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I was loking at a gas weld on some planes from about 1930. most of the tubes are about3/4 or 7/8 inch or thereabouts. I have noticed the the welds are VERY beautiful and perfect looking. What is striking about them is the diammeter of the bead. The tubeis about .040 inch wall but the weld beads are about 3/8 inch wide . They have the stacked dime look but pretty closly spaced compared to TIG. My question is HOW did these brilliant craftsmen of the day get such a wide bead ........ I assume theywere using a pretty small rod like 1/16 for such a wall thickness. The only way I can immagine that they might have done this is to get the puddle hotand move it along as usual, but feed the rod more into the flame than into the puddletrying to keep a large liquid ball on the end of the rod and let it fall into the puddle makinga large round hemispherical dome of filler. seems like it would be pretty tricky to keepthe puddle just right and feed the rod into the flame at JUST the right speed so the heavydroplet falls off just when you expect it to so it goes into the correct position along the length of the bead. I tend to weld kind of slowly. Does truning the heat up so you have to have a fast travelspeed naturaly lead to this effect ???????Any thoughts ????????PS. I'll try to post a pic if I can figure out how to ........
Reply:Post some pictures;Might want to try looking up this book and several others from Lindsay Publications; Aircraft Welding Reprint by L.S. Elzea, 136 pages, No 22911.Many old aircraft books come and go through this distributor.Lindsay Publishing, some books are good alot some are a waste of money, but if you pick one or two things up from a book then it is worth it in the long run, you are always learning.And alot of manufacturers like Beech continued welding with oxy-acetylene long after ww2. The welders were skilled, likely through mentoring with only one instructor, objects jigged and mitered for consistency and known HAZ limitations, well thought out structural engineering, it is rare that any one member likely took the entire structural load.
Reply:Jethro,I am into aircraft welding as well (experimental). The old welds sure are beautiful. There is a lot of information available from the EAA on this stuff (books and dvds, etc..). I have been practicing here and there (getting ready for my Supercub project), and I too am trying to develop those large beautiful fillets. I have been using 1/16th inch RG45, but I think I might try 3/32 inch RG45 and see how that goes. Unfortunately, I haven't had time lately to play around; however, I should be able to spend a lot of time in about a month. Please post some pics of your progress if you get time. I'll try to revisit this thread when I get more time to weld, and hopefully add some pics of my own.DanP.S. - tinmantech.com sells a really good aircraft welding dvd that I have learned a lot from. Also, hopefully Makoman1860 will chime in on this. He knows a lot about this subject..Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Hey Guys, It was common in the days of production OA welding on aircraft tubing, to use larger filler (1/8 ) larger tips, and welding quite fast. Remember, it was production. Basicly with a trained weldor, you can create and manipulate quite a large puddle. Much of it was a side effect to rapid welding rather than indending to create such a large bead. On prototype airplanes you see the more familiar weld size as would be created with a "standard" tip size and 1/16" filler welded at a pace more consistent with a "one-off". As a side note, much of the tubing you see in the 1930's is NOT 4130, its more like a 1020, 1018 and the like. It was common to use 4130 in highly stressed areas, and mild steel in the rest. Jethro, dropping filler globs in a weld as you describe was never a technique that had and merrit, in fact all texts I have fround from the time period fobid it. Now for welding a thin gusset to a tube, you can "scale" weld it, which in process is the same as what we call pulsing now for tig.
Reply:Hey Aaron,Good to see you again! Thanks for the info, I didn't know that the tubing on the 30's era airplanes wasn't primarily 4130. That is cool information! Thanks. I'm glad I had a chance to read through this thread. My airplane will be a "one-off", so I will stop going after that production look, and keep practicing the way I was. As a side note, I was looking at a Sonerai fuselage a couple of weeks ago, and it had the larger fillets. My A&P friend mentioned that the quality was "good" for a homebuilding, but not quite aircraft factory quality.Just for my own knowledge, when say, restoring an old airplane from the 30's, should you use 4130 tubing? Also, would it be desirable to try to get that "production look" to give the fuselage that factory appearance?Thanks,DanEsab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Originally Posted by PilotDanHey Aaron,Good to see you again! Thanks for the info, I didn't know that the tubing on the 30's era airplanes wasn't primarily 4130. That is cool information! Thanks. I'm glad I had a chance to read through this thread. My airplane will be a "one-off", so I will stop going after that production look, and keep practicing the way I was. As a side note, I was looking at a Sonerai fuselage a couple of weeks ago, and it had the larger fillets. My A&P friend mentioned that the quality was "good" for a homebuilding, but not quite aircraft factory quality.Just for my own knowledge, when say, restoring an old airplane from the 30's, should you use 4130 tubing? Also, would it be desirable to try to get that "production look" to give the fuselage that factory appearance?Thanks,Dan
Reply:Hey Aaron,Thanks again for the info! I'd love a copy of the AC, my email is [email protected] Once I get back to welding (been pretty busy and haven't had any free time lately), I'll send you some pics of the welds. I'd really appreciate some tips and pointers from you after you see the pics. I think that I'll probably start welding up the rudder pedals towards the end of next month. I've got to get through this semester of school while working full time before I can really have some fun with the torch again. I did pick up a Smith Gas Saver that I need to install. I figured that would give me a nice way to deal with the torch throughout all of my welding. Hopefully it works well, I've never actually seen one being used, but it looks pretty simple..That is really interesting about the tig weld not being noticed. But I guess when you're looking at the complete airplane, some of the details are bound to go unnoticed.Thanks again!DanEsab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Originally Posted by pistolnoonPost some pictures;Might want to try looking up this book and several others from Lindsay Publications; Aircraft Welding Reprint by L.S. Elzea, 136 pages, No 22911.Many old aircraft books come and go through this distributor.Lindsay Publishing, some books are good alot some are a waste of money, but if you pick one or two things up from a book then it is worth it in the long run, you are always learning.And alot of manufacturers like Beech continued welding with oxy-acetylene long after ww2. The welders were skilled, likely through mentoring with only one instructor, objects jigged and mitered for consistency and known HAZ limitations, well thought out structural engineering, it is rare that any one member likely took the entire structural load.
