Welding on factory frames Tua’h
- Thread starter J Mack
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- Thread starter
- #22
Does anyone make the information available to the public, I looked at:
The National Institute for Automotive Service Excellence (ASE)
The Society of Collision Repair Specialists (SCRS)
The Inter-Industry Conference on Auto Collision Repair (I‑CAR)
And nothing easy jumped out at me. It would be cool to find a trusted source of information for us home built guys to reference. Hoping someone with better Goggle can jump in and find something.
Some random thoughts that would be nice to get the experts opinion on…
If it’s unknown mild steels, high-strength steels, ultra-high-strength steels do we assume at least (HSS) and proceed with best practices for that?
Pre heat and post heat always or not needed. If no pre heat should the moisture be chased out of the parent material before welding, if yes only acetylene or is propane okay?
Fish plates, needed or not needed. If needed when are they needed?
Supporting the area to be welded, needed or not needed. If needed what’s the best practice for a guy at home?
Welding start and stop locations, matter our not. If it matters what do we need to consider when planning out our weld strategy?
Drilling holes and random spots on a crack repair, needed or not. If needed where do we put them?
Vertical welding yes or no. If yes up or down, any special precautions?
I’m sure we will have more questions but this kind of covers what I see most repeated with guys trying to help each other on their projects.
The National Institute for Automotive Service Excellence (ASE)
The Society of Collision Repair Specialists (SCRS)
The Inter-Industry Conference on Auto Collision Repair (I‑CAR)
And nothing easy jumped out at me. It would be cool to find a trusted source of information for us home built guys to reference. Hoping someone with better Goggle can jump in and find something.
Some random thoughts that would be nice to get the experts opinion on…
If it’s unknown mild steels, high-strength steels, ultra-high-strength steels do we assume at least (HSS) and proceed with best practices for that?
Pre heat and post heat always or not needed. If no pre heat should the moisture be chased out of the parent material before welding, if yes only acetylene or is propane okay?
Fish plates, needed or not needed. If needed when are they needed?
Supporting the area to be welded, needed or not needed. If needed what’s the best practice for a guy at home?
Welding start and stop locations, matter our not. If it matters what do we need to consider when planning out our weld strategy?
Drilling holes and random spots on a crack repair, needed or not. If needed where do we put them?
Vertical welding yes or no. If yes up or down, any special precautions?
I’m sure we will have more questions but this kind of covers what I see most repeated with guys trying to help each other on their projects.
In my formal education as a truck (big rig) mechanic we were taught never to weld on a frame. We were also taught that you are not supposed to drill the frame besides in the web. In terms of an fj55 frame, it is my understanding from 20+ years as a mechanic and fj55 owner that the frame is designed to flex and twist.
Rivets and small well placed tack welds allow that to occur to the extent that it was intended to occur. Weld the mounts on and you effectively remove a bunch of tiny flex points and make the frame/body much more rigid. That's exactly what you want if you're building a stock car or certain other types of machine.
For a 4x4 that gets used off road, id think that removing those small strain relies is eventually going to cause a new strain relief in an area that wasn't designed for it.
Have i got any experience that proves this out? No because I cannot afford to personally perform that sort of independent testing.
Ive also seen a lot of automotive hackery and this at least looks good so when push comes to shove and its time to sell it, the perspective owner may also look at it as an upgrade ...
Often these things are poorly thought out and poorly done and also way more dangerous things than this.
Since the damage is done, run it, keep an eye on things and watch for cracks starting to form.
Rivets and small well placed tack welds allow that to occur to the extent that it was intended to occur. Weld the mounts on and you effectively remove a bunch of tiny flex points and make the frame/body much more rigid. That's exactly what you want if you're building a stock car or certain other types of machine.
For a 4x4 that gets used off road, id think that removing those small strain relies is eventually going to cause a new strain relief in an area that wasn't designed for it.
