Welding Tips and Tricks

Double post

Tried to polish it and etch it a little

Looks fused in pretty good to me.

The fusion appears to be focused on the bottom tube, and far less on the intersecting tube. And, you should try a few samples running hotter. Don't worry about blowing through, that's the job of the filler to make up and chill the puddle.

If you want to bash it with a hammer, lay it flat and bash the intersection, squashing the main tube. See if your welds hold up against the force in that direction. Then, weld on a longer section (18" for both) so you can hang a long lever and really apply some force. Short sections break less because of limit to leverage.

Maybe I'm a bit off base here, but I'm not liking this shown. I'd prefer to bevel the left member some and not have that seam left 100% untouched. In a situation where you can't get to the other side of the joint, I'd want that to penetrate all the way.

YMMV.

Oscar wrote:Looks fused in pretty good to me.

+1...nice penetration without any lack of fusion. Do measure the throat size to make sure it is adequate. if not, add another pass.

BugHunter wrote:Maybe I'm a bit off base here, but I'm not liking this shown. I'd prefer to bevel the left member some and not have that seam left 100% untouched. In a situation where you can't get to the other side of the joint, I'd want that to penetrate all the way.

YMMV.

I am not an engineer, but I believe if he has adequate throat size and a large enough bead, full penetration is not required.

https://www.lincolnelectric.com/en-us/s ... ation.aspx

BugHunter wrote:Maybe I'm a bit off base here, but I'm not liking this shown. I'd prefer to bevel the left member some and not have that seam left 100% untouched. In a situation where you can't get to the other side of the joint, I'd want that to penetrate all the way.

YMMV.

I’m with you. Good fillet but no root penetration. That would get you flagged on a weld test.

Louie1961 wrote:I am not an engineer, but I believe if he has adequate throat size and a large enough bead, full penetration is not required.

https://www.lincolnelectric.com/en-us/s ... ation.aspx

I don't know, I can look at two different sections of that page you linked and I could agree with you or me, depending upon what viewpoint I want to take. One of their examples shows fusion buried deep in the root and another one shows basically what the op posted in his picture. The bottom right of the very first picture shows an example of what I would try for if I was welding roll cage. Maybe full penetration isn't required because he's doing enough build up, like I say I might be off base here. But I know he can do it because the welds he showed on page 1 of this thread had better penetration than this last one. Yes, this last one looked prettier but I bet the ones earlier that were too hot were actually stronger.

I'm just thinking even if he chamfers 50% of the wall thickness, then welds at the heat he used on the last welds, and adds a little more filler, I think that would be closer to Ideal.

Then probably somebody will come along who knows roll cage welding inside and out and they will probably say that Overkill is actually a bad thing.

For most tubing assemblies, especially ones the size of roll cages, the needed strength is in the tubing itself and the design of the assembly. When over stressed, the tubing runs will buckle and fail long before the welds fail...even if the welds are just barely adequate. That's the nature of structural tubing and those coped joints. Of course, welds should always be their best, though. For any type of welding.

And unless you're burning holes or undercutting, you can't weld chromoly too hot. Keep in mind that for decades they welded it for aircraft using oxy-fuel exclusively. It wasn't until us TIG welders started having a go at it that "pretty" welds became more important than strong/efficient welds. If anyone wants to get back to the basics of making good welds on chromoly, I suggest watching some of those old oxy-fuel welding videos that still float around on youtube.

My only concern about the lack of root penetration would be that that sharp edge will be a focus point for stress, especially because of the vibrations and torque that a roll cage would see. Not immediate failure but probably the first place to stress crack.

Poland308 wrote:My only concern about the lack of root penetration would be that that sharp edge will be a focus point for stress, especially because of the vibrations and torque that a roll cage would see. Not immediate failure but probably the first place to stress crack.

That was exactly my thoughts was creating a weak area right there. Given the fact that it is tubing and there will be a complete circumferential Bond, it may not be a problem. I just figured since he has already demonstrated he can get rid of it, might be time to get rid of it. LOL

BugHunter wrote:

Poland308 wrote:My only concern about the lack of root penetration would be that that sharp edge will be a focus point for stress, especially because of the vibrations and torque that a roll cage would see. Not immediate failure but probably the first place to stress crack.

That was exactly my thoughts was creating a weak area right there. Given the fact that it is tubing and there will be a complete circumferential Bond, it may not be a problem. I just figured since he has already demonstrated he can get rid of it, might be time to get rid of it. LOL

You’re right, Bug. He needs better penetration in that joint. He upped his wire but ran too cold and the arc was pointed at the base not the root.

Keep practicing and improving!

I'm going to practice some more tonight. Been too busy with work the past few days. I'll try some more heat and better tip angle. After hammering the other test pieces to a pile of rubble I'm convinced the welds are strong. Now it's just a few more tweaks and build time. Bender is getting here today.

BugHunter wrote:

Poland308 wrote:My only concern about the lack of root penetration would be that that sharp edge will be a focus point for stress, especially because of the vibrations and torque that a roll cage would see. Not immediate failure but probably the first place to stress crack.

That was exactly my thoughts was creating a weak area right there. Given the fact that it is tubing and there will be a complete circumferential Bond, it may not be a problem. I just figured since he has already demonstrated he can get rid of it, might be time to get rid of it. LOL

A total weld like that is actually very susceptible to that kind of stress. That’s why you don’t bottom out pipe in a socket joint.

The build has begun.

Dash bar, intrusion bars and a pillar bar tacked in

Good luck with the build. Looks like fun!

C pillar bars fabbed up.

Should be done with fab work this weekend.

awesome

All the bars are fabbed. 80% of the welds are done. Need to take it off and weld the ones I couldn't get to. And after welding a few of the overhead bars I've determined overhead welding is a nightmare lol.

They aren't pretty but they seemed to have good penetration. The 4 corners where I attached the connectors I did 2 passes. Second pass I kind of zig zagged to get some more material on there.

Door bars all done. Now just lacking roof mount tabs and window net tabs.

Interesting. I can't say I've seen door bars like that before, are those safe? I imagine you are trusting a lot on the hinge components? I'm not in the off-road world so pardon my ignorance.