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Jack, I'm interested in buying your roll bar. How much and where are you? Is the reason that the CMC roll bars are "decortative only", because of the why they are mounted, or because they are not made of the right material? If mounted properly would they be OK in the event of a roll-over?
I would not say that the chroming weakens the metal or structure. A portion of the process requires an acid dip. Aluminum is not good in acid. The only thing you have to worry about acid is mild wall loss. The are only a few things that can change the metals properties- Heat , fatigue, cold working.
I bought a JPS chromed roll bar for show. I have welded bottom mounting plates to it so it can be remove when my children go for a ride.
You should NEVER chrome plate any part that is intended to be load bearing or may inadvertantly become load bearing such as a roll bar during an accident/roll-over.

There is a side effect of the chroming process known as hydrogen embrittlement, I believe that it's partly due to the acid dipping and partly due to the electroplating process itself. Either way once chromed the metal is weakened to the point of uselessness other than for show.

It will eventually fail.

Of course, a plated roll bar/show bar does looks pissa . . .

Luck,

TC
TC: Are you sure about the "eventually it will fail" thing?. I was under the impression that Chrome Plating could be accomplished without hydrogen embrittlement (sp?) occuring if the plater knew what he was doing. I could also be wrong on this one.

I do know that for years race car builders used a Nickle Plating process on suspension parts, roll bars, etc. that when polished looked great and definitely did not lead to any structural weakening.

If you want some good information on building roll bars (material thickness for car weight, design, etc.). Order a GCR (General Competition Regulations) from SCCA. It will tell you all you need to know to build a roll bar (they call it roll over protection) that will keep you alive in the unfortunate chance you do end up going endo. The web site is www.SCCA.org.

Bill
Talking to our depts. metallurgist he does agree that you do have a potential hydrogen embrittlement(HE) failure risk with chrome plating high strength steels. No problems with stainless steels or aluminums. To remove the trap hydrogen a bake out procedure must be followed. Based on the thickness the temp range can be 300-500 F for 1 hour. It is true that racing orgs such as SCCA and NHRA do not allow chrome roll bars. There must of been on failure out there that started the rulings.
Now for the local cruiser or the classic cars ...it's all for show. The hydrogen worry is not an issue for the street guy that wants a chrome roll bar.
If hydrogen embrittlement is an issue with plating..... the guys with the classic chromed speedster wheels may want to consider another option. The wheels tend to take alot more road stress than a chrome roll bar. Chromed plated steel wheels have been around a long time. Has anyone seen a HE failure on a chromed wheel?
Hydrogen embrittlement. is a metallurgical phenomenon that occurs in many different metals. However, high strength steel by far seems to have the highest sensitivity to embrittlement. Hence, hydrogen embrittlement. of high strength steels dominates the file records of aircraft / aerospace components which have failed over the last 40 years. therefore, we have chosen to limit the discussion in this newsletter to steels only. Almost 75% of all the elements known to exist in the universe are metals, so it is easy to see why man has chosen to utilize metals so extensively in out civilization. One of the most important properties of metals is ductility. Ductility can be more commonly understood as the ability to deform under stress. Although this deformation or stretching under stress can sometimes cause problems in itself, it is still one of the advantages of metals compared to other structural materials such as ceramics, concrete, stone, etc. Hydrogen embrittlement. is a metallurgical interaction between atomic hydrogen and the ferrous metallic atomic structure which inhibits the ability of the steel to deform or stretch under load. therefore, the steel becomes "brittle" under stress or load. In general terms, as the strength of the steel goes up, so does its susceptibility to hydrogen embrittlement.
The failures for which we are concerned result from very small quantities of hydrogen where traditional ductility bend tests will not detect the condition. This atomic level embrittlement. manifests itself at levels as low as 10 ppm of hydrogen. Although difficult to comprehend, numerous documented cases of embrittlement. failure with hydrogen levels this low are known. This type of embrittlement. occurs when hydrogen is concentrated or absorbed in certain areas of metallurgical instability (e.g. stress risers). This concentrating action occurs via either residual or applied stress, which tends to 'sweep' through the atomic structure, moving the infiltrated hydrogen atoms along with it. These concentrated areas of atomic hydrogen can coalesce into molecular type hydrogen, resulting in the formation of high localized partial pressures of the actual gas.
Other theories show the hydrogen to act as a grain boundary surfactant that reduces the surface film energies at the grain boundaries, promoting dislocation slip movement, and eventually micro cracks within the steel. These micro cracks tend to grow quite rapidly upon formation, since the stress intensity factor at the crack tip is astronomically high. Fracture via this type of embrittlement manifests itself by not only ductility loss, but more importantly by the actual loss, via micro cracking, of load supporting or cross sectional areas within the part. For example, a part may start out with one square inch of cross sectional area on the outside, but at time of fracture an actual load bearing area 10 to 20% lower than this may be present. The facts are plain. The hydrogen has inhibited the metals ability to deform, and as a result the metal will break or fracture at a much lower load or stress than anticipated. It is this lower breaking strength that makes hydrogen embrittlement so detrimental in nature. Design engineers rely on the capability of metals and alloys to carry the load or stress for which they are designed. However, after the part is no longer a "blueprint" but has been manufactured, it becomes quite sensitive to the processing that takes place. Although most of the problems with hydrogen embrittlement have occurred with aircraft / aerospace parts, the part doesn't have to "fly" in order to "die". Hundreds of human lives have been lost over the years because of hydrogen embrittlement. The effects of hydrogen on metals is serious, deadly serious!
part2
SOURCES OF HYDROGEN-Hydrogen can enter steel from a multitude of places, starting from the original steel making operation. Hydrogen can also enter steel from subsequent casting and forging operations. Even grinding operations after final heat treatment can induce hydrogen absorption, especially if sparking occurs in a moist environment. For the metal finisher, the two most important sources of hydrogen damage occur from acid type cleaning, and most electroplating operations.HYDROGEN REMOVAL
A high percentage of hydrogen embrittlement is removed after chemical processing by baking. The normal baking temperature is between 375 and 400 degrees Fahrenheit. A lower temperature is required on components where the final tempering temperature is less than 375 degrees. The baking temperature must not exceed the final tempering temperature for obvious reasons. Most of the hydrogen is removed in the first three hours of bake time. However, the harder the material, the more bake time is needed for sufficient hydrogen removal. Up to 24 hours at temperature is required for the hardest structural steels (e.g. 300M).A final but very important point for you, the parts manufacturer: KNOW YOUR PARTS, i.e. what is the strength / hardness level of the steel part you are machining. Don't assume it's a soft, low strength steel. Ask questions of your customer. Make sure you know any specific or unusual aspects about your parts, and, most importantly, relay this information in writing on your purchase order to your processing vendors.
Sorry to bore you!
Back a few years ago, when the "personal pickup truck" craze was growing by leaps and bunds, Ford decided to get in on the aftermarket craze for those huge roll bars. They offered factory direct single, double and even triple bars which mounted directly to the truck frame behind the cab(most had half a dozen driving lights mounted up there also).

