Best welding rod (tig) for welding 4130 chromoly tubing

[Aerometalworker]

I've got a closet full of them, first Grandpa's old clothes, then some of my pop's.

In years past we used them often on exhaust pipes with gas heat.

They actually work pretty good.

Back on subject, inspect, inspect and then clean and inspect. Think it is great the project is moving forward, no one teaches maintenance any more...

Hey Aaron, thought that would get a rise out of you

Ha Ha yeah, I have seen the old hangers, they were made from some pretty soft iron to be able to be formed like they were, maybe it was just a simple low carbon drwn iron wire not too different from RG-45. For fun I should dig one up and have it scanned. The torch is pretty forgiving of filler, in fact the less alloying elements, the more fluid it seems to weld, kind of the opposite of electric welding. You know back in the late 1960's , most of the aircraft companies were using Oxweld 1 and Oxweld 65 for their tig welding on 4130?

[FusionKing]

what about using oxweld #32 cms or #7 for this Aaron? on O/A. What are they made of?

Also even the filler mfgs (Harris) say er80 is for use with post heat treat only. Never mind what they think.

BTW...I'm not sure I would trust MY life with the stupid@$$ practices Mckinney did
IIRC he was even using the wrong material to begin with.
Somebody ought to post a link to that thread.

[Aerometalworker]

what about using oxweld #32 cms or #7 for this Aaron? on O/A. What are they made of?

Also even the filler mfgs (Harris) say er80 is for use with post heat treat only. Never mind what they think.

BTW...I'm not sure I would trust MY life with the stupid@$$ practices Mckinney did
IIRC he was even using the wrong material to begin with.
Somebody ought to post a link to that thread.

FK,
Oxweld 7 is basicly a drawn iron wire, and was the standard for most weldments in 4130 up to about 1/8" thick. Thicker then that Oxweld 1 was usually suggested and is a "low alloy" filler. 32CMS was heat treatable as was used in areas that would recieve a heat treat above the normalized condition and contained chromium, moly, etc. etc. Of course there was no hard and fast rule as it has a lot to do with the joint configuration and application. In WW2 military aircraft design prints you see mostly oxweld 7, with oxweld 1 being used in some heavy critical areas like wing attach points and 32cms on heat treated gear assemblies. It should be noted that the tensile strengths of the pure filler is not what the weldment tensile strength ends up being due to intermixing of the alloys. the AMS did a bunch of testing years back on this for an aerospace firm, I dont have the numbers in from of me right this second but they ended up being much much higher then the filler tensile strength.
Now back to Tig, in a letter I have from one of the aircraft companies from 1964, it explains why they chose oxweld 65 ( now called er70s-2 ). It was due to the ductility and elongation of the material. They WANTED a softer material since the area of reinforcement ( weld bead ) more then makes up for the slightly lower strength compared to the base 4130, and the end result was a more ductile weldment. Unfortunately not much has been done in recent years as far as company sponsored engineering help as 4130 tubing is now mostly reserved for engine mounts and such. However the materials have not changed, so I tend to follow the trends from when the material was in the prime of its use in a critical application. I know im a bit of a "nerd" about this, you should see my library on this subject!

On a personal note, the old 32cms ( now replaced with RG-65 ) makes some beautiful welds if you ever section them or have to machine on the material!
-Aaron

[trstek]

ok... some pictures of the frame and welds...

So, where will you be running?

Who will be piloting this here craft? New to it, coming from Kart' s, whats the story.

A little bench racing is in order after a question like one that was asked.

[Aerometalworker]

ok... some pictures of the frame and welds...

So, where will you be running?

Who will be piloting this here craft? New to it, coming from Kart' s, whats the story.

A little bench racing is in order after a question like one that was asked.

Yeah interested here too! And what was your final choice for materials?

[scsfabrication]

I got an 1989 super pro s10 that is 910 horse and pulls the wheels 3 feet in the air for 80 feet out for the last 4 years. I used the ER80, purged the moly tubing and also used a trailing sheild, then wrapped the joint in insulation and so good so far. Alot of work but well worth the fun.

[Aerometalworker]

I got an 1989 super pro s10 that is 910 horse and pulls the wheels 3 feet in the air for 80 feet out for the last 4 years. I used the ER80, purged the moly tubing and also used a trailing sheild, then wrapped the joint in insulation and so good so far. Alot of work but well worth the fun.

Naw its not a lot of work, it shows you were thinking! The purging might have been overkill, and the filler deffinately was....well depending on joint design. The insulation was a good effort, if you got it on soon enough it may have helped the material auto-temper upon cooling.

Here is a Pic for you guys, how about Fenn's shop turning out some winning chassis while working for chassis research? Hmmmm notice the welding method of choice I think they had a bit more then 910 horse as well J/k

[KC1]

I use ER70s-2 on all my chassis I build Pro-Mod & Top Sportsman Chassis. This conforms to the S.F.I.spec and certification for 25.1E 6.00 flat and slower. Hope this helps.

[weldor180sd]

Funny, notice where that got them? Ever see the failed welds on the Force teams cars? Hmmmm.
-Aaron

The main cause of the failures is due to the fact that McKinney used 4130N tubing that was heat treated to make it stronger by an outside source before welding for the main frame rails, (it was not heat treated by the steel mill that produced the tubing because of minimum footage of the steel mill to make a prodution run was way too much $$$$). Now the big teams like JFR, DSR, etc make their own chassis in-house instead getting them from McKinney, Hadman, etc.

[Old Sporty]

Not to detract from some of the other answers, but I would listen to "AskAndy". He deals with this subject on a daily basis with the Nascar Sprint Cup builders and I feel like his knowledge is right on concerning this.