Posts Tagged ‘plasma cutter’
Friday, February 10th, 2012
Little thought is given to joint type or design while welding on light gauge metal. Occasionally on real thin metal, a lap weld will be made or some similar accommodation may be made, of course. But overall, until the material to be welded exceeds 11 gauge material, most of the time 100% penetration can be achieved with little effort.
As metal thickness increases, beveling and grooving the plate will be necessary. Very few experienced welders would think of trying to tackle a 3/8″ weld without at least putting a simple V into the joint. Most of the time, a full 60 degree joint with a slight “land” will be made. Depending upon the thickness, a double bevel may be made as well so the joint can be welded from both sides. Joints under 3/8″ will also receive some form of beveling, whether it is a “V”, or a shallow “U” groove. On thinner metal, it may only be necessary to groove one side of the joint. On many thicker joints, a “V” grooved joint will be ground out on the back side, creating a shallow “V” or “U” to remove the first pass to eliminate possible weld defects that are trapped in the open root.
Actual determining factors in joint design, whether it is going to be welded with MIG, TIG, or Stick will depend upon the WPS or local codes, and relative position. The ultimate goal, of course, is to create the highest quality weld possible. A large thick, single pass at a high amp range will only serve to create weak welds, even if 100% penetration is able to be obtained, because of overheating the metal, and the metal cooling before all the slag can be floated out. In the groove, each pass should not be any thicker than the electrode itself, and the weld puddle no wider than 3 times the width of the electrode.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine
Posted in Welders | No Comments »
Thursday, February 9th, 2012
A normal by-product of welding are fumes. These fumes can have immediate and long term health risks. Up until just a few years ago, it was common to walk into welding shops and see a blue, gray or brown haze in the air. This was just an accepted thing to see, until more study and occupational laws began to tighten up. The short term hazards, of certain fumes can range from mild nausea and disorientation to death. Long term hazards can result in serious health issues including cancer, memory loss, and asthma like symptoms. One of the fumes created by welding stainless steel is the infamous hexavalent chromium, the chemical by product made famous by the Erin Brochovich movie. This can create birth defects in children and tumors.
It is almost guaranteed that any amount of welding will result in some fume inhalation. The best that can be done is to use common sense when dealing with the fumes to try to reduce the total amount of exposure. Welding outdoors when possible is a good place to start. This allows most fumes to be vented away from the area quickly. However, some fumes wills still be present. When stuck indoors, the ventilation is a must. Doors should be open if filtered ventilation systems aren’t present. Efforts must be taken to keep the welder’s head out of the direct flume of fumes. Ideally, a respirator designed specifically for welder’s helmets should be used, but many small shops and homes don’t have that available as a practical consideration. Maintaining a watchful eye, and a conscious awareness of the presence of the direction the flowing fumes are taking at all times will cut down on exposure. As stated, it is nearly impossible to eliminate all exposure. But exercising caution combined with a little effort will greatly reduce much of the risk so that long term and short term health outlook is much better.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine, welding safety
Posted in Welding Safety | No Comments »
Tuesday, February 7th, 2012
From time to time, mistakes are made in a weld seam, or a repair to a weld will be needed. It can be quite time consuming grinding and cutting the affected area to get down to good metal. Especially in a field repair situation, something may need to be rapidly cut or gouged away. The best solution is the Air-Carbon Arc Cutting torch. It’s a relatively simple process. Though it’s not as neat as a plasma or even an oxyacetylene torch, the Air-Arc process is rapid. It can remove a lot of metal in a very short amount of time. The Air-Arc process however, needs plenty of amperage to do the job properly. A simple high amp output Constant Current power source such as a stick welder is used. The usual minimum amperage required is 300 amps, though smaller electrodes will demand less amperage. The carbon arc torch is very similar in appearance to the standard tong type electrode holder. However, it also has a starting button and an air hose that provides a “jet” of air from the torch. Instead of a wire electrode, a carbon electrode is used, which provides a super hot arc. It is fairly slowly consumed, but it does wear. The arc is struck and held short while the air is turned on. The air pressure starts to wash away the metal, as the torch is held at a relatively flat angle. This is technically referred to as “gouging”. Carbon electrodes can be a little expensive, particularly the copper clad ones which last longer, and provide a little more uniformity in the cut. The torch oscillated gently around directing the arc and the air to spread out the cut. If a deep cutting action is need the torch should be rotated to a steeper angle. Slag and sparks come with the job, so extreme caution must be used to prevent the wash of slag being directed toward any flammable surface. Also good personal protective equipment is a must to prevent accidental back splash.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine
Posted in Arc Welding | No Comments »
Monday, February 6th, 2012
Surfacing is a process of depositing metal on items that have been worn down, or are subject to wear corrosion or other damage to help extend the life of the tool. This kind of welding is done not for creating joints or for joining metal, but for building up, and laying a protective layer or bead on top of vulnerable parts and pieces that are subject to wear such as backhoe buckets, or farm equipment plow points. More often than not, the surfacing is done to restore the metal back to the rough original dimensions, or to protect areas receiving uneven wear. There are two basic types of surfacing. The first is called hardfacing.
