Archive for September, 2011

GTAW Process: Shielding Gas and Regulator Selection

Friday, September 30th, 2011

There aren’t many choices available for shielding gas selection in TIG. It’s fairly straightforward. Pure Argon is the most popular and common shielding gas. Most people buy and use pure Argon in whether welding aluminum or steel. Unlike MIG, blends of CO2 and Argon cannot be used. If CO2 is used, it will contaminate the weld and will rapidly consume the tungsten. Often Argon can be contaminated with CO2 since the welding supply companies can use the same tanks to fill Argon and Argon blends. Helium and Argon are often blended, especially while welding Aluminum to increase penetration. Blends of Argon and helium are more expensive and some problems can be experienced since argon sinks and helium rises in the atmosphere. Also when too great of a helium percentage is mixed, arc starts can be erratic or make the arc unstable. The operator should be aware of which type gas is being used, because amp and flow settings will be different.

Not all regulators are equal. There is the floating ball type that visually regulates the gas flow and then there is the less expensive gauge type regulator. The floating ball is easier to see and read at a distance, and is a personal favorite. Both do a decent job of regulating the gas, but be sure to select a regulator that is calibrated for the gas or gas mix that you are using. Some will regulate both MIG gases and TIG gases. Some have dual or triple scales for several different blends. Blends high in helium require much higher flow rates. Also check whether the gauges are calibrated in Liters Per Minute (LPM) or Cubic Feet Per Hour (CFH).

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GTAW Process: Torch Selection

Wednesday, September 28th, 2011

Almost all TIG welding units come with a base model torch or you must purchase a torch package at the time of purchase to suit your needs. For the beginner, the base torch package may work just fine, however, many people find that no one torch suits all their welding needs. The small shop will usually have a need for at least two different torches for any TIG unit.

Usually the TIG torch that is included as part of the standard package will not hold up to the full amp and duty cycle capability of the welder. Everlast takes a different approach with supplying a torch capable of the full maximum amps of the machine. However, this presents a problem for some because of the torch size required to handle the maximum amps, it is more difficult to to maneuver. Its hard to know exactly which torch will be best for all customers because of all the different variables that the customer may face. It’s up to the customer to decide which is ultimately best. The following information can be used to help with new torch selection.

1) Decide what amps you will need. This can be done by deciding what metal and what thickness will be typically welded. Use the 1 amp for every .001” as a general scale rule to decide the maximum amp of the torch. For example 1/8” (.125) would require about 125 amps. This is may actually put the amps required on the high side, but it’s a safe number.

2) Take a look around the shop for any other torches…Selecting one that uses consumables already in stock may be an important factor.

3) Decide if flexibility is key. A flex neck torch may be in order. Flexible necks can reach into tight spots and make things more comfortable while welding.

4) Consider the cost. Torches range in price. Some high end torches can exceed 200-300 dollars.

5) Decide if you will need a torch/remote switch included on the torch or if you want amp control built into the handle. A torch switch makes use of the panel programming on the welder. If a foot pedal is used exclusively this is not a consideration. But there are times in out of position welds that may require the flexibility of having a remote switch or amp control at finger’s reach.

6) If welding over 200 amps, a watercooled torch and water cooler will be necessary to keep the torch from melting and hand temperature tolerable. Even if welding is sustained over 120 amps, a watercooler may

7) While there are newer series of TIG torches, there are 5 basic sizes for most commercial welding: 9, 20, 17,26, and 18. These torches may have some prefix such as “WP” or “SR” but the consumables and basic torch design is usually the same for the same series torches. An F after the torch number indicates a flexible neck. A V indicates a gas valve for scratch start tig rigs. Here is a brief summary of each torch series:

