Some of you might be getting tired of all my welding woes, haha Well, what Ive been wondering about now is with mig welding thick steel (such as frames)...So normally on frames, I weld a bead (rather than a series of tacks as you would on sheet metal). Then, I smooth it to where it blends in with the surrounding metal as best I can... Lately, Ive really been wanting to build a frame and not grind down the welds. (People on here like Brian Bass and Steve Sellers provide tons of inspiration) I want to make the welds look as nice as possible while still maintaining its strength. What looks the best, to me, is a frame that has been tig welded, but I dont have a tig welder, and Ive never even used one dont know anything about them really. So anyway, if you do a lot of tack welds with a mig (rather than running a bead), you kinda get that look. It looks really clean and precise and just neat looking I guess. So finally getting to my question If you weld thick metal (say 1/8) by doing a lot of tacks how does it compare in strength to welding a solid bead? Is it safe to weld a frame up by just using a bunch of tack welds? Or is getting a good tig welder and learning how to use it well the only way to achieve the look AND have the strength too? Heres a couple pics of something I tried just welding a continuous line of tacks and dont worry, its not gonna be going on a car not a big deal if the weld fails One thing I thought of as a variable is on sheet metal, you stop and let each weld cool down before continuing,(assuming youre using a mig and wont be able to straighten it out with and hammer and dolly) when I did this in the pics, I didnt stop between the tacks, I just welded a continuous line of tacks, not allowing any cooling time in between. I thought this would be closer to welding a solid bead? Would that make a difference or is that completely stupid?
your top weld is a 100% better than your lots of spot welds- you need more heat in your spot weld,and you could use more heat in your upper weld. Only my though
yep... I turned the heat up after that bottom weld... also, are you going by discoloration on the top weld?... I wasn't thinking and cleaned it up with a scotch brite pad on a grinder before taking the pic... thanks for any input
yeh, that's what I figure too... just trying to put off spending the money for as long as I can... but I think the time of me needing a tig welder is very rapidly approaching... I'll look for some old threads on tig welding I guess... any particular tig welder you would recommend?
Don't "trigger" weld on frames. You'll be very apt to get cold starts....stops and start are very critical, and mig is already the toughest process to do it cleanly. I've never built a hot rod frame, but I always like all my welds to look good. With the large scale carriers and racks I build, I'll use a circular or weaving motion to get the welds to look nice. You can mess around with different motions to make it look right. Or you can get a nice smooth bead if you just keep the motion straight and smooth. -Josh
I've used Miller, thermal-arc, and Lincoln tigs. Right now the two machines I use the most are a Miller Synchrowave 350 and a Dynasty 200dx. I absolutely love the Dynasty, with a water cooled torch it would definetly handle your frame work. A synchrowave 250 or a lincoln precision tig may be cheaper alternatives.... if you're gonna be doing any aluminum an inverter based machine is the way to go!
Buy a Miller synchrowave tig welder. Yeah its a bit of green, but not unreasonable. With this machine you will be on your way to Bass craftmanship. Step up...you won't be sorry.
cool, thanks for the tips... on the mig, I can get a pretty decent bead (at least...I think), but I can't do a bead that looks anywhere near as good as something done by a tig...maybe I just need to work on it more...I don't know... Whenever I do finally get a tig welder... I definitely want to get the nicest one I can afford... With mig welders, when I was like 11 or 12, I screwed around with a cheap welder... then when I was 13, my dad helped me get a really nice mig welder...and after that, I'm convinced that it's definitely worth spending the extra money...
you can do pretty Mig welds with a continous bead, you need a good machine with a smooth feed, and hundreds of feet of practice, they can look great too, just dont expect the smaller bead size you get with tig. mig welds of equal strength tend to have more 'fill' to them. Oh, dont do the tack weld thing on a structural component. It WILL be much weaker than a continous bead and to my eyes looks like shit anyway (cos i know what you did )
well, looks like I really need to get a tig, and until then...when I use the mig, I'll stick to welding beads rather than a bunch of tacks...that's what I needed to know... cool to get all the quick replys
Wow! What welder is it? I'm not sure I could pull that off with my brother-in-law's 110v home depot lincoln mig
Josh, forget a TIG, continue with your MIG, from the looks of your pix, you are doing OK, especially when you are on 1/8 materials (mild steel). When welding on heavier metal (3/8--1/2), just preheat with torch a little before using the MIG.-------Don
Im not much of a welder but couldn't the same effect be duplicated by doing small circles? I have a mate that builds semi truck trailers and he showed me that. Looked good and was nice and strong. (Thank fuck, it was a roll cage in a rally car I totaled!) He used an old CIG 180 to do it. The tacks would be hard to get all uniform, at least if your pushing around a molten puddle it may be a little easier to control how neat it it. Or am I talking through my arse through lack of knowledge? Just seems that way to me. Doc.
To quote myself : The tacks are hard to get uniform, but do-able. There have been circumstances where I've done it. The real key is keeping the puddle hot and not getting cold starts. But a continuous bead is the way to go.
You can do a lot of stuff "The way you want", but seriously, any Structural Weldment held together with spot welds is nothing but a Candy Stick waiting to break. If your concerned, then I'M CONCERNED. Do a fillet fracture test with your spot welded candy stick & see what it does when you fold it over. Break the spot welds or Tear the steel material. Carl Hagan
The process you talk about in your original post is called stitch welding, only you don't really allow the weld to "cool" between spots. You only want the top of the puddle to "freeze" before you move and pull the trigger again. This is easy to see with a 10-11 shade helmet until you are used to the timing of the weld. Never move more than half the width of the bead! Another option is what is referred to as a "whip" weld; basically a continuous stitch weld where you are moving back and forth slightly in the path of the weld, not side to side (without letting up on the trigger). With practice, this technique will produce a bead pattern much like a TIG, but no one who knows will ever mistake one for the other. As posted above, there is no substitute for practice. Don't waste time running beads on solid plate... The most important gauge of weld qualtiy is penetration, so practice on the types of joints you will be running. When building a frame, one of the keys to good weld strength is an open corner fit. In other words, the edges of the metal should not overlap, they should just touch at the inside corner.