Hard facing generally involves the Stick or MIG process and uses special (and usually expensive) filler metal to build up the overall surface of the metal. These beads are often not laid solid across the entire face of the metal, but in random or organized patterns that intersect or overlap to provide a raid, bumpy like surface that takes the brunt of the wear or impact. Hardfacing is done to improve either abrasive wear or impact resistance of the metal.
The second method is known as “metallizing”. This is a special welding process in which nearly or all of the entire affected area is coated with molten spray of metal. This spray is used to build up the overall surface so that in many cases the original dimensions can be restored to the metal, such as in a crankshaft in an engine is deeply scored or overly worn on the journals. A special machine sprays tiny pieces of molten metal onto the crankshaft, building up the surface. Once it is sufficiently built up the area is turned back down in a lathe and polished so that it can be reused.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine
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Friday, February 3rd, 2012
MIG welding is most often used to join steel or stainless steel together. But with the properly equipped MIG, aluminum can be easily welded as well. Many MIGs use a device known as a spool gun to weld aluminum. It is a small, pistol shaped device that holds its own small spool of wire. The spool is approximately 4 inches in diameter and for aluminum use, the spool weighs in at about a pound. Welding aluminum requires the same DC+ polarity as other solid wire fillers. However, 100% pure argon is normally used. At times Helium can be added to improve the penetration. However for thin material, pure Argon is preferred. Aluminum MIG welding takes place in the spray transfer mode, which happens at a lower threshold than in Steel. Spray transfer is different from short circuit MIG. Trying to weld aluminum in short circuit mode, can make a terrible, wadded up mess. Spray transfer is smooth, quite, and the molten ball of aluminum pinches off before a “short” is ever created. It is a very hot process and fairly rapid and requires a much higher wire speed rate. One of the most overlooked details is that usually, the next size up contact needs to be used with aluminum wire. The greater swelling that aluminum exhibits, will cause the wire to seize up in the tip, if room for heat expansion is not left. There are other methods of welding aluminum with a MIG, including simply using the standard gun with a Teflon liner installed. In this type of setup, the cable has to be kept very straight and free from kinks or tight loops to feed properly. Of course a larger tip should be used as well. Also a similar device to the spool gun is used called a push-pull gun, which uses the cabinet to hold and push the wire, while a drive roller in the gun’s body “pulls” the wire to keep the wire from bird’s nesting inside the liner.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding aluminum, welding equipments for lease, welding equipments for sale
Posted in Mig Welding | No Comments »
Wednesday, February 1st, 2012
There are two basic ways to control the amps. The first is with the foot pedal which allows infinite control of amps real time. Though this sounds ideal, it is not a very scientific or controlled way of welding if the protocol for welding a particular joint, or metal type defines a narrow range of amps in which the weld should be conducted. The 2T/4T setting allows the operator to start the weld simply by pressing a trigger or switch located on the torch and use pre-settable features such as starting amps, up slope, down slope, and ending amps to manage the weld from beginning to end. Using the 2T function, the 2T normally indicates a press and hold type of operation of the welder. While the switch is held down, it cycles the preset programming automatically. This works well for some situations that require very little thought or skill. The 4T breaks this cycle up to allow manual initiation of each stage of the arc cycle. Pressing and holding the switch usually starts the arc. Releasing the switch will increase the amps to normal welding amps at the rate selected by the upslope. Pressing once again, will cause amps to begin to decrease according to the pre-set down slope until it reaches the final current, which is used to fill the crater so it won’t crack. Then, the switch is released to terminate the arc. Though this isn’t for everyone, 2T/4T does work well for most other countries in the world. A foot pedal is seldom seen outside of most US based welding shops.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine
Posted in Tig Welding | No Comments »
Tuesday, January 31st, 2012
Besides pulse, one of the most important adjustable features on a welder like the Everlast PowerTig series, or the Miller Dynasty series, is the adjustability of the AC frequency, and the AC balance. Both play their part in getting the most out of a AC arc while TIG welding.
AC frequency has been covered before. However, many people fail to realize just how important this feature is, especially if they have never used an inverter with features like this before. Standard transformer welders don’t have any choice but to operate on the same frequency that is supplied to the welding machine through its primary transformer. In the US, that is 60 hertz. Though that is adequate for many welds made in aluminum, it is far from ideal. A more ideal setting would be twice that at 120Hz. This level focuses the arc cone, and improves arc stability. Inverters excel in this because the frequency is generated by electronic components rather than the input power line.
