Trailer frame welding question

admin

Ok, first off i have been a welder for a few years and i always thought the frame should be welded solid but i have seen some only welded on 2 sides. what would be the proper way to weld this frame. Attached Images
Reply:"proper"   is a loaded word.  I am sure that welding on only two sides to the connection between cross members and rails would be ok.  It could save on the cost of the trailer and produce a cheaper product.  In term of corrosion I would want all open ends closed to prevent moisture inside the tubing.  In effect you reduce the life of the metal by one half.  If you are in the business of selling trailers that might not be a bad thing.  It reminds me of an inspector who inspected some barge construction in China.  They expected a barge to last 3 to 5 years.  The customer expected the product to last 15 years just like the ones made/purchased in North America.
Reply:They expected a barge to last 3 to 5 years. The customer expected the product to last 15 years just like the ones made/purchased in North America.
Reply:Not to be a smart @ss and flame you, but this question falls in the category "if you have to ask, you should not be building a trailer at this time" Sorry, if you've "been a welder for a few years" and a pro it's something you should already know the answer to thru experience. If you are a hobbyist, you need to learn a lot more most likely. With out any info on what " welding for a few years" means, you are going to be lumped with hobbyist's who don't know.That's the basic answer, the more complex one deals with the loads expected and the filler you plan to use. There are charts and tables that tell engineers how long a weld needs to be with a specific filler and joint type, to achieve the results to take the load anticipated. I'll ignore the numbers, lets say after crunching them, the table says you need 6" of 7018 weld to restrain the load and you are welding on 4" channel to 6" channel. That means all you need is 1 1/2" across the top and bottom and 3" down one side. Any more is extra. The example is way over simplified, but the idea is to explain why you frequently see only one side welded, or just small welds. In a production environment, welding up the rest of the channel would add more than double the amount of filler used, plus all the time to do the weld, and it' doesn't add anything but weight to the design if everything is designed right. The steel will fail before the weld ever got close. It's why you frequently see huge beams with small welded clips bolted to columns. There is plenty of weld in the small clip to take the load. The beam doesn't require a full weld.I've said it before and other will too again. On road trailers are not projects for those who do not have the training, experience and tools to do the job correctly. If you have to ask basic questions, DON'T DO THIS PROJECT..Last edited by DSW; 01-15-2010 at 10:30 AM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Steve,I am going to apologize for the douchenozzle answer you just received. Not everyone gets a chance to go to an accredited college and take a metallurgy class, basic engineering classes or even welding classes. I did, I got As and Bs in class and I still have questions. Some people open the paper, apply for the job, get handed a mig gun and off to work they go. The latter seems to be the case for many production shops. It isn't good for anyone, but it does happen. Answers that belittle people for asking is a real deterrent to the purpose of a forum where people are trying to learn and hone their skills. Your question was simply asking how something should be done. I do recognize that your question did not imply that this was YOUR project or that you were even welding on a trailer. My answer to your question is simple. If it is YOUR name going on a piece, weld it completely for longevity. Have you ever seen what people do to those UHaul trailers? If it's for your shop, and your boss wants it welded on two sides...weld it on two sides. Now, if you purchase plans from an engineering company, they will call out on the prints where the welds should be, what type, what size and of what filler for the material. Just as important as the weld, is the base material. Is it the correct dimension? This should be in the prints too. You can find a lot of this information at your local library. You can learn how to read welding prints there too. Online works as well if you can find what you want. You could do yourself a huge favor and research these things in books to help you learn more and take abuse here less. Good luck bro!Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:ok i don't build trailers... but i'm gonna give it a shot personally i would weld it solid... then i was told trailers need to flex i'm coming from a background of building loader buckets. i'm just looking for a little insight
Reply:look at the photo as far as steel for the frame there is a 2 1/2" (1/4" wall) reciver tube that runs 120" front to back and the rest is 2x4" (1/8" wall) tubing, mounted to the frame will be 3500lb axle with 3000lb springs.