But Ford NEVER sold a "roll bar". Ford would sell you a "bed protector". The Ford product liability lawyers about had a cornary thinking about the potential for lawsuits.

I can remember back in college, one of my friends had his insurance increased when his agent discovered he had added a roll bar to his Austin-Healy. Obviously he intended to drive it inappropriately with such a "racing accessory"! One thing for sure, the speedster windshield ain't likely to help you much, so go for a decent roll bar.
Dr. Joe:

Man that was great!

After your first post it reminded me of what I had heard about chrome plating on racing parts. I always remember guys discussing the baking process.

I was looking through my SCCA GCR (it's a 1997 version, been a while for me, so I might be out of date) and could not find any mention of chrome plating not being allowed.

To be honest, I don't think chrome plating is disallowed on roll bars or suspension parts in SCCA racing. I might be wrong about this as a current rule, but I know for sure when I was running many guys had it. The only reason I ever heard of guys not doing chrome on suspension parts was you could not repair the part easily when you bent or broke a piece hitting the wall (something that happened to me a great deal). I guess (at least back then) they assumed you are knowledgable enough to bake it properly after the plating process.

For me, it was always Krylon as it was easy to remove when I had to do the inevitable and cut and nickle-silver braze a piece to get a usable A-Arm or Connecting Rod out of the tangled mess that was a corner of my car.

Thanks for the great information.

Bill
A bolt on roll bar on to a VW panned Speedster will not save you butt in a roll over. The roll bars are for show. If you go an extra step and built a tube chassis and adapt a roll bar whether a bolt on or weld in then you will have the protection. I have gone an extra step with my chassis setup. Though it does has a chrome show roll bar it also has a chrom-moly roll bar that is hidden directly behind the rear seat under the glass body. This setup not only gives strength for a rollover it also aids in protecting your back from a rear end collision. Would I survice a rollover in this car... probably not. I plan on keeping all 4's planted on the road. I have built some asphalt late model stocks and sprints in the earlier years . I do have some valued experience with chassis fabrication. Still welding though I have had to get reading glasses to to see the close ups. Eyes like a hawk ...just can see close anymore
Anyone want to talk about stress relieving chrom-moly welds to prevent them from cracking?
One issue about deco rollbars is taking a needless head injury on a bad bounce, a minor hit, etc. If the bar is placed too close to the driver's position and you are using lap belts, or get whipped back into that bar from the low backing on our seats,or a glass seat that may be pushed though it's mounts... well, a walk away may become gooey mess.... and the car never rolled over. Think about it.

Joe, your Sprint experience is a cool thing. I have followed Sprints & Super Mods here for years. Bill, I am still in awe. (looking at that BE60 too.)

