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Mig welding help



mattie
04-06-2008, 07:13 PM
Hello, New to this forum and i will be asking alot of questions, I know nothing about any kind of welding but went out and bought a mig welder Lincoln electric weld pac 100 hd.I got it for a deal and figured i could use it in repairing the floors and things in my 72 bug.I tried it yesterday and just made a mess.
First i cleaned all the metal with a wire brush,set my speed which i thought would work,set the lower knob i believe i temp? to b,c,d,a,d,b,c,etc.It was horrible any start up tips would be huge.also,i did have door open outside and fire exting sparks were flying.Thanx all

Gadget
04-06-2008, 08:42 PM
From what I have read, installing the gas option instead of the flux wire will improve the welds quite a bit. The only MIG welding I have done was with gas and that was 35 years ago so I can't offer much more help than that.
Gadget

EdKing
04-07-2008, 06:40 AM
First thing with MIG is you have to make sure the metal is very clean and rust free. The flux core wire is more forgiving than the solid wire with gasif the metal isn't perfectly clean.. If you look on the inside of the door on the side of the welder, there should be a chart that will give you a starting point for your settings. As with any other type of welding, practice is key. Start out with thicker metals (around 1/8') to get the feel for the machine, then progress to thinner. Wire welding is the quickest and easiest to learn, little bit of practice to learn the welder, and you should be fine.

Ed

mattie
04-07-2008, 10:26 AM
Ed,What would gasif be? and on the inside i have a place i can change the positive and negative? i have no manual and thought the spot welding thing was a piece of cake.So any starting point would be great.Thanks a

Mattie

EdKing
04-07-2008, 02:25 PM
Does your welder have a chart on the inside of the door ? It should tell you the basics of setting it up. I can't remember which is which, but you hook the electrodes one way if you are using flux core wire, and the reverse is using solid core. Your welder may or may not have the gas option, I had to purchase an add on kit for mine to use gas and solid wire. When using gas 75% argon 25% co2 is the mix generally used for regular steel. You have to do it in an area shielded from any wind or breezes. For the dirtier metal you will encounter doing body work on a car, I would suggest the flux core wire, as it is more tolerant of a little dirt or rust. The easiest way I found to spot weld with a MIG is to drill holes in the sheet of metal that will be on top in relation to your weld. Turn the voltage to its lowest setting and just try to flow a little bit inside the holes you drilled. Like I said before, play around on some scrap first to try to get a feel for how it will work.

Hope this helps some.

Ed

mattie
04-08-2008, 04:48 AM
Ed, Thanks for the info i will give that a shot and see if i can get some info from Linclon.

Mattie

EdKing
04-08-2008, 08:11 AM
Look at the chart on my Weldpac 100 hook up is DC - (gun negative, ground positive) for flux core, and DC + (gun positive, ground negative) for solid wire with gas shield.

Ed

mattie
04-08-2008, 03:09 PM
Thanx that helps alot.

Jake323
03-08-2009, 07:15 PM
clean metal will make a world of difference

Uncle Ed
05-15-2009, 11:27 AM
figured i could use it in repairing the floors and things in my 72 bug.I tried it yesterday and just made a mess

I am sorry to tell you that MIG for welding sheet metal might not be easiest for you start with as it's gonna run pretty hot and you are going to burn through.:razz:

That being said those little Weld-Paks are darned handy to have around. Here's what I recommend for what you want to do:

Read the welders manual many times until it sinks in as it includes many welding tips along with the safety info. If you didn't get one you can download it from Lincoln's web site.

For best welds and especially sheet metal get the gas kit for your welder. I hope yours came with it. Flux cored wire (gasless) is thick and will burn too hot for sheet metal. The shielding gas, while making better and prettier welds also cools the work and reduces burn through and warping.

Use the smallest copper clad wire, like .023-.025, and a C-25 or C-10 gas for the thinner welds and use your heavier flux cored wired for general purpose welding on scraps and stock.

You have 2 knobbies. One for the CURRENT setting and the other for SPEED of the wire feed. Balancing these two controls your heat and penetration. This balancing act along with many other things is what makes welding a skilled trade. There really aren't any hard rules.

