Floor pan repair question, To drill the spot welds or not Options

[Bartlett 914]

I am in the process of replacing the floor pans. I have the car on a rotissiere. I can drill out the spot welds with my Blair spot weld cutter. This is still a lot of work and my elbow is protesting. What if I were to cut the pans out but leaving the strips of metal where the spot welds are and weld the pans ofer the top. Is this ill advised? My thoughts were to save time and maybe more metal is better. Less chance of weaking the long with welding heat.

[rick 918-S]

In the body shop leaving the strip of metal is a widely accepted production method for changing large panels like quarter panels and roof skins. I must have done 100 or more rolled over Broncos like that. This allows the factory integrity to remain while changing the damaged panel.

The concern would be, that with a floor pan you may have hidden rust between the layers of metal. Also, because there is added stress by passanger weight and vehicle dynamics, there would be a concern that the new pan would only be attached in places to the left over strip of floor pan and not the structure.

I wouldn't be overly concerned about it. Just examine the areas between the spot welds. If they are bulging from rust, remove that section and clean up the rust.

Another method of removing spot welds I use is to identify where they are by tapping (gently as nt to damage the part you want to save) a sharped standard screw driver between the panel being removed (in this case the floor pan) and the structure beind saved. This caused a bulge around the spot weld. You can then take a 4" cut off tool or die grinder and surgically grind away at the spot weld until the metal is thin. I do a row of them and come back with either an air chisel, (mostly I just use a sharped standard screw driver it's neater and less damaging) or a sharped screw driver and slice the old panel off the body. This mostly leaves a small bump from the left over spot weld you simply finish grind while preparing the the surface to accept the new floor. After you get the hang of it, this method is faster than the spot weld drill and far less damaging. Actually I haven't used a spot weld drill for 20 years. Oh ya, and it's easier on the body!

In restoration work I always remove the strip but never use the Blair tool.

[Johny Blackstain]

In the body shop leaving the strip of metal is a widely accepted production method for changing large panels like quarter panels and roof skins. I must have done 100 or more rolled over Broncos like that. This allows the factory integrity to remain while changing the damaged panel.

The concern would be, that with a floor pan you may have hidden rust between the layers of metal. Also, because there is added stress by passanger weight and vehicle dynamics, there would be a concern that the new pan would only be attached in places to the left over strip of floor pan and not the structure.

I wouldn't be overly concerned about it. Just examine the areas between the spot welds. If they are bulging from rust, remove that section and clean up the rust.

Another method of removing spot welds I use is to identify where they are by tapping (gently as nt to damage the part you want to save) a sharped standard screw driver between the panel being removed (in this case the floor pan) and the structure beind saved. This caused a bulge around the spot weld. You can then take a 4" cut off tool or die grinder and surgically grind away at the spot weld until the metal is thin. I do a row of them and come back with either an air chisel, (mostly I just use a sharped standard screw driver it's neater and less damaging) or a sharped screw driver and slice the old panel off the body. This mostly leaves a small bump from the left over spot weld you simply finish grind while preparing the the surface to accept the new floor. After you get the hang of it, this method is faster than the spot weld drill and far less damaging. Actually I haven't used a spot weld drill for 20 years. Oh ya, and it's easier on the body!

In restoration work I always remove the strip but never use the Blair tool.

(IMG:style_emoticons/default/agree.gif) , especially about hidden rust in the seams. (IMG:style_emoticons/default/cool_shades.gif)