key, flint lighter, and a carrying stand of plastic. While it does not include cylinders, it supports “R” oxygen cylinder of 20 cubic feet and “MC” acetylene cylinder of 10 cubic feet.
This one is perhaps the most portable as well as durable kit for welding, brazing, and cutting. The kit comes with two regulators of 2-1/2-inch diameter, cutting attachment, check valves, legible 2-inch regulator gauges, and double line hose. The handle is of brass and stainless steel, which adds to longer life shelf than normal handles. You also get tip cleaner, welding nozzles (0, 2, and 4 sizes), flint striker, cutting tip, dual line hose, goggles with #5 lens, and heating nozzle with rosebud tip. The kit is perfect for welding up to half inch of steel and cutting up to 6-inch of steel with proper tips. You also get a protective case for storage.
This is a medium-duty kit for welding up to 1.25-inch or 1/4-inch using optional nozzles and cutting up to 6- or 1/2-inch using optional tips. It includes ESS3 Edge regulators, check valves, flashback arrestors, 100FC torch handles, cutting attachment, heating nozzle, cutting tip, welding nozzle (size 1), T grade hose, tip cleaner, striker, and shade 5 goggles. Small cylinders can easily fit into this outfit. Above all, it offers all tips required, welding tip, cutting nozzle, and heating (rosebud) tip. This unit gets the job done without giving the heavy or bulky feel.
This is another portable kit to consider, but comes with Dot stamped tanks for medium duty processes. With this kit, you can weld up to ¼- or 1-1/2 inch by using optional nozzles and cut up to ½- or 4-inches by using optional tips. It comes with two regulators, check valves, flashback arrestors, 100FC torch handle, cutting attachment, welding nozzle, a T-grade hose, cutting tip, goggles, and a striker.
This kit is ideal for not only welding but also gauging, soldering, and cutting metals. For this purpose, it comes with several hoses, nozzles, and fittings. There is also a torch set including regulators for both gases, twin hose with fittings, handle, welding nozzles (Sizes of 0, 2, and 4), cutting tip, and tip cleaners. You also get a heavy-duty case for storage. However, there are no check valves and flashback arrestors. Because these safety features are lacking, this kit is ideal for hobbyists doing small jobs.
While you will find several kits with most basic and additional accessories, it can be confusing to choose the right one. To overcome the confusion, it is best to go through the expert and customer reviews of popular and reliable outfits or kits. Even after analyzing these promising products, it would be wise to choose the one as per your requirements and budget. Requirements involve the metal to be welded, its thickness, types of applications you will be undertaking, and frequency of usage.
Just bear in mind that there is no best welding kit out there. What is best for one operator might not be even good for you. Thus, you need to choose according to your needs.
We recommend going through our reviews for getting an idea and taking an informed decision.