Reply:Originally Posted by DSWNot to be a smart @ss and flame you, but this question falls in the category "if you have to ask, you should not be building a trailer at this time" Sorry, if you've "been a welder for a few years" and a pro it's something you should already know the answer to thru experience. If you are a hobbyist, you need to learn a lot more most likely. With out any info on what " welding for a few years" means, you are going to be lumped with hobbyist's who don't know.That's the basic answer, the more complex one deals with the loads expected and the filler you plan to use. There are charts and tables that tell engineers how long a weld needs to be with a specific filler and joint type, to achieve the results to take the load anticipated. I'll ignore the numbers, lets say after crunching them, the table says you need 6" of 7018 weld to restrain the load and you are welding on 4" channel to 6" channel. That means all you need is 1 1/2" across the top and bottom and 3" down one side. Any more is extra. The example is way over simplified, but the idea is to explain why you frequently see only one side welded, or just small welds. In a production environment, welding up the rest of the channel would add more than double the amount of filler used, plus all the time to do the weld, and it' doesn't add anything but weight to the design if everything is designed right. The steel will fail before the weld ever got close. It's why you frequently see huge beams with small welded clips bolted to columns. There is plenty of weld in the small clip to take the load. The beam doesn't require a full weld.I've said it before and other will too again. On road trailers are not projects for those who do not have the training, experience and tools to do the job correctly. If you have to ask basic questions, DON'T DO THIS PROJECT..
Reply:the photo is from sierra 4x4 trailers.... and you guys answered my question i was just  curious why i see trailers that are not welded solid
Reply:Originally Posted by jmanI'm a hobbyist and NO I don't build trailers, but if I wanted one, I sure as hell would likely build my own before I bought a NEW one.
Reply:Up to certain degree would agree with DSW. If somebody's life depend on it - you have to know what are you doing.Another point - may be against DSW - what if you know or intuitively understand what are you doing - how do you prove that without some document or building something that proofs it?...But after all I can see that DSW has very strong point - from TS original question - "how to weld this frame?" - does not look good.The proper way to build anything - is to provide tech specs - engineering - manufacturing.Answering DSW's formulated questionWhat's the general opinion on welded solid vs welded partially and how that relates to flex."Flexibility or rigidity of a frame has nothing to do with welds. Welds must solid and sufficient for maximum loads with safety factor.Flexibility or rigidity defined by members and theirs deformations.Last edited by Nomand; 01-15-2010 at 12:45 PM.
Reply:If the ENGINEER designed and calculated everything properly, then do the welds as he/she put them on the print.If the bean-counters say to use the cheapest materials and the cheapest supplies and the cheapest laborers and the cheapest processes and to do everything to the 'minimum', then just hit them.  Sometimes partial welds are desired, sometimes they are acceptable, and sometimes they are not acceptable.  It all depends.As to the question of a trailer or other structure 'flexing', that's another "It depends" kind of answer.  But even on flexible structures (and to some degree, EVERYTHING is flexible) you -usually- don't want the welded joint itself to be where all the flexing is taking place.  YMMV.  Using 'good' materials and then 'poor' contruction, either in design or workmanship = bad product.Using 'poor' materials and 'poor' construction = really bad product.Using 'good' materials and 'good' workmanship but 'poor' design = bad product.As the old saying goes:  Good, cheap, or fast.  Pick two.  And I have seen bunches of trailers where even -if- an engineer designed and analyzed and specified partial welds on a 'small' trailer, it still looked 'wrong' and like crap.  IMHO  Pretty much every small 'commercial' trailer that I have glanced at from big-box-stores falls into that category.  If the joint is not fully welded, then there is an open seam and that open seam soon rusts.  Cause rust and corrosion NEVER give up and never sleep.    The best laid schemes ... Gang oft agley ...
Reply:Many trailer manufacturers are building crap trailers. I build them and I am registered with SAE to do it. If you are putting together a 3500 gross single axle trailer, that would be considered a small utility trailer and most hobbyists on this forum are qualified to build one. Generally, the folks on this forum will over-build compared to regular trailer manufacturers. Flex on a trailer this small is really a non issue since you wont have a caterpillar or back hoe on it. Have fun with your build, and do some good solid research on the subject.
Reply:It really gets boring the hear the same  comments from people knocking anyone that asks questions about building a trailer on these forums and others.I have seen some homemade trailers that looked and held up well and some others that were crap. One was a factory made, and I am sure was designed by an "engineer" .Another one I was called out to make an emergency repair on in the middle of the road. It was a flat bed semi trailer, less than six months old and was hauling a motor grader, when the driver pulled out of the driveway he drove right out from under the trailer, the king pin was still in the fifth wheel. The plate with the pin separated from the plate where it was welded to in the bottom of the trailer, broke all the way around the weld bead in the haz. Put it back in enough to get it off the highway and the trailer manufacturer was notified and I guess they came and did a repair on it.I realize that you need an engineer, but from my point of view that mainly is to cya.Sorry but had to vent a little.  Just get a little tired of hearing everyone get jumped on every time they mention building a trailer.Trailblazer 302Hobart Stickmate AC/DCLincoln SP 135 TSmith torchSpoolmatic 30A
Reply:As for the original post; there is no such thing as a stupid question. And the first reply answers the question, cautiously, but effectively."SOUTHPAW" A wise person learns from another persons mistakes;A smart person learns from their own mistakes;But, a stupid person.............never learns.