Jim

Jim & Joel,

Absolutely. We used to tape very thick high density foam with electrical tape around any part of the roll cage that could come in contact with our head. That was thick high density foam AND we were wearing Snell Foundation current helmets.

The more I think about it, the more I think it's best to not put yourself in a situation where a roll bar is a good idea.

Man now I know I am getting old!

Bill
Jim and Joel , you have great safety issues regardiing the roll bars. Someone that is going to install a roll bar whether it is show or go must understand the fitment of the driver's body. A roll bar will ring one's bell if not mounted correctly. A driver head must be below at a minumum of 1 inch (top of helmet actually) Remember the racer's that are in the need of roll bar system do wear helmets and they are secured in the car with a tighly fitted 5 point belt harness. I bought a JPS chrome show roll bar over the summer. Intitally I was 100% wanting to install the roll bar. Now it's 50-50. Compromise- make it removable. 6 bolts will take it right out. I've welded some threaded lug into the substructure. It works great.

Always ask yourself WHAT IF? and What is the worst thing that could possibly happen? You will start to look at risk factors.

Though in racing there is risk.......It was fun.
Bruce
There was only one speedster at the vintage races at Sebring a couple of weeks ago. He had a complete cage including side impact protection. It looked more like something out of a stock or sprint car than the old bars that were approved for SCCA racing when I was at it. (of course they had just gotten away from leather helmets then) He needed the side protection because his doors appreared to be heavy duty aluminum foil over bent coat hangers. We had a nice chat in the pits and he did pretty well in the race, beating serveral nasty looking 911s. Of course they really don't race in that series. Sorry, didn't have my camera with me.
ed
When it comes to roll bars for the simple minded people like myself. I would think that a large, high, tubular bar that goes down into the floor pan AND back through the engine compartment back to the frame would be enough. After all the car doesn't weight much.

Oh and a 3 POINT safety belt.

But if you get smashed into by a 4'11" blond in a Cadillac SUV doing her makeup ain't nothin's gonna help.

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  • Doug
Roll bars, mounted correctly, are extremely important. The first photo is of a Porsche that was entered in the 2002 Silver State Classic in the unlimited division. The Silver State is a 90 mile race accross a closed high desert 2 lane highway north of Las Vegas. In the unlimited class cars are started at 3 minute intervals. The object is for the driver to cover the 90 miles in the fastest possible speed and also set the highest speed thru a speed trap. It is up to the navigator to keep the driver informed as to what to expect next as to curves, sweepers, turns and road conditions ahead. The Porsche had just entered a downhill right sweeper when a rear tire blew. They figured about 13 rolls before coming to rest. The driver and navigator were air lifted to Las Vegas hospital, some broken bones (arm, lower leg) but were back at building a new car within 35 days. Roll cage saved their lives. (driver was 74 yrs. old, his wife navigated and was 72).
Second picture is the car I was navigator in. We covered the 90 miles in 28.36 minutes ( better than 180 mph average) went thru the speed trap at 214.21 mph and came in second in the unlimited class (1st was .42 seconds faster). What a rush!!!
Jeff,

I thought that Porsche was sat on by those two corn fed beauties standing there looking at the car! LOL.

I remember a few years ago a couple were in a bad wreck in the race, driving a 911, maybe a Turbo and they also blew a tire. One was killed, maybe both. Reason was a low speed rating tire that they overcooked. Man, hope they tighten up their tech inspections after that.

You guys did great, wow, 214 thru the speed strap. what beat you by .42 sec? Is that a Camaro? Obviously doesn't have a stove bolt six in it.

A former workmate and his son runs a 50 Olds 88 with a chevy crate engine in it in the Pan American Carrera road race renewal in Mexico, don't know if he still does or not but he did quite well also. Took a 3rd in class one year. Of course the car that always wins is, ahem, a 53 Studebaker coupe with a monster motor. Has won many times, its the streamlined shape for sure!

Are you running the race again or was once enough for your heart?

Bruce
Was a NASCAR Monte, 1995 built for road races, beefed up for a passenger seat and occupant, full cage, wore arm straps, helmet restraints, etc. I had the honor of trying to read course notes, read a GPS and try to breathe while puckered for the 90 miles. Yea, once is enough for awhile at least. Winning car was one bad a** camaro.
A few years before our try a ferrari missed the turn that starts the canyon double S curve section and killed the occupants. Tech is very tight now but still if something happens bad there are not that many check points for help to come from. I understand this past race they made the unlimited class do their run at Las Vegas speedway. No fun there, all left hand turns, after a few laps it had to be boring.
Old F*^ts is right. Driver was 62, I was 60. The driver this year built up a BMW M5 as a rally car, shipped it to Sweeden and entered in a rally from Stockholm to Sidney, Australia. Many breakdowns later he arrived in Sidney on a hook, burnt the trans. 423 miles from finish. Next year he is doing a rally the length of South America, has asked me to go along. What to do??? Know how the wife will respond. Also begins same time as Carlisle and I missed that last year. Decisions, decisions.
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