LOnSLO

iTrader: (15)

How much weight difference is there really? Not a huge difference in price, just kind of wondering what you guys are running, and if anyone has a weight difference. Also, I heard you have to use a special wire to weld chromemoly. What is it?

AndUAndI

I understood 20lbs difference when I researched for my car. From Spohn that 20lbs cost $250...not chicken feed but not huge. Plus I believe that you are right about welding.

Overall for my needs I went with mild steel, but I'm not trying to set land speed records.

99taws6

iTrader: (2)

Ah **** Ryan.... You gonna be fast with a cage...... Get a mild steel, the weight savings does not make it worth the cost.......

Classic

iTrader: (3)

If you plan on tin-canning the car, go with chrome-moly. But its all about money vs. performance anyway. You could always put that money towards the spray, not that I'm suggesting that of course. But I'd be interested in knowing the difference in weight as well.

LS1x2

iTrader: (11)

Go look at the aftermarket parts that you buy to reduce weight. Compare the price. It's worth the money. You'll feel like an idiot buying a chromoly k-member for twice the price of the difference on the 2 cages.

LOnSLO

iTrader: (15)

That's kind of what I was thinking too George. It's about an extra $130 for the Chromemoly 6 point over the mild steel. About 20 lbs less weight though. Any other thoughts or advantages of either?

LOnSLO

iTrader: (15)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 4mulaJoe:
<strong> Go look at the aftermarket parts that you buy to reduce weight. Compare the price. It's worth the money. You'll feel like an idiot buying a chromoly k-member for twice the price of the difference on the 2 cages. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Good point. Got any idea on what type of wire to use to weld chromemoly?

LOnSLO

iTrader: (15)

[/qb][/QUOTE]you cant mig weld it you have to tig weld the chrome moly, I forgot the type of wire, its in my book at home [/QB][/QUOTE]
OK that's what I needed to know. I only have a MIG, so I guess it's steel for me.

kazman

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LOnSLO:
<strong> That's kind of what I was thinking too George. It's about an extra $130 for the Chromemoly 6 point over the mild steel. About 20 lbs less weight though. Any other thoughts or advantages of either? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Chrome molly is also more expensive to have installed. I was quoted twice the price over steel. TIG welding takes a lot more time and is a more costly process. I went with the 20lb heavier steel cage.

LS1x2

iTrader: (11)

You can MIG weld the chromoly too, but it won't have the same tensile strength and won't be as neat. Mine will be Tig welded. I'm having it done at a shop.

Big Rick

iTrader: (1)

Joe is right. Chromoly can be MIG'd but it's not as strong as TIG. NHRA mandates that all chromoly is TIG. That is the reasoning for TIGing moly. Plus it looks a lot cleaner =)

BIGBOS

Moly is defiently the way to go I've been told..

I plan on doing a 6pt moly from Speed Inc. in the near future... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Pro Stock John

iTrader: (34)

The weight difference is 30 lbs.

It's like 60 lbs vs 90 lbs.

The Juggernaut

iTrader: (7)

If you go moly you can go 1 5/8.
If you go mild steel,you have to go 1 3/4.
(as per NHRA rules)

I went with an 8 point moly it weighs about 55#'s.

comp#2122

Im sorry but i had to post to this topic , the answers given to you are incorrect , 4130 or cromoly as its termed "CAN" be MIG welded as a matter of fact it can be mig welded, tig welded, gas welded, stick welded, fcaw welded, friction welded, laser welded, electron beam welded,so basically you can weld any welder with 4130 (cromoly) , as for your decision i would advise the cromoly route , the weight saving is greater the ability of using small diameter tubing gives you more room in the cockpit and its stronger ... Fellas the filler metal and weld joint configuration is what determines the strength of the weld not wether its TIG'ed or MIG'ed , if you are gonna mig use er80sd2 filler metal , and it will be just as strong as TIG'ed ... I hope this helps you out

GeorgeC

Also, I think you're off on the tubing size...

I don't think you can use 1-5/8" tubing unless you're installing a full roll-cage, not a 6-point roll-bar like originally mentioned...

I'm not 100% sure on that, you'd have to consult a rulebook...

xaon

iTrader: (12)

GeorgeC is correct. Both mild steel and chromoly are required to be 1 3/4" OD for 6/8pt Rollbars, 1 5/8" for roll cages. The wall thickness is different however. .118" for MS, .083" for CM. NHRA also requires that all chromoly to be welded with an "approved TIG Heliarc process"

These are the rule of thumb for the roll bar/cages. There are some parts to the cages that are allowed different OD/wall thickness. You'd need to refer to a rule book to get the specifics.

LOnSLO

iTrader: (15)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by comp#2122:
<strong> Im sorry but i had to post to this topic , the answers given to you are incorrect , 4130 or cromoly as its termed "CAN" be MIG welded as a matter of fact it can be mig welded, tig welded, gas welded, stick welded, fcaw welded, friction welded, laser welded, electron beam welded,so basically you can weld any welder with 4130 (cromoly) , as for your decision i would advise the cromoly route , the weight saving is greater the ability of using small diameter tubing gives you more room in the cockpit and its stronger ... Fellas the filler metal and weld joint configuration is what determines the strength of the weld not wether its TIG'ed or MIG'ed , if you are gonna mig use er80sd2 filler metal , and it will be just as strong as TIG'ed ... I hope this helps you out </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">FINALLY! Somebody out there knows what kind of wire filler to use. Thanks a million. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

LOnSLO

iTrader: (15)

Also like to add, you guys have brought up some good points, and given useful information to folks like me who have no NHRA rulebook, or any idea about cages in the first place. I'll say it again, THIS FORUMS KICKS ***!!!!

comp#2122

Mustang HTR
I took a college course to get certified in weldong to do just what this topic is , weld , chassis , roll cages , cylinder heads , intake manifolds etc. ... as far as books go the best and most accurate i have read is a book from Home Depot .. believe it or not .. its titled WELDERS HANDBOOK written by Richard Finch it is a GREAT start to MIG , TIG , ARC & OXYACETYLENE if you are starting out or just wanna learn tensile strengths and about materials its a great book