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Old 08-01-2005, 07:42 AM
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Question on Mig Welding - HOW to

I just got my new HTP 160 MiG on Thursday. I have NO welding experience whatsoever and am completely learning from scratch.

1. Would it be better to learn on heavier metal (say 1/8") and then transition to sheet metal or other way around?

2. I ran a couple of beads on some angle (3/16"). I got the welder "tuned" nicely when pushing the gun, but with the same settings, pulling the gun resulted in the Mig going out of "tune". When pulling the gun, do I need to increase or decrease the wire feed? No matter what I did, I could not get the nice bzzzzzzzzz sound when pulling.

3. How do you see the seam when welding? I've got a self darkening helmet so I can see where I start, but once I get going, all I can see is the arc itself and I have to go along using the "force" . Would additional backlighting on the part help?

I'm going to be signing up for a welding class at the local tech school, but classes don't start until October... thanks for the help!

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Old 08-01-2005, 09:12 AM
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i know where you're coming from. i had no welding experience before i bought my welder. i experimented a little bit just running beads and stuff. what i found when i first started was that a lot of times i didn't have my welder set hot enough. i would weld something and it looked like it was welded but with a bit of prying it would come apart. i haven't really got into much more than 1/8" - 3/16". whenever i do those i get the welder set nice and hot. if i burn thru then i know it's too hot. if you're getting a lot of sputtering it could be that your wire feed isn't fast enough. you'll figure it out.

i know it's hard sometimes to watch where you're welding. i try not to look at the arc but at the weld pool. it's easier to see where you're going if you push rather than pull because the gun tip isn't in the way then. you'll just have to keep plugging along. you'll get it eventually.

one thing i've noticed on my project is sometimes i'll find a spot where i welded something when i was just learning and i can tell, now, what i did wrong. at the time i thought it turned out okay. it's kind of bittersweet because you know you didn't do it well enough but you know you're better now.

my $.02

JB
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Old 08-01-2005, 11:43 AM
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Centerline (I think) had a good "How To" post up here but I notice it's missing from the FAQ sticky???
It get moved someplace else??
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Old 08-01-2005, 12:50 PM
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You just need to practice on the different thicknesses of steel, and don't forget to try other positions to weld. Because horizontal welding is much easier than vertically.

Hasn't your helmet got a lever to adjust the darkness while welding? Then maybe you can set it a bit lighter.
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Old 09-11-2005, 07:08 AM
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wire feed welding

Hey
After thirty years of stick welding I changed over to wire feed.
Wonce you get it down you will never pick up a stick again.
I went to a frend and he showed me some tricks.
Pushing or pulling yur weld do not have much matter.
Do not try to draw cicrles or figure eights. On 1/8 to 3/16,
Start by leaving a small space between material and drwa a half circle between material, overlaping about a 1/4th inch on each side.
You must stay on alittle longer to start your bead then watch your ark.
The most important is to listen to the sounds. They must be smooth and equial.
Adjust your hemet to a lighter setting and move aroud til you can get a good viewing position.
Wire feeds take a while to get used to.
You may have to change your feed speed to equial your welding speed.
Its not the welder burning through its your hand speed.
I hope this info helps. Rember the sound is the most important.
LOU
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Old 09-11-2005, 07:54 AM
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“Basics of Basics” MIG Welding
By Brian Martin

Let me start with safety, DO NOT SKIP, YOU NEED TO READ THIS. The UV rays that are produced at the weld can and will cause damage to your eyes you know that. But did you know that it WILL damage to your skin as well? I have gotten “sun burn” from welding. I have only “peeled” from regular sunburn a few times in my life (I have a dark Portuguese complexion) I have peeled from MIG welding more! This was a long time ago, I would never let that happen again. Wear a light long sleeve welding jacket. A “Tildon” jacket is only about $25.00.You want jeans and high top boots on too. Wear welding gloves, go down to the local auto parts or hardware store and get yourself some nice SOFT gloves. Some are made so stiff that it is hard to work in them. I got some at ACE hardware that are dang near sensual . Get a good helmet, I have a Cherokee ( http://www.accustrike.com/ ) that is only about $90.00. It is a hands free helmet that you open the shaded lens with your chin! I have had it for about 15 years without a problem. When open it gives you a full 4x5-inch or so CLEAR lens, unlike the “self darkening” helmets that are always shaded. You can flip up the lens and grind anytime you want. I want the full control of when to see through a shade or not. I highly recommend this helmet. Also, another thing that I have only begun using a year or so ago (I hate thinking about how long I didn’t use it) a welding respirator. A 3M NOISH approved are available at ACE hardware for about $18.00. If you are welding with weld-thru or “E” coat primer you are making ZINC FUMES! And can get “zinc fume fever” VERY easily. Even when welding clean metal, you are still making fumes that are hazardous. Be sure the respirator fits under your helmet. The Cherokee helmet for instance doesn’t have room for a cartridge mask so a single throwaway is all that will work. HEAR ME NOW BELIEVE ME LATER, PROTECT YOURSELF. Even if you don’t care about the protection because you are such a bad-*****, do it because you will produce a better weld. It is hard to lay a nice bead when you have a hot molten ball of steel in your shoe or pants. 

