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Discussion Starter #1
Okay, I am starting to get frustrated !!!

I am welding with a MillerMatic175 220v and it says 3.5 volts at 70 wire speed.

I'm embarrassed to even show the pictures, but I am in need of some advise. As I "pushing" the weld too slow?



Any advice ?!

-BRent Thomas
Ohio
 

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welding

Follow the settings on the inside panel(if there is). You should be running .023 solid core wire(NOT FLUX CORE) with a mixed gas. Mig mix gold would be praxair's version. Weld voltage should be close to the minimum(about 2-3 volts in my mind, with about 40 wire speed).

Now for the bad news. This machine has what is called wire speed tracking. It's a dose. I dislike this welder and because of it, I would not buy one.

It automatically adjusts your wire speed for you(in relation to voltage). Handy eh? For experienced trades people it's manageable, for the weekend "lets weld a patch panel on" person, less than impressive.

If I look at the pic you provided, my first thought is that the existing sheet metal is too thin. Check the thickness to your patch panel. Even though it's not rusted on the outside, rusting on the inside will reduce
thickness.

Another tip, when prepping the existing edge, DO NOT use a grinder. Grinding this edge will reduce the thickness too much(causing burn through like yours). Use an orbital with 80-120 paper.

When you burn through like that, turn the welder down and tack weld, hold the wire in one spot and pull the trigger for one second. Move over an eight inch, do the same. Cool with compressed air. The surrounding material should never get so hot that you can't hold your hand on it.

And also NO GAPS, tight fitups.:)
Good luck,
Floyd.
 

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Explains a little why I was having problems with my trunk. I cleaned up all the edges of my Goodmark panels with a grinding wheel. Used a sanding disc to clean up the edges on the trunk that were already there.

You but your panels together? What about over lapping?

1fasbu said:
Follow the settings on the inside panel(if there is). You should be running .023 solid core wire(NOT FLUX CORE) with a mixed gas. Mig mix gold would be praxair's version. Weld voltage should be close to the minimum(about 2-3 volts in my mind, with about 40 wire speed).

Now for the bad news. This machine has what is called wire speed tracking. It's a dose. I dislike this welder and because of it, I would not buy one.

It automatically adjusts your wire speed for you(in relation to voltage). Handy eh? For experienced trades people it's manageable, for the weekend "lets weld a patch panel on" person, less than impressive.

If I look at the pic you provided, my first thought is that the existing sheet metal is too thin. Check the thickness to your patch panel. Even though it's not rusted on the outside, rusting on the inside will reduce
thickness.

Another tip, when prepping the existing edge, DO NOT use a grinder. Grinding this edge will reduce the thickness too much(causing burn through like yours). Use an orbital with 80-120 paper.

When you burn through like that, turn the welder down and tack weld, hold the wire in one spot and pull the trigger for one second. Move over an eight inch, do the same. Cool with compressed air. The surrounding material should never get so hot that you can't hold your hand on it.

And also NO GAPS, tight fitups.:)
Good luck,
Floyd.
 

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back off the power and wire speed a hair. just play with it until it is where u want it. and be sure you are getting good penetration.
 

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Mig Welder

Brent:
Your welder settings are not correct thats why your having problems. Machine setup is the biggest problem for most guys. I don't recall if the Miller 175 has the variable voltage settings, I thought it did, as well as the wire speed. I have a Hobart 185 MIG, and the voltage settings are a fixed range.
Open the side door of your welder and there should be a chart with the settings to use. It will probably say 20 gauge sheetmetal, it will give you the voltage setting to use, and the wirespeed. 70fpm on the wire speed is way too much. Secondly, are you using 75/25 gas mix? The chart will also give you the flow rate for the gas, usually about 20#. You didn't mention what size wire you are using, or if its fluxcore, but solid .023 wire is good for doing body panels. Another tip is to watch your gun angle to the workpiece. You want to make numerous tack welds, stitch-welds, not a continious bead. Jump around to keep the heat distortion down, and go back and fill in the gaps. For butt-welds try and keep your joints as even and tight as possible with clamps. As a rule the gap should be the same as or less than the wire size your using. Make sure your sheetmetal is really clean at least an inch on both sides of the joint to prevent contamination.
Test your settings on some scrap for practice. You may want to write down the settings that work the best for you, and the next time you do similar work you just dial=in the welder and go.
 

