Step 7: Grind down the weld

If your weld isn't on a piece of metal that will show, or if you don't care about how the weld looks, then you are done with your weld. However, if the weld is showing or you are welding something that you want to look nice then you will most likely want to grind down your weld and smooth it out.

Slap a grinding wheel onto an angle grinder and get started grinding on the weld. The neater your weld was the less grinding you will have to do, and after you have spent a whole day grinding, you will see why it's worth it to keep your welds neat in the first place. If you use a ton of wire and made a mess of things it's ok, it just means that you might be grinding for a while. If you had a neat simple weld though, then it shouldn't take too long to clean things up.

Be careful as you approach the surface of the original stock. You don't want to grind through your nice new weld or gouge out a piece of the metal. Move the angle grinder around like you would a sander so as not to heat up, or grind away any one spot of the metal too much. If you see the metal get a blue tinge to it you are either pushing too hard with the grinder or not moving the grinding wheel around enough. This is can happen especially easily while grinding thing sheets of metal.

Grinding welds can take a while to do depending on how much you have welded and can be a tedious process - take breaks while grinding and stay hydrated. (Grinding rooms in shops or studios tend to heat up, especially if you are wearing leathers). Wear a full face mask when grinding, a mask or respirator, and ear protection. Make sure that all your clothing is neatly tucked in and that you don't have anything hanging down from your body that could get caught in the grinder - it spins fast and it can suck you in!

When you are done your piece of metal might look something like the one in the second photo pictured below. (Or maybe better as this was done by a few Instructables Interns at the beginning of the summer during their first welding experience.)