MIG welding is actually just a “controlled short”. It is a short just like if you touch your two battery cables together on your car and it sparks. The MIG does the same thing, you just are in control of it. You are melting the metal with heat created by this “short”.


Basic principles of MIG welding are this: You have VOLTAGE, the pressure that pushes electrons through a circuit. Then CURRENT, (same as amperage) the amount of electrons being pushed. And RESISTANCE this restricts electrons from flowing. The gas (Argon, CO2, or a mixture of both 75-25% is most common) is blowing away the impurities in the air around and on the surface of the weld. If there is a breeze you may need to up the pressure from the recommended 25-30 cubic feet per minute or 3-4 PSI.

What the heck does this mean?

The arc that is formed when the wire comes out of the gun and hits the metal is your “CIRCUIT” (or current path), The welder has to have enough voltage to keep the current flowing. You control these variables with the “heat” switch (VOLTAGE) the wire speed knob (CURRENT) and the “stick-out” and or “arc length” (RESISTANCE).

The MIG welder has to be “tuned” just like a spray gun or your carburetor on you car. That perfect balance between too hot a weld (blowing holes) and too cold a weld (not enough penetration) is where you want to be. Fortunately this balance is pretty wide for at least “normal” welding on your car.

“Hot” or “Cold” weld. I will refer to welds in this way to describe them. Extreme “Hot” would be heavy melting, puddling, burning holes. Extreme “Cold” or “Cool” would be not enough melting thus not enough penetration.

To find this balance, get a piece of scrape metal that is the same thickness as the metal you will be welding (or very close to it). Clamp your ground clamp to it and lay a bead on it. Start the bead with the MIG set at the recommended settings on your welder. You don’t have to lay a bead to be proud of here, just weld. If you have someone to help this can be a big help, but if you don’t go it alone, you’ll need to learn to do it someday anyway. While you are laying a bead have your partner turn the wire speed (CURRENT) up and or down till you hear that perfect ZGHZGHZGHZGHZGHZGHZ and you will see in the bead that it is perfect. The weld will be laying out relatively flat with no “undercut” (at the edge of the weld there isn’t a low spot where the weld has burned away the metal and not replaced it with melted wire). If your wire speed it too slow there will be gaps in sound then pops. Watch the weld and see if the weld is “crawling” up the wire, that is a dead give away speed is too slow. If it is too fast, it have faster pops as the wire is burning away and quickly hitting the metal arcing again. These sounds can be very subtle so it may take a while to learn the sound, have patience.

Now if you have to do this alone, just hold the gun one of your hands and have the other on the wire control, it is very awkward at first but you will be able to do it well in no time.

I have to clear up an “old husbands tale” about the sound of the weld. I have heard and read many times that your weld should sound like “bacon frying”. Let me tell you right now, if your welds sound like bacon frying, you are laying some crappy welds! It should sound more like an electric buzzer “ZGHZGHZGHZGHZGHZGHZGZHZGH”. If it sounds like bacon frying “ZGHZZ-POP-ZHZGHZ-POP-CRACKLE-ZHZGZ” You are doing something wrong.

So, what does this technical stuff about voltage and current have to do with learning to weld? Well if you understand WHAT is happening, it is easier to MAKE happen what you want.

If you are welding a little too “hot” and are blowing holes, you could adjust this simply by creating more RESISTANCE by lengthening the “stick-out” or distance that you are holding the tip of the gun from the surface being welded. So as you weld a bead, if you see the weld puddling too much and fear that it may blow through, you can back the tip off the metal a little and create more resistance. If you are welding thin metal you can start with a longer stick-out and produce a “cooler” weld also. Now, this has to be done with caution because if you rise up too much, the gas does not shield the weld leaving the weld porous.

