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vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
4/25/23 5:30 p.m.

Opinions please. They were not done by me, but for me. Autopower weld in cage for VW. 1.5 inch, .120 wall thickness. TIG.

All criticism welcome.

4/25/23 5:55 p.m.

Main thing I see is that the welds surface was not clean enough.

ANYTHING that gets into the weld puddle turns into a gas and makes for a fizzy weld bead. Grind rust. Grind rust on the other side of the weld and then use brake clean ( non chlorinated) to get rid of grease.


Beauty of TIG is that you can go back and either re-flow the bead or grind and re-weld.  I have been known to go back and TIG a MIG bead just cause it looked and worked better.

Brotus7 Dork
4/25/23 5:58 p.m.

What's the end application for the cage? IE: who's gonna inspect it? For autox, you're fine. For lemons or other series - less so. You'll see undercuts, welds on welds, and a couple areas with little penetration. I wouldn't be happy if I paid money for that. Can dissect each picture of interested.

L5wolvesf Dork
4/25/23 6:01 p.m.

One thing I do not see is gussets. 

Welding-wise they LOOK average. But looks don't necessarily mean a lack of penetration or fusion of the metals. Far as I know only X-rays can determine that. If I were to be the intended driver I would re-weld like NOHOME said.

Patrick GRM+ Memberand MegaDork
4/25/23 6:07 p.m.

Booty. I'm not driving it in any situation where I may need the cage to do its job

if I was expected to pay for that I'd be raising hell

they may be fine strucurally but anything that ugly is getting lots of scrutiny from tech, and if the person couldn't be bothered to clean the joints first, which is obvious, who knows how decent a welder they are or if they even know how to set up a machine

I'm on one today, so feel free to show them my comments. 

Not pretty, penetration looks decent, I see a little undercutting here and there.  If I ran a shop that made cages, I'd want better welders than whoever did this.  Agree that gussets would be a great idea.

Rodan SuperDork
4/25/23 7:27 p.m.

Agree with others that most of it is probably sound structurally, but I would be pretty upset if I was paying for professional TIG work and it looked like that.  I've seen nicer looking MIG work on a cage...

DocRob Reader
4/25/23 7:33 p.m.

To be brutally honest, I would not pay for this work, because it isn't done. Not just done right, the job isn't complete. A proper setup with TIG requires prepping the weld area to ensure clean welds without oxidation of the weld. The prep wasn't done here. If the prep wasn't done, the job wasn't done. 

Maybe the penetration is okay. But the weld is dirty and a dirty TIG weld is long-term likely to be a weak(er) weld than a dirty ARC or MIG weld. Visible oxidation of the bead is bad news for TIG, because non-visible oxidation lurks below. A dirty TIG weld is certainly weaker than a clean TIG weld.

Finally, just to be a bit tongue-in-cheek if I want mediocre TIG welds on my roll cage, I could do it at home. We probably all can do this well with a scratch start inverter TIG and a bottle of Argon. These beads look about like my first beads with that same setup. 

wvumtnbkr GRM+ Memberand PowerDork
4/25/23 8:37 p.m.

Ooph.  Looks like it undercut and minimized wall thickness in several spots.


My first impression was that they didn't even clean the joints well enough for mig.


That E36 M3 is ugly and I'd be cutting it out (coming from a guy who Mig welded several bars in my racecar cage).  It's also weird in that some of the spots that are easiest to get to are the worst.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
4/25/23 9:18 p.m.

This car will be autocrossed and occasionally see a time trial with COM or other groups in the New England area. No fender to fender racing, no hillclimbs.

I did not pay for this. A friend offered to do it for me. He's a great friend. An older gentleman who helps out whenever he can. I didn't realize, having never Tigged myself, just how difficult it is. I feel bad, cause he meant well. I was actually surprised. When I think back it seemed like he was treating the TIG like a gas welder in many ways. But he's only ever used Tig or gas welding (brazing). Never MIG.

I'm really torn about how to move forward and not offend him. He's done so much for me over the last decade plus.

L5wolvesf Dork
4/25/23 9:54 p.m.

How much does the VW weigh? 1.5 inch seems a bit small. 

If you are going to be on a road course racing or time trials don't matter. If your car goes off at speed you need the best protection you can put in the car.

Its nice of your friend to help but it really does not seem to be good enough. I can't help with the what or how to tell him except remain honest. 

wvumtnbkr GRM+ Memberand PowerDork
4/26/23 6:21 a.m.

Gussets would help a great deal towards making that safer.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
4/26/23 8:36 a.m.

In reply to L5wolvesf :

weighs just under 2000 lbs. the diameter and wall thickness is what was recommended by Autopower

Peabody MegaDork
4/26/23 8:40 a.m.

1.5" diameter, .120" wall is overkill. It's ugly, but it should be plenty strong.

I have no idea why someone would tig that. It should have been mig welded

Toyman! GRM+ Memberand MegaDork
4/26/23 8:59 a.m.

I would agree, he's treating his tig machine like a brazing setup. Unfortunately, tig doesn't flow like braze does so he needed to stack his welds closer. 

