MIG, gmaw, flux core arc welding, gas metal arc welding q &A

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Gas Metal Arc Welding and Flux Cored Arc Welding Q&A MIG welding advice

Question

hello I’m after some advice as I’m in Finland i don’t fully understand their language. but in the next 2 weeks i have to do a test piece to obtain a EN ISO 287-1 with the MIG on uphill butt . have 2 plates about 300mm long 125mm wide and the plate thickness is 16mm.i was told to start with 2mm gap at bottom then going to 3mm. so what i want to know what is best root technique and capping run .all videos and info will be a great help thank you
Answer

If this is bare wire short circuit mig you are talking about, the best technique for the root is to use a slight land on the sharp edge of the bevel, …about 1.5mm.Hold a dead nuts straight gun angle and use a slight weave just enough to let the root flatten out. Or at least prevent a big crowned root. Subsequent passes should use a weave using a zig zag or slight rainbow arc where you trace the front edge of the puddle. Check with the test supervisor and read the procedure to make sure a weave is allowed. Some welding procedures limit the width of any weave.I would only weave about 20mm max anyway. If the bevel is wider than that just stack 2 or more narrower weave passes next to each other.I would guess the root would need about 17-18 volts and about 210 ipm of wire speed. That’s inches per minute . until now , I have been trying to give numbers in mm. Not sure if your machine will read ipm or what. But I am sure you are used to converting things.Good luck

Question

Question. I'm starting a welding business and seen your quote price for TIG is around a buck an inch. What would be the ball park for MIG welding process standard mild steel? Thanks
Answer

A ball park mig quote per linear inch of weld would be about 50 cents plus 50 cents per tack weld.That is for steel. And is just a way to quickly have an idea of what to quote. Of courser there are all kinds of other things that come into play like need for fixuring, or if its stainless sheet metal, need for shielding the back side, etc.But just for a down and dirty way of giving someone a preliminary price 50 cents per inch plus 50 cents per tack would get you in the ball park.Think about it …a 10 inch mig weld on a gusset would probably take about 4 tack welds. 4 + 5 = 9 bucks.The weld would probably take around 5 minutes start to finish even with tacking, aligning it straight, etc,If you can make 9 bucks in 5 minutes, that is around 108 bucks an hour if you could crank them out without ever coming up for air. But we know that’s not possible so…. By the time you figure in gases, filler wire, etc, along with down time for material handling and such, its more like half that per hour. Not too bad.

Question

Hello. I am a decent welder and self taught. Years ago I bought a Miller 250 MIG machine and had a bubble regulator and used cheap ass wire. But, I could weld anything with that machine and not have to spend all my time adjusting and readjusting to be able to weld. Now, I just bought a brand new 252 and I hate that machine with a passion. I spend more time adjusting then welding. I have called the vendor out twice and he finally said hey I will replace it with a new Lincoln 185. Now we all know that I paid a shit lot more for the 252, but the 185 has tabs/contacts instead of the pots. When I bought the 252 I thought I was getting a 250 with some upgrades. That being said, my brother is the only guy from Dallas to Midland that is certified to work on these machines. Here are some things that it is doing. It will weld about 6 inches and the n start popping, acts like the ground is bad. So I ground the area and then tacked the ground to the metal, no better. I can feel the wire pushing and jerking in my gun. I have bought the best wire money can buy, changed every type of tip and nozzle, changed the cog's from "V" to "U", adjusted the tension by rolling it out in my hand. Hell you name it, I've done it. My brother told me he has seen these machines that had been dropped and messed up the Inverter. In a last ditch attempt to tell you how poorly this machine runs, mind you it has those shitty standard regulator on it rather than the bubble, but I finished this 3 week job up with my 30 year old 200 amp Lincoln Cracker box. Rule of thumb, 'You want a wire machine_ MILLER... you want a rod machine-Lincoln. Was I wrong????? It has always worked for me before. Pipeliner-Rod. MIG-185,250,251,252. I ain't made a dime off this machine yet and the guys i bought it from are a good bunch of guys, but I am not impressed with how they have handled this. Hell they want me to load the machine up and bring it to them instead of bringing out some other machines for me to try out. I am the customer and I am the one out the $2,500.00. Can I get an Amen.....?
Answer

Amen!!! Ok we got that out of the way.I use old millermatic 250 mig machines along with 251 digitals and they are great. I know a guy who has a 252 and the readings are jumping around all the time. It welds ok but it makes me wonder if he is in for trouble.I would get the name of your district miller rep and ding on him. They should make this right. You may have to haul the machine, but it will be worth it if you get taken care of.I have a feeling we will all curse digital readout welding machine one day. I really like being able to see exact voltage and wire speed in ipm, but those old knobs lasted and lasted, and I never had trouble with them.The new inverter tig machines are kind of the same, great with lots of bells and whistles, but they don’t seem as tough as the old conventional transformer machines.Again. Amen brother, customer service is what I look for in a welding supply and if they fail the test, I move on.