AC balance gives a choice between penetration, and cleaning. Older transformer TIG welders have pretty much the input power line balance of 50/50 ratio between Electrode Negative and Electrode Positive. This offers typically more “cleaning” than is required to break up the oxide layer on aluminum. And it also overheats the tungsten, creating a molten ball on the tip of the tungsten, destabilizing the arc. A sharp tip can be maintained while increasing the penetration of the welder with just a 20-30 percent setting of Electrode Positive. Again, inverters open up the possibilities here by offering adjustable balances. Even when times call for it, inverters like the Everlast PowerTig series can operate at nearly 90% or more of full electrode positive, creating huge amounts of cleaning. Though that is unusual, and a little harsh to weld with, it is nice to know you have that adjustability at your finger tips.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, tungsten, Welders, Welding forum, Welding lease, welding machine
Posted in Tig Welding | No Comments »
Monday, January 30th, 2012
Pulse is more than just a setting you make or switch you flip on the machine. Though some “simple” machines may only have an adjustment for pulse frequency, there are other components to the pulse cycle that can be made with most welders. The appropriate terminology for pulse settings is not clearly standardized. This is mainly because of gaps in welding terminology and difficult terminology used by electronic engineers to technically describe what s happening. It is also because of differences in function between brands of each feature Pulse Amps, or Peak Current is used to establish a “high” current setting on some welders. On welders that use a ratio, or percent scale, this is actually a “dip” in current and is sometimes referred to as background current, or even base amps. In a welder that uses a fixed amps setting you will typically see base amps/ current, and Peak amps/ current used. In ratio controlled pulses where percentage of another current is used, this will often be listed as Main welding amps/Peak amps, and Pulse Amps/ base amps/ background current.
Next you will typically see a setting for Pulse width, Pulse Balance or Pulse time on. This is sometimes referred to as pulse duty cycle, but is often avoided because of the confusing terms involved with actual welder operation times referred to as duty cycle. The length of each stage of the pulse cycle is controlled by setting this function. It means that you can make the high amp stage of the pulse cycle longer or shorter than the low amps stage of the pulse cycle. Each half cycle doesn’t have to be balanced…it can be skewed to achieve the best result between melting and freezing. Even though the pulse is happening several times a second, each half phase of the pulse can be metered to give optimum results.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, Welding forum, Welding lease, welding machine
Posted in Tig Welding | No Comments »
Friday, January 27th, 2012
A lot of experienced TIG veterans weld all their life and never get to experience TIG welder with a pulse feature. The ones that are fortunate enough to try a TIG, say an inverter TIG like an Everlast PowerTIG, with Pulse, wonder how they could have done it so long without it. Pulse offers improved heat control over the weld, without sacrificing penetration, or speed. It is particularly useful in welding thin metals or edges of seams where the heat may wick over into the shoulder of the metal destroying the edge of a joint. It can also be used to create that stack of dimes look that all welders dream of, by allowing the operator to time the “dips” of the filler metal, according to the rate of the pulse. A slow rate of pulse can make a novice look like a pro in short order because of the dips will make an evenly spaced bead.
Most simply defined, pulse is a rapid oscillation between two pre-selected amp levels, one consisting of a high amp value and one consisting of a lower amp value. The high amp values represent a “penetrating” phase of the pulse, and the low amp value represents a cooling stage of the pulse, in which little or no melting of the parent metal occurs. The high amp portion of the pulse is when the filler rod should be added. The low amp portion of the pulse is the portion of the pulse when the torch should be moved forward. One complete cycle between high and low amp level in one second is one Hertz, or one pulse per second (pps). The frequency of most of these units is adjustable. The adjustability of the pulse frequency is important as well in the width of the arc cone. The faster the pulse the more narrow and constricted the arc becomes allow it to be pointed into tight corners.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for lease, Welding forum, welding machine
Posted in Tig Welding | No Comments »
Thursday, January 26th, 2012
A main issue often encountered with plasma cutters is angularity or “beveling” of the cut. Nearly all standard definition plasma cutters will exhibit some beveling. You’ll find more or less beveling between brands as well. Too large of consumables for the cut is a primary cause of beveling. Sizing consumables for the amp output of the cut will keep the beveling down. Drag cutting and moisture will also cause issues with beveling by increasing the wear on the consumable, and opening up the orifice to a larger size, even “angling” the hole in the nozzle, creating a more exaggerated bevel. Using a rolling stand off, or specially designed consumables that can protect the orifice where the flame exits by preventing the area from contacting the metal, will increase the life of the consumable. Of course using special dryers that you’d use in a paint booth, will increase consumable life as well. Reducing piercing, and plunge cuts will prevent the blowback of material on the torch face that creates rapid wear as well. Managing a consistent but minimal standoff height manually poses some challenge but is possible. Practicing will result in improved muscle control and smooth movement to reduce beveling caused by off angles caused from holding the torch wrong as well. Additionally, you will find that a torch will have a natural side, to which the bevel will always turn. Taking note of this will help in cases where the bevel is angled to the throw away side of the material.
Tags: Arc Welder, MIG Welder, plasma cutter, TIG Welder, Welders, welding equipments for sale, Welding forum, Welding lease, welding machine
Posted in Plasma Cutters | No Comments »
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