How do I fix this??????

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I am building my first trailer.  And now that I have the frame almost complete, I stood back and this is what I saw.I need help trying to figure out how to get it back flat.  I was thinking of just cutting the cross members on one side and then try to get it flat.  Will that work???? Attached Images
Reply:I would leave it intact , flip it over and secure the low sides.  then with a car. tractor, truck etc.. apply pressure to the high side.  on something with that few cross members, it should flex pretty easy.
Reply:I wouldn't try to just bend it back flat as that will put extra stress into the frame.  It might be possible to cut two opposite corners apart, and then clamp it down level and reweld.  If not you will have to cut two opposite corners, and one side of the two cross members to level it back up.  You will also need to take the axle off the frame as well.  How did it get off that bad?I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:I'm sure you can bend it back to place by putting blocks under the low corners and jumping on the high corners.However, if it flexes that easily, you probably will see problems with it in use.  My advice is to clamp it down flat and put more support into it so that it doesn't bend back to this position.
Reply:gas,Looks like you were off to a good start in spite of it.A couple questions:1) Did you notice the frame racked before you mounted the axle?2) If not, are the axle spring perches both welded to the axle on the same plane?3) If yes, is one of the springs bent?  Or both bent in opposite directions?4) Are you working on a level surface?5) Did you block and level the frame sections as you were fabricating?  If you don't have a level then you need to pick one up at Home Depot, Lowes or ??  A 2-4' unit will be plenty.If it's all in the frame and you can't force it back straight OR if it breaks over center and racks in the other direction it's under stress and you'll have to cut the crossmembers loose (one end first) to see if you can get it squared up.  If still not, then you'll have to cut one corner and see if it'll lay flat then.I hope you don't have to go all the way back to the begining but that's what you may have to do depending on where the cause started.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Cut the corners "one at a time" and you mght see which side is the bad one. weld it like you own it
Reply:It looks like it will flex pretty easy.  Perhaps if you secure it straight and deck it, it will be OK.  Other wise, cut it apart and start over.  The good thing about working with metal.Did you build it on a flat surface?David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Looks like you have the old 'cookie sheet' thing going there. Any open C shape is real prone to  allowing twist. Hind sight says it would have helped a small amount to cope what corners you could have. Any built in stress at all and it's going to do that. Cut open two opposite corners, see if it wants to go straighter. Get it blocked and clamped as straight as possible, maybe add some small plates to simulate boxing of that C shape in a few places, then weld the corners back up slow and easy. Some weld shrinkage on a sloppy corner could cause it to do that. A nice ridged 'A' frame tongue will hold some of that for you. That and some ridgid decking  like was mentioned.
Reply:Well it started out fine.  I think I might have messed it up when I had to turn it.  I did the whole lift and drop.  Here are some of the pic from the start.  Also this has been a build that has taken me over a month due to only having an hour here a half hour their.  So for my first build with my little Hobart 125, I should have started with the welding cart first.......LOLI should put a sign up called " Gettho Fab " shop.. Attached Images
Reply:The first question is.  How did you sequence the welds??If you started on one side and worked all the way down that side before starting on the other side,  there's your problem.On a project like this start by tacking the WHOLE thing together.  Fit it, then tack it before you do any finish welding.  Make sure the tacks are big enough to actually make a safe, and sound, connection.  Fit, and tack, from opposite corners working towards the middle.Now when you apply the finish weld, do the same thing.   Opposite corners(diagonal) towards the middle. What you're lookin' at is a bad case of distorition caused by the weld pulling the steel out of alignment as it cools.  By working from opposite corners, you can minimize this.  You're applying opposite forces to correct opposite forces."Any day above ground is a good day"http://www.farmersamm.com/
