WHY IS MIG GAS HOSE A WASTEFUL 1/4 INCH ID?

Hint, it’s Not for the Nonexistent Pressure Drop!

The typical 1/4 inch ID hose causes excess gas to be stored in the hose every time welding stops.  The stored excess gas blasts out and is wasted at every weld start (or even when inching the wire to position in the joint or to cut off the end!)  Fabricators find it causes from 30 to over 60% wasted gas!

Is this large hose size needed to handle pressure drop?  NO!  The typical 35 CFH shielding gas flow rate creates very little pressure drop.  A 100 foot 1/4 inch ID hose, operating with pressures needed to flow 35 CFH, has a pressure drop of less than 1 psi!  (Recently saw a comment on a Forum that told someone, who was extending their welder to 30 feet,  they should be using 3/8 inch hose to take care of the pressure drop!  That was totally inaccurate.  He might as well told them to double their already high shielding gas use caused by the gas blast at each start!  CLICK  to see summary below about pressure drop.)

Then why is typical MIG gas delivery hose 1/4 inch ID, if it is not to handle the nonexistent pressure drop?  MIG welding was developed in the 1950’s by two of the dominant US industrial gas producers at the time.  Working at the Welding R&D Lab of one of these companies, the Linde Division of UCC, it was located with our   equipment factory.  Our major equipment product line manufactured at the time MIG was introduced was Oxyfuel Welding and Cutting apparatus.  The flow rate of Oxygen required when cutting is quite high.  It can use 250 CFH and higher flow.  At a 50 psi regulator pressure setting 250 CFH will produce an 11 psi pressure drop in a 100 foot 1/4 inch ID hose versus the less than 1 psi at 35 CFH flow used for MIG welding.  (Note the pressure drop at 35 CFH will be under 1 psi even at 5 psi hose pressure.)  The highest volume gas hose made in the factory was 1/4 inch ID, which easily handled the pressure drop for the largest sales volume Oxyfuel hose lengths, 25 feet.  Fitting this size hose with end brass fittings was automated.

When the Compressed Gas Association  (CGA) committee developed gas hose fitting specifications they designed them for various size hoses.  The inlet end of these fittings can handle hoses up to 3/8 inch ID.  Using CGA designs, 1/4 inch inert gas fittings are relatively easy to make.  Production starts with heavy wall tubing, making drilling the gas passage hole quick and economical.  A minimum amount of material is required to be removed with this design approach.  Functional hose clamps are also readily available for 1/4 inch hose fitted to a hose barb.  Therefore 1/4 inch hose, hose fittings and  hose clamps were readily available and lowest in cost!  Production economics is the reason MIG gas delivery hose was 1/4 inch ID and that is what is mostly used today!  It's Simple, "Follow The Money!"

SMALLER MIG GAS HOSE SYSTEM CUTS WASTE 80%

By using a small ID gas delivery hose with an integral surge flow control orifice, our patented Gas Saver System (GSS^TM) eliminates the excess "gas blast" at each weld start (See Why.)  This small ID MIG gas hose 50 feet long will flow more than sufficient gas with flowgauge regulators, typical pipeline pressures and  regulator/flowmeters.  With typical pipeline pressures we have customers using GSS lengths over 100 feet long.
We have a number of customers on pipline gas supply that use 100 foot long GSS's.  If a maximum of 25 foot gas delivery hose is used, even cylinder supply flow control devices can be used.  If longer hose length is needed when on cylinder gas supply, Email there are a number of model regulator/flowmeters or regulator/flowgages that can be used.

DIFFICULTIES OVERCOME TO USE SMALL ID HOSE WITH THE GSS

The patented GSS employs unique components allowing it to utilize a small ID gas delivery hose for MIG (and TIG) welding.  To handle the rugged environment the custom extruded hose has a very heavy wall.  It is also fiber reinforced so it will not wear through even when dragged on the shop floor.  The large OD to ID ratio prevents the gas from being blocked even when the hose is stepped on.  The CGA fittings can not be made from large ID heavy wall brass tubing as can 1/4 inch hose fittings.  This makes them more difficult and costly to manufacture.  The cost is more than twice the more common 1/4 inch hose barb fittings.  The accompanying photos provide a comparison between these two CGA hose barb sizes.

