| Author | Message | ||
     Reepicheep |
A big thanks to XRing who sent me a very good welding guide. I poured through it, wanted a gas welding rig, but figured I could not really afford it, but was watching anyway. A friend sold me (for an embarrassing low price, I talked him up before I took it, but he kept throwing other stuff in) an oxy-actylene rig, and I got to try it tonight. Brazing is really simple and makes some extremely nice looking joints. The welding was a lot harder (I was joining steel tubes), but I was making usable but not pretty welds within the first evening... Mainly thanks to the great tips in the book. I got to play with the neighbors MIG welder, and that was even easier, but it seems to lack some of the potential of the gas setup. I think the MIG will make extremely solid joints very quickly without a ton of skill, the gas welding rig looks like it will reward patience and skill with absolutely beautiful welds and will let me joint just about any metal to any other metal. I feel silly admitting how much fun it is to melt and join metal. I feel like a 10 year old on Christmas morning  Thanks again XRing! | ||
| Jackbequick |
So many good tools, so little time... The interesting part is that O/A welding is probably the most suitable process for use on motorcycles. The reason for that is that most tubular frames are made from a carbon steel tubing like Chromoly 4130. Most were made using the TIG welding process which creates a narrow Heat Affected Zone (HAZ) at and along the weld. The HAZ is brittle and the weld will fail there if the entire frame or at least the welded portions of it are not annealed after welding. The annealing process is an inherent part of the manufacturing process if TIG welding is used. But when you weld with a O/A rig you are heating a much larger area of metal. If you let that cool slowly it eliminates the HAZ brittleness problem. Generally, anyway. You don't want to force cool most things when you are welding. The insane desire to cool things quickly creates hardening, brittleness, warping, and produces absolute nightmares if things have to be drilled or machined after welding. Jack | ||
| Reepicheep |
Thanks for the tips Jack! So what filler materials should I be using for what metals? There was not much of a selection at Home Depot, so I just got some small steel rod. It's probably too thick, but it is working, and they did not label well as to what kind of steel it is. I know MIG welding uses stainless steel wire, should I just get a spool of that and feed it by hand? Or should I be getting electrical welding rod, and just using those? Or are there specific gas welding rods they would have at a real welding shop? The used rig I got was almost out of oxygen, so the next challenge will be to see if I can find somebody to fill that for me, instead of making me buy a new tank. | ||
| Jackbequick |
For O/A and getting started, you want a general purpose steel filler rod, about 1/16" or so, and some brazing rod, probably 3/32 or 1/8" or so. The thicker the metal you're welding the bigger the rod you need but it is easier to use two small rods for the occasional bigger stuff than it is to try to weld small stuff with rod that is too big. On the brazing rod it is best to buy the rod bare and get a can of powdered flux (like Marvelux). Store a 1 pound can dry and it is about a lifetime supply. The pre-fluxed brazing rod takes moisture out of the air, the flux chips off, and you never have enough flux where and when you need it. Find a good welding supply place, they sell rod by the pound and it will be cheaper than the stuff at Home Depot or Wal-Mart. On most metals you want a filler that is the same as the metal being welded. But on O/A the choices narrow to steel or brass (bronze) rod for brazing. Brazing can be used with most ferrous metals. Silver soldering is really just another form of brazing, most of the gas welding I did was on smaller work in gunsmithing and a lot of it was silver soldering. You can't do aluminum with your O/A rig. In MIG welding (which I've never done) the wire is the electrode and the filler. It is advanced (power fed from a spool) at the same rate it is burned/deposited. So you can't do MIG by hand, it needs a "gun" and a box with a brain in it to feed the wire. In TIG welding the Tungsten electrode is not consumed, you control the arc by hand and the filler rod is fed from the side with your off hand. You tap the molten puddle the filler rod to add filler. TIG welding steel is done with DC and it is the process that lets you weld with surgical precision. TIG welding Aluminum is done with AC current. Lots of AC current! When you see a low bead with overlapping ripples, that is a TIG weld. One ripple for each filler rod tap. The SS welding rods used for TIG can be used for a lot of ferrous steel welding as long as