Have i got any experience that proves this out? No because I cannot afford to personally perform that sort of independent testing.
Ive also seen a lot of automotive hackery and this at least looks good so when push comes to shove and its time to sell it, the perspective owner may also look at it as an upgrade ...
Often these things are poorly thought out and poorly done and also way more dangerous things than this.
Since the damage is done, run it, keep an eye on things and watch for cracks starting to form.
- Thread starter
- #24
These are my thoughts on my questions. I’m not an expert and as always if you read something I wrote do your own fact checking never take my word for anything. I’m the definition of an armchair internet prick sitting in the peanut gallery but I will always try to be helpful and share what I believe to be true.
If it’s unknown mild steels, high-strength steels, ultra-high-strength steels do we assume at least (HSS) and proceed with best practices for that?
I will almost always assume at least HHS and preheat and cover after to help cool slowly, I don’t go out of my way with temp-sticks or follow a defined procedure other than getting some heat in it first then covering with a glove or something like that.
Pre heat and post heat always or not needed. If no pre heat should the moisture be chased out of the parent material before welding, if yes only acetylene or is propane okay?
Like I said above yes I like to preheat and I’ll chase the moisture line out as my indicator as to how much heat I have, I use propane but I’ve been told the moisture in propane will create issues in your weld and not a good source of heat for preheat.
Fish plates, needed or not needed. If needed when are they needed?
I like the Idea but I don’t do a lot of fish plating unless I feel the extra strength is needed like a previous repair failed and I’m stacking a weld over an existing weld or a complete frame section being added.
Supporting the area to be welded, needed or not needed. If needed what’s the best practice for a guy at home?
I feel like this is important if you don’t have the ability to check and adjust straightness after the fact and believe you are starting with a straight frame, I have two methods I use here in my home shop. I have three 2’X4’X3/8” plates I can bolt to the floor then use 2” and 3” adjustable tubes tack welded to the plates and frame (like cheap jack stands) to bolt the frame to the floor. I’ll do whatever work I do then cut the tacks from the frame, if the frame still lays flat on all 6 or more points that it was supported on before the work was preformed then I assume it’s still straight and move on, if not I address the issue while the (jig) is still setup. That is a pain in the butt to setup and to be honest I haven’t done it in a while but I do have several chunks of large I beam and I use them all the time to support something while welding and it’s the same process of scrap steel welded for bracing kind of thing. A dedicated frame jig or table would be fantastic but not in the cards for me space wise for the amount of that type work I do.
Welding start and stop locations, matter our not. If it matters what do we need to consider when planning out our weld strategy?
I’ve never given it much thought but @Cruisers and Co was talking about wrapping his welds and now has me thinking more about this.
Drilling holes and random spots on a crack repair, needed or not. If needed where do we put them?
I’ve always drilled a hole at the end of the crack because that’s what I was told to do and I’ve never questioned its effectiveness, I’ve also heard drill a hole every inch but I haven’t done that. Another thought I’ve had that would be interesting to hear what the experts say is if an automotive frame cracks not from an impact then it’s likely work hardened in that area. Would you address that with some annealing, extra fish plating beyond the area?
Vertical welding yes or no. If yes up or down, any special precautions?
I know it’s unavoidable but I try to keep it to a minimum and will make something on a diagonal at the very least if possible, I’ve always heard vertical up is the preferred method but very seldom do it and to be honest I haven’t given it much thought until we started talking about it here. I would come up with a secondary doubler plate or a different design all together if I have to put several vertical passes in a short span (I don’t have any facts to back this up but it FEELS wrong to have mutable vertical passes all together on an automotive frame)
Don’t judge me on spelling and grammar this morning it’s been a long couple days and I tried to bang this out quickly.
If it’s unknown mild steels, high-strength steels, ultra-high-strength steels do we assume at least (HSS) and proceed with best practices for that?
