Frame Warp

[crazycyclist]

When building my frame over Christmas Break I created a problem. The frame warped from the heat of welding. The back of the trailer sagged about 3/8 -1/2 inch. This would not be good when attaching the walls which I am getting close to doing. So today I decided I needed to fix the problem. Below is a picture of the frame during the building process. The frame is upside down in the picture.



I started by putting the frame on jack stands and dropping the auto shop lift on it. But that didn't do any good. So with the help of a friend I took it a step farther. We moved the frame so that it was near the back door and he brought over the backhoe and we lowered the bucket on it. Tada! It worked. But it worked too well. So we dropped the axle off, flipped the frame over and applied pressure the other way (with a little more finesse, making it just right!

Now I'm kicking myself for not taking pictures of the process...

[doug hodder]

Congrats on creating your solution, fun having a piece of equipment to bend what you want. I think most of us "shade tree" welders have the same issue on frames. I gave up on fighting it. Short of a jig, or access to a rotisserie or other equipment it's a tough one to remedy. Seems that no matter how flat it is...once I weld on the spring hangers...it's arched. I build in pretty light square tube on the floor so it tends to move a lot. Look at it this way...it's lots easier to deal with that than being out of square, but with a backhoe...that's an easy fix also! Doug

[crazycyclist]

I've been thinking of how I would solve it had we not had a backhoe available. Probably the simplest solution would have been to take it to a near by Auto Body shop and paid them to straighten it. Another alternate would be to find a way to tie it down and apply lift at the point you want to bend it - flipping the frame in my case. The lift could be done with a wench, engine hoist or even a jack. They key is to be sure the pressure is applied evenly.

[Larwyn]

Chain or cable attached end to end with a jack in the middle. You could have the wench operate the jack I suppose. A winch could be rigged to do the same thing, but not sure my wench would hang around for that.

[bmacke]

I had the same problem when I replaced my C-channel tongue with a 3" square tube. I tried chaining down the center and using jacks on the outside corners. I could get it flat, but as soon as I released tension, it would go right back and going past flat would've pulled the anchors out of the concrete floor. Ended up taking it to the Vo-Tech welding shop where I take classes periodically and putting the torch to it along with jacks. Got it as close as possible.
I am glad I'm not the only one who's had this problem.

Brian

[Larwyn]

Yes, a rosebud tip on an O/A torch can be used to pull the metal back to where it belongs by someone who knows what they are doing. I have a hint but can usually make matters worse, as in bent twisted and warped by the time I am through......... If you take your time, tack everything then weld equally on opposite sides the weld itself should pull the metal back into position. At least that seems to work better for me than anything I have done to try and straighten out anything that I managed to warp. Careful fit up and taking the time to flip the part and allow the opposite weld to pull the part back before you make that next weld to stiffen and reinforce the misalignment is worth while. The proper application of some good clamps can go a long way toward holding things where you want them too.

Welding is just a hobby to me, so do not take any of this as "expert advice".

[bmacke]

Larwyn, I totally agree with the "someone who knows what they are doing" I had the instructor at the welding shop do the torch work. I didn't want to mess it up even more. It definitely takes time, patience, and some skill. Welding is a hobby of mine too, I've been lucky enough to have been able to take classes so that I have a little more confidence in what I'm doing.


Brian

[crazycyclist]

When straightening with pressure you must bend it beyond true the other direction so that when you release it it springs back to where you want it. That's where the fun comes in and why we ended up bending it too far the first time.

[RichAFix]

Okay, not an expert, not even a novice. Truth is I haven't touched a welder since high school, but the week after next I will be welding my frame. Here is my thought to avoid this, perhaps some with a little more experience than me (which is "any" experience) can tell me if this makes sense?

1. tack the entire frame up first on the ground (my driveway is flat, trust me the puddles that just sit there confirm this)
2. don't weld too much at any time to avoid getting anything too hot
3. go back and forth from corner to opposite corner (kind of like tightening lug nuts on a car)

My brother (who has more experience than me) says I am nuts for thinking of doing this on the ground as I will not be able to stand up straight for a month afterwards, but I am worried about warping. Would keeping it flat on the ground help keep it flat/from warping?

[crazycyclist]

The warp appears to happen where I attached the spring hangers. The hanger was also lined up with a cross member. I think you have the right approach, however I would pay the most attention to the welding of the spring hangers and not try and do everything at once.

You should be fine. Just remember that if it does warp from welding it is not that hard to fix. May take some creativity, but it is doable!

[halfdome, Danny]

Instead of welding on the floor you could buy 4 cement cinder blocks to hold the frame up. A lot easier to weld and you won't be dragging your knuckles on the ground for the next week. I borrowed that idea from Amy. I level and shim the whole frame before any permanent welds are done. I too had some slight warping ( 1/4") around the axle from too much welding at the time. I get excited (welding is fun for me) and don't stop and let things cool sometimes . It seemed to straighten as I installed the walls. I guess I could have used my fork lift to straighten it but I would have had to read this thread first. Danny

[Billy Onions]

Good advice Danny

"I level and shim the whole frame before any permanent welds are done."

I wouldn't even think of doing it on a floor. A pair of trestles shimmed level is about right.

The best advice I can give someone who is welding for the first time would be that just because something is square/flat when you position it don't assume it will be after you have welded it.

It will move twice during the process. One way when you apply the heat and back again as it cools. This is where mistakes are made. Welding one side of your chassis then allowing to cool completely for turning over and welding the other is a common error which will lead to the frame bowing along the length.

[Wolfgang92025]

My neighbor and i are in the process of welding up the frame. And the tail sags by about half and inch. I don't have a backhoe like cray cyclist, but the string gave me a solution. Set the frame on cinder blocks under the garage door frame. place a 4x4 across frame. set a bottle jack on top of 4x4 . cut a 4x4 to fill in the space from the bottle jack to the garage door header.
now you can jack down the frame under verg good controll to get the bow out. It will have to wait a week for me, since in on vacation near Gettysburg, PA.

What to you think......
Your opinions are welcome

Wolfgang

[jplock]

When my father in law welded our frame it was warped slightly we used a railroad tie,chains, and a jack to straighten it. It worked great.
jplock

[sleepercatcher]

O.K.
So far I think I understand the 4X4 solution best. My frame was cut down from 6ft wide to 5ft wide and it is warped. I have it on sawhorses to paint it and the back left corner is about 4 inches off the sawhorse. Can I use the 4x4 solution with the garage door frame to correct it? I'm hoping to touch up some places I missed this weekend and then put the axle back on. I don't want to start building on a warped frame that will be a problem when I put the walls on.

SC