Broken trailer frame

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Ok guys today was loading the backhoe up after a little project and i don't know why but glances in the wheel well and said that looks like a crack in the main frame of the trailer. Sure enough here is what i saw. Here is the area zoomed out Needless to say this is a bad deal. So i limped my way to the shop. Cut quite a bit of the deck off and did this patch on the inside frame rail. Now i want to do more but i need to pick up some steel to finish it. So what do you guys think i should do to the outside and bottom frame rails?? The piece i used on the inside is an old frame rail off a semi frame. But i'm out of that. I'm think 3/8 plate with some holes in it but how long should i make it ?? Last edited by landman; 11-21-2010 at 04:31 PM.Millermatic DVIMillermatic 251Older buzz box Cheap 120 welder
Reply:It really depends on the shape of the frame member, and the amount of access that determines how I would address cracks and breaks. From the pics, it is not clear (to me) what I am looking at. But, I would clean out the area of the break or crack as much as possible. Keep in mind that plates are fine, but reweld that crack first. This is where I like 6010/11 rods, personally. Plates are said to be best when they are basically diamond shaped and with rounded corners. The longer, the better. Weld all around or intermittent,  I am not going to say which.City 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:I've got some 60?? something here That i'll use. It's C channel. I'm gonna cut the fender off and build everything up quite a bit.Millermatic DVIMillermatic 251Older buzz box Cheap 120 welder
Reply:Well if its breaking then your either overloading it or its not built well. So you might want to consider starting over with a new trailer, built heavier, too.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Originally Posted by tanglediver From the pics, it is not clear (to me) what I am looking at.
Reply:Welding across a beam that's intended to flex--as you've now done in the patch job-red outlines....in effect means you've created 2 separate beams connected byyour patch job. IOW-welding across a beam that flexes is a big no-no, which only creates other real or potential problems. (Just 'becuz' transverse beam welds may be seen on this site and others...doesn't make it correct.)Removing that patch and redoing, will not change the structure of the broken frame.Yes--first do full pen welding from both sides of the crack, then plate--but never weld across the beam--only in line with it--blue outlinesYes-patches in long diamond form can be suitable for framing patchesYes--stress risers, HAZ effects, (and possilbly all that full welding done on the fenders/trim created a strongback--in which that 'notch' happens to be the weakestpoint, which flexes the most--the 2 fender corner cracks give credence to this observation), overloading, etc.--contributed to this failure.You need to look at the other side of the trailer, as well as other areas--to see what other things are 'going-on'.http://weldingweb.com/attachment.php...1&d=1290401968http://weldingweb.com/attachment.php...1&d=1290401983 Attached ImagesBlackbird
Reply:All good advice was posted here about beams, stress risers, proper reinforcing etc.I would weld using 7018 rods, if your frame is mild steel, no difference but if you have a higher strength frame 7018 (or 8018 -10018 as appropriate) is necessary to prevent cracking.How much does your excavator weigh?.  Your frame looks like about 6" deep from the pics.  Remember that trailer frames are rated for a gross cargo weight and gross vehicle weight.  They are also limited as to how much weight you can carry in a certain length.  You should contact the trailer manufacturer regarding this, you may be overloading your frame even though you are not exceeding the gcw of the trailer."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:http://weldingweb.com/attachment.php...1&d=1290401983
Reply:Good info i will store in my memory banks......that trailer should handle 7...8000 easy....
Reply:if you can clean and weld crack shut,fishplate the outside of the frame (don't forget to miter cut your corners).then plate or suport your flanges on the inside.7018 for sure.