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7/1/20, 7:47 PM   #11
Re: Roll bar padding
TQ29m
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Quote:
Originally Posted by opnwhlmnd View Post
Because it's 4130 chromoly and most do not weld it properly. Cooling too quickly causes embrittlement and you see the breaks away from the weld joint. It also needs to be preheated to at least 80 degrees before the weld process, I like it even hotter than that. Ideally we would have an oven to preheat it do the welds and then back in oven to post heat.

I'm not an expert but when in welding class many years ago that is what they taught me and I never had tubing failure on any chassis I built or repaired.
I'll second that theory, I didn't preheat, but I did an operation called purge welding, where you run another hose thru the tube, and send in argon to the inside, and it makes the joint look inside, just as clean as it does on the outside, it is a requirement on anything in the medical welding process. I've not had a weld crack either, it works. If a guy had a powder coating oven, that would be about the right temp, I always felt powder coating returned the moly back close to it's original heat treat. Bob
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2 members like this post: jonboat15, opnwhlmnd
7/2/20, 11:54 AM   #12
Re: Roll bar padding
Ray3
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Originally Posted by DRC II View Post
You bet. all cars with roll cages should have proper roll cage padding. Everybody, including the sanctioning bodies think since you have full containment seats, you don't need padding. True you will probably never get out of your seat enough to hit the roll cage but what happens is the roll cage bends down to meet you in a bad crash. Nothing can be worse than a head hitting a un protected roll cage tube than maybe an arm getting mixed up in the cage during a flip. Sometimes I think nobody cares anymore.

Mike Devin
I get the feeling nobody cares anymore as well. Some of the stuff I see today seems like a total disregard for safety. And the problem is the longer it goes on the more the newcomers to the sport see it as "the way it is." I can't tell you the last time I saw a car with safety wire on it. And I absolutely cannot stand allowing body panels up to the driver's head to the point that they wouldn't have a chance of getting out if the car is on fire! The lack of leadership in our sport baffles me. Sometimes I feel like the people who write rules today are in a popularity contest instead of being good stewards of the sport. When you write rules you are going to piss someone off. That just comes with the responsibility of being in a position of writing rules.
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Last edited by Ray3; 7/2/20 at 12:00 PM.
 
2 members like this post: DRC II, jonboat15
7/2/20, 8:11 PM   #13
Re: Roll bar padding
DRC II
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All welded joints will break next to the weld when over stressed. The heat from the weld reduces the molecular structure of the metal. If it breaks through the weld, itís welded improperly. In a perfect world it will break somewhere else first but that seldom happens. SFI roll cage padding is stiff for a reason. USAC and SFI spent many months hitting helmets against tubing and measuring the force on head forms. Remember you have a helmet that is hitting the padding so the roll bar padding is secondary. It must absorb the load with no rebound and not capture the helmet. Soft padding is worse than no padding because it captures the helmet and pinpoints or concentrates the load rather than letting the helmet slide and dissipates some energy. A lot of work was done with padding and there is a reason it is constructed like it is. Donít second guess it. Also tape your padding to the cage, the glue back is great until the tubing bends.

Mike Devin
 
5 members like this post: luckybuc97, racenut69, Ray3, Speedwrench, TNRustler
7/2/20, 10:17 PM   #14
Re: Roll bar padding
Ray3
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Another safety problem that gets totally overlooked by race tracks, sanctioning bodies, and drivers themselves is the ambulance! When are we going to start requiring a minimum service on ambulances? Particularly an ALS (Advance Life Support) instead of BLS (Basic Life Support) ambulance!!

I can't believe the number of race tracks who buy an ambulance and use it on race day with an EMT and a bag over his or her shoulder. What good is that going to do? They end up having to call in the paramedics when something real happens every time!! Racers need to wake up and demand better.

And I don't want to hear how hard it is to get an ambulance , how expensive they are or how they are only 10 minutes away! I've heard that song and dance so many times and every time I call the ambulance company myself the truth comes out. Cost is between $400-$600 per night. I think a life is well worth that. What I do find when I check up on promoters is they can't get an ambulance because they are being refused service for lack of payment. I have found this to be true far too often.

If you can't tell, safety is one thing that gets me fired up. Far too many drivers have paid far too high a price for us not to be better.
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Last edited by Ray3; 7/2/20 at 10:31 PM.
 
4 members like this post: erich45, racenut69, Sandy Lowe, sprintracer82
7/3/20, 2:53 PM   #15
Re: Roll bar padding
Kinser11
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Quote:
Originally Posted by opnwhlmnd View Post
Because it's 4130 chromoly and most do not weld it properly. Cooling too quickly causes embrittlement and you see the breaks away from the weld joint. It also needs to be preheated to at least 80 degrees before the weld process, I like it even hotter than that. Ideally we would have an oven to preheat it do the welds and then back in oven to post heat.

I'm not an expert but when in welding class many years ago that is what they taught me and I never had tubing failure on any chassis I built or repaired.
Very well spoken!
Just because someone owns a welder, does not make them a welder. I wonder, how many cars, had the extra bars welded, by someone who, KNOWS how to weld on 4130?
 
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