Weld Repair of Factory Headers

[bmackinnon]

OK... I'll kick this section off.... only I'm going to ask, not post, a "how to".....

With little result, I have spent CONSIDERABLE hours, searching high and low, thru ALOT of archives, covering MANY years of turbobuick sites, forums, mailing lists, etc., looking for definitive methodology, and detailed reasoning/explaination for the PROPER way to TIG weld repair our factory headers. I know there are those that have had various degrees of 'sucess' using other welding techniques... gas, stick, mig, wire feed.... but I'm confident the real welding experts will agree that the truly proper way is to TIG. I'd like to hear, and hopefully compile here, the RIGHT way to do it.... and the reasons why... and I'm talking soup-to-nuts.... EVERYTHING from pre-weld cleaning/prep, weld/filler materials, tip prep, heat/wave function/amps, preheat, backgassing, post-weld treatment,...... and anything else that those who know, know :biggrin:

FWIW, I have no welding knowledge or skills, but have a great desire to acquire them.... in fact, it's one of my New Year's resolutions... :wink: So how about it, welding professors? Let the discussions begin.....

 

[garyk1970]

i cannot weld,but i can contribute that i drill each end of all cracks with a small drill bit to stop further splitting before i have them welded.

 

[QUIP'6']

a friend of mine put a triangular bridge in between 3 and 5 it keeps them from cracking again after welded up

 

[Just a Six??]

I do not weld & have No Idea what he used but this has lasted 15 years!
I added some liquid metal behind the brace about 3-4 years ago as I thought there may or may not be a leak? Didnt know 100% either way? No Leaks!

 

[hrhoward]

Alright, I will chime in....

I had mine done recently. They needed it. Here are the links to the threads, before and after.
http://www.turbobuick.com/forums/general-turbo-buick-tech/242433-can-header-repaired.html
http://www.turbobuick.com/forums/general-turbo-buick-tech/257999-stock-headers-back-welder.html

Now I have welded things in the past, but I do not like TIG. I like someone else TIG-ing. The few times I tried it, it shocked the crap out of me!!

There is some great info in these two threads. Read up and good luck!!

 

[scot w.]

I have done several repairs for members here. I weld in a 1/8" x 1' gusset between the bad spot.

Stops it from future cracks.
Makes it stronger.

Scot W.

 

[Mike Licht]

tig is the way the biggest problem I have seen is guys not cleaning them inside and out and also inside the crack. We used a blast cabinet with fine aluminum oxide to blast the area I also held the gun indide each tube. If carbon gets in the weld it will fail again for sure.
Mike

 

[scottyb]

My guess is that you just need a good weld/welder. I had a friend fix mine with his MIG welder, and he is by no means a professional. I fully expected it to fail again soon based on the threads here. It still has not failed after over 60,000 miles of hard use.

 

[hrhoward]

Mine were tigged. The fella who did mine works over at NASA in instrumentation. He is a fixture welder and he even rigged up something to pressure test them!! Just wish I would of known/thought of the gusset.

 

[Alky V6]

I use tig to repair cracked headers. Any other method is just sloppy.
Thoroughly clean the header.

Slightly V-groove the crack. Not absolutely necessary after you've done enough of them, but nice to do. I've found it unnecessary to drill holes at the ends of the cracks.

Setting on the machine is 75 to 100 amps. Post gassing is a must with stainless. The time of post gassing I use? I'll have to get back to you on that. I use the standard setting for the size electrode I'm using. Make sure it's long enough so that when the gas stops, the weldment doesn't change to a darker color. 1/16 electrode, 2% thoriated, red ID marking, ground to a point. Grinding marks lengthwise to the electrode. 100% argon gas for shielding.

Welding with stainless requires either back gassing of the weld or the application of a special flux paste to protect the back of the weld from oxidation. I've used both methods over the years and they both work well. I prefer the paste due to far less setup time required. Do not weld stainless headers without some kind of protection for the backside of the weld from air. It will make for a weak and ugly weld if you don't protect the backside.

I'll have to get back to you on the exact filler rod material. Something like 708.

Weld in short sections, taking breaks every 5 to 7 puddles. Don't overheat stainless.

 

[Alky V6]

Before.

 

[Alky V6]

After.

 

[Alky V6]

The filler rod is ER308. Diameter is .035". I was close.
Post gas time: 10-15 seconds.

 

[bmackinnon]

Very nice post, Donnie! :biggrin: This is the stuff I was looking for. When you talk about post-gassing... is that keeping the shield gas flowing over the new weld after you let off the heat? And is the back-gas (if using) also Argon? Beautiful looking fix.... thanks alot!

 

[Alky V6]

Very nice post, Donnie! :biggrin: This is the stuff I was looking for. When you talk about post-gassing... is that keeping the shield gas flowing over the new weld after you let off the heat? And is the back-gas (if using) also Argon? Beautiful looking fix.... thanks alot!

Yes and yes.

 

[X Ray]

I use tig to repair cracked headers. Any other method is just sloppy.
Thoroughly clean the header.

Slightly V-groove the crack. Not absolutely necessary after you've done enough of them, but nice to do. I've found it unnecessary to drill holes at the ends of the cracks.

Setting on the machine is 75 to 100 amps. Post gassing is a must with stainless. The time of post gassing I use? I'll have to get back to you on that. I use the standard setting for the size electrode I'm using. Make sure it's long enough so that when the gas stops, the weldment doesn't change to a darker color. 1/16 electrode, 2% thoriated, red ID marking, ground to a point. Grinding marks lengthwise to the electrode. 100% argon gas for shielding.

Welding with stainless requires either back gassing of the weld or the application of a special flux paste to protect the back of the weld from oxidation. I've used both methods over the years and they both work well. I prefer the paste due to far less setup time required. Do not weld stainless headers without some kind of protection for the backside of the weld from air. It will make for a weak and ugly weld if you don't protect the backside.

I'll have to get back to you on the exact filler rod material. Something like 708.

Weld in short sections, taking breaks every 5 to 7 puddles. Don't overheat stainless.

An excellent description Donnie ….I would like to add two additional comments ….you should only have the tungsten sticking out the radius of your gas shielding cup, so picking your cup OD is important ….and if you ever come upon a situation where you do not know what material you are welding…. you can cut a portion of your part off and use it as your welding rod….happy TIG welding….

 

[turbodave231]

I send the header through the shot blaster (stainless shot of course) before I attempt to TIG weld the cracks. It gets the header nice and clean.

Solar Flux is the product for protecting the back of the weld from ambient air................or you can back-purge the weld. I've done them either way.

 

[Alky V6]

If you have a shot blaster that's great. The above repair example was done after the header made a trip through the hot tank and the crack brushed over with a stainless wire brush.

Solar Flux! Yes, that is the stuff. Mixed with a little methanol to form a paste. You can also mix it with water, but it will take longer for it to dry before you can start welding it.

 

[Louie L.]

Just thought id post a pic of the repairs Ive been doing. This way it gussets the area for strength preventing the pulling that creates the crack. It also covers the entire area especially when a poor repair was done in the past.

 

[Bad Buick]

After sandblasting my headers with aluminum oxide,I glass beaded them. Then I took them to my welder,who "valleyed the area where the crack was.Then they were tig welded. A stainless steel support piece was then welded between the two pipes. I then had a "gusset" if you will call it that,welded in to reinforce, and cover up the welding. They were then re blasted, and coated with a high temp shiny ceramic coating. The inside of the headers got three coats of XMC Thermal barrier(good for 2000 deg.).
I did a lot of research prior,and no this inside coating will not flake off,and risk entering the turbo. Here's the finished product. Dave