The direction of travel and speed WILL also effect the “heat” of the weld. If you use the “drag” technique with the gun dragging away from the weld, it will be “cooler”. If you are using the “push” technique with the gun pushing into the weld it will produce a “hotter” weld. So, if you were to start on the left side of a seam and with the gun leaning to the right at 45 degrees welding from left to right, this would be “dragging”. If you were to start on the right side of the seam with the gun leaning to the right as before and welding left, to the left side of the panel, that would be “pushing” the weld. I find that when welding sheet metal if there is a burning through problem, changing to the pull technique will do the job most of the time.

Of course speed is obvious, the slower you go the hotter and flatter the weld. The faster you go the taller and cooler the weld. All of these techniques can be used with one and other through out even one seam (though you wouldn’t likely change from push to pull or vice-versa) to control the weld. Ideally you would have the weld set up and cleaned so you wouldn’t have to do this, but realistically you do have to change gun distance speed as you weld.

The first BIG tip I can give is to have a nice pair of angle wire cutters beside you at all times. You will want to cut the wire off at the proper length EVERY time you start a weld. This does two things, first of all it gives you the “stick-out” that you want every time. Second, it will give you a sharp tip to “pierce” the metal or weld-thru primer. Third, that little ball of metal on the end of your wire, it is oxidation! That is right, if you leave it there, you are pushing RUST into your nice new weld! I learned this tip from a certified pro welder (underwater even) and it totally changed the way I weld.

The second BIG tip is to have everything CLEAN and set up TIGHT for the weld. Like with painting, the preparation is KEY. Even the slightest grease, tar, paint, rust, etc. can cause BIG problems. As a rule the smaller lower the voltage your welder, the more critical this is. Clamp the pieces TIGHT, and keep the metal clean at least one inch from the weld with two or three inches preferably.

So lets weld a “lap” weld where a piece of sheet metal is laying over another and you will be welding the top piece to the one laying under it. I find that a pull technique with the gun at a 45 degree angle and pointing right straight at the seam the most effective. But the thing is, the upper sheet will burn MUCH easier than the bottom. The edge of that sheet has much less of a “heat sink” effect than bottom sheet. Sort of like starting to burn that log in your fireplace, if you start on the edge where it is thin it will start burning MUCH easier than if you started right in the middle right? Well, when you are welding this lap weld you want to start the weld on the bottom piece and even concentrate the weld on the bottom.
This may sound funny but if you get a piece of paper and fold it so you have a “lap” seam you can see what I am going to tell you. Hold this seam flat with a few pieces of tape but leave it exposed so you can “weld” it with some white glue. Lay a bead of glue on the bottom paper right next to the edge of the upper paper just as I described above. When you get real close to the upper paper edge you will see the glue sort of “grab” on to the edge. You don’t even have to move the bead all they way over to it, if you are very close and you just barely hit it with the glue, it will “hang on” to it. Continuing the bead down the edge with most of it laying on the bottom sheet, the edge of the bead will “grab” the edge of the paper, without any effort on your part.

Your weld bead will do the same thing. When you are concentrating on the bottom, harder to melt metal just move the bead over to touch the edge of the top metal and it will “grab on” to it. You can run the bead with most of the heat being directed on the bottom and just “grabbing” the top without blowing it away.

This goes for plug welding too. The size of the hole depends of a few factors, usually 5/16” is the norm. But sometimes you could go down to 3/16” or up to 3/8” depending on the thickness of the metal or how important the strength of the weld is. That sounds funny but if you are welding in a “backing” for a butt weld for instance, it is only being plug welded to hold it there till you lay the bead into it while welding the two adjacent pieces together. As before with lap welding you want to direct the weld into the “bottom” of the hole to hit the bottom piece of metal first, then melting it into the surrounding metal just like the lap weld. If you have perfectly prepared plug welds, you should easily be able to fill the hole with weld leaving the top almost flat. If you are ending up with a large hump, you need to raise your voltage, or wire speed to weld “hotter”. Weld a number of tests before going on to your car. Weld as hot as you can without burning through and look under the panel to see your penetration If the weld is coming through the bottom producing a hump under it, the weld is too “hot”. Either speed up, lengthen the arc or stick-out or lower voltage.

Hope this helps you produce better welds.

Last edited by MARTINSR; 09-11-2005 at 08:37 AM.
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Old 09-11-2005, 08:01 AM
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Martinsr,

This post just reminded me.
What is the status of your book?