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On sheet metal all you can do is stich weld. Otherwise, you will blow holes through the metal. Maybe, some experianced guys can pull off large beads.
that is the problem... no matter how experienced you can't pull off a bead on sheet metal, too much heat is generated...you must do a stich, basically a whole bunch of tacks but a little more penetration, do it on the whole thing and don't do it in one pass, go around the panel...if for example it was a square, do a tack or two on the bottom, then the top, then each side, then let it cool down a bit...i wait until you can hold your bare hand on it....if its too hot to keep your hand there, find something else to do in the time the weld is cooling....i may be worried that the weld you already attempted to put down is too cold and by the time you are finished grinding it down, there may be very little filler actually holding the patch in.....and don't turn the voltage down any, turn it up as a matter of fact so that you get good penetration...you can easily fill those holes and gaps using this technique, on larger holes or gaps i won't jump around, but let the weld cool and lay the weld on the previous ones so that they build up
 

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Like many of the others have posted I too use the stitch method on sheet metal. I tack the panel in place stitching it in at various points. The stitch is just holding the gun and pulling the trigger for an instant to produce a 1/4 inch welded place. I continue to do this dividing the space so it gets welded closer together. This allows me to get the panels welded in with no gaps between the panels too. Hard to bridge a gap in sheet metal. I find I have better luck with .030 wire on the galvanized, zinc coated floor pans on most cars. When I get the panels stitched in with spaces of about 2 or 3 inches then I just stay in one place and stitch the gap closed. I overlap my panels too but just a small overlap of 1/4 inch is how I do it. On floors I weld both sides too. That's my method and it's been working for me for many years. Best of luck. RM
 

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Ya Brent, in addition to whats already been said, I would say what ya need to do is get a couple pieces of scrap and practice welding them together til you get the settings right. On sheet metal, you ALWAYS stitch weld, to prevent blowing holes and warping the metal from overheating. Its also important to have it very clean, I use a wire wheel etc to clean prior to welding. That way you dont erode the metal away.

Another thing thats often overlooked when welding sheet metal is the importance of cleaning the UNDERSIDE of whats being welded, since the entire thickness of the metal is being fused together, not just the top side, so if a piece is dirty on the bottom side, its going to be just as hard to weld as if the top side were dirty. Hope that makes sense :)

Also, with sheet metal, you shouldnt be "pushing" the weld puddle, you should be "pulling" it...i.e. your tip should be tilted in the direction youre welding.

Im sure everyone uses different techniques, as far as tip movement, but I have found the "circular" motion easiest for me on thin metals, always keeping the tip moving. Sometimes its better to go side-to-side in a Zig-Zag™ motion. But figuring it out only comes about with PRACTICE ;) With a little practice, youll figure out what works best for you. Itll make it much less frustrating, especially when youre blowing holes in a SCRAP piece instead of your car lol.

As always, lets review...scrap metal, wire wheel BOTH sides (if possible), cold beer, stitch weld, jump around to different areas, cold beer, let metal cool, inspect (with cold beer), adjust settings, pull weld puddle, keep tip moving, cold beer, inspect, repeat. :D
 

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In addition to the good advice above try this method.
For welding sheet metal panels suggest you do this: tack...space... tack...space...tack....space, meaning do a quick tack weld the size of a small dot(you make one very quick touch of the trigger and release) then space about an inch forward to do the next tack weld and so on. Then come back to start your series of second tack welds by starting between these welds repeating the third series followed up by ever how many series of tack welds it takes to fill the seam. Do not run a bead! Take your time. Ever so often wire brush the area...Phil
 

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My experinence (for what it's worth) is this. To weld sheet metal, I have to play around a bit to get the right heat and wire speed. I have never successfully ran any kind of bead doing a butt weld with sheet metal. I have to do a tack-stitch method like the others are talking about. If you welding two peices that lap over, I find its a little more forgiving as far as blowing holes,butt welds though take a lot of patience and time.
I have rarely been able to "jump a gap" when butt welding sheet metal. It can be done,but I have to build up both sides a bit so that the metal is now a little thicker with material.
I found that it is crucial to having the sheet metal flush with each other(lap welds) or touching completley when butt welding.
Just some thoughts about my experience. (Learn as I go:) )
Brandon
 

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Discussion Starter #14
THANKS EVERYONE for the great tips and advise !!!!

