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Porta Pack

Porta Pack

Porta pack/oxygen & acetylene

Clean the nozzle on the head. This should be done with a fine, round metal file. Just make sure that this nozzle hole is unobstructed. If holes are obstructed, a torch tip bore cleaning tool may be to clean the nozzle. Securely fasten the “head” of the torch on the end of the hoses. It should thread into a socket where both the Oxygen and Acetylene hoses come together. Usually this joint is brass. Tighten both valves on the “head” that you just secured in the socket. Make sure these valves are shut completely; otherwise, your gas/air mixtures will be off. Turn on your valves on the tanks. Acetylene should be set at 5 to 7 psi (pounds per square inch). (If acetylene is turned up too high, it can become unstable.) For welding (fusing), the oxygen should be set between 7 and 10 psi. For cutting, the oxygen should be set between 10 and 15 PSI. Now, this is where a cutting head and a welding head are different. A welding head is simple, and has two valves located near the base of the head. To use this head:   Turn on the Acetylene valve until you hear a slight hiss of gas from the nozzle.

Brazing/Welding

Take your striker/lighter and light the torch. This should produce a dark red-orange flame which puts out very putrid black smoke. Now, slowly turn on the valve that controls your oxygen, until you see the flame change. Careful: too much oxygen and you can “bleed out” the flame — which means the flame will go out. In this event, turn the oxygen off and try again. The flame should be blue with a white inside tip. The inner, white tip should measure around 3/8 inches long.

For cutting,

There is a different head. You will notice a trigger, and three tubes going up to the nozzle. First, turn the oxygen that IS released by the trigger, all the way on. Turn on the Acetylene valve until you hear a slight hiss of gas from the nozzle. Take your striker/lighter and light the torch. This should produce a dark red/orange flame, that puts out very putrid black smoke. Now, slowly turn on the valve that controls your Oxygen (there are two vaulves for oxygen on a cutting head, one blocked controlled by the trigger, one unrestricted), until you see the flame change. Careful: too much Oxygen and you can “bleed out” the flame. Meaning the flame will go out. In this event, turn the Oxygen off and try again. The flame, when the trigger is NOT compressed, should be a blue flame, measuring about two inches, with about a 1/2″ bluish-yellow inner flame. When the trigger is compressed, the flame will become much shorter, louder, and faster. When cutting, always heat the metal up to a nice cherry red, and then compress the trigger. Caution: Sparks will be thrown, so be aware and safe.

Safety

Always wear appropriate safety equipment: A welding helmet with appropriate UV protection Leather welding gloves Shoes Long Pants A long, sleeve shirt This is hot work and the clothing makes it hotter, but safety is better than injury Welding and cutting different metals require different temperatures Cast Iron is the densest, so it requires the most heat Steel and Stainless Steel is the second densest, so it requires slightly less heat Aluminum is the least dense, and requires the least amount of heat. Adjust your heads, mixtures, and temperatures as required for these metals Anchor Never, ever weld or cut alone. If there is injury or accident, you need someone around to help or call for help.

Oxy-Acetylene Welding

Oxy-Acetylene (OA) welding is one of the many types of welding supported by the PRL. It is extremely versatile, and with enough skill and practice you can use this type of welding for virtually any metal. In fact, the oxy-acetylene flame burns at 6000 °F, and is the only gas flame that is hot enough to melt all commercial metals. Oxy-acetylene welding is simple in concept – two pieces of metal are brought together, and the touching edges are melted by the flame with or without the addition of filler rod. This document will help you get started welding using the oxy-acetylene set-up. Read the steps below to get a feel for what is going on, and then get a shop TA to walk you through the process the first time.  

Advantages of Oxy-Acetylene Welding :

It’s easy to learn. The equipment is cheaper than most other types of welding rigs (e.g. TIG welding) The equipment is more portable than most other types of welding rigs (e.g. TIG welding) OA equipment can also be used to “flame-cut” large pieces of material.  

