Where should I make my cut on these rust replacement panels?

[BonesDT]

MIG welding in new cab corners & rocker panels. Where are the ideal places to make my cuts?

For the cab corner, I have the choice of cutting right on the bend or on the flat part. Stacey David once taught me that you should avoid MIG welding on a flat visible body panel as it will show through the paint in the sun (something scientific about different expansion rates).

For the rocker panel, should I cut right down the middle of the nice flat sill, or should I cut on a bend? I could also use the whole height of the rocker panel which would save me a lot of welding, but I know you are supposed to avoid using more replacement panel than you need. Also the very top flange of the rocker panel is a little off from OEM.

Also, there is an overlap between the replacement cab corner & rocker. Where's the best place to join these?

Thanks

 

[BonesDT]

Replacement panels:

 

[MONMIX]

Stacey David once taught me that you should avoid MIG welding on a flat visible body panel as it will show through the paint in the sun (something scientific about different expansion rates).


Thanks

I have no clue what he is talking about there. Once you weld it up you will be covering it with body filler which you can not see through. I have been doing this for years and the joints have never been visible.

On the dog leg I would weld it ABOVE the two body lines to save you the trouble of cutting them back in again. Plus in the flat area it makes it way easier to smooth every thing together.

The rest of the rocker I would replace the whole thing. There is no reason what so ever to NOT use the whole replacement panel. Grind out the spot welds in the pinch weld. WAY cleaner job, WAY easier WAY faster and WAY better results.

BTW it looks to me like you dont even need the other panel. The rocker does both.

If you need any more help let me know.

 

[BonesDT]

I have no clue what he is talking about there. Once you weld it up you will be covering it with body filler which you can not see through. I have been doing this for years and the joints have never been visible.

I found the source (you can skip to 0:50):

 

[BonesDT]

On the dog leg I would weld it ABOVE the two body lines to save you the trouble of cutting them back in again.

Not sure what you mean by this.

BTW it looks to me like you dont even need the other panel. The rocker does both.

I definitely need both. The rocker only has the front half of the cab corner. The cab corner panel wraps around the back of the cab.

 

[MONMIX]

I found the source (you can skip to 0:50):

Okay I understand.
He is referring to a long splice. The dog leg is not a long splice.
Either way I would disagree. You make for MUCH more body work by working into the body line like that.

He also seems to be talking about not using body filler which you need to be a seriously bad arse welder and metal worker to accomplish that.

Lets make sure we are on the same page on this. You WILL be using body filler to do this job. It is just about the only way you will accomplish any thing and that is with zero disrespect intended.

 

[MONMIX]

Not sure what you mean by this.

On photograph 1 of your post. You drew two lines and above those two lines are two body lines on the existing panel of the truck. I would splice the replacement panel as high above those two body lines as I can.

I definitely need both. The rocker only has the front half of the cab corner. The cab corner panel wraps around the back of the cab.

Okay looking closer at the photo of the replacement parts I understand what you mean.

What an effing PITA. I would replace the dog leg with zero cutting and modification to the replacement panel.

The rocker I would find a happy area some where in the middle.

 

[BonesDT]

On photograph 1 of your post. You drew two lines and above those two lines are two body lines on the existing panel of the truck. I would splice the replacement panel as high above those two body lines as I can.

I just realized where you are talking about will eventually be covered by a decal, so that perfectly takes care of that.

However, I'm just curious why you say to cut so high, what is the advantage of going above the body lines instead of below?

 

[MONMIX]

However, I'm just curious why you say to cut so high, what is the advantage of going above the body lines instead of below?

three reasons.
1) More room to work.
2) Its WAY easier to cut an out side line in body filler than an inside line.
3) You are getting way out of the rust area.

One thing he didnt talk about in the video is a backing plate. When I do my replacement panels I butt the joints with a backing plate.
A few self taping sheet metal screws hold every thing together.
Like he said a tac every three inches or so then do several short beads spacing them apart.