Sport Bar / Roll Cage Material

[Lumpy Grits]

HH-Having worked with C/M a great deal in my life. I just don't agree about the welding deal. I'm not the greatest welder at all-BUT, I find true C/M easy to bend and weld. About the only metal I find easier to work with is the leaded steels.
As far as how Europe builds stuff. Think about this-what's faster/cheaper for production. Glue or weld? Of course, it's cheaper to bond(glue)the parts over welding.
Hope sometime, we can talk about this around a campfire.......

LG

 

[tarry99]

A reply to my friend IO's post above.......

Difference in price between ERW vs DOM?

There is Generally about a 20-30% difference in price between ERW vs DOM depending on volume and of course who you buy it from...

And they do both start out as the same alloy.......but that is about as close as the relationship ever gets going forward..........once the Tube is ran through the DOM Process , the gain in strength and structure really separates them greatly.

ERW Tensile strength 58,000 / Yield 42,000
DOM Tensile strength 80,000 / Yield 70,000

And the seam Bump inside that was mentioned above is the electric weld. Where the metal strip during the manufacturing process is joined together. Which also happens to be the will documented point where most ERW Tubing fails.

And although Grinding and / or smoothing welds may be fashionable on street rods and Custom cars it really has no place in a roll bar especially if weld joint strength is a factor.

 

[Woolyworm]

I didn't mean the thank on tarrys post - sry. Terry if you'd like to argue your case for bomb proof roll cages I suggest you do so on the opinion thread - in fact I've primed the pump for you there - cheers [emoji482]


Wooly

 

[tarry99]

I didn't mean the thank on tarrys post - sry. Terry if you'd like to argue your case for bomb proof roll cages I suggest you do so on the opinion thread - in fact I've primed the pump for you there - cheers [emoji482]


Wooly

Wooly............your surely welcomed to your opinion........but I have never promoted or argued "Bomb Proof" protection as you have suggested!

What I have clearly promoted is the use of stronger basic materials and industry guidelines that may help you or anyone else here survive an event or accident.

And Yes I have been known to spend many a weekend going over 200+ on the Drag Strip and feel very comfortable in doing so in my 4130 tube chassis car.........

And when I'm out hunting in the Jeep or playing with friends in the rocks I don't wear my fire suit , Hans device or strap into a 6-point harness...........

But what I do bring along and apply to my Jeep is good common since technology and safety features within reason that will allow me to at least have a better chance to get back home.

Bottom line it's your head and your more than welcome to go get it banged up!

 

[IOPort51]

A reply to my friend IO's post above.......

Difference in price between ERW vs DOM?

There is Generally about a 20-30% difference in price between ERW vs DOM depending on volume and of course who you buy it from...

And they do both start out as the same alloy.......but that is about as close as the relationship ever gets going forward..........once the Tube is ran through the DOM Process , the gain in strength and structure really separates them greatly.

ERW Tensile strength 58,000 / Yield 42,000
DOM Tensile strength 80,000 / Yield 70,000

And the seam Bump inside that was mentioned above is the electric weld. Where the metal strip during the manufacturing process is joined together. Which also happens to be the will documented point where most ERW Tubing fails.

And although Grinding and / or smoothing welds may be fashionable on street rods and Custom cars it really has no place in a roll bar especially if weld joint strength is a factor.

I disagree with nothing you have said.

 

[Hedgehog]

Lumpy - Then Bimota, Ferrari and several other money is no object manufacturers don't know what they are talking about.

 

[Lumpy Grits]

Lumpy - Then Bimota, Ferrari and several other money is no object manufacturers don't know what they are talking about.

Never said they 'don't know what their talking about' now did I?
Do you have a link so I can read up on the glue'n deal?
LG

 

[tarry99]

Sorry guys but Chrome Molly is well known for not handling welding very well. Many European auto manufactures of both motorcycles and cars prefer to glue their Chrome Molly tubing with double butted joints. CM and heat don't get along very well.

Any chance in seeing your backup or research on these two items you mentioned above?

 

[PistolDave]

Sorry guys but Chrome Molly is well known for not handling welding very well. Many European auto manufactures of both motorcycles and cars prefer to glue their Chrome Molly tubing with double butted joints. CM and heat don't get along very well.

As long as a lower carbon alloy (like ER70S2) is used for the weld filler, and you allow the joint to slowly air cool, I think you are ok using 4130 for a roll cage for a jeep. Aircraft frames have been produced for many decades out of thin wall 4130 that was O/A torch welded, TIG'd (Air Tractor) and even stick welded (Stinson). Critical aircraft frame joints are usually subjected to a post weld reheat and then covered to cool slowly if I remember correctly.

 

[tarry99]

As long as a lower carbon alloy (like ER70S2) is used for the weld filler, and you allow the joint to slowly air cool, I think you are ok using 4130 for a roll cage for a jeep. Aircraft frames have been produced for many decades out of thin wall 4130 that was O/A torch welded, TIG'd (Air Tractor) and even stick welded (Stinson). Critical aircraft frame joints are usually subjected to a post weld reheat and then covered to cool slowly if I remember correctly.