For what it is worth, I was just going off of the MillerMatic Settings (see below), but will try to lower to wire speed and volts and see if that helps.

Looks like I was doing somethings right, but making some mistakes as well. :eek:

I am using mixed gas and .23/.24 wire. I am tacking it about every inch or two around, but I was indeed using a grinder to clean off the matting edges (butt and lap) and was trying to bridge the 1/2 inch gaps. for the most part, bridging the gaps was working well, but every so often, I would blow a hole (as seen in the picture from above).

So, I am going to try a couple of you all suggestions and see if I can get better results.

(finding that sheet metal fllors is a good place to start learning to weld the thin stuff)

Thanks again everyone !!!
-Brent Thomas
Ohio



 

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basketcase said:
Nope ....Thanks!
;)
Well then, if you can't beat them, join them. I'll be adding these tips to the linked thread for future use.
 

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I have found a low volt with high wire speed helps this problem, I would leave your wire speed and lower the volts. I also start the arc real close but then move away about 1/2-1" standoff.
 

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Filling holes

Something that hasn't been mentioned about filling holes. If you're trying to fill a hole in any material, put a piece of copper behind it(pennies may work depending on alloy). The weld will not stick to the copper, but will stick to the sheet metal. I butt weld my panels always, but I also TIG weld so there is a bit more control. It comes down to patience, patience, patience and practice, practice, practice. It sounds as though you realize what you're doing wrong, so keep trying and good luck.:)
 

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I take it you were assuming that was 16 ga metal, judging by your settings? Im sure its much thinner, unless you fabbed em up yourself. Most body panels are 22 ga I think and most trunkpans/floorpans are 19-20 ga I think. Im not 100% sure about that, but Im sure "someone" here who deals in metal panels could chime in and enlighten us :D (cmon Jonesy!!!) So I would tend to agree with Novastar and lower the voltage and keep the wirespeed fast.
 

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Discussion Starter #19
Yes, I was assuming, but also comparing the thickness to the thickness on the chart. Maybe my eyes are going quicker then thought. :)

I had some copper tubing that I pounded flat to use for a couple of the gaps and holes, but had one hell of a time trying to get it under the car, in place and not fall, while I was in the car... I didn't work, so I threw the copper in the trash at 80 mph (out of frustration !!).

If I try it again, I'll probably try to wrap some wire on it and pull it through.

None the less I will have to try to lower the power and see how it goes.

Thanks again all !!
-Brent Thomas
Ohio
 

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Welding Magnets

BTHOMAS67Wagon said:
Yes, I was assuming, but also comparing the thickness to the thickness on the chart. Maybe my eyes are going quicker then thought. :)

I had some copper tubing that I pounded flat to use for a couple of the gaps and holes, but had one hell of a time trying to get it under the car, in place and not fall, while I was in the car... I didn't work, so I threw the copper in the trash at 80 mph (out of frustration !!).

If I try it again, I'll probably try to wrap some wire on it and pull it through.

None the less I will have to try to lower the power and see how it goes.

Thanks again all !!
-Brent Thomas
Ohio
Brent: if you have a Harbor Frieght store in your area, or Home Depot, Lowe's, get a set/pair of "welding magnets" to hold your copper in place. When its not possible to use a set of clamps. They are like an extra set of hands when you need them.They will also help in aligning and fitting your panels.
Forgot to mention before on the setup of your machine, make sure your using the right polarity for the wire, and check the tension on your wire spool feed.
 
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