the difference in appearance is not important. And SS welds on ferrous steel can't be blued in gun work. You can MIG weld steel and aluminum too, On aluminum the bead of a MIG weld looks like it was applied with a caulking gun (higher and more rounded) in comparison to TIG. To be versatile with a MIG welder I think you need a collection of about 26 different spools of various kinds and sizes of wire. The welding shop will either fill your bottle or exchange it for a full one, it varies from place to place. There should be a date stamped on your bottle, 5 years from that date it will need to be hydro pressure tested and then it is good for another 5 years. Last I knew, Harbor Freight had some of the best deals on new gas bottles. I'm not a real welder, I am guy that used to do some. Anything I say is open to correction. Sorry about going on and on guys! Jack | ||
| Henrik |
Jack, feel free to go on. I always enjoy learning - thanks for taking the time. Any opinions on a small stick/TIG welder? Henrik | ||
| Xring |
Yes, you can weld aluminum with OA. Some claim it is the best way. It does take a lot of practice...Aluminum doesn't change colors when being heated like steel does. It just suddenly drops out. I use a little Lincoln MIG for aluminum. Here in WV you can't get tanks filled unless you have a contract with the shop and/or have proof of ownership of the tanks, or something like that. Anyway it amounts to having to buy or lease tanks from a certain shop and then using that shop for refills after that. Welding and brazing don't take a whole lot of gas, but cutting goes though it pretty quick. MIG wire isn't necessarily stainless. Jack is right about the quenching of welds. It is a bad idea. Quenched welds are far more likely to fail. Wherever you get your tanks filled should have the welding and brazing rods you need. I agree about using powdered flux as opposed to flux covered rods. If you find the right place they can guide you as to what you need; a good shop doesn't mind a lot of questions. I've found most welders have strong opinions about what to use/not use. I originally learned to weld by collecting all of the broken and damaged metal silhouettes from the local rifle range and fixing them up. I then built a tandem axle trailer, and later a Cadplans backhoe. Getting some scrap metal and just practicing, or planning and building a project is the best way to learn. Lincoln Electric is a good source of information for arc, MIG and TIG welding. http://www.lincolnelectric.com/ I wish I'd bought a AC/DC welder when I bought my AC 225. That way I believe that I could have converted it to TIG. I've never TIG welded but the guys I know who have say it is the best. Have fun, Bill | ||
| Bomber |
Jack -- re:welding aluminum -- was I flashing back to the late 60s when I saw a guy do just that (gas weld aluminum) -- seems that folks were joining aluminum long before TIG/MIG came along -- not getting in your face, just doing a buncha research before jumping into the Wide World of Welding thanks for sharing your knowledge with us! | ||
| Jackbequick |
You guys are right, I should have said that gas welding aluminum is somewhere between not easy, not practical for everyday use. The welder that is arguably the best for guys like us is a multiple process welder that will do both stick and TIG. But save your O/A rig too, it will still be needed for preheating, bending, annealing, etc. A few years back the perfect machine IMHO was the Lincoln Synchrowave 175 or something like that. Now that the new inverter based machines are becoming prevalent (much lighter, smaller, and more efficient) I'd have to research that from scratch again. Those combo machines are DC only on the basic box. But if you are only going to have either AC or DC, it is best to have DC. Trust me on that. To do both steel and aluminum with a combo stick/TIG machine you will need to have both AC and DC and add some optional components. The classic old "buzz box" stick welder can be a very useful machine. Especially, like Bill says, if you have an AC/DC model. I've not welded anything in some years but my Miller Thunderbolt 230 AC/DC is still there and ready when I need it. It is one of those tools that you never get finished with, it has to be kept forever. Jack | ||
| Reepicheep |
Jack just meant *I* can't weld aluminum with O/A. That's an accurate statement. I'm not above melting pop tabs for fun though, or just to see how molten aluminum handles. These are really helpful tips, thanks for all the good information. I managed to weld up a 2" square of mild steel square tubing... one braze and 3 welds. The brazing was really easy, and looks just about perfect. All those years of soldering electronics I suppose. The welding will come slower. They turned out OK structurally, but weren't pretty. Even after the grinder For non ego feeding jobs, brazing will probably solve most of my problems really well, but I want to be able to lay a nice weld bead with a gas setup, just to say I can. It's on my "be a man to-do list (no particular order)": 1) Be able to shoot accurately. 2) Be able to weld a good joint. 3) Be able to catch fish. 4) Be able to fix a broken motor. 5) Be able to pray for somebody. 6) Be able to enjoy a cigar. 7) Be able to ride a motorcycle well. 8) Be able to give a good reason if you tell your kids "no". I'm hoping there's a test | ||