Question

I really enjoy your videos, I have a question regarding 50/50 helium argon mix. Does it work as well on a MIG welding aluminum? (Millermatic 350p)

Answer

Thanks, yes it works for thick aluminum on mig as well. You would not want to use it on say 14 ga aluminum , but if you need to weld something thick like ¼”, it will help

Question

hi in about a week i will be taking 6gr welding test w/flux core .Could you please give me some tips on running a good root pass...
Answer

Wow, good luck with that. Of course the root pass is the same as without the restriction ring but the trick is repositioning your body so that you have a good line of sight to see what is going on.I would spend a lot of time with the machine turned off and with the gun in your hand, moving around the pipe and training your body to remember to reposition so that when you flip your helmet down and light up, you will remember how to move. Set the machine by the wps welding procedure specification and use a piece of scrap to check settings if you are allowed.

Question

I would like to start a small welding shop when I finish tech school. I found a Millermatic 350 MIG welder still in the box with all the accessories for $2,500.00. Is this a good price? Is this a wise way to spent my start up money or would you recommend a different/smaller model? Thank you.
Answer

That sounds like a great price. If you can afford it , jump on it. You will never regret it.Lots of welders regret buying a mig welder that is too small. Very few regret stepping up and getting a Cadillac.With that size welder, you can run .045 flux core with or without shielding gas, you can get some 90/10 or 95/5 argon/cO2 and use spray transfer for thick steel where speed and penetration is really important.Get it . that is not much money for something that can make you a lot of money. Not to mention the fact that its like money in the bank. I will bet you could use it for 5 years and actually make money if you decided to sell it.

Question

Hello..I have a Ironman 250 mig machine and just purchased a spoolgun 3545. The problem is that the gas continues to run when the trigger is not pulled. Is there a flow control that I missed when I was hooking it up ? or does all the gas run all of the time ?? seems like a waste. by the way, the MIG gun and gas works great for gas control, it just doesn't work that way with the spoolgun. What gives ???
Answer

I just did some searching and found the pdf for that mig spool gun.. http://www.hobartwelders.com/pdf/spec_sheets/Spool_Guns_3035-20_3545-20.pdf

I don’t know what your problem is , but it is not supposed to be that way. The gas should only flow when the trigger is pulled. I would call Hobart at: 1-800-332-3281 (for Technical Service & Warranty) and try to get a new gun or get a new gas solenoid for the gun.

Question

A little background, I have 26 years of welding experience. I completed a pipe welding course in 1983. I have been doing pipe and structural since, everything from stick, MIG, TIG, and flux core. I have tested and certified in all of these, bend tests, magna flux to x-rays, flat to horizontal, overhead, 90 degrees vertical, E6010, 7018 and stainless. I recently took a 3G flux core test. The machine heat and wire were preset and I was told to not touch them. The plate was an inch thick and maybe at an 80 degree angle and the wire I believe was .035. I believe the amp setting was at 160 amps. I could not make out wire speed. Since I had no say on the setting I did not concern myself with the settings. I did ask if I could practice on a separate plate and was given the go ahead. Before I started the test they said no weaving. If you weave you will bust out. I was told that they wanted the weld to look like smooth toothpaste squeezed out of the tube. I have done that weld on a flat surface but never uphill. My root pass second and third passes were pretty flat and the flux peeled off of them. So the setting was okay, as far as heat and wire speed. The groove helped in supporting the welds. My other passes instead of lying flat, got thin and had high ridges in the middle. Somebody came by and told me that the best thing to do was to grind them down and start over. I did that several times and the only way to flatten them was to cheat and make tiny weaves. I was still grinding them down. On one of the passes with no weaving, I got ridges again and that is when the inspector came by and said that I was not going to pass the visual test. As far as he was concerned I had already failed the test. I told him I was grinding the welds and he said it did not matter as far as he was concerned I was leaving slag inside my welds. I did not have issues with slag. I could just buff it off. Then he went on to tell me I could have welded on a 44 degree angle. Go figure. I would have had a snowball chance in hell. As I said before, I have taken this test several times and have passed with weaving. Here is my question. Can you tell me what is the procedure on a G3 uphill flux core with no weaving even on the caps (the caps being no more than 1/8” high) and pass the bend and x-ray test? Can it be done?
Answer

Some things never change. Engineers are always trying to discourage weaving because of stress and heat input. They don’t realize that in the field, welders are going to weave. At least enough to make the passes flat enough not to trap slag at the toes of the weld pass.I have done a bit of experimenting with flux core lately and here are some things I have learned. If you keep gun angle, stickout, and travel speed right, it is possible to run stringers that are not crowned too badly.The trouble is if you stack the second to the last stringer too close to the plate or pipe wall, you will have to grind in order to avoid trapping slag. When you can weave a little bit, its good to leave plenty of space for that last pass. But if you just plain are not allowed, then the beads have to be stacked just right. And in a weld test situation, that is a crap shoot. Sorry about you busting the test. I am not sure where the test inspector was coming from, you would like to think he had his reasons, but I have come across a few who were dicks.

