Q: What gas should I use to weld Aluminum?
A: This will depend on the thickness of material, if the material is under ½” then you may use Pure Argon gas. If the material is thicker than a mixture of Agron/Helium would work quite well. However keep in mind that the addition of Helium will be more expensive then just a Pure Argon as well the Cylinder size may not be suitable for the size of your job.
Q: I am restoring my old car what is the best gas to use?
A: A C-25 which is made up of 25% Carbon Dioxide with a balance of 75% Argon. This gas is a good short arc gas which means your arc voltage is low which translate to a lower heat input into the base material you are welding on. Short arc welding typically runs between 16 – 22 Volts and has a sizzling bacon sounds when set up properly.
Q: Which Tungsten should I use?
A: Tungsten size is determined by the thickness of the metal to be welded and the welding current used, a rough rule of thumb is 30 to 40 amps per millimetre of metal thickness, Typical current ranges are: 1.6mm, 30 to 120 amps, 2.4mm, 80 to 240 amps, 3.2mm, 200 to 380 amps.
Q: Why should I TIG Weld?
A: TIG welding provides a professional looking weld with no spatter or smoke. The process offers high precision for thin materials. It can also be used to weld on a variety of metals including steel, stainless steel, aluminum, copper and magnesium.
Q: Why is preheat sometimes required before welding?
A: Preheating the steel to be welded slows the cooling rate in the weld area. This may be necessary to avoid cracking of the weld metal or heat affected zone. The need for preheat increases with steel thickness, weld restraint, the carbon/alloy content of the steel, and the diffusible hydrogen of the weld metal. Preheat is commonly applied with fuel gas torches or electrical resistance heaters.
Q: Does shielding gas affect the quality of the finished weld?
A: For most mild steel applications, CO2 will provide adequate shielding, but when you must have a flatter bead profile, less spatter or better wetting action, you may want to consider adding 75 to 90% argon to your CO2 shielding gas mix.
Why? Argon is essentially inert to the molten weld metal and therefore will not react with the molten weld metal. When CO2 is mixed with Argon, the reactivity of the gas is reduced and the arc becomes more stable. But, Argon is more expensive. In production welding, selecting the perfect shielding gas can be a science of its own. Attributes such as material thickness, welding position, electrode diameter, surface condition, welding procedures and others can affect results.
Common gas mixes for the home hobbyist and small fabricator would be:
- 100% CO2 -Lowest price, generally greatest penetration, and higher levels of spatter. Limited to short circuit and globular transfer.
- 75% Argon - 25% CO2 -Higher price, most commonly used by home hobbyist and light fabricator, lower levels of spatter and flatter weld bead than 100% CO2. Limited to short circuit and globular transfer.
- 85% Argon - 15% CO2-Higher price, most commonly used by fabricators, with a good combination of lower spatter levels and excellent penetration for heavier plate applications and with steels that have more mill scale. Can be used in short circuit, globular, pulse and spray transfer.
- 90% Argon - 10% CO2- Higher price, most commonly used by fabricators, with a good combination of lower spatter levels and good penetration for a wide variety of steel plate applications. Can be used in short circuit, globular, pulse and spray transfer.
TRY C-25 SHIELDING GAS (75% Argon, 25% CO2 )
Q: How important is a good electrical ground in MIG welding?
A: In arc welding, an arc is established from the electrode to the workpiece. To do this properly, the arc requires a smooth flow of electricity through the complete electrical circuit, with minimum resistance. If you crimp a garden hose while watering the lawn, the flow at the sprinkler head is much reduced. Beginning welders often make the mistake of attaching the work clamp (or electrical ground) to a painted panel or a rusty surface. Both of these surfaces are electrical insulators and do not allow the welding current to flow properly. The resulting welding arc will be difficult to establish and not very stable. Other telltale signs of an improper electrical connection are a work clamp that is hot to the touch or cables that generate heat. Another key point to consider when attaching the welding ground is to place the welding ground on the piece being welded. Welding current will seek the path of least resistance so if care is not taken to place the welding ground close to the arc, the welding current may find a path unknown to the operator and destroy components unintended to be in the welding circuit.
SO . . . FIRMLY ATTACH WORK CABLES TO CLEAN BARE METAL AND CLOSE TO THE WELDING ARC.