Welding on factory frames Tua’h (23 Viewers)

[bobm]

Way back in 83 or 84 I spent several weeks in Lovelock, NV drilling a supply well for a huge natural gas storage tank site. Every inch of weld on that tank was x-rayed. Turns out certified welders can’t weld perfect either, Bob.

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Never claimed all certified welders could weld @gonzopancho just the ones that Iv'e known during my lifetime. The ones that can't probably read the Cobweb covered 3rd edition instead of the 5th . Pig looks great, glad ya driving it .

 

[J Mack]

You can’t trigger me. I got to drive my pig today for the first time in many months.

I am beyond excited for you, no one deserves to drive a new pig project more than you! I cant wait until you get to drive the rest of them..

But on street-driven vehicles? I’m gonna quote the best opinion I ever heard, “it’s a hobby, there are no wrong answers.”

You're 100% correct on all accounts and I don't believe I've said anything different.. My questions to the rest of the peanut gallery should have been phrased differently to exclude you and I'm still sorry for making you sad.

Seems to be silent on the subject, fren. Got a page number?

I started this thread and said I have certain beliefs on the subject of automotive frame repair and modification, I’m not an expert but my beliefs are mine and if anyone is willing let’s talk about the subject and see if we can learn something new and maybe help someone else in the process.

You have made comments like.

“ I'm sure I've forgotten everything I did back in college on finite element simulations of welded structures, so you're probably right.”

“If you want to continue, let me know if you're asking about notch stress concentration factor of fillet welds or something else.”

You sounded at the time like you might have some real knowledge on the subject and “YES” I did have and still do more questions but didn’t want to offend you by asking them somewhere inappropriate. I felt like this was the right place to ask questions and talk about interesting subjects that pertain to building 4X4 station wagons.

Early on in this thread you posted a link to a weld theory book and said that book would answer all the asked questions, later you said “Please reference section 2.2.3 (p 13-14) of the work I posted first in this thread on why controlling your weld pool (“puddle”) size is important”

I’ve read that section and a bit beyond and asked you “as someone that has read all 267 pages” what are your thought on this “new” technique of making your MIG welds on steel look like TIG welds on aluminum (stacking dimes). You didn’t give a direct answer and said you are just getting back into it so I gave you some examples to explain the process with a video showing a couple guys that are very good at it telling you to turn the machine down and use smaller wire stacking weld on top (cold joint) to give it the TIG weld look. I posted a second video with what appears to be an older guy saying basically the same thing and doing some testing but giving his opinion on why you shouldn’t do it. J F Lancaster talks about proper weld penetration in the “book” and I agree if we are welding for strength the stack of dimes weld is not a process we would do, it should be considered ornamental welding and limited to non-critical areas if failure would cause harm.

Since you Bob and I are the only ones asking each other questions and he and I mostly agree on everything would you mind sharing your thoughts on supporting a frame during welding?

When you were in college and sitting in your finite element simulations of welded structures class what did they talk about warping the structure during the process?



Hope you have a great day and get some quality miles on that new pig!!

 

[WarDamnEagle]

You won’t last a shift with that attitude.

Someone has to put the slips in the bushing or pull them, or step in to guide the joint into the stem, or to place the next 40’ section of casing on top of the last one.

Sometimes if the string of casing is heavy you have to use a hammer to set the slips or even run a bead above the slips to give it all something to grab. That means you’re heads down / ass up under the load, so not standing and I guess “OSHA approved”?

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Those are suspended but guided loads. Very different than saying "...put 100T of load on it and stand under or even work under the ****ing thing". I've been around the oil patch a bit but thankfully never had to work there. Pretty sure you can do all those jobs without putting your body directly under the load. It's not ideal but usually okay to be in the shadow of the load as long as it's safely guided. And you wouldn't last a shift on any petrochemical plant construction project if you get caught standing or walking under a suspended load (at least not in the US or Europe).

 

[bobm]

Gittin Deep

 

[gonzopancho]

Gittin Deep

RC Farms was my next to least favorite pump job. The wasn't that deep, but it was slippery.