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<p>Absolutely great instructable, especially for the beginner - thanks a lot! But I have possibly the most idiotic question of all that was not answered. I had a stick welding crash course some two years or so ago and they taught us to calculate the space between the electrode and the workpiece. It' such a f**k. Now, in MIG-Welding DOES THE WIRE TOUCH THE WORKPIECE or do you have to maintain a space just like in Stick welding? I know it's a stupid question... Thanks everybody in advance.</p>
<p>The wire touches the workpiece in MIG welding</p>
<p>&quot;A grinder and paint, makes me the welder i 'aint&quot;</p>
<p>love it!!!</p>
<p>Where can I find more info on flux-core mig welding?</p>
<p>Great tips in here!</p><p>though one incorrect tip is opening the valve halfway; you should open it <strong>all </strong>the way or you will lose shielding gas</p>
<p>Thanks! I used to weld for a Scene Shop that made stuff for cruise ships. Everything from stage trusses for lights to massive props (e.g. a &quot;rock&quot; that opened up to be a winged monster, whose mouth the dancers came out of!), to massive, curved stair cases, lit, with inch thick plexi treads....</p><p>I haven't welded in ages and seriously miss it. So, I was brushing up, in case they'll let me stop by and play with their equipment on a couple of projects I have. Either way, I appreciate the great info and it should help lots of people. Cheers.</p>
awesome information for beginners <br>
<p>Thank you for this! It's a great intro for me, a woman-of-a-certain age group wanting to take up welding! </p>
In regards to Gas Tank Regulator Valves, An oxygen setup should always be opened completely so as to seat the stem of the valve against the packing. Failure to seat the internal stem's packing will likely cause a leak-resulting in a potential large scale explosion. The potential of a leak is more common than one would think. Imagine your garden spigot that you water your pansies with. Open it all the way and it usually works fine. Turn it a just few times and, usually, it drips-not a big deal. It's just a little water right? Apply this situation to your stuffy garage. You are welding a few things and the phone rings. 30 minutes later, your garage is a blasting cap just waiting for ignition. You get back to your work, strike an arc, and all of a sudden, you see a white light and your late grandmother welcomes you &quot;Home&quot; into God's kingdom. Now, we all would like to see Grandma again but I'm sure she can wait a few more eternities before you show up. Now, I'm not saying all regulator setups will blow you into grandma's arms again, but the Oxy-Acetylene setups are potential fatalities- now you know.
i was reading the comments just to see if someone let them know that the value should be open all the way, can be very dangerous. the value works both way up and down
<p>Aside from Acetylene, which should only be turned 3/4-1-1/2 full turn, Most other tanks should be opened fully or they will leak. He also mentioned Oxygen as Flammable, which it isn't. It's an accelerant, which is different. Still not something you want around flames though, or grease/oil, because then it can become explosive.</p>
<p>Thanks for the tutorial ! </p>
<p>I am a bigginner welder and I am looking for welding helmet, come across <a href="http://weldinghelmethq.com/" rel="nofollow">here</a> and see some choices, please tell me which one is the best. Thank you !</p>
<p>this is one of the better &quot;how to welds&quot; ive seen on the internet. most are so full of errors and misconceptions or ignorance its crazy. good to see that you did your homework. and took the effort to make a good instructible. :)</p>
so much valuable info
<p>noahw did a fantastic job with this instructable. @psik - because you don't understand welding or the instructions in the article, doesn't make them wrong.</p><p>I will clarify some basic things for you though since you don't understand what the rest of us do.</p><p>1) The electric arc is caused by a short circuit. That's what electric welding is; a controlled short circuit.</p><p>2) CO2 is used a shielding gas, even with pure steel. Oxygen prevents a proper weld, so inert gas is used to push it away.</p><p>3) When he said to increase the pressure, it means increase the gas flow. Increasing the pressure of the gas is achieved by turning up the flow.</p><p>Do try in the future not to insult someone else's work simply because you misunderstand it.</p>
<p>Although it is very helpful, this Instructable has many erroneous information like:<br>- heat is generated by short circuit - not true, electric arc is a heat source in welding<br>- 100% Argon or a mixture of CO2 and Argon is used as a shielding gas - not true, for steel pure CO2 is mainly used to heat up the arc. It's also much cheaper than Argon<br>- you have to increase pressure when there is not enough shielding gas - not true, you have to increase gas flow instead</p>
<p>Nice write up!</p><p>Now for fun, here a video of how NOT to weld.</p><p>https://www.youtube.com/watch?feature=player_detailpage&amp;v=Us7VDZT-NcQ</p>
<p>HG, I hope you defied them at your high school and took welding anyway. Recently reading about women and painting in the early part of the 20th century when women were expected to do pastels and water color. Oil was deemed to difficult for women to undertake. </p>
<p>The 20 CFH you mention is a very good starting flow and the correct default setting for most mig welding. Depending on gas mixture, stickout and nozzle position relative to the tip you might go as high as 25 cfh, but any higher and you risk getting a venturi effect that sucks in room air and further decreases weld quality.</p>
<p>Interesting point. Thanks. </p><p>BTW I think that converts to just over 9 l/min for the rest of the world.</p>
<p>Great instructable, thanks for putting all this info together</p>
