Excess Gas Use Problem

Most users of MIG welding consume 3 to 5 times (or more) the amount of shielding gas that they should.  An article published Trailer Body Builder Magazine, entitled, "How To Save 20% in Welding Costs," quotes a representative from Praxair, a leading supplier of shielding gas stating "A minimum of 5 cubic feet of shielding gas is required per pound of wire, but the industry average is 30 cubic feet."  This supported very similar data presented in the  the Fabricator Magazine on the subject of shielding gas waste.

WHY AM I USING SO MUCH SHIELDING GAS?

A major cause of the shielding gas waste in MIG welding results from the build up of  gas in the shielding gas delivery hose every time welding is stopped.

Refer to figure:

While welding, the gas pressure needed at the end of the hose near the solenoid is only 4 to 5 psi depending on the torch length and other restrictions.  However when stopped, the pressure in the hose raises to 25 to 80 psi depending on the type of regulator/flowmeter employed.  Excess gas is therefore stored in the gas delivery hose when welding is stopped.  That excess can be up to 5 times the hose volume.  When welding is started, or even if the wire is inched to cut off the end or position it in the joint, the stored gas is expelled and the excess wasted!

The expelled gas is not only wasted, the high surge flow rate also pulls air into the shielding gas stream.  This air entrainment creates excess spatter or weld porosity at the weld start. 

For a mathematical explanation and quantification of the amount of excess gas that is present when welding is stopped visit  the Technical Reasons for Gas Waste Page.

WA Technology Solution

WA Technology provides a simple solution to this major cause of shielding gas waste, excess stored gas in the gas delivery hose.  The patented product is called the Gas Saver System (GSS^TM) and incorporates a specially made small volume gas delivery hose which in combination with a gas start surge limiting orifice located at the wire feeder end eliminates excess "gas blast" and waste at each weld start.  It quickly delivers sufficient extra gas, at a limited peak flow rate to purge the weld start are and gun nozzle or moisture laden air.

The outside diameter of the custom hose is large and it is made with fiber reinforced construction to handle the tough welding shop environment.  There is only a small pressure drop in the GSS hose and surge limiting restrictor.

The GSS is unique compared to other products which have been proposed to solve this problem over the years.  It has no moving parts to wear, need repair or leak, no knobs to adjust or pressures to set.  Simply replace the existing shielding gas delivery hose with the GSS.  It's unique, patented design maintains  the system pressure  to quickly provide a small amount of extra gas at the weld start to rapidly purge the air which diffuses into the torch lines when welding is stopped.  This controlled amount of extra gas at the weld start also quickly fills the gas nozzle and floods the weld start area with shielding gas.  Maintaining pressure preserves the systems ability to automatically compensate for variations in hose restrictions which occur while welding.  Unfortunately, in the real world, the hose is often stepped on, kinked or pinched when it is dragged on the shop floor.  A high regulator pressure is needed to automatically compensate for increased pressure drop without  requiring welder interaction.  To provide this automatic feature, it is necessary to have the regulator pressure (measured as absolute pressure or psia, i.e. psi + 14.7 psi = psia) be at least twice as high as any pressure restriction which might occur (also measured in psia).  Technical information is available that explains this phenomenon.  This is one reason welding regulators were designed with higher pressures!

If you have used a simple surge flow restriction orifice at the feeder, you may have reduced the initial gas flow surge but just prolonged the gas waste over a longer time, perhaps 3 seconds.  You may not have saved any gas!  Lab tests with this type of system are demonstrated in the .  Also see "Why you need some extra gas flow at the weld start."

"Lean Welding Manufacturing" Learning Program

"Optimizing Shielding Gas Use and Eliminating Waste" includes details of this information in a Do-It-Yourself 7 Module Program 

It quantifies waste due to surge flow, leaks, ways to monitor leaks and the gas flow settings where air is pulled into the shielding stream.  Unfortunately many are using far too much gas flow, wrongly employing the philosophy, "If Some is Good More Must be Better" !