Standard hose clamp designs that work well on 1/4 inch ID hose do not function adequately on the heavy wall GSS hose.  A special constant tension spring hose clamp custom fit to the hose OD is used.  These are similar to that employed for automotive fuel injection systems and are also more expensive.

BOTTOM LINE

There is no need to use large 1/4 inch ID gas delivery hose when MIG welding and thus creating shielding gas waste and making inferior welds starts.  Our patented GSS:

Response to an inaccurate Forum comment about pressure drop in MIG shielding gas hose:

First lets set the record straight.  Your setting flow NOT pressure on your MIG flowmeter even on a regulator/flowmeter (Pictured Right.)  Look carefully and you'll see the output gauge says CFH NOT psi.  What does that mean?  CFH stands for Cubic Feet per Hour.  That is what your setting.  Pressure is measured in Pounds per Square Inch (psi.)

A point of confusion on required hose size may come from what is needed with an  air compressor.  Even a small air compressor may be rated at 10 CFM and does need a large hose!  That stands for Cubic Feet per Minute!  So even a small air compressor can flow 10 CFM x 60 min/hr or 600 CFH!!  Sure, at that flow rate you need a big hose!  But not at the 25 to 30 CFH used in MIG welding.  That flow rate is only 1/2 CFM (30 CFH / 60 min/hr!)  Pretty low flow.  In fact that is about your breathing rate!  Anything much more and air is just being pulling  into the gas stream due to turbulence!

At 25 to 30 CFH flow rate with a 25 foot GSS  hose there will be about a 2 psi pressure drop.  In a 1/4 inch hose it is hardly measurable! 

The person recommending a 3/8 inch hose was indirectly also telling them to waste 2.25 time more gas at each weld start!  How can that be?  The physical volume of a hose is proportional to the diameter squared.  Therefore a 3/8 inch hose will hold (3/8)² / (1/4)² =  2.25 times more gas volume than a 1/4 inch hose every time welding stops.  If your using a regulator/flowgauge, like the one in the above picture, you'll have plenty of excess pressure. Defining how the system works so you'll see why: 

With a regulator/flowgauge you're actually setting pressure!  Your setting the pressure above a very small orifice in the outlet of the regulator.  Typically the orifice is about 0.025 inches.  It takes about 40 psi above the small orifice to flow 25 CFH.  Why do they have such high pressure?  So the flow will be constant when spatter builds in the gun nozzle and as you bend the small MIG gun cable gas passage. 

Typically the pressure needed at the inlet to a welder/feeder is 3 to 7 psi and vary was you weld and the cable is bent etc.  By having about 40 psi above the small orifice the flow will remain at the flow you set.  (SEE Automatic Flow Compensation if you want to know how that works.)  If you put a pressure gauge between the welder/feeder and the gas delivery hose you'll measure about that 3 to 7 psi when your welding.  However when welding stops, gas will still flow through the small orifice and will rise quickly to the 40 psi regulator pressure. (Note, if using a pipeline gas supply and a flowmeter or flow control orifice it will quickly reach the pipeline pressure.) That creates excess stored gas and the big surge of gas at the weld start which is what our GSS  eliminates!

Now if you read about Automatic Flow Compensation you found  twice the  pressure was needed above that small orifice compared to below it to achieve that constant flow. (Note, all pressures measured a absolute pressure which equals gauge pressure + atmospheric pressure, nominally 14.7 psi.)  With 25 feet of our GSS  hose with its ~2  psi pressure drop you have more than sufficient pressure with even 25 psi to achieve constant flow.

Probably just provided more information than you wanted to know but if you have any questions Email: TechSupport@NetWelding.com

PURCHASE PRODUCT-- DETAILS

One Page Summary of Gas Saver System

PayBack Averages Less Than 2 Months even at $2.00/100CF gas cost-   CLICK HERE FOR CALCULATION