D/C or DC = direct current = (~180A max typically) = most common. used for welding steel / stainless.
A/C or AC = alternating current = optional extra, used for welding aluminium, often has pulsed mode.
Duty cycle = percentage of time that a machine will safely operate without overheating, within a certain time period, at a given amperage. 200 Amps @ 30% means that it will operate at 200A for 3 minutes within a 10 minute time period. For the remaining 7 minutes, the machine will switch to thermal overload to cool down.
SMAW = Shielded Metal Arc Welding = stick electrode = think ‘sparkler stick’ that gets shorter as you use it.
MIG = Metal Inert Gas Welding = CO2 gas shielded wire-feed spool gun welder = think ‘point & shoot’ welding everything in sight.
FCAW = Flux Core Arc Welding = gasless wire-feed spool gun welder. Requires a basic DC capable MIG welder unit and is cheapest to run for frequent and varied welding jobs.
Note: FCAW does not require shielding gas. Instead, flux-cored wire shields the arc from contamination.
GTAW = Gas Tungsten Arc Welding = same as Tungsten Inert Gas = TIG = think ‘soldering with hot molten lava’.
Electrode connects to negative terminal i.e. DC Electrode Negative (DCEN; also referred to as Straight or DC-). Comes with a shielding gas pigtail that needs to be connected to the front panel as well. Ground clamp connects to Positive terminal.
First gently screw in back cover and tighten, then screw in front copper collet body loosely with matching collet insert. Insert tungsten rod and tighten collet body until tungsten rod is fixed in place. Lastly. screw on the ceramic cup. Ensure electrode protrudes about 5-6mm from the cup (‘stickout’).
Electrode needs to be sharpened like a pencil to generate a clear arc.
All you need is pure tungsten (for aluminum) and either thoriated or ceriated tungsten (for steel and stainless). My WeldSkill 200HF came with grey electrodes (1x 1.6mm and 1x 2.4mm diameter) and matching torch copper collet body and collet.
The whole purpose of the different cup sizes is a) to provide proper coverage in relation to heat input vs. material size b) to allow access to the joint.
My welder came with size 4,5 and 6 pink ceramic cups. Some people prefer clear glass Pyrex cups for improved visibility.
To prevent metal warping and shrinking when it cools down, you need to clamp everything onto a flat surface. Weld sequencing using tack welding is used to fit everything together before running bead welds. Tack welding corners gives best results. Use 90 deg ‘welding arrow’ magnets in corners. Use clamps to secure corner magnets. Clamps! clamps! clamps!
You can TIG tack without filler. It helps to put a bit of leftover filler rod in the vicinity of the needed tack to ‘fuse’ it in.
A (pulsed) AC welder is recommended. This is because AC current can penetrate the high temperature resistant oxide layer on top of aluminium better than DC. You can sort-of weld aluminium on a DC welder by swapping the leads so the electrode is connected to the positive terminal i.e. DC-Electrode Positive (DCEP or DC+) but this will burn up your Tungsten electrodes in a heartbeat (!)
TIG welding uses a tungsten electrode in the torch and filler rods in the weld pool. MIG uses a spool wire-feed. Stick welding uses sacrificial stick welding electrodes.
Common electrodes used in Stick welding are 6010, 6011, 6013, 7018 and 7024 with the most common diameters ranging from 1/8- to 5/32-in. Each of these electrodes offers all-position welding capabilities (except 7024). The first two digits of a stick electrode represent the “as welded” minimum tensile strength: 6010 provides 60,000 psi tensile strength, for instance. The third digit represents the acceptable welding positions for each electrode (1 = all positions, 2 = flat or horizontal only, 3 = flat, horizontal, vertical down and overhead). The fourth digit refers to the coating type and the type of welding current (alternating current (AC)/direct current (DC)) that can be used with the electrode. Here’s a brief rundown of each electrode typically found in this application (courtesy of Hobart Brothers):
6010: All position electrode only suitable with DC power sources. It delivers deep penetration and has the ability to dig through rust, oil, paint and dirt. This electrode features an extremely tight arc, which can make it difficult for inexperienced welders. Excellent for penetration on joints with a tight fit-up. All position electrode for use with AC and DC power sources. It produces a deep, penetrating arc that cuts through corroded and unclean metals – ideal for maintenance and repair. Excellent for penetration on joints with a tight fit-up.
6011: All position electrode with a soft arc and minimal spatter, moderate penetration and easily removable slag. Suitable with AC or DC power sources, this electrode is better served on newer and clean materials, thinner materials and wide root openings.
7018: All position electrode with a thick flux and high iron powder content, which makes it one of the easiest electrodes to use. These electrodes produce a smooth, quiet arc with minimal spatter and medium arc penetration. Produces strong welds with high impact properties (even in cold weather) and can be used on carbon steel, high-carbon, low-alloy and high-strength steel base metals. Suitable with AC and DC power sources.
7024: For flat or horizontal welding with an AC or DC power source, this electrode contains a high iron powder content that helps increase deposition rates. Performs well on steel plate that is at least ¼-in. thick and can be used on metals that measure over ½ in.