Reply:Alot of beginners start out with"utility trailers" in fact it's in all the beginner books I have ever seen. If you are working on loader buckets, and I assume you mean payloader. I am sure you know about penetration and joint fit up. Just weld it solid, enjoy your self in your shop and if you have at the minimum, middle of the road skills, you will have a superior trailer to the mass produced, economic engineered crap that is traveling our roads every day. If you think the trailers are bad take a look at some of the aluminum flatbeds they are selling for 3 and 4 grand, it disgusting. Don't want a war but lets help each other here, if you think some one is not qualified, give them good advice, what to watch out for , and how or where to get more advice or how to develop a technique.  " When someone tells you you can't do that, your on the right track"   A year ago I didn't know didley about the electronics on engnine drive welders, now thanks to the great advice from some very knowledgeable members here I got by asking " Stupid" questions I have brought some absolute junks back to life for very cheap money. I find it fun and relaxing.  By asking questions we all grow.Last edited by kolot; 01-15-2010 at 09:08 PM."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by steve28Ok, first off i have been a welder for a few years and i always thought the frame should be welded solid but i have seen some only welded on 2 sides. what would be the proper way to weld this frame.
Reply:At this fab shop I used to work, they had this sign up in the office.You can have it Fast and Cheap, but it won't be Good.You can have it Good and Cheap, but it won't be Fast,You can have it Fast and Good, but it won't be Cheap.
Reply:Was this built by a amateur or professional??South Arkansas RebelMiller 210 W/ Spoolgun& dual tank rackMiller Thunderbolt AC/DC
Reply:Was this built by a amateur or professional??
Reply:Originally Posted by Eric NThis question is very vague.I know many people that work as welders that def shouldn't.I also know quite a few very good 'amateur' welders.Your question should have been phrased"Was this built by a good welder/fitter or a poor welder/fitter?
Reply:I just can't see ripping a person apart for asking a question!!!Answer it or just be quiet.......
Reply:Originally Posted by Eric NThis is probably the best advice. This is a welding forum, you have to expect people are going to come here expecting advice on welding.
Reply:So, basically only one person tried to answer the question of TS.The rest is non-related arguing...So, is anybody going to take responsibility and answer the question?For TS - steve28 - still interested in an answer?
Reply:Originally Posted by NomandSo, is anybody going to take responsibility and answer the question?Originally Posted by NomandSo, basically only one person tried to answer the question of TS.The rest is non-related arguing...So, is anybody going to take responsibility and answer the question?For TS - steve28 - still interested in an answer?
Reply:One more thing I'll add.  There is a reason why tractor trailers, ect,, use channel not square tubing, and they use bolts and rivets as well   Way off course from the thread, but the point was about considering flex. weld it like you own it
Reply:Originally Posted by steve28Ok, first off i have been a welder for a few years and i always thought the frame should be welded solid but i have seen some only welded on 2 sides. what would be the proper way to weld this frame.
Reply:Here is your best bet. Attached ImagesCity of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Originally Posted by steve28Ok, first off i have been a welder for a few years and i always thought the frame should be welded solid but i have seen some only welded on 2 sides. what would be the proper way to weld this frame.
Reply:One instance where I did a partial bead on a flat deck highway trailer involved "Corten" material.  It is a step above mild steel and is brittle enough that if you form plate the wrong way the bend will crack.  I was instructed to weld all the hangers off this trailer on one side only.  The reason given to me was that an additional bead on the other side would create too much stress and cause the hangers to crack off the main frame rails.  Although I did not know much about trailer building I did know that Corten was a strong but finicky material.  That is another example of too much welding being a bad thing.  Each situation is different.
Reply:For the trailer in the OP, my tendency would be to weld it all-around unless otherwise specified. Won't be a problem on a trailer like that.lotechman, I have done the Corten also on some ore hauling pots. Definitely a situation where there is a specified procedure and parameters to be adhered to.[B]Forever learning[B].
