Another Welding Question?

JCRVETTE
The only thing I pre-heat are aluminum blocks and heads before welding because they soak up and dissapate a lot of heat when welding.
When welding chromoly tubing most of the time you will be welding .059 wall tubing. Welding that thin of wall tubing I don't think it would be necassary to pre heat it. It won't take much for it to get hot and stay hot, but then again I maybe wrong.
From now on I am going to use the rods Bob Meyer & Rusty suggested and weld the way Bob suggested.
Avoid tiny weld beads and go with a wider weld bead.

Bob Kraemer

[ September 04, 2005, 09:29 AM: Message edited by: Bob Kraemer ]

 

Thanks for the info, it is greatly appeciated. I am told that the tiny cracks come from the C/M cooling to fast, that is why I started warming the tubing up a little so there would be a little extra heat,not really preheating (as I called it) to gain penetration, but to allow it to cool slower. I look at the welds with a magnifing glass when done, and it seems most all (if not all) of the smallest hairline cracks that aren't visible to the naked eye are gone now. I was also told (by Jerry Bickle) that if a breeze blows in the shop on a hot weld it can cause it to crack. Maybe all this comes from where, not how, I do things. How can somthing so simple cause so many problems?LOL Thanks, Paul@JCR

 

JCRVETTE
Not only will a breeze blowing through the shop cool a weld to fast but it will also blow away the Argon shielding gas and thats not good either.
When I weld in my shop and it is only 24 x 20 I found out the hard way I have to turn off the ceiling fans and any other fans I may have running because it will blow away the shielding gas

Bob Kraemer

 

I personaly use the pedal for most all my welding. I have used the hand control but find them difficult to get used to. You have to get used to operating the pedal with different body parts. I can "elbow..knee..thigh and foot' my pedal with good results. And when it gets too uncomfortable my daughter has a pretty good reaction time on the "throttle" after 10 yrs of practice with me yelling more..less...off. LOL

 

Hi Bob, I've really enjoyed your comments on this thread so maybe you can shed a little light on this subject, a friend of mine works for the air force as a welding contractor and he tells me a good thing to do is too flood the rails with argon gas as you do the weld, by that he means have a plug either end of say a chassis rail with one end connected to the gas bottle and the other end with a small hole in it allowing the gas to flow through the rail, apparently this really helps the weld say when you attach an upright etc...

Cheers Ray

 

Ray
I never heard of having to purge 4130 tubing while welding. But that doesn't mean you shouldn't do it.
I do know you should purge Titanium while welding.
Maybe Bob Meyer, Rusty Kramer or some of the other guys on ITA can answer this for you.

Bob Kraemer

 

Ray and Bob;
Of course a constant argon atmosphere would be nice, but not necessary as in Ti.
Just think of all the 40's & 50's aircraft that were oxy/act. welded still flying above our heads on all the continents every day.

 

Geez; I just noticed I hit 100 posts! Do I win anything ? Maybe a beer from an Aussie when I get there for the Nats. ?

 

DEAR MR MEYER:

GEEZ ? ? ? ? ? IS THAT SOME MINNESOTA ROUGH TALK ? HAVE A NICE VISIT DOWN UNDER AND I HOPE TO SEE YOU UPON YOUR RETURN.... PERHAPS AT THE WINTERNATIONALS IF I AM STILL ABOVE GROUND...................

YOUR FRIEND IN OREGON,

LARRY

 

Back Purging only for Stainless and Titanium. Not needed for 4130.

[ October 03, 2005, 10:15 PM: Message edited by: Rusty Kramer ]

 

Certainly would have a tough time arguing the logic Mr. Meyer has provided….however….

If you have the patience to set up for "backgas" -"purge" or "inert atmosphere" (choose your terminology) the back side of your weld joints then by all means do so. This will promote better rootside penetration and reduce the potential of oxidation.

When you perform this practice, you will minimize potential failure points. Granted this is not as much of an issue with shear, torsional and tensile loading (typical stress’s implied in racing) but is defiantly an issue in high cycle fatigue scenarios(vibatory type frequency/loading)

Your aerospace buddy has been doing his home work! Good luck.

 

Thanks for your replies, this has been an excellent thread of info. i am embarking on my new chassis very soon and there has been a lot of good do's and dont's for us novices.

Bob we'll have to catch up at the Nats for a beer, If I am ot mistaken your partners in crime would usually be Bob Brackham from Romac.

We should start a new thread...How many Bob's are in drag racing.