  • A) 9, air cooled with maximum amps of 125 and duty cycle ranging from 60-100%. Uses same consumables as the 20. Standard whip design with bare cable running inside the argon hose. The smallest typical torch with the lightest feel.
  • B) 20, watercooled with a maximum amps of 250 and duty cycle ranging from 60-100%. Uses same consumables as 9 series. The smallest water cooled torch for general use.
  • C) 17, air cooled with maximum amps of 150 and duty cycle ranging from 60-100%.Usually sold with standard whip design, though it is available with a separate gas and power line. A good medium sized torch though not the size of the 26, even though it uses the same consumables as the 26 series and 18 series.
  • D) 26, air cooled with maximum amps of 200 and duty cycle ranging from 35-100%. Usually sold with a separate, two piece gas/cable design. A fairly large torch with nearly the size and bulk of the 18. It shares the same cons as the 17 and 18.
  • E) 18, water cooled with maximum amps of 300-350 and duty cycle ranging from 60-100%. The largest torch commonly used that most welders will own. There are larger sizes of course, up to 600 amps, but these are in a whole different class.
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GTAW Process: Tungsten Selection

Monday, September 26th, 2011

TIG welding of course could not exist without the “T” in TIG. The “T” stands for tungsten. The tungsten is a small shaft of elemental tungsten used as a semi-permanent electrode to produce an electrical arc between the tungsten tip and the metal. Though considered a consumable, it does not consume at a rapid pace as in MIG or Stick welding. However, they will wear rapidly in hands of inexperienced users, through overheating, and constant immersion or “dipping” into the molten weld pool.

Tungsten can be offered as pure tungsten or combined with some other element to exhibit different welding characteristics. Along with each element, varying percentages of the secondary element can be offered. Each Tungsten with its own percentage of alloying metal carries its own color marking on the Tip, and is commonly referred to the color instead the actual components and percents. However, there are some variations in color from country to country. Much of today’s tungsten is imported, and different colors than the standard color can be expected.

Green tungsten is referred to as “pure” tungsten. Pure tungsten is traditionally used only with AC welding. However, with todays high performance inverter welder machines such as the Everlast PowerTig series welders, pure tungsten is a very poor choice. It will not last long and exhibits poor arc stability. Many websites and texts still recommend green tungsten for welding aluminum, borrowing recommendations from material written up to 50 years ago. This old information is confusing to many old and new welders, especially when the pure tungsten just melts away when it is stuck in an inverter machine. It’s still suitable for welding with transformer based welders, and is welded with a fairly large molten ball forming hanging on the end. It will not allow the pinpoint arc precision as some other tungstens, since the ball does not focus the arc and is subject to wander around the ball if proper technique is not used.

GTAW Tungsten Selection

GTAW Tungsten Selection

Thoriated Tungsten (2%) has been the standard for the welding industry in the United States for DC welding. Again, things have changed with the advent of inverter TIG welding systems. Commonly referred to as “Red” tungsten, it has excellent arc starting and overall welding capabilities. It can be used for AC or DC welding with inverter machines, such as the Everlast PowerTig 250EX. But it’s not the best choice for AC welding in transformer machine however, though it can be done. It can be sharpened to a fairly sharp point, and does not have to be balled while AC TIG welding aluminum. However, if overheated, it can split and form nodules on the side of the tungsten, creating a destabilized arc. One drawback of the thoriated, is that it is slightly radioactive. However, the radiation exposure is small compared to some other daily forms of radiation that exist. As long as the tungsten grinding dust is not breathed in, little risk, even while handling exists. Some foreign countries frown upon the use of Thoriated tungsten for its radioactivity. However, the risk does seem to be low as proven by many years of use in the industry. Overall, it probably offers the best performance for the price with a higher amp tolerance level for any given diameter.

Ceriated Tungsten (2%) has been recommended by major manufacturers of welding machines as an acceptable alternative to Thoriated tungsten for users of inverter welders. It has good low amp performance, with easy arc starts at low amp levels. However, the Orange tungsten is quite expensive compared to the Red. Some people swear by it and its performance. Others are not quite sure. Testing of Ceriated tungsten has shown that there may be some deficiency when compared to Lanthanated Tungsten. But there seems to be some strong opposition to that from people who regularly use Ceriated. Keep in mind it may be difficult to find at the local welding supply store. Many online sources have it so be sure to shop around as the price and quality varies greatly.

