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Best way to mate two chromemoly tubes.


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22 replies to this topic

#16
larryo

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Well Guys I think we just about beat this post to death. Thankyou for the hardness lesson.

I'm not sure if the last gentleman left an option for post heating, but I got a feeling I'm just goin' to
weld some tubes together with an oxyacetylene torch. To tell you the truth I think I could get away
with the stick welder, but that was only a test. I think I can do better...LOL!

On the one tube I have already welded to an upright I can litterally lift the whole front of the car with just that one tube. I was kind of impressed, but it might break. I feel I could break the main tube that I welded it too if I really tried, but I'm a little scared to push my luck.

Since I'm only goin' to weld three joints, which I feel are non-structural, I'm not really worried..lol.

But as Midget Man has suggested if I really feel I have hit bottom of the barrel I might buy a Tig
Welder, but trust me, Tig welders were never designed to weld Chromemoly. They just happen to
do a good job or excellent if you know how to weld. And trust me not to many people know how to or
will ever learn how to use a Tig Welder. I have seen about 10 welds with a Tig that people thought
were excellent from the outside but all failed destructive examination testing. Looks can be decieving.

I always like to mess with people...lol! Have you every heard of Berryllium Tubes. They are the
strongest in the world. The lightest and most expensive and they can literally kill you. We stopped using
them about 20 years ago. I think we should still use them, but we went to carbon fiber.

Sincerely,

Larry "O"..it been fun! Thankyou very much.



#17
larryo

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biggrin.gif Update.. Awwwwwwh...I thought we might get one last new comer to comment. In the last
few days I took the advice of one of the readers and bought a Tig Welder. And some "GAS" argon/C02 mix.
Don't know if that is the correct gas to use. Some regulators and flow meters and hoses and welding
rod.

When I read the label on the rod that was suggested and again it was only 60,000 strength.
I noticed it said it was for mild steel. I probably got the wrong rod. And the label also said this rod
was for brazing?...hmmmm I wonder if I'm still not their yet. This is not brass rod. I think it is steel rod,
which I think it said it had manganese in it.

But I got to thinking on thin tubes... .050 inches thick, maybe I'm really brazing the tubes together
with a steel rod and not really melting the steel and welding them per say? Any ideas.

thanks,

Larry Otani

#18
Midgetcar98

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Larry,

I use stainless steel filler rod as it has very similar properties to chromoly. As for your welding/brazing thoughts I would suggest that you think about it this way. If you are tig welding a butt joint properly you will use VERY little filler material at all. The majority of your weld comes from the weld pool of the two pieces coming together. All you do with your filler rod is keep the pool from becoming too small.

Keep trying... it took me several years of trial and error to get my welds to a professional level. I never took a welding class, but learned from reading and observing other professionals do it. In time you will be fine, but you should remember this - If you aren't absolutely confident in your weld on a car, do not put it on a racetrack. When something breaks, it is rarely a single car incident and no one wants some one elses fabrication problems or experiments to ruin their night.

#19
zeromotorsports

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when i sarted building cars i did it with the mind set to build it like my kid may be in it raceing, and the new chassis design i came out with in 2005, was not just to be a crazy looking car, it had safety in mind, with a teenager following my foot steps, i wanted to give the safest car possible

#20
larryo

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smile.gif Well guys thanks for the helpful information. I don't think I will put something on the track that is unsafe.

And we go through tech. The modifications may not pass tech. I'm not exactly sure what's legal and

what's not...ie.. meaning the thickness of the tubes and if the tubes actually have to be welded to

one another. I kind of welded the tubes to a 1 inch square plate in position #1. Then welded the two

plates together to connect them. It's easier that way.

Right now, I'm kind of proud of myself, because the idea is coming together, but it's heavy

with the .120 tubing and 1 sq extra plates.

I'm learning a lot.

1) The front panhard rod is now about 12 inches longer.

2) The RF shock is now mounted right next to RF wheel. It's now more like a pavement RF shock

location, instead of being close to the frame rails on a narrow chassis.

3) And the sway bar is located and is a fairly light installation. I think I want to get a specially
made small diameter Front sway bar made. Something like a .375 inch diameter. Right
now installing a .660 diameter without changing anything else makes the car too stiff.


P.S. Johnny I finally bought a book on Mopar sprint cars engines.

No wonder those cars are fast. They recommend Billet cranks from Sonny Bryant.

2) Blocks with a I think 1/2 " deck, not to be milled less than .400.

3) Run short strokes and huge bores....like 3.30 for 360's and 3.85 stroke for 410's

4) Everthing on the front seems gear driven. Huge aluminum plates front and rear to
mount all the pumps and such.

7) Huge valves and 15 degree heads and such.

8) The flow numbers on those heads were like 360-380 cfm. That seemed huge.

9) And they were talking about cams with lifts like min .800 inch.

Build a motor with those kind of specs and it just got to be fast.

Larry Otani







#21
BFB

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*feels sorry for the poor SOB who drives a car Larry welded*

#22
Dwight Shroot

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QUOTE(BFB @ Mar 15 2007, 11:16 AM) View Post

*feels sorry for the poor SOB who drives a car Larry welded*


Why just limit it to just that poor SOB? There are others who need sympathy too.
If I had wanted your opinion I would have tortured and interrogated you to get it. Did I do that to you?

#23
larryo

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tongue.gif Well, the poor SOB will be me and I will probably only make it to a practice.

So all should be well. I'm more worried about the Poor SOB that has to race against over agressive
drivers.

And from the busted frames I have seen on the internet boards, I should be OK. I have a tendency
to over due things so strength should be not a problem. Wt is. It's too heavy. That's when you
get into trouble, lightening things up too much.

Larry "O"





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