Welding on Frame Question?

[crawln68]

I was over at a friends shop today sand blasting my frame and I was telling him how I was going to weld on some 1/4 inch plate on the both sides of my frame (and sleeves) to stregthen the frame where the power steering box bolts on and he told me something that I had never heard before. He said to only weld the horizontal sides of the 1/4 inch plate, NOT the verticle sides. We got interupted and I never got to ask him why? I am just learning to weld, so I am asking all of you, have you heard of this? If so, why do you not weld the verticle sides? TIA.

 

[67ster]

Next to any weld will be what is termed the heat affected zone and it can be a stress riser causing a crack to develop . On a box section frame the upper plane is under a compression load , the lower under tension .The web or side plane is under the same loads with the center of the web as a neutral loaded member . To weld an overlay plate it is best to shape it as a diamond <=> or >=< on the vertical so a crack can't run across the web in a straight line .Most welders refer to this as a "fish" plate , it can be welded fully . We routinely use this method on heavy truck frames when shortening or lengthening wheelbase .Hope this helps .

 

[Miley]

I hope some of the vendors pay attention to this thread as none of them offer any of their weld-on products with this design!

I welded my Cage radius arm mounts from top to bottom! I suppose now my frame will crack and half and I'll slinky over the trails. ;D

James

 

[Skiddy]

Go ahead and weld it all the way around. Fish plates are good if your splicing two pieces together but if you just reinforcing it with the plates you will be good to go. Plus you won't get water in there and start rusting. The haz (heat affected zone) won't have that much affect on it. hope that helps

 

[crawln68]

Okay. That helps a lot. Thanks for the feedback. I just wanted to make sure that I do the right thing. ;D

 

[rcmbronc]

The problem with having a square fish plate and welding all around is from the two different stresses that are in action on the corner welds of the fishplate. These areas will eventually crack. That is why as 67ster said it is best to use diamond shaped fishplates. This allows the stress to lessen before it is changed in direction. Square fishplates should only be welded top and bottom. You can caulk around the other edges if rust is a concern.

 

[cheesenip73]

frame cut out

So make a fish plate if you are doing an overlay patch? Can I fully cut out the damaged frame wall and put in a new piece. For me this is a Christmas Break project. I'm itchin to get out in the snow. I want to do it right! (the first time)

 

[67ster]

Cutting out the damaged section is a good idea if it's webbed with cracks , your call though . Make sure your sleeves are a snug fit to the shank of the bolts so the box will stay snug , clamping force from tightening the bolts is not enough . I'll stand with the fish plate design as it does lessen the stress risers and offers more welding surface .

 

[j.r.nice]

To weld an overlay plate it is best to shape it as a diamond <=> or >=< on the vertical so a crack can't run across the web in a straight line .Most welders refer to this as a "fish" plate , it can be welded fully . We routinely use this method on heavy truck frames when shortening or lengthening wheelbase .Hope this helps .

Got any pics of your description, I'm having a hard time interpreting.

Thanks

J.R.

 

[rcmbronc]

I have attached a link that may help. If you look closely at the point that the frame makes a bend you will see a diamond plate. This is the way I am talking about.

http://www.howeracing.com/Chassis/Index-FrontFrames-LLM.htm

 

[crawln68]

So when I put my reinforcements on my frame, where the power steering box bolts on, I should make the plates with a diamond shape ends <=> rather than a rectangle shape? Then I can weld all the way around it for strength.

 

[rcmbronc]

Yes, That is the best way in my opinion.

 

[highrlr]

How about the post about the radius arm mounts? I will also be installing my long arms soon and was planning on welding the mounts to the frame, what would be the best way to go about this? I suppose I could cut out a diamond shape of steel, weld that to each side of the brackets and then weld all the way around the diamonds??? Make any sense at all? Or am I misunderstanding this all and is it only necesarry on a bend?

 

[67ster]

I just looked at my stock radius arm mounts and the rear spring perches , the way they are built , they form an angle that mounts to the side and bottom planes of the frame . The RAMs are riveted and stitch welded and the rear spring mounts are welded but not all the way across either the web or the flange . Makes me think the factory engineers knew about stress risers too.

 

[4x4x289]

I agree with the diamond shape concept in general for combating fatigue from bending stress but the frame up near the steering block does not experience a whole lot of repetitive bending stress. Up there, its just a cantilever with a relatively light load, with some short durations of heavy bending stress from usage of your winch if you have one, and mainly torsion and side compression from the steering block. The biggest problem I’ve experienced up by the steering block is crushing of the frame when the tubes surrounding the block bolts give out. These will sometimes rust out and collapse. For mine, I cut out a ¼ plate, drilled out the bolt pattern, and didn’t even weld it. My plate extends above and below the frame to minimize crushing and to help distribute the load like a landing pad. It also moved my steering block away from my radiator. If your frame is rusted out, then weld it. I can’t see how welding in this area would have any negative impact. Grind the weld smooth to minimize stress concentrations. I could be wrong. Its just my opinion.

 

[RRRAAAYYY2]

I don't know much about welding, one of my sponsors is a good fab shop, so I don't need to know much anyway. Many welding machines come with fancy ground clamps that say you don't need to disconnect your battery. They are correct in about 99% of the cases. But if you are like me and end up always being the one percent, take the 5 minutes it takes to take to disconnect one side of your battery. It is the only way to 100% gaurantee that you will not blow the diodes out of your alternator. And besides I would bet dollars to donuts you haven't cleaned your battery posts in awhile. LOL