I will almost always assume at least HHS and preheat and cover after to help cool slowly, I don’t go out of my way with temp-sticks or follow a defined procedure other than getting some heat in it first then covering with a glove or something like that.
Pre heat and post heat always or not needed. If no pre heat should the moisture be chased out of the parent material before welding, if yes only acetylene or is propane okay?
Like I said above yes I like to preheat and I’ll chase the moisture line out as my indicator as to how much heat I have, I use propane but I’ve been told the moisture in propane will create issues in your weld and not a good source of heat for preheat.
Fish plates, needed or not needed. If needed when are they needed?
I like the Idea but I don’t do a lot of fish plating unless I feel the extra strength is needed like a previous repair failed and I’m stacking a weld over an existing weld or a complete frame section being added.
Supporting the area to be welded, needed or not needed. If needed what’s the best practice for a guy at home?
I feel like this is important if you don’t have the ability to check and adjust straightness after the fact and believe you are starting with a straight frame, I have two methods I use here in my home shop. I have three 2’X4’X3/8” plates I can bolt to the floor then use 2” and 3” adjustable tubes tack welded to the plates and frame (like cheap jack stands) to bolt the frame to the floor. I’ll do whatever work I do then cut the tacks from the frame, if the frame still lays flat on all 6 or more points that it was supported on before the work was preformed then I assume it’s still straight and move on, if not I address the issue while the (jig) is still setup. That is a pain in the butt to setup and to be honest I haven’t done it in a while but I do have several chunks of large I beam and I use them all the time to support something while welding and it’s the same process of scrap steel welded for bracing kind of thing. A dedicated frame jig or table would be fantastic but not in the cards for me space wise for the amount of that type work I do.
Welding start and stop locations, matter our not. If it matters what do we need to consider when planning out our weld strategy?
I’ve never given it much thought but @Cruisers and Co was talking about wrapping his welds and now has me thinking more about this.
Drilling holes and random spots on a crack repair, needed or not. If needed where do we put them?
I’ve always drilled a hole at the end of the crack because that’s what I was told to do and I’ve never questioned its effectiveness, I’ve also heard drill a hole every inch but I haven’t done that. Another thought I’ve had that would be interesting to hear what the experts say is if an automotive frame cracks not from an impact then it’s likely work hardened in that area. Would you address that with some annealing, extra fish plating beyond the area?
Vertical welding yes or no. If yes up or down, any special precautions?
I know it’s unavoidable but I try to keep it to a minimum and will make something on a diagonal at the very least if possible, I’ve always heard vertical up is the preferred method but very seldom do it and to be honest I haven’t given it much thought until we started talking about it here. I would come up with a secondary doubler plate or a different design all together if I have to put several vertical passes in a short span (I don’t have any facts to back this up but it FEELS wrong to have mutable vertical passes all together on an automotive frame)
Don’t judge me on spelling and grammar this morning it’s been a long couple days and I tried to bang this out quickly.
I doubt any practicing PE would answer the questions over liability concerns.
Why would you assume this given they weren’t used on 1970s era Toyota trucks and the welding properties are so very different?
Read the book, Jim. Or don’t. ¯\_(ツ)_/¯
Holes are typically points of increased stress. Round holes are typically worse than ovals. None of us have the engineering data on a fj55 frame to run the FEA.
- Thread starter
- #26
I say in general if I don’t know its mild steel less than 0.3% carbon then I assume it’s not and assume that it’s at least 0.3% to 0.6% carbon and would use pre-heating and post-heating to avoid cracking during the welding process.
Does your book suggest this is not a good practice? Yes I will read it when I get a chance but you seem to already know the answer so just tell me I’m wrong if I am and I’ll learn something new today!
Do you know the carbon content on 70’s era frames? What would you personally do before you welded on one?
- Thread starter
- #27
Yeah you're probably right no individual licensed engineer is going to come on Mudd and make official recommendations to us but lots of organizations have recommendations that the general public can accesses like the SFI Foundation here, Drag Racing Chassis | SFI Foundation - https://sfifoundation.com/drag-racing-chassis/
Would be kind of cool if we worked together and found something helpful for our friends here wouldn’t it?