Disadvantages of Oxy-Acetylene Welding :

OA weld lines are much rougher in appearance than other kinds of welds, and require more finishing if neatness is required. OA welds have large heat affected zones (areas around the weld line that have had their mechanical properties adversely affected by the welding process)  

Preparation :

Assemble all of the materials needed to make the weld. This includes parts, OA equipment, fixturing, tools, safety mask, gloves, and filler rod. Clean the parts to be welded to remove any oil, rust, or other contaminants. Use a wire brush if needed to remove any rust. Assemble and fixture the parts in place – the parts need to be stable for a good weld line. Ceramic bricks, vise grips, pliers, and clamps are available in a file cabinet in the weld room for fixturing. Select the nozzle you plan to use for welding. Nozzles come in a variety of sizes, from 000 (for a very small flame – typically used for thin materials) to upwards of 3 (for a large flame – needed for thick materials). Larger nozzles produce larger flames and, in general, are more appropriate for thicker material. Choosing the right size nozzle becomes easier with more experience. Ask a TA or make some test welds to determine if you are using the right size nozzle. Clean the nozzle. Carbon deposits can build up on the nozzles which interfere with flame quality and cause backfiring. The cleaning tool has a wide flat blade (with a file-like surface) which is used to clean carbon deposits on the exterior of the nozzle. Use it to scrape any deposits from the flat face of the tip. Use the wire-like files to clean the interior of the nozzle. Pick the largest wire which will fit inside the nozzle, and the scrape the edges of the hole to remove any carbon buildup. Attach the nozzle to the gas feed line by hand. Don’t over-torque – the nozzle and hose fitting are both made of brass which doesn’t stand up well to abuse. A snug, finger tight fit is the sufficient. Check the pressure levels in the oxygen and acetylene tanks. There should be at least 50 psi in the acetylene tank. The oxygen tank can be used until it is completely empty. If needed, ask a TA to change bottles. Note: The oxygen used in OA welding in NOT for human consumption. It contains contaminants that could be unhealthy if taken in large quantities.  

Lighting the flame

Open the main valve on the acetylene tank ~1/2 turn. This charges the pressure regulator at the top of the tank. Open the pressure regulator valve on the acetylene tank (turn clockwise to open) and adjust the pressure in the acetylene line to 5 psi. DO NOT pressurize the acetylene over 15 psi – it will explode. Open the acetylene pin valve on the handle of the welding tool, letting acetylene escape. Tweak the pressure regulator valve until the regulator pressure is constant at 5 psi. Close the acetylene pin valve. Open the main valve on the oxygen tank. Turn the valve until it is fully open (until it stops turning). Open the pressure regulator valve on the oxygen tank (turn clockwise to open) and adjust the pressure in the oxygen line to 10 psi. Open the oxygen pin valve on the handle of the welding tool, letting oxygen escape. Tweak the pressure regulator valve until the regulator pressure is constant at 10 psi. Close the oxygen pin valve. Slightly open the acetylene valve (~1/8), until you can just barely hear acetylene escaping. Make sure there is no person or anything flammable in the path of the nozzle. Use the striker to ignite the acetylene. The flame should be yellow and will give off a lot of soot.  

Adjusting the flame

Open the acetylene valve further and watch the flame near the nozzle tip. Add more acetylene until the flame is just about to separate from the tip. (The flame will separate from the tip of the nozzle if you add too much acetylene.) If so, reduce the flow until the flame reattaches to the tip, and then open the valve again to the near-separation point. Slightly open the oxygen pin valve. If the flame goes out, turn off the gases and try again. DO NOT try and ignite the flame with both oxygen and acetylene pin valves open. As the oxygen is added the flame will turn bluish in color. The blue flame will be divided into 3 different color regions – a long yellowish tip, a blue middle section, and a whitish-blue intense inner section. There are three types of flames as described below : Neutral – This type of flame is the one you will use most often in the shop. It is called “neutral” because it has no chemical effect upon the metal during welding. It is achieved by mixing equal parts oxygen and acetylene and is witnessed in the flame by adjusting the oxygen flow until the middle blue section and inner whitish-blue parts merge into a single region. Reducing flame – If there is excess acetylene, the whitish-blue flame will be larger than the blue flame. This flame contains white hot-carbon particles, which may be dissolved during welding. This “reducing” flame will remove oxygen from iron oxides in steel. Oxidizing flame – If there is excess oxygen, the whitish-blue flame will be smaller than the blue flame. This flame burns hotter. A slightly oxidizing flame is used in brazing, and a more strongly oxidizing flame is used in welding certain brasses and bronzes.  

