Quote Originally Posted by simontibbett View Post
You sure do talk a lot of crap to someone you don't know, I've stated engineering facts, if you're majoring in mechanical engineering I feel horrible for whatever school you go to and I am horrified of what job you may have when you graduate.

Tell my how the weld is stronger then the metal. I've never done this before and have never had a weld fail, I've never done this because it's common sense you just DON'T do it. No shop would even consider doing this.

Think of it this way, I break a plate in half, I glue it together down the middle, is the plate still strong? No.

I know I don't know everything about cars, but I do know a lot about chassis setup which in return means welding and structures. I know NOBODY in there right mind would cut a roll bar in half and weld it back like you mentioned, I also know nobody with real engineering knowledge actually just common sense would think this setup is safe.

You're the only one being an e-thug here.
First of all, i go to tech, so don't give me crap about my schooling.

as for the plate example you gave, there are all different types of bonds, different glues, some glue doesn't work on some material.

anyhow, in this case if the weld was done properly there's no problem. by properly i mean that if the weld was controlled and cooled at a certain rate (which a good welder can do, and i'm not saying this guy is a good welder b/c i don't know him) the grain boundary of the new metal (the welds) would be the same as the original grain boundary of the car metal. In this case it would have the same structural strength as before. The smaller the grain boundary, the more brittle, the larger the the grain boundaries the softer the material is. (I know that introducing new material into different metals can affect the softness and brittleness of it as well, but i don't think that's the case here) a good welder will know what kind of cooling rate certain metals need in order for the weld to not be too soft or too brittle. They will also know what kind of material they are working with.

I guarantee you that if this is done properly (said it now for the millionth time) that it will be just fine.

Now i just saw that this guy is using a mig welder, a tig would be ideal for the best control over the weld so i'll give you that one.
My whole point though is that this can be done, and it can be just as safe as before if its done properly, i'm not trying to sound like an ass, if i did my b.

what year are you in ME?