It’s not my book.
JIS has standards (or did in the 70s) for the steels used in automotive frames.
I am reading along here with interest. I don't have the background to dig in deep, but can we ping any of our Australian friends who have gone through modification as their gov has strict rules on modificaitons? I did a surficial search and found this: National Code of Practice for Light Vehicle Construction and Modification (NCOP) and VSB6 – National Code of Practice for Heavy Vehicle Modifications; but I didn't see any specific regs under it that outline requirements. Likely the government defers to stamped drawings to put the liability on the engineer, but maybe there is something there?
- Thread starter
- #30
So what do you believe the carbon content is in a 70' Toyota frame and would you pre-heat before you welded it?
Yes. In .au you have to get a licensed engineer to sign off on the modification(s).
In a similar story, the kid designed and built a CNC router for his high school robotics team as his Eagle Scout project. The local BSA Counsil wanted a PE to sign off on the design before they’d approve it. That process was more work than the design and construction phases.
Combine industrial processes under software control in the presence of teenagers if you want to explore that rabbit hole. Oh, and the construction is by volunteers (teenagers, again) with no real QA process in-place…. And what happens as things invariably wear (increased tolerances) over time?
Sign: “This machine is only to be used for cutting MDF and plywood”
Random individual: “I read on the internet that I can cut 1/2” aluminum plate on one of these. Hmm, no recommended speeds and feeds in the manual, I’ll wing it with a climb cut, because I’m special sauce and someone on the forum said I could.”
We got it done, but it was a lot more like Real Engineering(R) than anticipated.
I believe they are low carbon steel. I don’t believe any pre-heat is necessary at the thickness found in a light truck frame of that era.
- Thread starter
- #33
Do you believe pre-heat or chasing the moisture out of the base metal is a bad idea before welding on a frame if you don't know the carbon content or you even if do know it is less than 0.3%!
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- Thread starter
- #34
When I say "chasing the moisture" as a heat indicator this was the term used by the old timer that taught me as a heat indicator and as he referred to it as you want the steel hot to the touch but not turning color and chasing the moisture line is a good place to start...
I don't believe it's a bad idea. I used this method on winch mounts made of C channel and hot rolled steel plate. The channel was 3' tall and welded upright on a 2' square hot rolled plate that was 3/8" or 1/2" thick and welded entirely around. I will try to answer the reast of your questions above.
I would'nt be so sure about that! HSLA ( high strength low alloy steel.) Has been around since the 50s and 60s and AHSS (advanced high strenghth steel.) Came shortly after. So the HSLA could have been used as early as the late 50s or early 60s in automotive frames
.
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- #37
I read the JIS standard he posted and only found references to thicknesses nothing about carbon content on automotive frames specifically but I didn't want to argue so I just agreed that he was right.
But I also agree with you that I wouldn't be sure it is mild steel and most likely has a carbon content as high or higher than what would traditionally be considered mild steel here in the US..
1st let's get back in focus on the purpose of this discussion and not make it a Pissing contest. The focus in on the regular Joe Smoe working on his pride and joy in his garage or ( on da ****ing ground in da dirt
.) Looking for a source of information in Layman's terms that he can rely on, and seeking advice and help from people he considers expierienced and his or hers friends 
. Not someone who is going to sit down and read an outdated ( yup last updated 45 years ago in 1980.) 267 page Metallurgy book when all they want is an honest answer so they can get back to work and not study for a Master's degree. By the way there is a 5th edition by the same person that I think I'll read in case something changed in 45 years 
.I would'nt assume mild steel on any automotive frame, it would flex too much. So I believe all frames have a certain carbon content and it allows flex and still maintains structural integrity
. Visited a frame company years ago in Seattle that Hydro formed there frames .