Reply:A little inside so many machos on WW would understand what the hell they are doing building those trailers…Referring to formulas Pic 1:1.Let’s define the loads. Say this is 3500# trailer. What happened when it hits a pothole at 60kms/h? It’s a subject for PhD dissertation – dynamic engineering - what kind of loads applied to this trailer. Let us assume double load (that is for very low speed) 7000#. Although this is a question to automotive engineer – what is “normal” driving conditions? What kind of loads vehicle 3500# shall be designed for?2.Let us assume welding route 1/8”. And this formula assumes “ideal weld” – what is “ideal weld” – deposition penetration, undercuts, porosity etc – subject for another PhD dissertation – weld engineering.3.Assume materials – again – PhD dissertation – materials engineering. Welding material allowable stress at least 30ksi, welded material black steel 11ksi – 4”x2” x1/8” box. Length of the weld 4”4.So, normal stress (all dissertations were already written) = 7ksi.5.From Moore’s equation – max stress = approx. 11.3ksi. As we can see 1/8” root already is not sufficient for this trailer. So the root should be 3/16” at least. And taking into account inaccuracies ¼” will be better. But then for this design we have to take into account for some cycling – that is subject for another PhD dissertation. And we did not account for imperfections of the weld (this happens…)But obviously – more aggressive cycling is – less stresses are allowed…There is NO structural merits not to finishing the weld. Furthermore – open ends are places for corrosion. But they probably want to preserve flat surface and better look…So, the proper way to do it would be close the weld and grind it for flat surface (not popular I think)…So, this is brief engineering aspect of one weld. We did not look at members themselves. Suspension, finishing, attachment, electrics etc, etc… Attached ImagesLast edited by Nomand; 01-17-2010 at 04:39 PM.
Reply:I'm aroused, lot of formula for and 8 foot garbage can hauler. You forgot ohms law, and the square root of Gyronic Motion.Last edited by kolot; 01-17-2010 at 11:27 PM."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Originally Posted by kolotI'm aroused, lot of formula for and 8 foot garbage can hauler. You forgot ohms law, and the square root of Gyronic Motion.
Reply:Wow People have to make it so hard. The only way to learn is to ask questions. First answer to Steve It's a simple answer weld it solid. I would and have on trailers I've built.Last edited by tzhauling; 01-18-2010 at 12:35 AM.
Reply:To weld or not to weld? It depends mostly on  joint design.Attachment 44533For example only, in this case, 100% weld or not, the weak link is where the square  receiver meets the rectangular side rails. There's no meat there. Somehow that connection should be (and probably was) modified so that the two side rails are better tied together, and more of each rectangular tube's wall connects to the square receiver tube.I also wonder about the purpose of the long receiver tube?Because piercing the long receiver through the cross-tubes makes for a lot of fit-up. And cutting large holes in the cross-tubes takes the heart out of the tubes, which now should probably be 100% welded around the receiver tube. And of course all this takes away from "flex" in the cross-tube, and in the entire  trailer. And flex is our friend in trailer design.Again, it was for example only. Yes, I realize that we're talking about only 3000 lbs, and that this was an in-progress picture of an unfinished design. I'm sure it all came together just fine.But my point (which again, has nothing to do with the picture) is that 100% weld on an inadequate joint design, is not as good as 25% weld, on a joint design which is adequate with 25% or less weld.And the other side of the coin - The 100% welding of a joint specifically designed for 50% in a certain area, does the design no favor. Good LuckLast edited by denrep; 10-19-2010 at 11:43 PM.
Reply:Because piercing the long receiver through the cross-tubes makes for a lot of fit-up. And cutting large holes in the cross-tubes takes the heart out of the tubes, which now should probably be 100% welded around the receiver tube. And of course all this takes away from "flex" in the cross-tube, and in the entire trailer.
Reply:steve28,Nice layout pictured, when completed your gonna have one Bad Mamma Jamma utility trailer.Thanks for sharing!
Reply:Originally Posted by Marcel BauerThe cross-members are channels, I can see that in the pic.
