mike was probably referring to welding the lap joint (where you spliced into the remnant metal) on both sides so you don't have an open flange. twice the welding but does ensure a stronger joint. i did this method on my transition pan and it turned out to be a whole lot more work. of course i was concerned about looks on both sides (top/bottom). if your not concerned about looks or finish grinding, then this by far be the easiest. however it's one less opportunity to learn to butt weld in my opinion. but then again, if it's one of your first times you have welded, a butt weld on a large floor pan my cause you enough frustration that you may be hesitant to finish the job.

 

I welded the underside for strength as well as I was finishing it off to look original.When I put my floor pans in, complete floor assembies were not available and I really could have used one.Of course they came out about 6 months after I finished the floor.

 

Copper is a heat sink when welding, in other words weld won't stick to it. You place this on the back side of a panel when you fill a hole or want to prevent blow thru. There's also a vice-grip version. As for the 1/4" vs 3/8" plug weld....when welding you'll find the panel on each side of the weld wants to pull up once it cools: warping. This is caused by heat, and over heating increases this effect. I found by decreasing the size of the plug, and increasing the number of plugs helps to prevent the warping. As you get better at welding, increasing to a 3/8 plug won't be a problem.

 

I have an old copper hammer that I hold in behind holes when I am welding them. It works great. It is a neat old bodyman trick that a lot of people don't know about.

 

There is a airtool that has a punch for plug welds as well as flang crimp tool for lapwelds.

 

Magnets....those big magnets work really well too. Use them to hold sections together while you weld.

 

just don't get those magnets too close to where you are welding, or it will screw with your welding wire.

 

Sorry, haborfreight, some one prolly makes a better1. I just knew i saw it on ther site.


http://www.harborfreight.com/cpi/cta...temnumber=1110