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Hi Ron!
There's lots of good suggestions here. A few things to keep in mind:
--When setting up a stick welder, you have to select the proper electrode (rod) type and size for the workpiece. Electrodes come in a myriad of alloys, with an equal myriad of flux coatings (the stuff on the outside of the rod) to create the best result not only to match the metals being welded, but also the position which you'll be welding. A horizontal-position weld (looking down on two pieces of flat plate, for example), is easy to weld with just about any rod, but an OVERHEAD position (lying on your back, under a cracked frame) is a totally different rod.
NEXT, you have to set up the welder's heat range and polarity to match the rod type and size. The BOX (or can) that the rods come in, will identify electrode polarity (positive, negative, or AC), as well as what current level. Too little heat, and the rod will not 'hold' a proper arc, as the flux coating will not burn off (and outgas) at a rate that will yield proper shielding. Too much heat, and the flux will burn off too fast, and leave the weld unshielded. Finally, a rod with moisture IN the flux, will not burn properly because the flux will 'break off' and not burn/outgas at all.
An experienced welder's technique, is to totally analyze the weld situation prior to even putting on leathers, and when starting, will already have chosen the proper position, electrode type, set the heat ranges, and established a proper ground
A wire-feed welding operation is no different- you have different alloys of wire, and different fluxes. MIG is commonly used to describe all wire-feeding, but there are many types, the two common being gasless (flux-core) and bottle-gas shielding. The shielding concept does what a stick welder's flux does- it displaces oxygen and other gases from the weld area to prevent contamination of the weld. One of the benefits of wire-feed welding, is that there is no real need to be concerned with position, because the shielding gasses will flood effectively in essentially any position, and furthermore, heat range is widely adjustable to suit many applications, without even changing wire. Note that many WILL discount the concept of flux-core wiring, do NOT write it off as an invalid method- flux-core welding is an incredibly effective relative of the submerged-arc welding process, every bit as good as gas-bottle... just happens that most people having problems with flux-core don't read the instructions, so they don't set the electrode polarity correctly.
If you want a really, really good deal, here's what you do:
Set up your shop with a 240v/50A outlet... a dryer plug. I own a Hobart Handler 120v 80A welder that I have fitted with flux-core wire for those tasks when I need something quick and dirty, in a place where I can't get a big welder to go... but at 120v, the little welder is darned near out-of-breath for anything larger than 3/16" or tacking a couple pieces of larger steel. I DO use it for tacking together special stuff (like a hydraulic pump bracket that needs to be assembled and fitted in-situ, then tacked, then removed for finish welding), but realize that the downside of tiny portable welders, aside from limited power, is severely limited duty-cycle... you need to make short welds, and allow LOTS of cooling time (for the machine) between welds. The other achilles' heel, is that these little portables, at 120v, DO NOT work worth a hoot with ANY sort of common extension cord. They'll use every bit of a 120v/20A electrical circuit (that's 2400w), and any resistance to the power supply feeder will dim that arc to worthlessness. A 240V unit will have twice the power available (4800w), but still, the small cord is a limiter. FWIW- Many guys cuss and dump their little portables after being dissatisfied... you can oftentimes find a good used one, for cheap, because the guy wasn't bright enough to hook it to a good power source, with a short cord... OR, they didn't set up the electrode polarity correctly for their flux-core wire.
But if you want the REAL DEAL, for a price that totally obliterates everything else you see on 'the market'... find a well-used popular brand/model of true industrial 3-phase welder- like the Miller CP-200 MIG, or the SRH-333 DC stick/TIG. They were made in large quantities, and are plentiful at auctions... with They sell for low prices on account of most guys not having 480v/230v 3-phase power. Convert it to 240V single phase. These old industrial welders are incredible workhorses- powerful beyond the wildest dreams of most garage guys... and considering that they can be had for under $200, converted for under e$100, parts are plentiful and cheap, they last forever (in garage duty) and have no problems running at 100% duty cycle. There is absolutely NO reason why a guy should ever consider buying a new welder.
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I agree with the big spool recommendation- if your spool has time to corrode, it'll foul the feeder and liner, and cause poor contact at the tip, hence, welding performance will tank. Either keep the smallest spools that make sense, or keep the shop humidity low.
FWIW- one of the best things a guy can do for his shop, is recycle a broken-down refrigerator, preferably the old 'dangerous' 1950's era units with latching handle. Put that fridge in a convenient spot, and put your welding electrodes, wire, and liners in it. In really damp conditions, put a 15w light bulb in the socket, and wire it through a timer to kick on for about 20 minutes a day. The fridge's seal will turn it into a nice dry storage cabinet, and your supplies will always be ready.
It also saves the landfill of one otherwise perfectly-good fridge.
Oh- and if anyone wants to know how to convert an industrial three-phase to single:
http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/miller-cp200-converted-240v-single-phase-199832/
Edited by DaveKamp - 16 Oct 2010 at 7:13pm
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