8.8 tube welding

[MudDawg]

OK...I have searched till my eyeballs (all 4 of them) are gone whacky. Hopefully this will turn into a thread where there will be a definative answer as to exactly how to weld the tubes....rod material, prep work, technique, power supply (a/c, d/c, polarity, recommended amperage ranges,etc). I can't even find a definative answer as to what the center section material is.

There are plenty of references to welding the tubes, but they say "welded the tubes"...I'm doing the swap on my MJ mainly to get low cost disc brakes and SOA conversion. Please....no comparisons to 44's or 9in or other axles.

I want to do this ONCE and do it RIGHT...thanks guys.

 

[Dirk Pitt]

The center section is cast steel.

That's as much as I can do for you.

 

[Roxtar]

You're thinking way too much about this.
It ain't rocket science.
Just weld them up.
You want four 1" welds around the tube/housing.
Mig is fine, stick is better.
Preheat the casting, weld, and add a little heat afterwards to slow down the cooling.

 

[Dirk Pitt]

Mig is fine, stick is better.

Out of curiosity, why is this?

 

[Roxtar]

Out of curiosity, why is this?

Stick just tends to get better penetration and a more uniform bead.
I rarely use it just cause Mig is so much simpler, though (and the fact that my stick work sucks).

 

[low900rr]

I prefer mig myself. Crank the welder up and go.

 

[RWKHausSupply]

well I did just what was recommended up there. I was always concerned though that the cast would just crack away. I tried to pre-heat with a propane torch but since I dont know anything about welding cast I was just very questionable as to the over all quality.


Then I did a TnT truss that spans from one tube to the other and comes close to the center section in a few key spots adn thought that I would weld the truss to the center section in those areas. One area is a good 2.5" long and one only about 3/8" long.

first I did the four outer corners of the truss at the tubes then after heating and welding those two areas on the center section I let everything cool with the axle on end as TnT recommends.

Then when I went back and welded a stitch about 2" long at the for inner corners, on the third one I heard a sharp bang that was not very loud but I heard it and thought no way. Well that 2"+ weld on the center section cracked right between the bead and the housing. Hair line bit it ran the distance.

So this leads me to believe that I didnt pre-heat and post heat as I chould have but since no one really explains it well anywhere (here or otherwise) then I would say you best get a good definent answer as to the exact method.

As a side not, I was lucky to have a few holes in the the center of that 8.8 to bolt to and then weld the other end to the truss to get a center attachment to that was very strong and not questionable any more. How that helps you in the future.. Well TnT did say that every truss they have installed on 8.8's, non have spun a tube without any tube to center section welding. It may be an option to get you a few benifits all in one piece?

 

[CRASH]

I had both sides stitch welded like Kid said, and I promptly broke the traction bar side, twice.

The new housing is welded all the way around, with a mig, and I used an over-the-housing truss to help spread the load of the traction bar.

The big issue is to clean the weld area very well, get the grime, paint, and gear oil out of there. This means lots of brake cleaner, a wire wheel on the grinder, and a flapper wheel on the tubes. Now, preheat your weld area. You are trying to reduce the thermal shock and buffer the different rates of expansion that occursa between the cast steel center and the mild steel tubes.

Now, if you are using a stick, use a high nickel content rod, which is generally more brittle than a 60 or 70 series rod. This filler more closely resembles the physical properties of the casting, and will contract at a more similar rate as it cools. The welds I've broken when MIGing the housing have all cracked at the housing side, so now, when I'm prepping a housing for a weld, I like to cut about 4 lateral grooves in to the housing material to provide a mechanical "lock" to the torsional forces being applied to the housing/tube juncture. Fill this groove with the weld bead as you go by the groove.

 

[Roxtar]

The perfect rig? (updated AGAIN!): front leafs, in-boarded 63" Chevy rears, full width, passenger drop 10 bolt welded front, 28 spline 9 inch welded rear, flipped and doubled 231's, square drive shafts, Chevy 305 with Holley 650 double pumper, TH350, cherry bomb pipes, black poop-pipe exo-cage, 42" boggers on 2" BS black rock crawlers.

No white (rusty) wagon wheels?
Also, real rigs wear Ground Hawgs.

 

[cj7xjmj]

The preheting serves to functions. One is to create similar expansion and contractions properties, the other is to clean off all the paint and oil. When welding cast it is best to weld in small areas 1-2" at a time, and to space your welds out 180* from each other. Also spend the money and use HI-nickle rods, and if you dont have acess to a Stick, pay some one to do it.


BTW i think MJ's rock Here is al ink to my webshots page

http://community.webshots.com/user/cj7xjmj

and to my current build that I am just paying to have done, cause I dont have the skills required, or the tools

http://independent4x.com/generic67.html

 

[MudDawg]

This is the kind of sink yer teeth into it tech advice I was looking for. And yup, Brake cleaner is the ulitmate parts cleaner. I use it to clean the weenie little .058 4130 tubing I use for wheelie bars and frame struts before I TIG em together. I just have ZILCHO experience with any kind of cast.

 

[OT]

Got a CJ in for gears the other day and I noticed lube leaking from the plug welds.
After a day of waiting for them to find another axle, I got the okay to weld the tubes on this model 20.
I got it good and clean of debris before hand.
I preheated it for about 5 minutes and postheated it for the same.
Now, I didn't stitch it, like some, but it should be fine.
Oh, and I migged it.

Anyway, this was the best thread on tube welding I could find, so I figured this was the best place for pictures.
Here's the best pics from the job.
Sorry about the poor picture quality, but it's a crappy work camera.

 

[OT]

Oh yeah, coincidentally, this was my first serious welding of the year.
Will someone rub on the aloe?

 

[Captain Ron]

Jeez.

Am I outta touch.

--ron

 

[Captain Ron]

...I like to cut about 4 lateral grooves in to the housing material to provide a mechanical "lock" to the torsional forces being applied to the housing/tube juncture...

Not counting the weld, of course.

Hocus pocus.

--ron

 

[Ramsey]

Oh yeah, coincidentally, this was my first serious welding of the year.
Will someone rub on the aloe?

bring some to clayton and i'll gladly do it.

 

[OT]

bring some to clayton and i'll gladly do it.

:shiver:

 

[Captain Ron]

Oh yeah, coincidentally, this was my first serious welding of the year....

Keep your day job.

...
I like to cut about 4 lateral grooves in to the housing material to provide a mechanical "lock"
...

Almost forgot... This works well with Elmer's Glue too.


--ron

 

[Roxtar]

Whether to use a case spreader for doing gears no longer an issue here, huh?

 

[OT]

Whether to use a case spreader for doing gears no longer an issue here, huh?

I welded it while it was assembled.