Frame Repair

Your welds look much better than mine (I'm getting better though) so I don't think your welding ability is at question. I believe what concerns most here is how brittle your frame looks at all the key stress points. Mine cracked at all the spring mount locations, mostly from driving up and down the Catskill Mountains during hunting season it's entire life. But the rest of the frame was very solid. Looks like you are smart enough to know when to stop if it's not welding properly. Good luck with it, we have to try to save before we scrap

 

This is why I would strap the entire bottom length of the frame with one piece of new material. I'd buy two 20' sticks of steel the width of the bottom frame rail, remove the spring hangers, and stitch weld the new steel along the entire length of the bottom frame rail. I'd weld one inch, skip two, etc. along both sides of the entire bottom length. Then I'd drill through the new material and mount the new spring hangers on top of the new material, spanning the old and the new with the spring hanger welds.

If you think about the way a C-channel works to support weight, the top rail is in compression and the bottom rail is in tension. The web between the rails mostly serves to keep the rails in the same position with respect to each other. IMO stiffening the web is a bad idea, because it will form stress risers. Adding plates or short lengths of steel makes the local section more rigid than the rest of the frame, causing a stress riser at the transition. We have discussed this before - and not everyone agrees with my take on this. A lot of frame repair is done with fish plates on the outside of the web... though the fish mouth/tail is specifically intended to mitigate the stress risers.

 

What concerns me is how thin the metal looks on most of his frame. I think the repairs that have been made on it before shows how fatigued the metal is. If it were mine i would look for another one thats more solid. they are easy to find, But thats just my opinion for what it's worth.

 

I respect your ambition for wanting to repair what you have. But, I'm also with the "find a different frame" crowd. What you have has been absolutely beaten to death. There is so much stress and fatigue in that steel that it will be prone to cracking forever. If you were to make all the repairs, you need to be very, very careful how you do it as to not induce yet more stress and fatigue into the frame, or cause stiff spots, similar to what you did when you welded the two frames together. Seriously, take you losses and walk away from it. That frame will haunt you forever. I'm not sure how your state works, but in some, you can't legally drive a welded frame on the street, it will fail safety inspection. Look for a frame like that one in the pics of your other thread. Good frames are out there and can be had for just a few hundred bucks, which in the long run, will end up being much cheaper.

 

As was mentioned, an M38A1 frame will work. They are heavy duty, already partially boxed, and usually low miles.

Plus you get a machine gun mount included. (!)

 

With your fab abilities, and you have time and steel, I think I'd look into making a new frame. There are several guys here who have made their own frames. I know you want to repair the one you have but it's at last another option to think about.

 

I had worked as a welder/welder instructor for 35 years .I have rebuilt several dozen Jeeps over the last 40 years so , although no expert( like some of those guys on the welding websites!)I am somewhat familiar with what you are facing.
The welds on your trailer are good looking welds and it appears to me that you understand the process. Apply the same technique to you frame repair and you'll be able to sleep worry free! I've fixed frames that were way worse than yours and they are still going strong. From your pictures it appears there is minimal rust out and cracking in the " normal" stress areas. Likely from misuse in its past life. Cut out the rusted areas, weld in new stuff and your good for another 50 years.
When welding aim for 100% penetration, weld up those cracks,weld a plate over them and your finished.
The key to making the fix last is: weld to good, sound metal and avoid any porosity,voids or discontinuity in your weld. These faults are what we call stress risers or "notch effect" and can lead to weld cracking( especially in a dynamic loading situation such as a car frame).
Remember that that pesky stress looks for ANY cracks, voids, unfinished weld beads etc. to do its dirty work.

 

I have to ask what are normal stress areas? Looking at those pics, I see large sections that probably have less than 50% of their original cross section strength. And while they do most often crack around spring hangers and cross member joints, they also crack right through the main sections. It's the old adage that if you spend enough time on money on something, anything is possible. Is it worth it? In this case, I'm going say NO. CJ 5 frames are not a rare item and as Tim stated in a previous post, the tubs almost always disappear before the frames so finding one shouldn't be a big problem.

I can see many many hours spent on that frame and still end up with something marginal for a finished product.

 

As a certified welder and current structural steel and welding inspector here in los angeles, I can say without reservation that the welding on the jeep frame is criminal. The trailer frame welding is perfectly fine. However, as a steel inspector I would reject the proposition of repairing the jeep frame with extreme prejudice!!. There are way too many areas where rust has compromised the structural integrity , and the heat from all the welding necessary to make all the repairs would be of concern as well. Noble idea, but starting with a frame with less cancer would be more prudent, costwise, and personal mentalhealthwise.