Reply:BTW.... Been here, done thisAlso, you don't necessarily need a flat surface to do your fitup.  As you're clamping prior to tacking, step back about 5-10 feet and sight along the upper or lower surfaces of the steel members.  The human eye is really accurate.  Another way to do it, is to split the view.  What I mean is, look across the project, and visually seperate both side rails, so that you see an air gap.  Then look from side to side along the side rails and compare the air gap.  When it's even, you have a good level build.Shimming with scrap underneath the steel (if it's up on a sawhorse/blocks) before you tack it will close/open the gap.  Clamp it.  Tack it."Any day above ground is a good day"http://www.farmersamm.com/
Reply:When I started the welding after get it set up.  I tacked all the corners.  Then welded the outside weld on one corner.  Then went to the opposite side and welded it.  Then welded the third then forth.  If you look at the second set of pics.  You can see that even after welding the outer frame then adding the cross members it still sits flat on the " Weld Table".   Originally Posted by farmersammThe first question is.  How did you sequence the welds??If you started on one side and worked all the way down that side before starting on the other side,  there's your problem.On a project like this start by tacking the WHOLE thing together.  Fit it, then tack it before you do any finish welding.  Make sure the tacks are big enough to actually make a safe, and sound, connection.  Fit, and tack, from opposite corners working towards the middle.Now when you apply the finish weld, do the same thing.   Opposite corners(diagonal) towards the middle. What you're lookin' at is a bad case of distorition caused by the weld pulling the steel out of alignment as it cools.  By working from opposite corners, you can minimize this.  You're applying opposite forces to correct opposite forces.
Reply:And yet another BTWYou still may see some distortion as you sight along the finish welded members.You can alleviate this to a great extent by what I call "backbeading".  Dunno if it's a real term.  On the opposite side of the metal from the finish weld, apply another bead.  Simple flat weld, no grinding.  It will often pull the metal enough to get rid of what little distortion remains.  This weld isn't structural, but it applies force.  Simply grind it down after ya make it.You can do the same thing (with a different technique) with a rosebud.  It's all a matter of shrinking the backside of the steel.  Rosebud doesn't leave a grind scar that shows up under the paint.  But, it's more bucks to spend to get the equipment."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Did you do EVERY  weld at an opposite corner?what I mean is, start with just the inside weld at each corner,  do all 4 in the diagonal.  Then do the top and bottom welds on the short legs of the channel on opposite corners (top and lower legs again in a diagonal sequence).  Then finish with the weld on the outside corner of the channel if you weld that way.So each corner is actually a sequence of 3 seperate operations"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I'd proceed some and see what happens. You're going to be able to tweak that light gauge around.I remember a dump trailer that twisted in a roll-over accident; the box would not settle on the twisted frame.As soon as the insurance check cleared, the trailer was loaned out and put on heavy scrap steel  hauling.The frame straightened itself after a few runs!Good Luck
Reply:Woke up thinking about thisDid the frame get wierd after bolting the axle to the hangers?  Or before the axle was mounted to the trailer?This really is a mess.  I imagine you're not too happy.  I can empathise"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Is this built out of c-purlin?
Reply:Originally Posted by OldtimerIs this built out of c-purlin?