<p>Thankyou for sharing this info about welding! When I went to high school in British Columbia, Canada welding, carpentry and electricity plus drafting was offered in school. I had a space in my schedule that would accommodate these interesting &quot;crafts&quot;. However, I was mocked and jeered for putting my name on the list SINCE I WAS A GIRL. Hesketh, the principal of my Junior High School, laughed and mocked me in an all school assembly. I felt very ashamed that I had made the request. He singled me out for wanting to learn the basics of &quot;manly crafts&quot;. At the time, I was unaware that my Father's family had for generations in Canada and Eastern European been noted craftsmen in this field of interest. It was within me. Nevertheless, after that public humilation, 20 girls signed up for the same courses. Unfortunately, I was leaving the Junior High School and entering the Senior High School, where same stupid policy was in place. So, thankyou once again for sharing. Some of us, are just born with the natural yearning to learn these so called &quot;manly crafts&quot; as well as being an expert on vacuuming, washing the dishes, laundry and crafting a decorative 4-5 layer sponge cake. I can also plough a field and milk a cow. And, I have changed the oil in my car several times including changing the filters. Handigirl. </p>
<p>Handigirl, the way you were treated is nothing short of disgusting! Ones sex should not matter whatever the craft or skill. My god, where would we have been if not for all the wonderfully skilled women mechanics, welders, lathe operators and engineers during World War 2? I am a 52 yr old male who does not underestimate the power of any other man or woman. I can weld (gas, MMA and MiG) but I can also sew and love it. I also bake a very nice coffee cake :) These are all human skills not male or female skills.</p>
Handigirl, good for you! I would be proud of any of my daughter's to take on that task. Btw my Mom (Mum for our friends in Canada) was a welder during WWII along with many other women.
<p>I forgot to mention, TIG has (IMO) the steepest learning curve. While it can be just one hand for autogenous welds, it can involve up to both hands and a foot, so if you weren't a drum set player in another life, it might be a tough thing to get started with. Stick isnt bad once you learn to strike the arc, but IMO again, mig is by far the easiest to pick up for a beginner. Worth trying that in a class next time around.</p>
<p>Most courses require but do not provide PSE (Personal Safety Equipment). Which is honestly good for you, as the class would be much more expensive if they did. In my experience for a mig class, you'd be expected to show up with a pair of safety glasses, helmet, vice grips or pliers, mig pliers (AKA welpers) a steel brush, mig/stick gloves and a jacket or at least long sleeve shirt. Some also require or recommend a welders cap. For what its worth, starting with TIG IS probably the hard way, and both mig and smaw(stick) are though different from each other, easier to pick up than TIG.</p><p>Lastly, a word regarding cost. When you price out buying/renting a tank of gas, a professional level wirefeed unit, a high quality power source, a decent mig gun, the regulator/flowmeter, an endless supply of coupons(metal pieces to weld together for learning), the consumables such as tips, nozzles etc, the spool of (presumably) ES-70-6 or similiar for mild steel that you might use up or more often make welding classes a real bargain. And any PSE you buy you keep for after the class.</p>
<p>Almost all welding requires a proper welding helmet / goggles. Most guys buy their own but in any classroom they should be available along with proper FRC coveralls.</p><p>TIG needs a little more co-ordination than mig or stick but I would have stuck with it if I were you as once you master that the other forms of welding would have been much easier.</p>
Sorry but o2, oxy is not flammable but an oxidizer which helps things burn.
<p>Great 'ible' Thanks for taking the time.</p>
<p>Great intro.</p><p>Only exception I have is the all position comment. </p><p>Sure if you are not too bothered about integrity but for a fully qualified weld I would say no. I have some great pictures of overhead welds done with mig that look fine for profile etc. etc. done buy welders with years of experience, but all of which failed. v-up gives better pen. but v-down with mig is often just a cosmetic weld that can be useful as a cap for a v-up. </p><p>It sure is easy to learn though. Back in the 70s my instructor told me &quot;Ya can teach a monkey to mig weld&quot;</p><p>Its also great for large gap / bridge welds to lay down something to backfill where stick would not cut it or you don't have something to use as a filler bridge.</p>
<p>I think this article is really well done. You did a super job of it and this should bring people into MIG quickly, and easily. The only caution I would sound is that you made it sound SO easy people may not think that having an experienced welder around the first couple of times is needed. I do think it's needed. You can make a friend, get some tips &amp; tricks and keep it safe...all at the same time! Find your nearest Maker/Hacker Space, check it out and see if they've got this gear already for you try before you buy, with an experienced facilitator at your elbow. Once you've got your &quot;sea legs&quot; underneath you, the sky is the limit!</p>
<p>Having just read the instructions for MIG welding I have to say it is a load of rubbish. Why do people think they can weld when it is very clear they cannot. I speak as a teacher of fabrication and welding (15yrs) my first year students after correct instruction would lay a weld 100 times better than what has been shown here. You guys out there that want to weld correctly, take the time and do an evening course at your local college. </p>
Always clean your nozzle after every weld and when changing your tip. A clean nozzle prolongs the life of your tip and ensures a quality weld. A clogged nozzle also restricts your gas flow causing porosity.<br>
<p>I have written so many articles on welding procedures <br>but after reading this article felt like never knew anything about MIG welding. <br>Great job author.<br><br>www.red-d-arc.com</p>
<p>This has been so helpful to me. I'm a freshmen in high school and I take welding class, I have gotten past my other 1st year class mates and I moved onto mig welding and this has helped me greatly. </p>

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