| Jackbequick |
"Jack just meant *I* can't weld aluminum with O/A. That's an accurate statement." It's not just you. It takes a lot of heat and you can't get the small, localized, puddle that you get with steel. Have you seen the "golden BB" thing on steel yet? If you heat one spot until you have a puddle, when you seen a small bead in the center of the puddle, that is when it is hot enough and you want to tap the puddle with the rod. That's more evident in TIG than gas but it is a real clue to controlling the process. Here's another good clue. It is easier to gas weld with too much heat than it is to weld with too little. And most new welders tend try to weld with too little. Those 1" or so thick fire bricks are great for gas welding small stuff on. Make a small angle iron frame that will hold 4 of them for a gas welding/brazing table. To braze a broken casting, use a carbide cutter in a Dremel tool to chamfer the edges of a break and leave a bright clean edge along each side of the break. Line it up clamped to something and braze a weld that spans the bright metal and the gap. Heat the brazing rod and dip it in the powdered flux to get a good coating of flux on it. Some old/bad castings have so much free carbon in them that they can't be welded. It is like trying to weld dirt and you'll just produce globs of brass. Good list! Have you got a "don't do" list? Here are some things for that" 1 - Never play poker with a man named Doc. 2 - Never drink with anyone with more troubles than you. 3 - Never eat at a place called "Mom's". Jack | ||
| Ceejay |
Reep-I know it is a bit dated, but I get my gas at Valley National, I just leave my little bottle of CO2/Ar at the front door give the man 25 bucks and walk out with a fresh bottle. It looks like they have a couple in the cincy area. I'm sure you've found one since but if not... | ||
| Reepicheep |
Thanks CeeJay, I will try that. The place I found for the first O2 fill said "we aren't supposed to do this unless you have an account but...." and let me do a cash transaction since the bottle was clearly marked as belonging to them. I also heard that Tractor Supply will exchange bottles without a contract as well. Don't know if they are the same size as mine, or if I really care if they are a little smaller. But I will try Valley National as well... I think I called them and they said that so long as I have a bill of sale (any bill of sale) for the bottles they will switch them. Meaning they probably don't even check for the bill of sale (which I have anyway). Thanks for the pointer! | ||
| Davegess |
You guys are givin' me the itch. I haven't cracked out my O/A torch in years. Probably should get new hoses before I try to fire it up. no sense in burning down the house. | ||
| Ceejay |
Hope they can help you out. My regulator just crapped out on my MIG, I just got my new one in and hopefully I can make it down to the gas shop for a refill tomorrow, so I can get some more work done this weekend! I've never tried TSC, but I wouldn't doubt that they refill/excange cylinders considering the majority of thier clientel are farmer types, who always seem to be welding something-actually that's how I learned... | ||
| Ceejay |
some good info here. http://www.esabna.com/EUWeb/oxy_handbook/589oxy14_ 1.htm | ||
| Reepicheep |
For the record, I did exchange an "unknown" acetylene tank at Tractor Supply. No problems with lack of title or proof of ownership (I bought it at an estate sale). It was the biggest tank (waist high on me) and it was $85 or so (which includes $15 for an unknown cylinder exchange). Thats about twice what it probably would have cost elsewhere, but that'll last me a long time, and it's nice to not have to fuss with anyone. I now have a receipt for my tank as well... which helps future transactions elsewhere. But its nice to have a retail outlet that will work with me, so I might just let them have the profit... those tanks last a long time. | ||
| Reepicheep |
Great link by the way! | ||
| Ceejay |
Reep-I don't know, my little tank(won't make it to my knee) costs about 30 after all is said and done including the hazmat charge. I'd like to get ahold of one of the larger ones, for the same reasons you stated. After reading how much fun you were having with an OA I started looking into it a bit more, once you get the settings right it is pretty cool and fun to do, I may have to buy one of them there things-I was playing around with it during some down time at work. | ||