 

[gonzopancho]

I am beyond excited for you, no one deserves to drive a new pig project more than you! I cant wait until you get to drive the rest of them..

You're 100% correct on all accounts and I don't believe I've said anything different.. My questions to the rest of the peanut gallery should have been phrased differently to exclude you and I'm still sorry for making you sad.


I started this thread and said I have certain beliefs on the subject of automotive frame repair and modification, I’m not an expert but my beliefs are mine and if anyone is willing let’s talk about the subject and see if we can learn something new and maybe help someone else in the process.

You have made comments like.

“ I'm sure I've forgotten everything I did back in college on finite element simulations of welded structures, so you're probably right.”

“If you want to continue, let me know if you're asking about notch stress concentration factor of fillet welds or something else.”

Perhaps you're doing a lot better than me and have figured out how to retain the specifics of things you've not touched for 40 years. Most days I can't remember what I had for lunch yesterday. I tried some of the kid's E&M homework problems 6-7 years ago and ODEs/PDEs, a subject I really worked at 40-ish years ago, are just ... gone, and I'm not even a grandfather yet.

The issue was (and still is, afaik) that most of FEA (or FEM) is done in the linear elastic region. The stresses and strains are established without considering defects and higher order effects. I'm not sure what is being done to model cyclic loads.

Notch stress (K(t)) is a real thing. For example, for a (circular) hole in a plate under stress, K(t) can be 3. This means that stress at the edge of the hole is 3x the nominal stress in the plate. I don't see anyone warning about drilling a hole in the frame.

Specific to fillet weld stress analysis, here's a video . Here is another:

Specific to the hardness of the material (which informed the arguments about if Toyota uses a HSS or low carbon steel) Stress and Crack Growth in Fillet Welds - https://youtu.be/cz6lDp8-H8o?t=439

Early on in this thread you posted a link to a weld theory book and said that book would answer all the asked questions,

I specifically said it was non-required background reading.

later you said “Please reference section 2.2.3 (p 13-14) of the work I posted first in this thread on why controlling your weld pool (“puddle”) size is important”

I’ve read that section and a bit beyond and asked you “as someone that has read all 267 pages”

seemed snarky, but then, we both do.

The thread then departed into various opinions on grades of steel with several people insisting that these frames from the 1970s must be a HSS alloy, or even a high carbon alloy.

Larger trucks in the 1970s had these, (I vaguely remember the warning etched into the frame about welding on same) and certainly today Detroit has moved to use them, and hydroforming, and the result is that they're typically non-repairable, (link) but all of our trucks were made well before this was the state of play for SUVs.

what are your thought on this “new” technique of making your MIG welds on steel look like TIG welds on aluminum (stacking dimes). You didn’t give a direct answer and said you are just getting back into it so I gave you some examples to explain the process with a video showing a couple guys that are very good at it telling you to turn the machine down and use smaller wire stacking weld on top (cold joint) to give it the TIG weld look. I posted a second video with what appears to be an older guy saying basically the same thing and doing some testing but giving his opinion on why you shouldn’t do it. J F Lancaster talks about proper weld penetration in the “book” and I agree if we are welding for strength the stack of dimes weld is not a process we would do, it should be considered ornamental welding and limited to non-critical areas if failure would cause harm.

I'm generally not going to offer an uninformed opinion, other than "I do/don't like it." I don't have an opinion on 'stacking dimes'. I don't know how to do it, but I do plan to try. (pic of my son welding over a decade ago included for ... distraction.)

Since you Bob and I are the only ones asking each other questions and he and I mostly agree on everything would you mind sharing your thoughts on supporting a frame during welding?

supporting any workpiece is important, but the work can be done without it. That's why I posted that picture of the lattice (laced) frame on the pump rig.
I do agree with your recommendation to check the straightness (before and after would be best) on a frame table.

When you were in college and sitting in your finite element simulations of welded structures class what did they talk about warping the structure during the process?

No. As above, FEM is typically done while the stresses are still in the elastic region.

Hope you have a great day and get some quality miles on that new pig!!

Thanks.

 

[Hornd]