Precision Tig Welding

PRECISION TIG welding requires three thing, heat, shielding, and filler metal. The heat is produced by electricity passing through the tungsten electrode by creating an arc to the metal. The shielding comes from a compressed bottle of gas that flows to the weld area to protect it from air. The filler metal is just a wire that is dipped by hand into the arc and melted. The way these three things come together is pretty simple. First the welder turns on the gas flow, many times by a valve on the TIG torch itself. The gas begins to flow and starts protecting the weld area from the air. The torch is held over the weld joint just far enough for the torch not to touch the metal. Then the welder presses a foot pedal, and the TIG torches tungsten electrode starts an arc. Once the arc is started the two pieces of metal begin to melt by creating a puddle of metal. Once the puddle is established the welder with the other hand starts filling the joint by manually dipping a welding wire into the arc to fill the joint. Ultimately this process creates a single piece of metal.

PRECISION TIG WELDING can weld almost any metal. This is possible because the main gasses used are noble inert gasses and their properties do not alter the weld properties. Most other welding processes use some type of flux or chemical additives to the filler metal. With PRECISION TIG welding it is pure heat that creates the weld joint and that allows any metal that can be melted to be joined as long as the filler wire is compatible. Some of the exotic metals that are commonly welded are:

• Hastelloy
• Copper Nickel “CUNI” and Copper Nickel Alloys
• Magnesium
• Titanium

One of the less common welding practices is welding of dissimilar metals. Precision TIG welding has a lot of options when it comes to welding dissimilar metals. Most of these options depend on the design of the filler wire. In a few cases there are two steps to welding dissimilar metals but in the end theses metals can be joined. Some of the combinations of dissimilar metals that can be  PRECISION TIG welded are:

• Copper to Everdur
• Copper Nickel to Everdur
• Copper and Everdur to Steel
• Copper to Stainless Steel
• Hastelloy Alloy C to Steel
• Nickel to Steel
• Stainless Steel to Cast Iron
• Stainless Steel to Inconel
• Stainless Steel to Low Alloy or Carbon Steel

When PRECISION TIG welding there is some common problems and weld defects. Most of these problems are easy to solve when you know what to look for. Some of the common problems include:

Weld Porosity

Weld Porosity can be caused by many factors. Some of the common causes of weld porosity are:

• Arc length is too long. Shorten your arc length.
• The joint is not cleaned properly. Clean with grinder or wire brush.
• Gas flow rate is too low or too high. In the event of the gas flow rate being too high the turbulence caused by the high flow rate will pull in air into the mix.
• The wrong cup size is being used. Change cup to proper size.
• Check for a draft coming into the weld area. If this is the case put up a barrier to stop the draft.
• The filler rod is oily, dirty, or corroded. Try a new filler rod.
• The shielding gas is contaminated. Change the gas.
• The wrong gas is being used. In most cases pure Argon is the proper gas type.
• The cup or is not tight enough. Check all TIG torch parts for tightness.
• The hose lines may not be tightened or have a leak. Check connections for tightness or use soapy water to find any leaks.

Tungsten Deteriorating or Unstable Arc

Tungsten deteriorating or an unstable arc is typically due to the following causes:

• Gas flow is too low. Raise gas flow rate.
• Arc length to long. Shorten arc length.
• Wrong gas being used. Change the gas.
• Tungsten is contaminated. Break and reshape the tungsten.
• Tungsten contacted the puddle. Clean tungsten and shorten stick-out.
• Tungsten electrode diameter is too big or small. Replace tungsten with proper size.
• Wrong polarity. Change polarity or voltage type.
• Amperage is too low. Raise amperage.
• Ground clamp is not contacting properly. Clean ground connection.
• Weld metal is not cleaned properly. Grind or wire brush weld joint.
• TIG torch connection is loose. Tighten TIG torch connection at power supply.