Question

I have a Miller 251 MIG welder. I am having a problem with an air bubble forming in my bead just as I pull the tip away. Suggestions?
Answer

Sounds like either….not enough gas flow, or possible paint , oil or rust on the metal. Make sure the tip is not clogged with spatter too.

Question

hey man great site, you have a lot of tips for GMAW solid wire, how about a few more tips on industry related stuff like overhead welding with FCAW?.... mainly because that's what I'm having trouble with, hey thanks
Answer

Thanks for the tip…working on it. Just ran some flat fillet weld break tests to compare with flux core with bare wire mig. Might as well throw some overhead in there too.

Question

I was wondering if you could give me some analysis on my welds vs. another welder. I have been MIG welding for about 9 years now, i have been TIG welding for about 3-4.

I have a great passion for metal working especial when i can do a welding project and then sit back and take some pride in knowing i just built that and not everyone can do it!. The other person that I’m comparing my welds to has been welding for about 20 years, but it’s always been just a job to him he doesn’t own a welder and do any home/side projects.

Not that, that makes him a bad person just saying. Anyways here are the links to some pics, when i cut the welds in half in a band saw i could see the penetration area.. so if you could help with how i can get that to show.

Ok, here is a link to his welds http://i138.photobucket.com/albums/q261/jlaudio29/IMG_0912.jpg

He does sorts the pause, let puddle build, then move forward a little, rinse repeat.

Here is my weld: http://i138.photobucket.com/albums/q261/jlaudio29/IMG_0899.jpg

I constantly move forward and weave slightly and my movement forward is at a slow steady pace. any insight you can give me would be great. few comments me and the other welder exchange.. he stated that he felt that if the weld was a little more concaved that he feels it penetrated more because more of the filler went into the metal.. he feels that my type of welds are colder.

Now keep in mind the welder was on the same setting when we both did the welds. here is the cut away view which isn’t very good at all. i suck at taking pictures of welds apparently

http://i138.photobucket.com/albums/q261/jlaudio29/IMG_0916.jpg

His welds are on the outer left and right and mine are on the inner left and right. Please let me know what you think.. Oh also this was using 75/25 argon/co2, he prefers to use 98/2 argon/oxygen. If you could give me some thoughts on that as well. Thanks a bunch!!!

Answer

Ok this isn’t going to settle any arguments but here are my observations…It appears that you pull, he pushes. That is the biggest reason his welds are flat and yours are kind of crowned. Of course technique makes a difference too. He is getting more spatter, again from pushing.

Honestly , I have to say I thing yours are slightly better. More throat. If you measure the cross section of weld on both , I bet the welds with the convex face are a good bit thicker and therefore will be stronger.

Other than that , its like art. Some people will like his welds better , some will like yours. If neither one of you is having failures, drive on.

If you really want to have a contest, both of you weld only one side and only about 3 inches. Then break it with a big hammer and inspect the root to see who penetrated and who didn’t and who’s weld takes more force to break.

Question

First off, THANK YOU!!! for sharing your experience and knowledge about welding. I bought a Craftsman welder about 10 years ago. I've been welding with flux-core up until today, when I finally broke-down and bought a 75/25 #1 tank, and when I attempted to loosen a nut on the polarity jumper, the bolt snapped off. Sears does not have this part anymore so I either try to repair it, or cross-reference it with another brand??? Any advice you could give me on how to fix this would be much appreciated? BTW: I WAS able to order a new liner and did so - I would not have thought of that until??? Thank you

Answer

You may need to drill and tap and put a set screw thru another piece of all thread…and then be careful no to break it anymore.

Question

Hi, I am going to be stick welding and am a newbie. I saw that you recommended the Northern Industrial Solar-Powered Auto-Darkening Welding Helmet. Do you think it would be worth the extra $50 to buy the one with the bigger view (Northern Industrial TECMEN Large-View ADF Welding Helmet — 92mm x 62mm View, Model# ADF750S)? It looks like it has about the same specs as the $50 helmet, but with a bigger view. Just wondering how much of a difference a bigger view area makes. Thanks,

AnswerI cant really vouch for the larger viewing area helmet, I have only tried the one for around 50 bucks.I don’t know that it will make much difference to you. I found the viewing area on mine to be just fine. exit mig questions page and go to welding certification