Those last two posts pretty much sum up what I think. With a tig, you can sit in one spot and not have to move because your filler is manually fed. This allows you to get proper penetration right from the start. You can't do that with a mig as the wire is automatically fed, so every start is effectively cold. To try to stitch anything structurally together like this (stop start) is asking for weld failure. Its also a good idea to feather your stops ready for the next start. Its the only way to do it for xray so must be good practice. As far as a pattern in the bead goes, thats directly related to what you do with the torch. Have a play. Try side to side, forward and back or what I like the look of is figure 8's.
That is the KEY the pre heat for the 110 welders will keep the do it yourselfs out of trouble on the fab work. not all can have the 250amp wire welders Right on Deuce Daddy Don.......
The truth about welding, is fusion. It is the only thing about welding that truly matters. In fact, if you are judging a weld by the way it looks, you are missing the point. True, a "good" weld, will look good, but a poorly penetrating weld can look good also. Use a test piece of the material you are going to weld, and TUNE THE MACHINE to weld that thickness and variation of metal,(whatever the process you should choose). You should see weld both below and above the thickness of the original stock, in a UNIFORM deposit. I.E. if you are welding a piece (or pieces) of 1/8" metal, the width of the bead should be slightly wider that the thickness of the stock, in three dimensions. If you make a perfect bead, the weld will be a perfect circle if you cut in in half. Picture the weld in your mind before you make it. What it will look like when you are done with that pass. Dry fire the weld all the way through before you pull the trigger, and don't cheat on shape, or "position". If you have to stop, or interrupt the weld, to make it perfect, do so. The integrity of what you are doing requires near perfection, you should ask yourself, "would I stake my life on it?" Beyond all the boring mundane stupid shit you can do on a ride, your weld is the single most important thing you are responsible for. Not only are you putting yourself on the line, but anyone else that would happen to ride with you. Test welds cost almost nothing, do as many as it takes until you get everything right. In the end, a perfect weld is something spiritual, it's like the perfect wave, or the perfect line on the roadcourse, or the perfect inverted kill manuver in a dog fight. Nobody ever gets there without practice. Practice and learn, and drive on. Peace brothers...
My experience with MIG welding has taught me that if I want to join two important or structural pieces of steel together I better use three. 'Fish' plates, as they are sometimes called, or luggs are great because they allow you space the seams slightly to get more weld between the pieces, because with the MIG more weld = more heat which = more penetration. at that point the only thing to worry about is cheap steel, that breaks around where the penetration stopped. My personal opinion is that unground welds look tacky (pun intended). So, if you're going to grind it down any way, do two passes in opposite directions, that way at the end of the second pass you know you got good penetration over the first 'cold start'. Start the first pass at the 'outside' of the seam (where material is thinnest), with the gun pointed roughly 30 to 45 degrees in the direction you're going to weld. Pull the trigger, let some material build then start a circular motion that overlaps the the edges of the pieces and the previous weld to be joined by a width equal to the gap (deviding the circle in thirds). In theroy the penetration mark should kind of 'egg out' over the length of the weld, with the best penetration at the last weld. If you have the gun at the right angle and you make your circular passes correctly you will push the heat down the seam and out across it create a good penetration mark and your weld will have that 'laid over roll of dimes' look that 'looks good' and also functions. If you're welding in a circle (or square) and can make one pass in one direction, the heat will push back into the 'cold start' spot. Then grind it down smooth with a sanding disk, and if you REALLY want to make it special, take a cut off wheel, and cut a V or U down the middle of the weld and start the second pass 180 degrees from where you started the first, going the opposite direction. Grind that pass down smooth and it will break anywhere else but there. Its time consuming, but well worth it. There will be cases when you cant do a second pass, because you cant get an air tool down where you can get the welding tip to grind it down. In those cases, I use washers to create a 1/6in gap and fill it once, with all the welds from 'inside' to 'out'. you'll know you have the welder set at the right voltage and speed when as you make your circular pass, its makes an even 'bacon sizzle' sound. If your welds are bulbus, turn the wire speed up first, then if it just pops, turn up the voltage. Remember, the wire speed effects the voltage too, so don't just immediatly assume you're not useing enough voltage. And of course the last part that is never stressed enough, is no matter what kind of welding you're doing ARC (TIG/MIG/STICK), Brazing, whatever, PROPPER PREP OF YOUR WORK IS CRUCIAL TO YOUR WELDS BEING SUCESSFUL!!!! which mean removal of everything that is not directly attached to your piece from it, including but no limmited to rust, grease, pen, pencil, tape, your beer, your hand, 'cold' or otherwise bad welds. One Exception: soap stone. Sand blasting is best, but many forms of grinders work too, as long as all the abrasive material is removed as well. Doens't matter hold old you are or what tools you have, nobody can weld rust. Oh and one other thing, never weld accross a bearing it'll really fuck em up. That is all. I hope I provided some useful information.
I have to agree with Dirty Hands. Proper prep is key to any sound weld. Your first example is good. You have to remember when welding a miter joint without a gap the weld will have a high crown. Mig welding can have a nice bead profile without spot welding. I suggest not to over oscillate the weld because that will cause a cold weld. Just practice and it will come along. Also pushing the weld will make a flatter wider bead. Pulling the weld will make a deeper weld with a higher crown.
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