Reply:With this design, a rear receiver could be easily added for pulling tandem, I like it.Many here are just to fast to criticize without any consideration. Not the friendliest board to post on. If one does not have a high post count and has not become a gang member, beware! Someone slings mud their way and the gang goes nuts. Man, what an image being created by a few that reflects on so many.==================================================  ==weldingweb.com Estimated Worth $21,075.10 USDTitle WeldingWeb - Welding forum for pros and enthusiasts - Powered by vBulletinDescription Forum for Welding Professionals and Enthusiasts To Interact and Learn - FreeDaily Pageview 8955Daily Ads Revenue $28.87Viewers by Country:76.0% UNITED STATES  17.0% PAKISTAN 02.5% CANADA 00.7% PHILIPPINES 03.8% OTHER  More stats:http://www.quantcast.com/weldingweb.comhttp://www.websiteoutlook.com/www.weldingweb.com
Reply:Originally Posted by Marcel BauerThe cross-members are channels, I can see that in the pic.
Reply:Originally Posted by slag_magWith this design, a rear receiver could be easily added for pulling tandem, I like it.Many here are just to fast to criticize without any consideration. Not the friendliest board to post on. If one does not have a high post count and has not become a gang member, beware! Someone slings mud their way and the gang goes nuts. Man, what an image being created by a few that reflects on so many.==================================================  ==weldingweb.com Estimated Worth $21,075.10 USDTitle WeldingWeb - Welding forum for pros and enthusiasts - Powered by vBulletinDescription Forum for Welding Professionals and Enthusiasts To Interact and Learn - FreeDaily Pageview 8955Daily Ads Revenue $28.87Viewers by Country:76.0% UNITED STATES  17.0% PAKISTAN 02.5% CANADA 00.7% PHILIPPINES 03.8% OTHER  More stats:http://www.quantcast.com/weldingweb.comhttp://www.websiteoutlook.com/www.weldingweb.com
Reply:Originally Posted by WHughesDont be discouraged, we are not all like that, its a select, vocal few.17% Pakistan, really?
Reply:Originally Posted by Marcel BauerThe cross-members are channels, I can see that in the pic.
Reply:The question is very vague.  The trailer's loading is what determines the size of the steel required and that determines the welding required.  Based on the size of the steel selected, it looks like you are building a seriously beefy trailer.  I don't know what kind of loads you are expecting to haul with it, but in my limited view of the world, I have never seen that small of a trailer with that much steel.  My guess is that you are overbuilding it so that you know that there is no way that it will fail with the loads that you are planning to carry.  If that is your plan, then go aread and weld it all the way around just to stay with the same philosophy.  If the amount of welding is a concern, then it will take some engineering calculations to determine exactly how much welding and where.  If it was mine, and I didn't bother crunching numbers, I would weld all the way around.  I am just a hobby welder, so I know that my welding opinions are probably seen as a hobby welders (aka worthless), but I am also a mechanical engineer, and have a good idea about the strength of materials and steel design.  BTW, I assume that the tongue of the trailer is going to sit where the open section is on the front of the side members.  Otherwise, I see that as the weakest point on the trailer.Rene
Reply:As a side note, I just took a look at my cheap, Harbor Freieght trailer.  It is built mostly out of formed sheet metal c channel which looks like 14 gauge.  I have put a full ton on it more than once with no issues even though it's rated for 1200 pounds. I changed the axle out for something better.  Yeah, I know that it's stupid to overload a trailer, but I also know that anything made of steel has a lot of safety margin built into it and generally fails in a way that gives you an opportunity to recognize that you have gone too far. Obviously I am talking about a trailer and not a bridge or suspended load on that.  Steel tends to bend and let you know that there is a problem when you first load it.  Over the road stresses can be a huge factor as well, so checking it while you travel is always a good idea until you have a solid Idea of how it behaves.   Bottom line is that unless you are planning to haul 10,000 pound loads on that trailer, you are more than good to go.  If you are planning on hauling seriously heavy loads, you may want to crunch some numbers just to be sure.  Just my $.02.Rene
Reply:Solid! ya can't go wrong!
Reply:Hello,Name is Chris, and I am Sierra 4x4 Trailers. I was searching Google and ran across this thread. That frame was my Proto-type frame. The frame is welded 100 percent by my choice to last for years to come. The front connection is boxed in and has a triangle gusset on the bottom too.The frame is over built for a 1500-2000 pound "camping" trailer, I build them differently now. I had a shop build the first one for me and they "thought" I was building a 5-ton dump trailer.It sound like somebody is trying to build there own trailer? As we all know, Trailers are easy to build. The question you have to ask " is it built well, and will not come apart on the highway and kill other people?
Reply:Originally Posted by Broccoli1Quote:Originally Posted by WHughes View PostDont be discouraged, we are not all like that, its a select, vocal few.17% Pakistan, really?IT people