Reply:Originally Posted by PilotDanJethro,I am into aircraft welding as well (experimental). The old welds sure are beautiful. There is a lot of information available from the EAA on this stuff (books and dvds, etc..). I have been practicing here and there (getting ready for my Supercub project), and I too am trying to develop those large beautiful fillets. I have been using 1/16th inch RG45, but I think I might try 3/32 inch RG45 and see how that goes. Unfortunately, I haven't had time lately to play around; however, I should be able to spend a lot of time in about a month. Please post some pics of your progress if you get time. I'll try to revisit this thread when I get more time to weld, and hopefully add some pics of my own.DanP.S. - tinmantech.com sells a really good aircraft welding dvd that I have learned a lot from. Also, hopefully Makoman1860 will chime in on this. He knows a lot about this subject..
Reply:Originally Posted by skywestSupercub? From Plans? Or did your "friend" swap ends on landing.
Reply:Originally Posted by PilotDanhehehe, no swapping of ends on landing.. lol Technically, the airplane is a Wag Aero Sport Trainer with the Super Sport option.. But most people have no idea what that is, so I just call it a Supercub project.. That appears to work for the most part as most people know what a Cub looks like. Technically, it is more of a J3 with a 150hp engine (lots of little differences). No matter how I look at it though, its bound to be a very cool project and I plan to have a lot of fun building it!
Reply:http://www.wagaero.com/sportrain.htmlthats the plane I'm working on. I am planning to build from plans, however, they do sell kit options. Very cool place (they make parts for cubs and stuff like that as well), and its only about a half an hour drive from my house. Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Ummm yaeah, you are in EAA land. I'm a little jealous of that.Lincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:I know what you mean about wanting to weld! I had been spending a lot of time trying to decide what to build. I was really torn between a few planes, but the desire to weld (and the coolness factor of putting Alaskan Bushwheels on an airplane) helped me make up my mind. Still would like to build a sonex though. So far, I am really enjoying welding on the tubing with the torch. I'm not great at it yet, but I have gotten much better than when I first started. I'm still in the practice stages, but I think next month I'll be welding together the rudder pedals, brake pedals, and control stick assembly. I'm getting really excited about the project! Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Well if it makes you feel any better, I was in the Lincoln, NE airport one day and saw an 80's era one-design prominantly on display. It won various trophys and had pics to go with. Basically a big deal on the local level. Anyway, I looked closely at the tube clusters and was simply stunned. I have done better work on bookshelves.So I guess the point is make it stick. Don't have to be pretty.RyanLincoln PowerMig 180cVictor O/ABandaids and aspirinI don't know what I don't know!?
Reply:Wow, lots of replys ! Thanks all !Makoman, yes, I think I remember that dropping liquid balls was not good technique.The only way I could see how to do it ws to use LOTS of heat and have a relativelylage HAZ and then go REALLY fast ! From what you said , thats what they were doing !The plane I am help with , I am told that only the landing gear and engine mount tubes are 4130, the rest being something milder. I think If I was doing OA every day in a factory I would just go a little faster naturaly asI got better and better ( and more relaxed) . PilotDan :I LOVE welding ! I love gas AND Tig. I am trying to decide what type of plane to build.I could do an RV ok ( I enjoy sheet metal!) but I want to do a rag/tube .I like the Hatz biplane but I wouldn't mind something a little larger. There is a Travel airreplica that looks interesting (travelair 2000) . I like the Culp special which uses the m-14 radial ! The fuse. doesn't look very complicatd. A great looking aircraft. The culver cadet has a plan for a steel tube version ( called cadet stf ) thats prettycute, but I think only 1 has been made in steel . I wish someone would make plansfor a stearman fuse. (?)Would love to restore a Waco cabin biplane . Probably rare and expensive even for a basket case. Saw a new waco with a 360 HP M-14 installed ! didn't get to see it fly though.I found a weld picture which I will attempt to attach !Tim (jethro)sorry , this thing wont let me "paste" into the message from the clipboard and the "manage attachments" button doesn't do anything.I'll keep trying.
