Welding Mistake

[MarcInBoise]

A friend help me weld my frame for my trailer and everything was looking great (and when I say "helped" I mean he did the welding).

I purchased a Dexter axle with weld-on brackets... I put the frame up on saw horses and "we" welded on the brackets...
Evidently the steel got too hot, and the frame sagged. The front end is okay because of the tongue and "A" frame braces, but the rear is now about an inch (or maybe a little more) raised - because the frame was upside-down on the saw horses.

Anyone have ANY idea how to straighten 2" steel tubing?!?!
I was thinking about putting it on a curb with a brick or something under it so it didn't move too much, and driving my jeep on it....

[Socal Tom]

I would try and use a jack to bend it back, possibly including adding a little bit of heat to the area. How much is the end raised vs the middle?
Tom

[tony.latham]

A friend help me weld my frame for my trailer and everything was looking great (and when I say "helped" I mean he did the welding).

I purchased a Dexter axle with weld-on brackets... I put the frame up on saw horses and "we" welded on the brackets...
Evidently the steel got too hot, and the frame sagged. The front end is okay because of the tongue and "A" frame braces, but the rear is now about an inch (or maybe a little more) raised - because the frame was upside-down on the saw horses.

Anyone have ANY idea how to straighten 2" steel tubing?!?!
I was thinking about putting it on a curb with a brick or something under it so it didn't move too much, and driving my jeep on it....

It didn't sag, it warped. Heat distortion. It's possible to fix the problem by heatering your tubing opposite of your welds. Either with an oxyacteylene torch or welding. I haven't done this fix so I'm not Capitan Solution with this issue, but that should get you Googling in the right direction. Hopefully somebody will chime in and talk from experience.

Take a look at what Farmersamm posted on this forum: http://weldingweb.com/showthread.php?10 ... rped-frame

T

[rockinrobin]

You could turn it over and heat the area with a gas rig red hot. Might take a torch on both sides at once tho. Did you weld it with Gas, Tig, Mig, or stick? Ronnie

[rockinrobin]

Lol We all posted basically the same thing at the same time!

[MarcInBoise]

Mig welding. I don't have a gas rig... closest I have is one of those hand held torches for soldering copper and I don't think that's going to get it hot enough.
It looks to be about an inch off. I haven't actually put anything flat on it, and measured.

[KCStudly]

I suspect sagging, especially if the mounting brackets are on the bottom and the frame has bent upward.

Warping from welding almost always goes toward the weld bead; the hot side shrinks as it cools and pulls the base metal toward it. The more filler you add, the more mass there is that has to cool and the more warping.

On my self made frame there were many items welded to the bottom of the main rails (reinforced spring mounts, shackle mounts, upper shock mounts, bump stop mounts and the A-frame members) that contributed to a noticeable crowning of the frame. I'm lucky to have a fully capable fabrication shop at my disposal; toward the end of this post is how my friend and I straightened my frame using a fixture table and hydraulic ram (look for the paragraph that starts, "Things started moving faster...".

Another option is to do like Aggie79/Tom did on The Silver Beatle; build a very rigid cabin and use bar clamps to pull the frame to the box at assembly.

Your idea of driving on it with your truck has been used successfully before. If I was going to try that approach I would try to support the frame evenly and creep up on the size of the shim slowly until you get a feel for how much spring back there is. For example, block one end up the full amount you want (maybe a tad more), then place shorter blocks or shims along each side to control where the bend will occur. You don't want to end up with an 'S' shape, you want to try to control where it will bend back. Wood would be better than brick. Brick can crumble and will mark up your steel. just be aware that whatever bracket was welded on that caused the warping will also stiffen that location making it that much harder to bend back, so the remaining sections will want to bend more/first. You probably will need to add more shims and try it again, but it is always easier to bend it more, than it is to try and bend it back.

[MarcInBoise]

Thanks for all the ideas guys, I appreciate the help. I'm going to start by trying to clamp bending it, if that doesn't work, probably the car method.
Definitely hadn't thought about creating an "S" bend...

[tony.latham]

I suspect sagging, especially if the mounting brackets are on the bottom and the frame has bent upward.

After rereading your post, I think KC's right. (Don't tell him). But clamo a straight edge and measure your problem. This is just what I call a "teardrop moment." It'll get fixed.

T

[ctstaas]

I too would block it accordingly and then drive on it. I have had to do it at home on many occasions and it works fine. Take your time and sneak up on it because you don't want to over bend. I found a 5' s.s. straight edge at a drafting store for under $10 and it is perfect for checking for straight. Be careful when performing straightening operations cause things can go boing and fly.
Enjoy, Chris

[KennethW]

I guess I am not that fussy. Why not just shim the floor and get on with the build? A lot easier.

[MarcInBoise]

I guess I am not that fussy. Why not just shim the floor and get on with the build? A lot easier.

I considered that, and may do it if I'm still a little off... but...

I put the frame on a couple 2x6's and drove the jeep up on top of it to act as a paper weight, then put a auto hydraulic jack under the low spot and bent it back.
All looks good now! I cleaned, primed and painted the frame over the weekend - using a self etching primer and Rustolium truck bed paint.

I'm very happy with the result! Going to give it a couple days to dry, then bold up the axle and it's off to DOT for inspection and VIN assignment!
Next up: Building the floor.

[KennethW]

Good glad to here you got it straight. Be aware that steel will have some spring back over time.