Lanthanated Tungsten is popular in 1.5% and 2%. Testing of both has shown that having more is not necessarily better. Lanthanated 1.5% is marked with a Gold paint, and Lanthanated 2% is marked with blue. Both have found considerable favor in the industry with many preferring the 2%. Many Everlast customers, who prefer not to use Thoriated tungsten have reported that this seems to work better for them than Ceriated. It seems to be found in more local locations than Ceriated. Price is slightly lower than ceriated overall.

Other types of tungsten are available, of course, and with the race to be newer and better, there have been unique blends with custom names t. Zirconiated has been promoted for AC use in transformer machines, but no real benefit is achieved for inverters. Custom tri blends have been recently promoted by a few companies, and sell at a premium price. However, they have not been around long enough to gain wide spread acceptance. Whether or not these actually provide a improvement remains to be seen, whether they perform all around better or not.

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GTAW Process: Consumables

Friday, September 23rd, 2011

TIG welding accessories and related items required to weld can require the largest cash expenditure besides the welder purchase itself. Items needed are basic consumables like Cups, collets, back caps, tungsten, and gas lenses. Consider byying these in full box volume. The overall cost per item will be lower when bought a box or full package at a time, and the peace of mind is well worth the extra cash. Many welding supply stores will sell partial box quantities of each, yet they can charge up to 50% more for small lot items. Usually items such as tungsten can be economically in 10 packs. Collets and cups can be bought in 5 and 10 packs as well. Gas lenes are usually sold individually and last for some time. However, different sizes should be considered along with the appropriate cups. These quantities are manageable for most small shops and home garages.

Cups are the ceramic nozzles that train the flow of shielding gas. They are fragile by nature and dropping the torch, overheating it, or any mistreatment will result in breakage. Fortunately, when bought in box quantities, the price is manageable. Multiple sizes will be required to suit different parameters such as joint type and amperage. Gas lenses help improve gas flow, and special designed cups are used with gas lenses. If a gas lens is purchased, then an extra assortment of cups will be required.

Collets hold the tungsten securely in place while welding and allow shielding gas flow to pass through to the cup. Collets are sized to match the corresponding tungsten diameter. Collet bodies hold the collets and the tungsten tightly as the back cap is tightened against the collet. They are usually sized to correspond to the appropriate collet size, however some collet bodies will work with multiple sizes of collets. Collet bodies aren’t as prone to damage as collets, and only a few of these are needed, one or two per collet size. However, collets can be damaged from the heat and from inexperienced welding techniques. 5-10 of each size to start would be ideal.

Back caps come in short, medium and long lengths. This allows greater flexibility in reaching tight areas. While fairly resilient, they can break through mishandling or over tightening. At least a couple of each size should be kept in inventory. These are usually purchased in single lot quantities.

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GTAW Process: Proper Wiring

Wednesday, September 21st, 2011

After securing the appropriate TIG welding PPE to be able to safely weld, the next step is to prepare the welder station. To get started, the power supply must be properly wired to input volt and amp requirements of the TIG welder you have purchased. It’s actually cheaper to buy a welder that matches the power supply that you already have. But in a home garage or small shop, the correct receptacle may not be present that meets the wiring codes for a welder. An electrician who knows and understands the NEC section 640 should be hired. Wiring requirements for welders are much different than for appliances. De-rating is allowed to match the duty cycle of the welder, and breaker requirements are different as well. Welders are wired differently as well. For example, a welder running on single phase 220/240V power requires only two hot wires, and a ground wire. No neutral wire is used.

GTAW Process: Proper Wiring

GTAW Process: Proper Wiring

A 3 prong NEMA 6-50 plug is usually recommended and is the standard plug for most welders. Depending upon your existing wiring, this may be a considerable initial expense. Consider having an extra outlet or so for your welder or additional purchases put in at the time the electrician is on site to reduce additional costs later. An outlet every 25 ft is a good starting point. If not, make sure it is centrally located to where most of the welding will be done. Extension cords for welders are not a good idea. The welders should be plugged directly into the outlet whenever possible. Note that many TIG welders have an additional grounding requirement to help reduce issues with High Frequency interference. This usually requires a second bonded ground that is connected to a ground wire directly to a copper or steel rod driven into the ground that is connected to the rear of the machine via a separate cable. Keep in mind, a licensed electrician should always be consulted and codes followed.