Reply:Partagas, I think it can be straightened so long as you do it now, rather than after you add more material. I would straighten it like was said, deck the thing by supporting the lows, and pressing down the highs. If it takes a bit more pressure than you can exert easily, I will give you an idea we had to use more than once: 2 trucks, some 2x4, and a decent piece of 2x6. find the HIGH corner, or one of them. Push it down to the ground, and....park a truck on that corner. the frame will now rack, sitting on the 2 low corners, with one high corner under a load. The other high corner will be WAY high. Try to jump it down first. 2 big guys, holding a couple beers can often do the trick. Anyway, after 'testing it' to see how much it settles, you will have to back the truck off, and put a 2x4 under the LOW corners. Park the truck back on the high corner again. Now, take the 2x6, and lay it onto the high corner. Now, with a second truck, slowly drive onto the 2x6, and progressively get further up onto the frame to add the pressure needed to straighten it out.BABY STEPS!!!!! Do NOT just go right after it. Test each small adjustment, because if you go after it hard, you will bend the heck out of it, and there is no getting it back after that. Good luck, and patience.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:I thought it might be stuff they make industrial shelving out of.Even if it were purlin, and pretty light stuff, should you be experiencing this sort of distortion?"Any day above ground is a good day"http://www.farmersamm.com/
Reply:The frame is made out of 3mil sheet, that has been bent.  The bends where used for making door frames for prisons.  The place I used to work for sold it to me due to the holes sizes have changed.  Here is a sample pic.  I also tried to bend it back by driving my truck on the high side.  That did not do a dam thing.  So I have a feeling I will have to tear it down and redo it. Attached Images
Reply:Take the axle off and evaluate the warp.  Work your way backwards from there.Also, there nothing wrong with working off of blocks on the ground (other than hard on the knees and back) -IF- you align your blocks or the work on the blocks to be flat and planar.  If you don't level things out, your work comes out warped.Been there, done that.  I have to use more of the adjustment range of the leveling feet/casters than I expected because of that oops.The ground is rarely flat or level.  Some floors aren't flat or level either.Another thing to do is to use some strongbacks as you are setting the pieces in place.Of course a big FLAT plate welding table/bench helps a lot.  I wish I had one too.  The best laid schemes ... Gang oft agley ...
Reply:Loosen up the two U bolts on one side of the axle, it will flex back straight or with a little help.Tim Beeker.
Reply:Assuring a flat fitup is paramount.  But, I'm still stuck on sequence of tack, and weld, in order to hold that innitial setup.And, as Moonrise says, it don't have to be set up in a jig.  I don't work offa anything more fancy than sawhorses.  Square it with a tape, sight the edges, and tack.I don't know how 11ga. compares to the material at hand in the trailer, but this is a project I did last winter.  The bottom of the feed bunk was the first sub assy.  Everything else depended on it to be square, and on a level plane..  It ain't the Brooklyn Bridge, but it's kinda like a trailer frame at the beginning of the project. Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I will try the loosen the bolts.I am glad that I am not the first to have this happen.In all your photos except the one with the axle attached the frame looks flat. This leads me to think that the axle mount might be causing the problem. What type of springs are you using  double eye or slipper type? With either type the  mounting bolts should allow for free movement when tight. If they are double eye type the link bars are missing.
Reply:Originally Posted by triptesterIn all your photos except the one with the axle attached the frame looks flat.
Reply:The frame is made out of 3mil sheet, that has been bent. The bends where used for making door frames for prisons. The place I used to work for sold it to me due to the holes sizes have changed. Here is a sample pic. I also tried to bend it back by driving my truck on the high side. That did not do a dam thing. So I have a feeling I will have to tear it down and redo it.**************************************************  **************************************************  **If this is the same materials we used in doing some prison work a while back it is not the best coice of materials for a trailer. What we had to use was a hardened high strength brittle steel for all of the steel frame work on the doors and windows. Very prone to warpage and will crack very easily. I'll see if I can find out some more info as to the actual name and number of the steel but when made it goes through some form of a lamination process to form it in layers. DaveI am what I am, Deal with it!If necessity is the Mother of Invention, I must be the Father of Desperation!
Reply:Originally Posted by partagas I also tried to bend it back by driving my truck on the high side.  That did not do a dam thing.  .
Reply:That trailer frame will never be right.Sorry but the problem is that when you welded it it was on 4 blocks.Were the blocks level in both directions?The other thing is that the outside corners were welded and not the inside first.When you see a trailer frame that has transverse welds on the bottom to mount the springs you will see equal length welds on the top of the rail. That causes the rail to not curve downwards from shrinkage. shrinkage is 2% per inch. Check the welding rod box or package and you will see ELONGATION rate.That the shrinkage for that rod.AWS certified welding inspectorAWS certified welder