Welding a cage is hard. It's like building a jungle gym while you are trying to climb on, under, and through it. 10% of the time you are trying to weld in locations you almost can't see. I can't imagine trying to tig one. I always mig them. If I was going to tig one, I'd probably cut the roof off the car so I could build the cage in the open and then install it. 

For the events you plan to run, it's probably fine. For anything else, I would probably want to replace it. 


DocRob Reader
4/26/23 9:39 a.m.

It sounds like TIG was what was handy. And to be honest, if you've done a lot of gas torch welding/brazing TIG is actually pretty easy to pick up. But of course, you can't treat it like gas, you have to clean the workspace much better.

I might dig a little deeper and grind away at a couple of the sketchier looking welds with a die grinder, to make sure there are not voids or pockets in them. If they look good maybe just clean them up a bit with the die grinder, add some gussets (with a MIG welder) and paint the whole thing. 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
4/26/23 9:41 a.m.
vwcorvette (Forum Supporter) said:

I did not pay for this. A friend offered to do it for me. He's a great friend. An older gentleman who helps out whenever he can. I didn't realize, having never Tigged myself, just how difficult it is. I feel bad, cause he meant well. I was actually surprised. When I think back it seemed like he was treating the TIG like a gas welder in many ways. But he's only ever used Tig or gas welding (brazing). Never MIG.

I'm really torn about how to move forward and not offend him. He's done so much for me over the last decade plus.

Since you have a good relationship and you're concerned with protecting that relationship, i would simply ask if he could go over a few areas of concern, and point to specific sections of a rule book esp re undercut and cleanliness.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
4/26/23 11:19 a.m.

In reply to AngryCorvair (Forum Supporter) :

Well, I have the car at home now. I told him I'd have someone else finish weld it with gas mig. Does that seem reasonable? Tough part is finding someone willing to finish it.

lotusseven7 (Forum Supporter)
lotusseven7 (Forum Supporter) Dork
4/26/23 7:06 p.m.

Clean everything before making a second attempt. 

SV reX
SV reX MegaDork
4/26/23 7:20 p.m.

I don't inspect car welds, but I am more familiar with structural welding on a building. 

Those welds would be rejected on my job site. There are voids and undercuts (which indicate they weren't prepped well), and welding inspectors would say they are not able to inspect welds that have not been cleaned at completion.  

They would also reject them because some of the welding was done downhill, and there is no ASTM testing standard for downhill structural welding (this may be completely irrelevant on a cage, but it is definitely a thing in structural welding).  

Structural welding would also not permit welding over the old welds.  They'd have to be ground out and started again.

Your plan with him is a good one. Keep it pleasant, and be thankful for his help. Pay someone else to clean it up a bit.

bigeyedfish Reader
4/28/23 3:03 p.m.

I agree with almost all of that.  While there is no prequalified downhill procedure for structural, you can absolutely qualify a procedure through testing the welder and the procedure itself.  We welded all kinds of D1.1 work downhill at my previous job and it was all code compliant.

The arc strikes are a little concerning since they can't really be repaired.  I would assume this was welded with a scratch start rig.  No problem with that, but it is more difficult to do well, especially out of position.

SV reX
SV reX MegaDork
4/29/23 9:41 a.m.

In reply to bigeyedfish :

The only downhill weld that is approved per D1.1 is a cover pass, and that can only be done after it is inspected.

Theoretically you are correct. There is no pre-approved procedure, but a welder and procedure could be submitted for approval.  So if someone wanted to create a coupon, submit it, spend tens of thousands of dollars to get it tested and approved, it would be ok. Except it hasn't happened.

Im not saying you can't weld downhill.  I'm saying there is not a D1.1 approved procedure, and third party inspectors will reject the work if they see it.

dean1484 GRM+ Memberand MegaDork
4/29/23 10:19 a.m.

I can weld better than that and I consider my self to be not that great at welding.  

Lack of prep tells me there is a lack of giving a E36 M3 about their work. The last thing I want is a cadge that was assembled by someone that did not care.  

EDIT:   People often complain about the cost to have a cadge welded in. Structural welding is a skill that is worth paying for. Anyone can weld a intake together. Welding together a custom a-arm is a whole different level. I put cadge welding on the same level.  

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
4/30/23 12:30 p.m.

Cage is removed. Considering my options. Lesson learned.

bigeyedfish Reader
5/1/23 9:41 a.m.

In reply to SV reX :

If you're welding in the field, it probably isn't worth the effort unless you come across the same set up all the time.  If you are in a shop where you can control  variables, downhill procedures can pay for themselves very quickly.  Downhill welding is quite a bit faster than uphill, but it is also less forgiving.  It's a good tool to have in the toolbox.

As I mentioned, I worked in a shop that did it everyday in compliance with D1.1.  Inspectors were in the shop everyday, and they never had an issue with the procedures.  We had QC issues from time to time just like any other shop, but never rejection of procedures.

Qualifying a procedure is not difficult.  I've been involved with it in D1.1 and D1.5.  I've never been around it myself, but lots of pipe is welded downhill too.  I'm not looking to argue.  I just wanted to share in case this could make your work or anyone else's work easier and/or more profitable.

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