Welding

Put on a dark face shield to protect your eyes from the light of the flame. Make sure you have on long sleeves and all natural fibers. You can wear a leather welding jacket and/or gloves if it makes you feel more comfortable. Apply the flame to the parts to begin heating. Use the region of the flame near the tip of the bluish inner region. The metal will begin to glow. Continue heating both parts being welded until a small pool of welded metal appears near the edge of each of the parts. You must get molten pools on BOTH parts simultaneously to create the weld. The may require adding more heat to one side than the other, and takes some practice. After the molten pools have formed on both sides of the weld, use the flame to gently stir the two pools together to form the weld. This also takes a little practice. After the two pools have joined, slowly move the flame along the weld line, lengthening the pool using metal from both parts. A gentle, circular, swirling motion will help mix the molten metal from both sides as the puddle is lengthened. This process is highly dependent on the materials and part geometries being welded. Practice, practice, practice to get better control. Welding sample parts is a good idea.. Continue this process until the entire weld line is complete. Once you’re done, turn off the flame. Close the oxygen pin valve first, and then the acetylene valve. Note: Welded parts can remain hot for a LONG time.  

Backfiring

Improper operation of the torch may cause the flame to go out with a loud snap or pop. This is called backfire. It is caused by one of a few things. The first thing to do is turn the gas in the torch off, check all the connections and try relighting the torch. Backfiring can be caused by touching the tip against your workpiece, overheating the tip, operating the torch at other than recommended gas pressures, by a loose tip or head or by dirt on the seat.

Shutting Down and Cleaning Up

When you’re completely finished welding and are ready to quit for the day, you need to clean up. With the flame extinguished and the pin valves closed, close the main valve on the oxygen tank. It should be firmly seated at the bottom. Open the oxygen pin valve to bleed off all of the oxygen in the regulator and feed line. Close the pin valve once the feed line pressure has gone to zero. Fully back out the oxygen regulator valve so there is no pressure in the line. DO NOT close the valve, as this will pressurize the line once the tank is open again. In the case of the acetylene, if it is pressurized over 15 psi, it may explode! If you are not sure about doing this properly, find a TA to help you. Repeat steps 1 through 3 for the acetylene line. Return all of the tools to their proper storage places and coil the feed lines around the handle on the gas cylinder cart. Note: Do not remove the nozzle from the feed line. The feed lines should always have a nozzle attached to prevent accidental damage to the threads used to attach the nozzle
Gas bottles taps must be closed, if they not closed they will leak. Please look after the nozzle cost of replacement R240. 00. Damage to gauges - replacement cost R800 each. Close taps if not in use check gauges must work and not damage pipes for leaks nozzle for blockage do not operate in highly fla mm able areas for the risk of fire . We charge upfront for all the gas in the bottles. You will be refunded for the gas you return. Each bottle has a gauge, we note in quarters how much gas is in each bottle when we issue to set to you. When you return we charge per quarter for the gas that is used. Oxygen R200 per quarter. Acetylene R350 per quarter.
- If we deliver you must phone for collection please - we do not automatically collect.
- Machines are not insured, if not returned you will need to pay for the full replacement.
- Make sure you know how to use the tools. Ask if you need help, our friendly staff will assist. Also, make sure of safety requirements.
- Hires are charged for time out – not time used. Minimum 1 day (1 day = 24 hrs)
- Scaffold is charged weekly, all other tools daily.
- Tools must be returned Clean please. e.g., if you paint onto a ladder, we charge for cleaning.
- Negligent damages get charged separately.
- Consumables not used, may be returned for refund.
- Only use heavy-duty extension leads, not thin household leads.
- If you pay by cash we can refund in cash, if you pay by card we refund onto the card. (we can't refund onto debit cards) - Card refunds can take up to 10 days.
- Weekend hire starts after 2 pm Friday until 9 am Monday = 1day charge. ( Sundays are free) If you are late on Monday it is for 2 days.
- If you keep machines for a long time we can give you a better rate, discuss with your hire controller in store.
Brazing metal plating cutting up to 4 mm steel plate heating metal

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Festive season trading hours

Southfield and Paarden Eiland Branches

Closed and will reopen on 4 January 2024

Brackenfell Branch

Open with full service incl. deliveries on:

27, 28, 29, 30 Dec and 2 and 3 Jan from 8am – 12pm

Thanks to all our regular clients for your support in 2023! Have a wonderful festive season and best wishes for 2024.