I have a 66 Malibu Convertible, of which I am in the process of installing Quarter Skins, so far I have cut the original quarter back to about 3 inches below the body/style line. My plan is to trim the replacement skins to about 2 inches below the body/style line and thus leave a 1 inch overlap after mig welding. My question is this: Do you recommend just simply laying the new skin over the old and spot weld in place or should I use a "flange tool" which I see are available from Eastwood Company among others. The flange tool is new to me but would possibly reduce the grinding and body filling at the joint. Any suggestions or advice on this? Of course if there is no distinct advantage then I will proceed without the extra cost of the tool.
Thanks in advance.
Brian

I am no expert, but I did weld new quarters on both sides of my 65. I also bought a 69 that had new quarters installed as you propose, the overlap, weld on top method. Here is my take.
Don't overlap and weld on top as it creates a one inch or more overlap of metal that will trap moisture, cause later rust, which will push up the body filler you need to level the area off. This is occurring on my 69 unfortunately.
Using the flanging tool is better in that the overlap is minimal and the filler needed to make the area flat is much less. But you still lay one metal on the other which will trap moisture and it will push up eventually as rust.
The best method is to butt weld the new quartet to the old. There is no overlap of metal and when the back side of the butt weld is covered with seam sealer, you minimze the potential for rust on the weld line.
70isfine, a poster on this site in the past, has excellent photos of how to cut and butt weld the quarters. Email him.
Basically proceed as follows. With the new quarter laying on the old, use an air body saw or thin cutoff wheel to lay against the new panel and cut the old panel. After cutting the old panel exactly alongside the new one for about 6 inches, stop, push the new pane down level with the old and tack weld it. The gap caused by the air saw blade or cutoff wheel is about right to enable a good tack weld. Then cut another six inches along the new panel. Stop, push the new panel down level with the old, tack and proceed to cut and tack the new panel in place. After the cut and tack weld, you will have the overlapping metal on the backside fall away. Proceed to butt weld the joint and brush seam sealer on the rear of joint. Once you see 70isfine photos the above will become easy to understand.

Thanks, I looked up 70isfine and his posts - the pics link did not open anymore (I think it is too old), I sent him an email.
Butt-welding sounds like a good way to do it, I only have a 3 inch cutoff wheel, I don't know if that will heat up the metal too much or not when cutting.
Thanks again for your reply.

to make the cut, how about putting a tiny cutoff wheel on a die grinder, lots of people do that. Use a 3M cutoff wheel, green, as all the rest turn to dust too quickly. A jig saw might work with patience, as the blade would leave a gap just about right for butt welding. Not sure if the gap created by the 3 inch wheel will be too big, but usually you can narrow the gap by pushing up on the new panel so it is closer to the old one. Maybe experiment on an old car hood, door skin, etc. to get the feel for grafting a new piece of metal to an old one, after you see 70isfine photos.

The gap left by a cutoff wheel is too big for a butt weld. Yes it can be done but a thinner gap is better. Think about it, the GAP would be BIGGER then the metal thickness that you are welding!!!

An air saw makes a perfect gap for buttwelding IMO. Mine is a IR 429 I bought it for around 100 bucks right from the local parts supplier(NAPA).
Looking at the June issue of Eastwood's in the catalog on page 50 is an air saw. Its 56 bucks, part number 43377.

Not only will it make butt welding easier but it cuts faster and smoother as well.

I agree that an airsaw does the best cut for butt welding, as that is what I used. It is a great tool and a good investment if you are going to do sheet metal rust repairs.
In my description above on how to graft the new skin to the old, I forgot to mention that you should screw the new skin to the old one with sheet metal screws, say 2 or 3 feet apart. After you make the entire cut and have the tack welds in place you remove the screws and weld up the hole.

Thanks for the advice, I am shopping for an air saw right now.
What do you think is the best way to attach the new skin in the area where the new skin meets the rear portion of the rocker panel, just in front of the rear wheel? I left about 1 inch of the original quarter there when I cut it off, just in case I needed to weld it to the skin. Right now, I plan to lay the new skin underneath the 1 inch strip (original qtr) and weld. Does that sound like it would be OK or should I totally remove the original metal and somehow tack weld the new skin to the inside top of the rocker, by going through the interior side to weld it down. I just don't want to leave a bulge spot like I would get with a normal overlap. What do bodyshops do?

One more question, do you think an electric recipricating saw would do the trick or do I need to buy an air powered saber saw? I already have the electric and if that would work, I can save myself a few bucks. What does the air powered saw do that the electric doesn't? Perhaps the stroke of the electric is too much, or not enough rpm's?

Not sure about the answer to your first Q. An overlap is likely inevitable given that the quarter skins don't fold under themselves like a NOS panel would.
The electric reciprocating saw will definately cut the old panel, as that is how I removed alot of my old quarter. But it will be a rough cut I expect due to the long stroke. Practise on an old hood or quarter at a boneyard to see.

Eric may jump in here soon. He recommended using the new adhesives to attach lapped panels when I was doing another project. I have not done it yet but I plan to with a quarter I need to replace on the 70.

If you have access from the backside and the quarter is made so the flange is like OE quarter I would fully remove old panel and weld new one to the rocker.

Professor, this just came to mind. I remember you looking for patch panels for a mid 90's sub, but had no luck. I just got the new Classic Industries catalog, on page 437 they offer 88-98 front door lower section. Part number T70147 for the left and T70148 for the right. They are 8" tall and cost 24 bucks a piece