PistolDave:

Glad to see someone speak up positively on the subject of 4130......and your absolutely right if your fathers father had worked building Airplane's years ago the only method at the time was Oxygen / Acetylene torch welding. Since then the more refined method is via Tig Welding using a 100% Argon as a shielding Gas........But to get even more technical if the part would need to be certified then shielding gas on tubing would also be required to be purged inside the tube during the process along with later normalizing and in some cases the re-heat treating of the part.

ER 70S2 is the common standby filler rod for 4130 but there are many other fillers that do a better job in certain applications.........one of which is 309 stainless.

And as far as what others have mentioned like: "Chrome Molly is well known for not handling welding very well" or that " CM and heat don't get along very well" ...............that is an incorrect statement , as I weld it daily and have so for 4 decades with no issues while still passing all SFI Specs.

 

[Lumpy Grits]

When I was the Leadman for the vertical mills at Robinson Helicopter in Torrance, Ca. The copter's frame was made from 4130 & 4140 steel and TIG welded. Then each weld was X-ray'd.
Never had any issue with the frame's integrity.
LG

 

[Hedgehog]

Tarry99 - I'm not going to resurrect the research I did a year ago, essentially you are calling me a liar if I can't do it. I won't jump through your hoops and if you'd like to call me a liar please sir, go ahead and do it.

The Chrome Molly opinion came from the days where I was really into motorcycles. There was a time period there where several articles came out on new manufacturing techniques and why it was better than welding or for that matter brazing. The article s were wide ranging talking about Ducati, Ferrari and many bicycle manufacturers going away from Chrome Molly for frames. Locally at least one custom bicycle frame manufacturer won't use the stuff do to many problems. Again, I'm not about to dig up any of the articles previously mentioned, either you trust me or you don't.

Lumpy - It's not supposed to be the over all quality of the weld. It's the heat and what it does to the metal around the weld area.

Yep, I'm a frequent poster, but I'm working on that..............

 

[Lumpy Grits]

Well-We'll just have to agree, to disagree here. I've had very good results welding CM with my un-shield'd wire feed, Lin. Welder.
You need to post MORE. NOT less!
LG

 

[IOPort51]

Does anybody have a source of reference on Roll cage design? I have heard people speak of A pillar and C pillar. I think design and configuration may be of greater importance in our instance than material , within reason. No galvanized water pipe.

 

[tarry99]

Tarry99 - I'm not going to resurrect the research I did a year ago, essentially you are calling me a liar if I can't do it. I won't jump through your hoops and if you'd like to call me a liar please sir, go ahead and do it.
..............

Hedge , Never called you a Liar..........but what I did say to your statement
"Chrome Molly is well known for not handling welding very well" & " CM and heat don't get along very well" was that your statement is incorrect ..........and there is a real difference between calling someone a Liar and telling them they are incorrect......

And I would go as far as saying that your two statements are "Patently False"...........and you can categorize that into anything you like but it still does not change the credibility of what you said....

First and foremost this site is supposed to be an educational site where everyone gets a chance to learn something while also sharing personal credible knowledge. This is also a place where someday you may be the Teacher sharing knowledge while another day you may be the student getting educated...........in either case I personally like the challenge as well as the education when the information is both credible and correct and no matter who it is if it's incorrect or false I will tell them so........

Chrome Moly in no way has the unthinkable traits that you have mentioned above.

Do you have to apply the correct known techniques in order to weld it , cut it and fabricate it? Yes you do..........There have been hundreds of articles written and tests done to improve these techniques some of which I have already mentioned above like normalizing the joint , purging shielding gas inside the weld zone , heat treating and the use of various filler materials all of which work better in certain applications........

And you don't have to believe anything I say. Just turn on your TV this weekend to witness hundreds if not thousands of Race Cars competing at the Professional level in sanctioning bodies like the NHRA , IHRA ,SCCA, IMCA , IRL , USAC, ALMS and GRAND AM where each one of these cars has hundreds of feet of Chrome Moly tubing throughout that is strictly certified and welded............Now do really think that all of us would be risking our life's if what you said was true?...............Not Hardly!

 

[mtnwhlr]

terry99 I know you know your stuff from reading your posts over the years and I appreciate you sharing your knowledge. I for one have learned alot from you :ty:

 

[Posi]

^^^ And you can add me to that list as well.

 

[Lumpy Grits]

terry99 I know you know your stuff from reading your posts over the years and I appreciate you sharing your knowledge. I for one have learned alot from you :ty:

^^^ And you can add me to that list as well.

As have I, and from many others here.
Hedge has shown me a fair share of 'tricks' also.

LG

 

[Woolyworm]

One of the better videos I've seen in notching. http://youtu.be/mHBanmfn_CA


Wooly

 

[Lumpy Grits]

One of, if not the very best vids on this subject I have seen!
I've done all of my 'notching' with a hand held, air-powered cutoff wheel. Would love to have the saw used.
Sure wish I could weld as well as he does
LG