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GTAW Process: Personal Protective Equipment

Monday, September 19th, 2011

For the Beginner, TIG welding does offer an exciting and sometimes frustrating experience. It’s encouraging to know, that with practice and time, those first ugly, ropey welds, that resemble 4 day old road kill can be often be turned into nice, tight little stacks of dimes.

Getting a handle on TIG welding equipment and what is required to TIG weld properly helps to prepare the first timer to get up and running as quickly as possible. There are other items such as personal protective equipment, and welding accessories that must be purchased along with the welding machine to get safely started.

GTAW Process

GTAW Process

Of upmost importance, the newcomer will require substantial safety gear. A GOOD auto darkening helmet (also referred to as a “hood”) is the first requirement. Do not rely on cheap 2 sensor designs to TIG weld. A more expensive 2 sensor design can be used, but if a lot of low amp TIG welding will be done (below 30 amps or so) , a 3 or 4 sensor design will be required for maximum sensitivity. A good welding helmet will usually start around 175.00 and can exceed 700.00 dollars. Clarity is of concern as well. Don’t automatically go for the largest viewing area. Instead, look for clarity and quality over a “big” lens. Consider a quality pair of safety glasses as well. Some are available, that while clear, do offer protection from stray arc rays that tend to reflect off other objects in the area and make their way under the welding hood.

Gloves while important are more subjective. TIG gloves come in many styles, lengths and materials. Commonly, you’ll see goat skin and deer skin as a common leather component, to maximize sensitivity and flexibility. However, TIG can be a hot process and too thin of a glove can lead to serious burns. Don’t be tempted to leave off the gloves. Skin cancer is a real risk. The welding arc rays are more intense than the sun’s and can quickly cause painful sunburn, in a matter of minutes. A rule of thumb in considering a good TIG glove is that you can pick up a dime off a flat surface with the gloves on.

Another essential item for protection is a welding jacket, or at the very minimum, welding sleeves. Welding jackets come in a variety of styles: capes, jackets, lab coats, made from leather, fire resistant fabric, denim or any combination thereof. The idea is to provide the most protection with a level of comfort that safeguards the worker. Welding sleeves do provide a higher level of comfort and freedom of movement especially in hot areas, but may not offer adequate protection against stray rays that can penetrate thin shirts. If sleeves are to be worn, a minimum of a heavy denim shirt should be worn. Regular T-shirts and other shirts still transmit much of the harmful radiation.

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GTAW Process: Overview

Friday, September 16th, 2011

The Gas Tungsten Arc Welding (GTAW) process, commonly referred to as TIG, has long been considered a fine art form of welding. As a welding process, TIG welding, requires the most knowledge, practice, patience, and overall skill. Even many professional welders are reluctant to add the GTAW process to their welding repertoire due to the skill level and practice needed to thoroughly master.

GTAW Process

GTAW Process

Thanks to many of the reality fabrication and do-it-yourself shows and a sluggish economy, TIG welding has gained in popularity. A lot of people have suddenly found themselves edging toward owning their own business, whether it’s a motorcycle, rod shop, or even machine shop after watching non-stop marathons of their favorite fab show on the Discovery Channel or Speed Channel. One of the first purchases often sought is a TIG welder, as it seems to be the backbone of every DIY show on television, so naturally, it must be the backbone of the new shop. Right? Unfortunately, it’s also the very same purchase that brings the first dose true reality to newest Chopper shop to open its doors. It seems that TIG welding is not as easy to master as it seems. For some, the sheer cost of just getting started buying TIG welding related accessories blows the budget. The disappointment experienced by many not to be able to instantly weld is often a setback to getting the business going. Over the next few blogs, we’ll look at various aspects of TIG welding to offer some guidance and support to the person interested in making their first TIG welder purchase and getting their business off to a successful start.

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