We'll try sheet metal as an example. "Sheet" metal goes up to 1/4 inch thick (I think) where it becomes "Plate" so auto body stuff is at the very thin side of "Sheet". I only mention this so when you read about sheet metal tips you keep in mind that they might be talking about heavier stuff. You did fine saying you were working on body panels instead of just saying "sheet metal" work. :D

You need to fuse the metal together while keeping all the surrounding metal cool enough to stay solid. That's what makes body panel difficult - there's just not enough metal mass to absorb much heat. Get some sheet of the same thickness or even thinner to practice on. Load up the thin wire (0.23) and use an 0.023 or 0.025 tip. It's important to use the correct tip to keep good electrical contact with the wire. A tip too large (like the 0.30 -0.35 used for flux cored wire) will allow the wire to wobble around and lose/reduce the arc many times and makes spotty and hard to control welds. Set the current knob to the lowest setting "A" and the wire speed about 2. Put the weld cup about...

Oh snap. I got carried away and don't even know if you have the gas kit, yet. Please accept my apologies.

Ed

woofer456
05-15-2009, 02:38 PM
To add to the advice above.

I, when welding Sheet metal or auto body work, use a large cup, small wire and higher gas flow (CO2) the extra gas flow with a larger cup cools the surrounding metal and makes it easer to maintain a bead if at all possible. I usually have to pulse the trigger and make rather short runs stopping and letting the material cool, another thing is to keep the cup over the weld until the gas has had a chance to bleed off helping to cool the weld. If you have a welding helmet that is automatic, set it for as little delay as possible and the sensitivity as sensitive as possible and wear some sort of flash glasses under your helmet (if you ware glasses they will do just fine) this will help reduce the risk of getting a flash burn to your eyes.

PS you can use flux core wire along with gas this may save you a little expense..

(sheet metal has a Gage Number rather than a dimension) one exception is 10 gage is often referred to as 1/8” auto body is usually 16 - 20 gage
Bob

DrBob
05-19-2009, 01:14 PM
You have 2 knobbies. One for the CURRENT setting and the other for SPEED of the wire feed.

Ed

Not quite accurate, Grebbler. The one knobbie is for VOLTAGE and the other is for Wire Feed Speed (WFS). The wire feed speed is roughly equivalent to the AMPERAGE or CURRENT in the welding circuit.

Starting with the voltage/WFS setting for the thickness of your filler wire and the gauge of metal you're welding, you want to adjust the VOLTAGE first to get the proper setting and then fine tune the WFS (AMPERAGE). Often you will find that the recommended settings are just fine. The other parameters you control are GUN ANGLE, STICKOUT (or distance of the tip of the gun from the weldment) and TRAVEL SPEED. With MIG, keep a 1/4" - 3/8" stickout, a 10-15degree angle (push for gas and drag for flux core). Keep your travel speed such that the wire is always feeding into the FRONT of the WELD POOL. There are many good videos out there to show you what to watch for. I like Ron Covell's "Mig Welding Basics" as a starter. He goes through alll the machine settings and then shows you what good and bad welds look and sound like. You can rent or buy it online.
BTW I forgot to mention that when you're using FLUX CORE wire, your gun is connected to the Negative terminal and the workpiece clamp to the Positive. For Gas (MIG) welding, the opposite. Set your gas flow to about 25 CFH or cubic feet per hour (more for Aluminum). The gas must be "C25" or 75percent Argon and 25percent CO2 for welding mild steel. If you're welding Aluminum use pure Argon (and of course, Aluminum wire). If you're welding stainless steel use Helium-Argon-CO2 tri-mix gas and stainless wire.

That oughta get you started. This short video from the Miller website might be helpful.

http://www.millerwelds.com/swf/flv/flashvid.html?swf=MIG_welding_principles.swf&w=320&h=240&v=8.

DrBob

Gadget
05-19-2009, 02:10 PM
Thanks for the good info DrBob. You should configure an avatar for your account and enter the contest for the MIG welder. You need 20 good posts (something of value like your first two posts) by June 17th to be eligible.
Dan