| Jackbequick |
Acetylene tank trivia: Ceejay's is a MC tank, Reep's is a B tank, MC = Motorcycle, B = Bus. Anyone remember acetylene headlights? No, I don't either. Acetylene bottles should always be stored and used in upright position. If it has been laying on its side, let it stand for 30 minutes or so before use. It has acetone in solution and that needs to stay on the bottom of the bottle. If a neutral flame starts showing a little purple in it, that means your acetylene is getting low and you are seeing some of the acetone in the flame. Oxygen to acetylene use ratio is typically about 2:1 so oxygen bottle should be about twice as big. You'll use more oxygen if you are doing a lot of cutting though. Jack | ||
| Reepicheep |
Man.. the thought of an Acetylene tank on with an open valve on a motorcycle scares me. I get nervous enough with it in the back of my car all buttoned up. So maybe that was an OK deal after all... makes sense that there would be add-ons. I got to cut some steel plate for a project for my father in law. Don't know where he got it, but it was probably 3/8 inch thick or more. That was a lot of fun... I used some particle board templates as well (suspended by a smaller wood block about 1" above the metal)... as I was doing an odd shape. The first cut was perfect, but by the time I got to the third one, my template had combusted to be unusable. Shoulda kept more water around, and soaked the template between cuts. (note to self, melted slag stuck to concreted driveways take time to rust enough to detach... two weeks and counting...) | ||
| Road_thing |
Reep--just put some newspaper down to catch the slag next time... ...and keep that water handy! rt | ||
| Fullpower |
B acetylene is 40 Cu Ft, original usage aboard Busses MC acetylene contains 10 Cu Ft, common usage around turn of century on Motor Coach (automobile) | ||
| Jackbequick |
Fullpower, Are you sure about the motor coach thing? I was told MC was motorcycle and that there was an intermediate size that did not come forward into modern use that was for cars. It's not important, was I was told about it in the past. Jack | ||
| Ceejay |
reep-if yer cutting a plasma is the bees knees. not sure if they'll cut 3/8" though-I'm sure that some will but you'll pay for it. I was doing some Mig welding the other night, and wasn't paying much attention(left a rag sitting on my bench), some spittle was laying on it, poof! I like fire but it's much better when it is outdoors and can do less damage... A small tank will last about the same length as a 2lb spool of wire, if that make sense. It would be pretty wild cruising around with a bottle primed all the time. We have to go through safety training at work once a year, and it always comes up-don't ride around with a bottle of anything in your car! The pictures are pretty amazing of what can happen...I still do it all the time, do you want to pay a delivery fee for a 30 buck tank? | ||
| Reepicheep |
I'll add plasma to the list of cool tools I can't afford I was amazed at how clean and fast the Oxy Act rig could cut. That was a thick chunk of steel and it went through it like butter. I'm sure plasma would give me an even better cut, and save the life of some poor innocent grinding wheel I'm a cheapskate, so I haul tanks when I must. The first time I was fairly paranoid, and pulled the seats out of the minivan and use wratcheting tie downs to anchor the tanks to the floor on the seat mounts. These days, I throw them in the trunk of the Saturn... I should be more careful. When they are in there, I don't mess around though... it's get them exchanged, then get the heck home. | ||
| Reepicheep |
Next question.... I tried putting some metal back into a stripped bolt hole (to then later retap it)... and it went badly :0 It was a rear brake drum, which was steel, but was a cast part. I was welding with Oxy Act. The weld went in OK (except that whole chunks wanted to drop out instead of just going molten on their surface)... but as the thing cooled, it cracked. I knew the part was toast then, so I tried welding up the crack and cooling it slower... and it cracked right beside the old crack. Is it possible to weld cast parts with normal gear? Or is it just not worth the trouble. Would MIG (with it's smaller heat effected zone) have worked better the gas? Thanks! | ||
| Blake |