Won't do me any good if I'm dead when you come out with it.
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Old 09-11-2005, 08:34 AM
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Brian Martin,Freelance adviser
 
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My enthusiasm comes and goes, so naturally, so does progress.

You better plan on living a long time.

What is that famous quote, "I plan on living forever, so far so good".


Brian
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Old 09-11-2005, 10:49 AM
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Martinsr covered that well and leaves very little to add but I would like to address that auto dark hood. A few years ago when those things first came out I thought they were the greatest thing to ever come down the pike but now, for MIG welding anyway, I am having second thoughts for just the very thing you mentioned and that is visibility at the arc. By the very design of the thing it gets darker at points of intense light thus being the darkest at the arc itself and in most cases simply makes small hard to see seams nearly invisible. After using several different brands, some costing over $400, I can not see any difference in severity of this problem between makes and since I had been using these daily for years I had become accustomed to the problem and did not realize how bad is. Recently I picked up an old conventional hood with a #10 lens we had in the shop to do a small MIG weld and I was literally shocked at how much better I could see the small seams(it wasn't my eyes failing after all ) so from now on I for one will no longer recommend these auto dark outfits for light MIG welding since any advantage gained from the convenience of the auto feature is more than lost by the lack of visibility. Setting the lens to a lighter shade only lightens the peripheral area and does very little to help the problem so, IMO anyway, the auto dark hoods are not much of an advantage if you can not see what you are welding.

I have not tried that Cherokee but it looks really good and I plan to get one to try but in the mean time my "high tech" hood is going to get the boot, at least for light MIG.
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Old 09-11-2005, 10:27 PM
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I have tried many autodarkening helmets, from a hundred bucks to many hundreds, I mean give a good test, and I always hand them back and go with my tried and true Accustrike.
Every autodarken helmet I have tried started out at a #4 or so shade. That is the shade you would use for gas welding, it is like VERY dark sun glasses. You can't see crap BEFORE you hit the trigger on the MIG. The Accustrike allows you to see perfectly and you can even open your chin fast and the lens will go up and stay up so you have a quick grinding helmet without having to switch.
The only bad part is you have to use the 3M disposable welding resperators which will cost you a little more over the years. You ARE using a welding respirator, right?

They are about $90.00 from their web site as I remember.

You only have to slightly drop your chin a little, not even enough to open your lips to open the dark lens.



Brian
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Old 09-11-2005, 11:28 PM
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I use the 3M-8212 respirator, should fit under anything. A good deal of the welding I do is out doors so the shaded light phase is usually not much of a problem but when I have to work after dark, which I do some times, it is a real PITA. I remember seeing those hoods a few years ago, just never tried one.
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Old 09-12-2005, 07:16 AM
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Good lighting on the welding area helps as well.

What I can't figure out is WHY your best looking weld's are alway's on the one out of plain sight.
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Old 09-13-2005, 07:29 AM
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welding helmet light

Last year I first started useing an auto dark.
It took a while to get used too. But now I don't use anything else.
I found if possible use equal lighting around you. Try turning the lights out
and weld in the dark for practice.
When you don't weld often,it seems each time you weld something is different. Its not it is your skill level. The only thing that can realy make a differance is practice practice practice.
Speaking of practice I think I will go and weld something.
he Mig welder is the most versitale machine you can find gas or no gas.
LOU
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Old 09-13-2005, 08:47 AM
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i finally made a stand for a flood light to put behind me. even with the auto helmet i had trouble seeing. with the light i can still see my path with the helmet dark.
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Old 09-13-2005, 09:53 AM
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I know those auto dark hoods are here to stay and I love mine for field work which is heavy welding that runs from 3/32" to 1/4" rods and 1/16" to 3/32" MIG and innersheild wire but for auto body or any thing that requires small wire and super thin panels I will go back to my #10 shade conventional hood. If your auto dark outfit works for you thats great but for me I have fallen out of favor with them for "precision" welds that require following a tiny hard to see seam. Try this little test and see how it works, I would really like to get others opinions on this to see if it is just me or if it is a real problem. Run a few inches of weld on the next panel you weld using the auto hood and then immediately switch to a regular hood with a #10 lens and see if you can follow the seam easier. This should be done in a real situation since simply running a few weld beads on scrap just will not match real world conditions. I had already been complaining about this for some time and now Modas comes up with the same gripe along with a few others I have talked to so it would seem that this may in fact be a legitimate concern.
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