Choosing A Mig Welder
Purchasing a MIG welder that is suitable for your application and yet fits your budget, without compromising on quality can be a tricky process.
We’ve pulled together a guide of features & pitfalls to look out for when you’re buying a MIG set and put you in know when it comes to terminology & questions to ask the dealer.
- FAN ON DEMAND: Lowers running costs and reduces contamination to internal components. The fan kicks in when it’s needed, rather than running all day.
- PRINTED CIRCUIT BOARD PROTECTION: If the machine's PCB's are protected from dust & kept away from the fan, reliability will increase. Some manufacturers’ have the parts that need cooling in a duct type housing & the PCB isolated separately.
- STEP SETTINGS: If you're looking at step voltage conventional MIG with multiple power settings – “the more the better!”
- MIG WIRE INCH BUTTON: A great feature. This will save you wasting your shielding gas when feeding wire through at the start of a new reel.
- GAS PURGE BUTTON: Another nice option. Save yourself some MIG wire, when you're setting your gas flow.
- BURN BACK: Not all machines have this externally, buy it's good to be able to trim the burn back to the wire according to the application & operator.
- SELECTING THE CORRECT AMPERAGE MACHINE: Generally, you should work on 35-40 amps per 1 mm diameter of material to be welded.
- DUTY CYCLE: The advertised amperage of the machine offers a headline guide, but the duty cycle of the machine gives up the truth. Light industrial machine duty cycles can be as low as 20%, but more heavy duty MIG's should range between 40-60%. If a 300amp MIG has 30% duty cycle for instance, it's on the edge of acceptability. Duty cycle is determined by how many minutes out of 10, it can weld at 100%.
- DUTY CYCLE TESTING: MIGS tested at 20 Degrees & 40 Degrees we consider good.
(Beware any manufacturer who doesn’t quote an ambient temperature for testing)
- MANUFACTURERS WARRANTY: Always a great guide to quality. A three year warranty is good.
- WELD CHARACTERISTICS: Make sure the arc is smooth & suits your application.
(Some machines are better suited at the low range and others at higher amperage range).
- EASY CONTROL PANEL: Simplicity is the key.
- DIGITAL METERS FACTORY FITTED: Great to have when you purchase and may be required for calibration requirements. To fit them down the line could be expensive.
- DRIVE ROLLERS: Metal rollers are the best. Nylon & plastic ones will always wear away quicker.
- DRIVE BLOCK SYSTEMS: Four roll would always be first choice, but some of the lower amperage machines won't have them & two roll therefore would be acceptable.
- BOTTLE TROLLEY: If you want a stepped voltage machine to be portable, you'll need one. If you have a full size industrial cylinder check that the running gear & cylinder rack are man enough.
- STEPPED VOLTAGE OR SYNERGIC: Synergic MIG's have the edge when you're welding stainless & aluminium as they are pre-programmed, easy to set up & portable. They also provide a better weld characteristic and so give cleaner weld bead with less/no spatter.
- INVERTERS: Considerably smaller and lighter and so ideal for site work. All inverters are stepless and so have infinite control. Also cheaper to run power wise.
- BUDGET: How much welding are you going to undertake? Gear your purchasing decision around the jobs you will be working on the most.
- POLARITY CHANGEOVER; A lot of welders at the light industrial end will to be able weld with gasless flux cored MIG wire. Is the switchover easy on the machine you're considering.
- AVAILABILITY OF SPARES/AFTER SERVICE: Ask where the machine is actually made. Even the more recognised brands largely outsource their production, which can lead to quality and after sales issues with lack of continuity of supply for spares.
- WHERE TO BUY YOUR MACHINE FROM? Are they a technically sound distributor with good product knowledge? Do they have service engineers who can advise/repair the machine should you have issues?