What is the best method?

[Fat Mike]

I am going to build the rear section of my frame with 2x6 tubing and want to know other than the butt joint weld, is it okay to do a fish plate on the inside of the two piece with a rosette weld. then weld the butt joint solid. then finish by boxing in that section of the frame to the existing frame.

[Tchia65]

On something like that I would "V" the joint so the weld finished flush and then fish plate.

[Fat Mike]

Fish plate on the inside or outside. I want it to look like it came that way.

[Tchia65]

If you're doing a whole new back frame and you have a big enough welder with proper penetration there isn't much need to plate anything. I like to "V" the joints because in ensures penetration and the end result is smooth frame. I just boxed my stock frame and the only thing I plated was my step notch due to it's size. I'm setting my truck up to sit on the rockers.

[troy54gmc]

Hey Mike im in the process of building the back half of my 54 with 2x6 tubing. i went with the v joint myself purely for strength and penetration. i also plan on fish plating on the inside just for added strength and piece of mind. so far it seems to be working. the hard part was getting the angles right on the notch so everything lined up correctly. here r some picts. i think u might have seen these allready. good luck. post some picts. on ur progress. Troy

[cajundragger]

you got the right idea.

miter all your joints, internal fish plates, bevel all welded edges prior to welding so when you clean everything up you have great prenetration, and box the new tube into the existing frame.

[BlueJeep]

Originally Posted by Tchia65

If you're doing a whole new back frame and you have a big enough welder with proper penetration there isn't much need to plate anything. I like to "V" the joints because in ensures penetration and the end result is smooth frame.

I agree, the only thing I would add is that you must be a competent welder. This is 2x4x.120 wall and welded with NO fish plates. It's seen a lot of abuse with no fatigue.