Reply:This is a pic of an 1930's weld . I think it is on the bottom of a rudder post where the tailwheel cables go in. (Fairchild F-24) Attached Images
Reply:The beads are wide because O/A puts a lot of heat into the material vs. arc welding.
Reply:Originally Posted by 76GMC1500The beads are wide because O/A puts a lot of heat into the material vs. arc welding.
Reply:A larger HAZ is never an advantage. Slower cooling of the weld with O/A can make a tougher weld on CroMo tubing which reduces the need for post weld heat treatment but... heat just makes aluminum weak.
Reply:Sorry, I didn't use the HAZ term to mean something negative in this case. I like TIG but on CrMo tube but I all most wish I could "unfocus" the arc a little to makethe heated area a little bigger and less penetrating ... more like oxy. My gut feelingis that the torch leaves behind a more gradual change in the hard/soft footprintdue to the weld (as compared to TIG ) and this might prevent the welded area frombeing more brittle than the unmolested tube. I have allways been impressed just how much penetration the TIG torch has. I have been told that there are welders which use plasma but I have never seen one. Would these have larger softer footprint thanthe TIG torch and be cleaner than oxy ? (one of the tig advantages )Anyone have any experience with one of these ???? Are they REALLY expensive????????????Tim
Reply:O/A just puts so much heat into the tube that it takes a while to cool off which results in a tougher weld. TIG is the most ideal process for weding CrMo. If you want the best strength possible, you'll TIG weld the joint and then post-weld heat treat it.
Reply:With everything I've read / had discussions about regarding welding on aircraft 4130 structures, I would prefer to weld it with an oxy/fuel torch. I have a tig, and I do use it occasionally on 4130. It works well. Lincoln Electric states that 4130 can be tig welded without post weld heat treatment, provided the tubing thickness is not over 0.120 inch. With everything I have read / talked about with people, I would still use the oxy/fuel torch to temper the metal. Ultimately, welding aircraft structures has been successfully done for a very long time using an oxy/fuel torch, and it's just fun that way. Well, thats part of my reasoning behind doing it that way.. Ultimately, I do not have any real expertice in this area, so I must find sources that are knowledgable and that I can trust. When looking for trustworthy knowledgable sources, its pretty hard to top what the EAA can offer.. I really do LOVE being in EAA land!! Ryan, Do you ever get a chance to make it to Airventure in Oshkosh?Tim, I think those are all awesome aircraft too! So what one are you going to build? I love all of the different designs available.. I just wish I had more money!! I'd love to build a bunch of different ones! But for now, I'll have to settle for just one airplane. Fortunately, I've got quite a few friends that are all into different kinds of airplanes. That makes it nice. We get together regularly and just have fun working together on the projects. Unfortunately, my project will probably be the slowest build of them all (I can't put too much money into it at any given moment), but its still a lot of fun working on the other projects. Right now I'm starting to get into prop design and manufacturing. I'm hoping to make the props for a few of my friends airplanes (all done on a large production cnc machine). Should be pretty cool. BTW, I can't wait to see some of the pics of the welding you are doing. I'll revisit this thread down the road and post some of my practice welds, and then some of the welds on my plane as it gets going.. Esab TradeMaster TorchSmith AW1A Airline TorchLincoln AC/DC 225/125Millermatic 252 w/ Spoolmatic 15aThermal Arc 190 GTSSpeedGlas 9100v
Reply:Dan, Glad to hear your still having fun with it, it should be. Making the "project" the hobby, is about the only way they ever get done. Building an airplane to get one done rarely ever ends in something flying. Im not going to get into a Tig vs. OA debate, especially on the internet. I used to, but then realized it wasnt worth my time. I teach what engineering and testing have proven to be the most reliable methods. Engineering and testing others have done, and I have done in our own lab. Anyone that comes by is welcome to see the "library". -Aaron
Reply:O/A is prefered for CrMo tubing because it does not require post weld heat treatment like TIG does, but with post weld heat treatment TIG is the better way to go.Originally Posted by 76GMC1500O/A is prefered for CrMo tubing because it does not require post weld heat treatment like TIG does, but with post weld heat treatment TIG is the better way to go.
Reply:Most people over power, titanium, nickle alloys, and chrome steels with TIG. You do need some time and preheating, not necessarily a large weld to make a good weld in these materials. This even done as fast as humanly possible still takes time. To give you an idea of the time and heat involved. When I finish welding there is almost a one and a half inch long portion of the weld, that looks like polished stainless steel. As it cools it turns blue. If I stop for some reason while I am welding that weld is actually a bright stainless steel. It just blues from the heat while cooling. I used a stainless steel toothbrush wire brush to just take some of the color off. Later it gets a better cleaning. This is the other end of the baluster. I love oxygen and acetylene welding though. It is almost like forging metal. Especially for rods, and thin steel tube I love oxygen and acetylene. Sincerely, William McCormick |
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发表于 2021-8-31 23:42:28