I'm not sure about welding the cast steel. I've never heard of any problems with that. Weldability is more a heat treat and/or alloy issue. Welding removes tempering and heat treat in the heat affected zone, meaning it significantly diminishes the material's strength. That may or may not be a concern for a brake drum. What I think might have prevented your problem is some good thorough preheating. ASW code actually requires preheating of thicker parts; the thicker the part, the more preheat required. This is to prevent the unfortunate consequences of severe differential thermal stresses. In that battle of differential thermal stresses, the bigger chunk or portion of steel usually wins. How thick is the drum? If I recall correctly, preheat requirements per ASW code come into play beginning with 1/2" material. | ||
| Reepicheep |
The outside cylinder (where the braking surface is) is probably more then 1/2, but the internal webbing where the lug nut bolts pass through is nowhere near that big. It was a $60 part new (aftermarket), so not a big deal, but would like to understand what I did wrong. | ||
| Road_thing |
I'm no expert welder, but I think Blake is right--preheating seems like a good idea in your case. rt | ||
| Jackbequick |
Cast steel is cast iron with more carbon in it, a better grade of cast iron so to speak. And it is more granular in structure than crucible steel. Crucible steel is steel that is essentially poured into billets while in a liquid state and then, while still at very high heat but below a flowing heat (liquidous?), is rolled, milled, or forged into shape. If you let the billets harden and cool, you have annealed solid steel that can be cut and machined into virtually any shape you want as long as you have the right metal working machines. A piece of angle iron for example starts as a rectangular billet, is passed through many stages of rollers, and turns into a much longer piece of angle iron. You wind up with what is called mild steel and it is a fairly good, not very granular, useful grade of steel. When you arc weld, you are forming a pool of liquid steel (of the same alloy as is in the welding rod) that melts the adjoining steel some, merges with it, and both harden as it cools. So, in your case you had steel of a granular structure and a puddle of less granular liquid steel being deposited on it. Hopefully with some mixing and fusing at the HAZ. But the cooling rates and amounts of shrinkage between the two types of metal are quite different and the weld pulled apart (cracked) at the HAZ. Preheating, the fluxing action of the flux on the rod and any other fluxes used, preheating, slow cooling of the weld and some other things like that may have given you a stronger weld. I did a lot of machine work for good mechanics, backyard mechanics, and myself and I simply don't consider the hardened bead of a steel weld (arc, gas, or MIG) to be a candidate for later drilling and tapping. If it was cooled quickly, it is out of the question. If the material was preheated and cooled slowly after welding you might have a chance. If you can drill it with HSS drills you might have a chance at getting it tapped. But that would be a long shot. Visualizing your part, I would probably want to repair it by machining an insert (on a lathe) that was larger than the exterior of the threads and then drilling and tapping that. Chamfer the outer shoulders of the insert to get rid of the sharp edges and gain some surface area for welding. If there were room for a flange on one side of that part, I might make the insert a "top hat" shape to resist pulling forces better. If your part had 1/2" of thickness there, I'd make the insert that length, as long as I thought there was enough strengh in the welds to keep the insert from being pulled out. Then I would drill a closely fitted hole centered on the damaged thread and chamfer the edge of the hole (on both sides if possible). Press the threaded insert into the hole (light press fit) or slip it in place and then weld it where the two chamfers meet. If it were a steel insert in a granular casting, I'd consider using brazing for the weld. The goal would be a nearly flat bead of well fluxed brazing around the chamfer and overlapping slightly on both parts. And on both ends if possible. If both parts were steel, I would probably like to try TIG welding for its ability to make small welds with good penetration and only localized heating. Again, small bead all the way around slightly wider and higher than the chamfers. The brazing and the TIG welds can be finished flat if necessary and that will take little or no strength from the weld. And I'd use preheating and slow the cooling rate if it seemed appropriate. When I was gunsmithing, as a business out of my home, and had the lathe, milling machine, and welding equipment all setting there, I could have done that work. I would have charged $25 to $50 an hour and would have estimated the job at 2 to 3 hours work. That was almost 10 years ago and I was not getting rich. I say all this not to second guess what you did or how you did it but to share my experience. I would have probably did the same thing you did if I were you and in that situation. Jack |
