Often the question arises, which is better Gas MIG welding or Gasless? Firstly, MIG welding is one of the simplest and quite a popular form of welding and when done properly, produces excellent results. There are mainly 2 kinds of MIG welding – gasless and gas. Typically, gas welding requires an external shielding gas, while gasless MIG welding is self-shielding and does not require a shielding gas.
Gasless MIG Wire
In gasless MIG welding, air is displaced by using gas so that the weld pool is shielded from the oxygen that is present in the air. So basically, gasless MIG wires in reality are self-shielding. The self-shielding MIG wire is actually a metal tube containing a flux core. The flux also burns as the wire melts due to the welding arc and this forms a gas shield around the welding area. So, we can see that gasless welding is not actually “gasless.”
While gasless MIG wire has its benefits, there are some drawbacks to the process too. The welding process produces a very aggressive arc which is not very good for steel that is thinner than 1.2mm. Gasless MIG wire welding also produces plenty of smoke and so, it is better to use this process outdoors.
Self-Shielding MIG Wire History
Gasless MIG wires or self-shielding wires were used first in the prairie farms in the United States. The MIG welder was a hand-held tool that ran on a 24-volt tractor battery. The welder was used by farmers for repairs and other jobs in the fields. It was in the 80s when the self-shielding MIG wires entered the UK market and became quite popular with welders here.
Gas and Solid Wire
The ideal way to utilise the MIG welding torch is making use of a gas cylinder and solid wire. In this method, as the welding occurs, gas is poured on top of the weld pool by the MIG welder to prevent the weld being contaminated by the oxygen or air. The process of using gas and a solid wire is much easier and also produces welds that are of better quality.
However, the best practice to follow, whether you own a gasless or a gas MIG welder is to always make use of it along with gas, except if you do not have a choice but to use a self-shielding wire. It may also be a good idea to shield the weld area with screens rather than using a self-shielding wire.
Can You Use Any MIG Torch for Gasless and Gas Welding?
You cannot use any MIG welder. A MIG welder is usually designed for use with self-shielding wire (gasless), wire with gas or both (i.e. gas and gasless) and they are differentiated by the welding torch’s polarity. The torch must be negative if you want to make use of a self-shielding wire and must be positive if you use it with gas and solid wire. A MIG torch that works with both gasless, as well as the gas wire can change their polarity as required and these welders are usually available as “Gas/No Gas” MIG welders in the market.
Both the methods of welding, gas and gasless, work well if applied properly and the type of wire you decide to use depends on the thickness of the application, the worksite location, shielding gas combination and the kind of equipment and to get the best results, it is a good idea to consider all the variables and then decide on the best one to use.