Welding for the first time - need advice

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ESP47

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I've dabbled with this welder a few times but I've never really gotten the hang of it. It's a Hobart 140 with gas. I have the voltage set to 1 and the wire speed is at 30. I'm practicing on a dented up fender I got for free. Just trying to cut pieces off and weld them back on. Still even with the voltage down to 1, it just wants to blow right through the metal. I changed over the polarity of the wires and all that in the machine as well. I have a ton of questions if anyone could at least answer some of them.

What am I doing wrong from the looks of the picture? The welds are a combination of me and a buddy who doesn't know what he's doing either.

How can I tell that the gas is working? I have the bottle open and the gauges read as if there's pressure but I have no idea if the gas is even working. Can you see or smell it? I almost feel like it's not working at all.

How much wire should be sticking out of the gun when I initially start the weld?

How far do I then have the wire away from the metal when I pull the trigger?

To tack the two pieces together, do you start on one side and quickly puddle to the other using the back and forth motion? Or do you just point right between the pieces and hold it still for a second while you tack?

I held the gun fairly far away from the metal on the welds that look like they are joining the two sides together. The welds look pretty cold to my untrained eye and don't look like they'd hold very well from the backside. Any help would be appreciated.



 
looks like the gas is not working.......should be making a sizzling bacon sound.........like that, i bet it make a strange sound like when you get water in your ears.
 
best guy to ask is Mr. Rob ....A.K.A crackedback...maybe he will chime in
 
the nozzle of the gun is where the gas comes out .....so if you held it really far away then that might explain why the gas is not working ...the gas is not getting where it needs to be
 
Easy to tell if you have gas. I'm not familiar with your welder, but they all have a tension device on the wire feed. Either turn the wire speed all the way down, or loosen (unlatch) the wire tensioner so it won't feed.

Hold the gun near your ear, being careful where you point it. When you pull the trigger you should HEAR gas flow. If you have a regulator with a low pressure side gauge, it should drop a bit with the trigger down. If you have a flow gauge, IE a "floating ball" etc, it should show flow when the trigger is down. You should hear a fairly loud thump for the gas solenoid.
 
You should be able to hear the gas when you pull the trigger, and you can put a match or lighter in front of the nozzle and the flame should go out.

Also, you need to be about an inch or less away from the weld so the gas can cover the weld area.

Turn your heat down a little more till you get it putting down some smooth bead with your gas.

Once you get it, those holes can be filled back in with quick short bursts so it doesn't get hot and do it again.
 
I'm no expert, but have the same welder...

When you turn on your gas you will see right gauge come up. turn the regulator in to about 23-24 on left. It should drop a couple when you pull the trigger if it is working and you will here the solenoid as mentioned already. 20 is probably good for inside, you will need more if you are working outside like I am most of the time.
I try to minimize butt welding as it is a bit tricky. You can use copper or brass behind it and it will allow a little more heat without blowing through. I rarely use setting 1. I believe I'm usuallya around 2/20-25 for body metal (20ga). I got a pneumatic flange tool at harbor frieght that allows for a neat, level overlap,
 
Either your gas is not working or you are holding the tip to far from the metal.
Do you have the ground on bare steel of the same piece of metal you are welding?
The tip of the welder should be about 1-2" -3/4" away from the surface.
Try using thicker material until you get used to the welder. I can use .025 - .030 wire welding sheet metal.
What size is the wire you are using?
There should be about 3/4" of wire sticking out of the gun when you pull the trigger.
 
Youtube is full of how to weld videos. I was in the same place as you a few months ago. If a picture is worth a thousand words, a video has got to be worth a million. check it out.
 
FJ5 said:
Youtube is full of how to weld videos. I was in the same place as you a few months ago. If a picture is worth a thousand words, a video has got to be worth a million. check it out.
Click to expand...

Good call.
 
You need a backer on the backside or close that gap up completely if your going to try and butt weld. You can't expose welding to air. That's what shielding gas or flux wire do. Protect the weld from exposure to air. Try and overlap the metal and you'll see a big difference
 
Make sure you are not welding outside if it is windy as the gas will just blow away.Tip should be as close to the metal as possible without touching, about 1/2" and wire should be sticking out about a 1/4".You can back up the metal with a thick piece of copper as that will help stop the blowout and if you are still blowing holes in the piece keep turning up the wire speed till you don`t.Butt welding thin metal is probably the toughest to do without blowing holes so keep doing very short tacks and jump around to keep the heat down.
 
I'd try running a bead on a flat section of the panel first. See if you can tune in the welder. Either the gas is not working or you don't have one of the settings set right.
 
I'm no expert, but the best advice is YouTube and practice practice. I used a flux core wire welder and found closer better, and more than one person suggested smaller diameter wire cause it takes less heat to melt, less chance of burn through. Makes sense to me, but I'm a rookie for sure. Wait for someone who has forgotten more than I know. LOL
 
Once you get your welder settings correct, try welding on some spare metal first until you get the hang of it.

Watch your weld bead. The bead can indicate to you if you are going too fast, or slow, or just right. The bead should be nicely curved. It should not be elongated. If it is elongated, you are going too fast. If the bead is bunching up, it is too slow. If it is nice and curved, then you are going just right.

Get some pictures of a good weld, then use that as your target weld. Keep practicing until you can match that.
 
I know there are members that can run circles around me with a welder.

What exactly are you using as a set up? Wire, gas, flow rate, etc.

One deal, once you turn gas on, leave the dials at zero, hold it to near your ear, pull trigger and make sure you can hear it flowing. You likely want 20-25 flow rate.

.023 wire may be easier to deal with. A good guideline, you want one amp per .001 of material thickness. For each amp you want a certain amount of wire in inches per minute, with .023 it's ~3.5" and with .030 it's ~2". So if you are welding .030 metal, you'd want ~20 amps and running ~105"/min with .023 wire and ~60"/min with .030.

