frame guessting

[fabr]

Look, it breaks down like this:
Im a first time builder, in my garage with barely enough money to piece together a buggy and barely stay married in the process. Those notch drop pieces are free and they fit into the intersection of 2 tubes where they meet pretty well. 90 degree works well, even shallower and steeper angles will accept these little scrap pieces. I disagree with anyone who says these to not add strength. Firstly, none of you can scientificly prove otherwise, so right, there---end of discussion already. But I'll bite. One of you (please be mstrfabr) try and prove otherwise. Who said the welding made it weaker?? You sir might be mentally challenged . My tube is 1.516 dia. Some quick pi gives me 4.76265044 inches of weld all the way around the circum of tube. (I can explain for the special people who don't know 6th grade math) lets say an average "scrap gusset" that I use only utilizes a 1/4 of it's circumference. Lets just call it an inch for aguements sake. 2 gussets on either side of a 90 degree intersection, that would be 1 inch of additional weld bead on one side of the gusset and another on the other side, for 2 inches of additional bead for 1 gusset. So add 2 more incehs from the gusset on the other side and thats 4 additional inches of weld bead holding those tubes together. (Yes is sort looks like ass, or at the very least not what everyone is used to) so when you take the 4.75 inches of weld on the intersection itself and add another 4 inches that 8.73 inches of weld.

Uneeded? Unproveable. And you Wyatt...Dont be my buddy on one forum and then talk smack behind my back on another...follower. 

OK,I'm bored ,the GD thread finally got buried .    Anyway I gotta try to explain why a well coped joint is as strong as you can get. You can make a weld joint stiffer with gussets but not stronger than a well coped tube joint. The simple way to look at it is that, as Glock said there is and using 1" tube for simplicity,3.14 inches of circumference but a properly coped joint will have in the area of 3.5 inches of weld bead due to the longer length of the coped profile. So the weld joint,properly coped and competently welded will actually be stronger than the surrounding tube due to being a longer weld than tube diameter. Therefore the tube is the weak link and why welds usually fail in the surrounding HAZ instead of the bead itself . That's why you rarely see gussets in cages in modern cage design. Triangulation and avoiding dead tube runs serves the purpose much better.

[sandycrack]

Just my .02 here and definately not a to be considered anything but a hack.  I have to agree with Faber on the following:
"There is evidence tho that suggests  gusseting like that will actually increase the likelihood of the tube failing where the gussrt ends and the tube begins to bear the full load due to concentrating loads in the tube itself instead of the joint." 
To me the the load bearing section of the tubing will be moved away from the joint toward the added material depending on the direction of the force.  Good luck on the build and welcome!

[Carlriddle]

Hopfully he will pop back in and post up a build log.  Hes got some slick ideas that will be incorporated into his build.  He's at the 2 steps back 1 step forward point that many give up at.  And still as enthusiastic as every.

[Wyattboche]

I had to get a dang membership here just stick up for myself.

What I never had to pay to get on here. Is this something new?

[SPEC]

No regular membership is free
Just whining cuz he has to be a member to post
Just like any other fooken forum

[Wyattboche]

Have a question about frame welding. Is it a good or bad idea to TIG weld a frame? Or is it better (for penetration) to weld with MIG?

[Nutz4sand]

Have a question about frame welding. Is it a good or bad idea to TIG weld a frame? Or is it better (for penetration) to weld with MIG?

Either is fine if you know how to use them. Heck even Stick COULD be used.

Tig DOES tend to look better (it offers a bit more control) if the operator is of a steady hand but a really good mig welder can lay in some keen looking welds.

[WelderPat]

Have a question about frame welding. Is it a good or bad idea to TIG weld a frame? Or is it better (for penetration) to weld with MIG?

 Wichever process you are most familiar with is the best one for you to do your frame with.
Either one is plenty good.
 As far as gussets if you need them to hold your frame together you lost the rabbit a long time ago.
If you have the right size tubing the right design and it is welded correctly gussets ad nothing but time and weight to the build.

[BDKW1]

As far as gussets if you need them to hold your frame together you lost the rabbit a long time ago.
If you have the right size tubing the right design and it is welded correctly gussets ad nothing but time and weight to the build.

Yup....... Also, if your building an all out performance race chassis, a TIG chassis will be lighter than a MIG chassis by several pounds on a little car. An IMSA GTP chassis was 15 pounds lighter TIG'ed..........

[BDKW1]

All of the FEA in the world won't prove anything.  It's applied force in one direction.  It doesn't take into consideration what has happened to the material in a molecular sense.  All of that heat input in that small of an area only to shorten the distance most forces would act on it by a couple of inches, is not only a waste of welding rod/ wire, but unnecessary weight, and is likely just making the area more brittle do to the HAZ.

FEA can be set up with force vectors in many directions. You need a SERIOUS computer to run these simulations though. It works much better for cast or machined parts. Weldments throw way to many variables and unknowns into the mix. With out accurate set-up info all you will get out of it is a pretty picture...........

[Wyattboche]

Wichever process you are most familiar with is the best one for you to do your frame with.
Either one is plenty good.
 

I'm not welding the chassis. Having it made at our race shop by the owners dad, who is certified welder.