the cost of moly is very, very dependent on how much you buy. my quotes for my new truck varied by 150%!!
for the novice / street vehicle stay away from moly! DOM in a crash may bend, saving your life. moly tends to crack. yes, all the best racecars are moly, including my new truck, but it took 2 months of talking to convince me to go moly even on my race truck. the biggest difference that i see is in a dedicated race vehicle there are way more bars than any part time race/street machine will ever have. strength in numbers! Another thing that would make me shy away is anything using a stock frame. you just can't engineer the thing good enough to make moly work. i am also going to use mild steel gussets at every joint to keep the joint from cracking.
i've seen some really scary results from crashes with moly, and these were cars built by some of the best fabricators in the country. make sure you know what you're getting into before building a moly cage.
the deal is through my friend Seth at Amplified Performance, that is his cost, i dont know who he gets it from or how much he would resell it for, but i will ask next time i see him, i know that i can by one stick or a thousand sticks and its all 2.62 a foot. before Seth started helping me out, the best price i could get was 2.92 a foot and that was for about 400 feet
At baseball games they play organs, in motorsports they donate them.
Chromoly really needs to be heat treated to give you all the benefits of the material properties. Hoek is right on with the brittle failure or cracking that occures at the heat affected zone at the edge of the weld. Some people shot peen to stress relieve, but I am not sure of the effectiveness of it. Maybe someone can post some links to data on this.
"i know that i can by one stick or a thousand sticks and its all 2.62 a foot" If you buy 1000 bars...you can beat that price easily...not that you would buy that many, but quantity is key in the mat'l market or any market.
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Just a little curious,but I'm not sure about the hole deal with the D.O.M. tubing.My last car was 100% chromoly,so I was just curious that when I go to start on my next car should I consider a D.O.M. chassis or stick with the chromoly?The chromoly treated me pretty well with the first car for type of driving I do.Just looking to get the heads up.
with modern nutrition, human bones and muscle are stronger than ever. you dont need a cage that will hold up in a crash, you will probably heal eventually. i recommend using exhaust tubing, just to keep the race tech inspectors off your back. same for prerunners that want to be "that much cooler". and really, while im on the subject, automotive engineers are making things stronger than ever before, why upgrade suspension, or box frames, or install cages? i envision a future where there will be only one class in all desert racing: stock tacoma. who needs all that safety crap, and fuel cells, and upgraded brakes? waste of money. spend the money on stickers, paint, and a bumpin stereo.
you'll have to ask lots more people than me to decide that. my point was just that you need to be very careful with moly. moly is not better all the time.
if you're referring to another stock frame rig like your toy, i'd prefer DOM, but it's up to you. the thread "accident in glamis" a couple weeks ago showed plenty of reasons not to use moly. i'd give odds that if that had been a DOM car, it would still be in one piece. it would still be junk, but the passengers would have been in better shape.
you say you had good luck with it on your last car, that's great, but did you ever really crash it bad? probably not. a moly chassis, even if welded too hot, and not built right, may be fine until the one time you really need it. you may never find one crack, but when you roll it good and hard and your life depends on it, will it hold?? i have two months into building my new chassis, and i still hope i didn't make the wrong decision going moly. my old truck was DOM and it had been rolled at least twice before i bought it, then i rolled it twice more, once was a pretty hard roll. the chassis was perfect, no bends, no cracks, just put new sheet metal on and go. too many people think that moly is best because all the best racecars are moly. i just want people to realize it is not always best and needs careful consideration.
the first roll cage i ever built was an EW cage, i'd never do that again, but 2 years after i built it i "cartwheeled" the truck at about 50 mph. the whole truck was upside down 6-8 foot in the air, and came down hard, right on my head. this cage was not built properly, it was a nice street cage, not enough bars, no gussets. the entire cage collapsed 3", just enough to compress my spine and screw up my back, i lived, i can still walk, that cage saved my life even though it bent. if it had been molly, i'd lay odds it would have cracked at the lower windshield, and behind my head. who knows what condition i'd be in now.
the most important thing to remember when building a chassis, is good gussets and lots of them, this is even more important in a moly car. i am going to use mild steel gussets on my new race truck.
