66 cj-5 frame welding questions

I have a couple of cracks in the 5 frame, the worst being on the drivers side under the floor pan. It is .125" wide at the bottom of the frame.
1. Should I jack the frame and close the gap to weld it or just weld it as is?
2. I don't have a wire welder and do everythng with a Lincoln pipeliner, what is the best rod to use? I have 7018 and 60ll or is there a better rod?
3. Do I need to preheat the frame first to weld?
4. Should I box the inside of the frame at that point or weld a scab plate on the outside of the frame?

 

Jack it up to close the gap and get it as straight as possible drill holes in the ends of the crack to stop it from spreading. V grind the crack lightly for good penetration. Box the frame on the inside if possible and add some plate to the outside for extra support. Top and bottom is not a bad idea also if possible, especially the bottom where it has separated. Stitch weld a bit at a time so you don't overheat the frame until the plate is welded all the way around. Make sure your plates are curved or rounded at the corners to minimize stress risers. This has worked for me on many frames for many years

 

nickmil hit the nail on the head. its been 6-7 since i took some welding classes so i dont remember what rod would be best for your application but there sould be a list online to help you choose. i dont think fully boxing is needed, a fish plate should be good enough.

 

The 6011 is a great rod if you want to be lazy and not properly clean the surface first. Then, go over it with a 7018. The 6011 is a way more complicated to run properly than the 7018.

I have repaired many frames with 7018 rods and plates. Fill in your cracks with 100% penetration (v it out). One habit I developed is never weld a plate directly across the frame. Make diamond or triangle shaped plates so that your welds going across the frame are at a 45% angle.

 

Thank you!! but what I am trying to find out is which rod is better as far as flexability and less prone to crystallization of the welds causing re-cracking. What are your thoughts?

 

Being a steel fab guy I know these frames are not a36 steel I would go to a8018 rod to match closer to the grade of steel. I am not sure but think the steel is like an a710 or an a514 and has a higher tensile then 7018 rod is made for. The first two numbers denote tensile strength of the rod. 70 being 70000 and 80 being 80000 and so on.

 

Now you are getting into an area I will not claim to have extensive knowledge. 6011 runs hot at will probably promote cracking without passes of something else over it.

I have never run a 8018 in a stressed application so I won't comment.

I have had failure with a 7018 weld that was on a plate with a weld running parallel to the original crack.

7014 has a more ductile weld and is easier to run but tends to trap slag and the surface prep has to be spotless.

Use a rod that is thin enough that you can get at least 3 passes without making a mess. This way on your final passes, you can concentrate the heat on top of the pass before and just over lap onto the plate or frame. This way you are not getting the plate or the frame too hot.

 

8018 runs almost exactly like 7018.

 

It is allin the prep bad prep equals bad welds.Worloch is right the prep is more inportant then the rod and arter a little reserch 7018 should wrok just fine. Just this cert.welder opinion.hope all this helps.

 

Thanks everyone for your input and advice!! Does any one have a pic of a welded fishplate without having to crawl under a jeep to get it?

 

i worked at international harvester back in the day been a waelder for 35 years.I know when we put a fish plate in we never welded the vertical welds just the flats you weaken the frame with verts.7018 rod is just fine grind all slag out tight fit as you can and weld her up dun done hope this helps alot of good info here

 

these day the only time 6010 is usually used is on the root pass of a pipe joint followed by 7018 for your hot pass and cover pass, so i would not use the 6010. for what you are trying to do the 7018 will work fine. if the rod is old or has not been stored in a rod oven do not use it unless you rebake it. the flux on the outside of the rod is what creates a clean sound weld not the filler metal of the rod itself. and no you do not need to preheat the base metal ( your frame ) the reason for preheating is governed by the thickness of the base metal and your frame is not thick enough to require preheating. if you are welding in below 0 deg. ambeint temp then you should preheat to 50 deg.

 

This



If you are unsure of your abilities, just extend the plates a little longer and don't weld across the frame.


I like to weld them all the way around.



Sorry, I am MSPaint impared


Those are my two favorite shapes I use. But, a lot of the time you have to think outside of the box to make some repairs stronger than factory without interfering with function.

 

Isn't 7018 harder to run in out of position conditions?

 

Them are hard because there not verticle but that a fish plate practice

 

if you don't have enough time behind a welding hood all weld positions will be hard reguardless of the rod. if you are asking what rod is easier to weld with, 6011 or 7018 the 6011 is an easier rod to manipulate your weld puddle as well as your stops and starts, 6011 also creates a lot of weld splatter. if you are not good enough welding out of position with 7018 you might have someone do the welding that is good with 7018, you need a strong weld.

 

I fit the description of not enough time behind the hood.