Pull the trigger, count/go 6 seconds, measure length of wire that gets spit out and add a zero.

The voltage tap you have it set at may be ok.

Good that you are working on spare stuff.
 
If you weld and it makes popping sounds like the wire is exploding, too much wire, not enough voltage.

If you hear hissing, not enough wire, too much voltage it's burning back up the wire to your tip.

I like about 3/8-1/2" wire stickout. Try to keep that distance consistent as you weld.

You want a small gap in the material, otherwise the wire has nowhere to fill and it will peak. If you can back it with copper, brass it will help with your blow through.
 
Make sure the polarity is set right for solid wire and not flux cored, the back side of the side cover will show you which way the leads should be. You need to clean more of the paint away from your weld and make sure the back side of the panel is clean too, if stuff is burning off the panel near the weld it will contaminate the weld. Set your heat setting as hot as you can without burning through, then adjust your wire speed and travel accordingly, if your not burning through occasionally your probably not hot enough. Use the chart on the inside of the side cover to set your heat and wire speed, then adjust to where your comfortable. Oh and practice practice practice.
 
Thanks for the huge response everyone. The weather is going to be iffy here for a few days so I'll probably give it another shot at the end of the week.

I did notice the gas gauge moved when I'd pull the trigger but I didn't hear or sense anything was coming out. I'll have to give it a listen or use the lighter trick next time I'm out there. I'll take your flow rate suggestions and make sure I have it set to that next time I try it.

I double checked and I have solid core wire on there and the polarity is correct.

I bought a piece of copper today to use behind the metal but it is possible to weld this without a backer right? When I do my quarter panel patch, I don't know if I'll be able to get the backer in there with the trunk extension in the way.

The flange tool is another good idea. I've read different opinions on whether or not it leads to more rust later on but I guess I could just always use weld through primer on the back to help prevent that.

I also watched a bunch of youtube videos all week but they didn't seem to help too much. The guys just kind of quickly explain what to do, pull the trigger for a second and a perfect weld comes out of it. Didn't work nearly as well for me in real life :D
 
ESP47 said:
The flange tool is another good idea. I've read different opinions on whether or not it leads to more rust later on but I guess I could just always use weld through primer on the back to help prevent that.

I also watched a bunch of youtube videos all week but they didn't seem to help too much. The guys just kind of quickly explain what to do, pull the trigger for a second and a perfect weld comes out of it. Didn't work nearly as well for me in real life :D
Click to expand...

I use the weld-thru and seal from the back. Not sure what you would do to the back if you cant get to it when butt welding? The weld will rust quickly if not coated. I've used regular seam sealer or neoprene roof caulk - depending where I am on the car. The neoprene worked great under the floor pans.

Here's a site I found with some good info and short vids of the actual welds being done. Also I see they have added a paint section I need to check out.
http://www.mig-welding.co.uk/mig.htm
 
To keep it simple, establish that you have gas coming out of the nozzle. You do this by listening for it with your ear close to it with the wire end pointing away from your face. Pull the trigger, and you should hear a shhhing sound like you are letting the air out of a tire slowly. Adjust it to 20-25 cfm if you have a guage.
Next, set the wire speed and voltage. In simple terms, wire speed is heat and voltage is penetration. For light sheet metal like body panels, i set the voltage to 1 or 2 out of 4 and the wire speed for about 50% in the scale for a starting point. Is there an owner's manual or a chart on the door of the welder to help you with basic settings?
Next, the metal has to be clean of rust, paint, oil, etc.
Establish a good ground, ''scratch'' the ground clamp in so it make good contact like you would when boosting a car with jumper cables.
Set your stick out. With mig, it should be about 3/8 of an inch give or take a little bit. This is measured from the end of the contact tip to the end of the wire.
Make sure the tip and gas nozzle don't have any spatter or obstructions.
Practice on a piece of scrap the same thickness you plan to use to get your settings right and so you get the feel for it as well as some practice. Do this on lap joint or just a flat piece to start, not an open butt like you were trying.
A few other pointers:
If using an open butt weld (gap), don't make it any more than the thickness of the wire that you are welding with.
Don't weld continuously on body panels, or they will warp. Use a series of small tacks spaced a fair amount apart so you keep the heat down. Then go back and forth until you are finished.
Make sure you have a #10 or 11 shade in your helmet, and look at the puddle from the side, and be as close to the weld with your helmet as you can so you can see properly.
Wear gloves and a long sleeve cotton shirt as well as a hat. Don't do what they do on t.v. and wear a short sleeve shirt and no gloves!
Wear safety glasses inside of the helmet and make sure the helmet and lenses are in good shape.
Keep pets away from where you are working and anyone else for that matter, anyone that gets an arc flash will be hurtin' for days.
Make sure the area is clean of all flammable debris and cover anything else up you don't want to get hot spatter on. Obviously move gas cans, oil, and rags out of the area.
Remember, cleanliness is your friend with welding, be it the material, the equipment, or your surroundings.
I hope this helps you, i am a journeyman welder, and have taught a lot of people to weld from square one!
Tom.
 
One thing that helps a lot in all welds but especially when butt welding is to dress the edges of the metal your welding with a grinder. Grind off all burrs or rough edges. These edges have little spurs on them that act like wicks & heat up really quick & start to burn away 1st very fast & that makes it burn through. If you grind it 1st taking away the little spurs it doesn't burn through as quickly. Copper backing really helps too.
 
From the pictures, it looks like you are starting your spot welds right on the gap between panels. Try starting your weld over one panel and draw your weld across the gap to the other panel. I have had the best success with this technique on sheet metal welding.
 
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