Couldn't resist. Just remember that each has its place and don't get too feisty over this - to each his own. Go over to PBB.com and you'll see a bunch of those guys swear by Schedule 80 pipe and believe it or not I think that even that stuff has it's place on certain vehicles (not a roll cage though).
I'm with Hoeker on this one too. I don't get your joke, or think it's funny to joke around about safety. Chromoly is not for everyone.
I think if you re-read the earlier posts, you'll see that that was the point these people were trying to make. No one is claiming to be anti-moly, they are just warning of the possible dangers of the misuse of a product. Example: just because someone installs a race seat and 5 point belts in their car doesn't mean it will save them in a crash if it was bolted to the floor boards with self tapping screws (I've seen that). The same is true with chromoly pipe, if it's not fabricated properly, it isn't any better or safer than DOM plain and simple.
And Prerunner68, you too are missing the point entirely. "do as I say not as I do" that's not at all what Hoek is saying. He's building the new truck with moly because he has the engineering and fabricating skills to do that.
The fact is, someone could build a roll cage from freakin pop cans, and if it's engineered properly, and put together by a fabricator who has the resources, skills, and know how, it will work.
7. Why do we use a Mild steel chassis as our standard vs Chromoly?
First of all we supply mild steel because we want our cars to stay affordable. Chromoly is about 3 times the cost of mild steel, it easily adds about $600 to the material cost. Thats not much, but when you look at what it takes to fabricate chassis with chromoly the labor costs and welding cost rise substantially over mild steel. Anyone will tell you mild steel is easier to work with and the processes of welding it is very defined. There is also a misconception about the weight savings, chromoly weighs the same as mild steel, its just that its twice as strong for the same thickness. Most builders are making chassis out of .083 chromoly with a little of .065 mixed in, which when combined is still stronger than the mild steel equivalent. It takes about 200 ft of materials to create a basic 2 seat chassis. 150 ft of 1.5 x .095 mild steel is about 219 lbs, 50 ft of 1 x .095 is about 50 lbs for a total of 269 lbs. The same in chromoly would be say 120 ft of 1.5 x .083 = 150 lbs, 30 ft of 1.5 x .065 = 30 lbs, and 50 feet of 1 x .095 = 50 lbs for a total of 230 lbs. That's only 39 lbs difference.
The second issue is stress relieving. Chromoly is much more susceptible to cracking after it has been welded especially if the grain structure has not been re-aligned thru a stress relieving process. Good welding processes, like cold welding, have evolved that help with this issue, but in reality heating a whole chassis for 2 days at 800 degrees is the proper way to do stress relieving. Boeing has done extensive testing on chromoly and have many extensive reports that can be found on the internet, or in the metals handbook. Obviously, nobody has that kind of oven or time to be doing that so welding processes have been perfected to help.
The rumors of a chromoly chassis being 4 times as strong as a mild steel chassis are absolutely not true. Especially when you consider the thinner tubing being used and all the complex angles.
Again we do believe in chromoly its just to stay affordable we offer mild steel to save costs, and also achieve a strong chassis. I have 6 hard years on my own mild steel .095 long travel chassis welded with our ESAB welder with no cracks.
As far as that accident in glamis goes I dont think funco or any other buggy manufacturer stress relieves thier chassis'.Dont use chromolly at critical points(cage) unless you plan on stress relieving it. And yes their are ovens big enough to stress relieve a frame. While maybe not perfect but better than not relieving is to use a temp stick (800-900 I think) or buttons on the frame about 3-4 inches from your cluster and heat very evenly.
while I'm no expert and dont have a degree I do know this needs to be done to properly put strengh in your welds.
Many buggy builders are only using chromolly because the uneducated customer only knows chromolly is stronger so it must be better. I know personaly about 4 years ago funco did just that(my family was going to buy one).