I'm having some trouble picturing how to weld patch panels on. I've never picked up a welding gun in my life, and I'm not about to try until I can at least picture the process in my head, and so far I can't. I've got Hayne's Welding Manual and Auto Body Repairing and Refinishing by Toboldt and Richardson.

The part that puzzles me is that it says you should cut out the patch panel to the size you need and then cut out the bad panel with a 1" overlap to make a lap joint. The next sentence in the Toboldt and Richardson book confuses me: "Trim the replacement panel to fit along edges and around other stopping points."

Does that mean that the replacement panel should be trimmed to make butt joints? Or, really, if you need a lap joint, how do you get the patch flush with the rest of the panel? If you just overlap it, wouldn't it just look like a plate over a hole? Do you push it in so that it's flush with the rest of the panel? And, if so, do you need to perforate the corners so that the existing panel will not lose it's shape?

Like I said, I'm just trying to figure out if it's even worth it to get a MIG welder to practice with. I figure if I can't make sense of it in theory, then in reality, there's no way I could do it. Are there any websites with good pictures of the process - I figured two books would be enough. http://www.camaros.net/forum/smile.gif

Thanks for any help.

--Brad

Butt weld the patch panel. weld the seams completely unless some of the sections are spot welded from the factory. I think lapping a patch panel or tack welding it only is a Half-A$$ job. If you lap weld you'll need more filler to taper the metal smooth. Practice welding sheetmetal. It's not that easy. There's a lot of trick t prevent warpage. Weld one tack at a time. Hold an aluminum block to dissapiate heat, weld with an air nozzle to cool each tack, or pre-stretch the seam before welding, etc....

Butt joints are the best way to go, but for a beginner welder not the easiest. Eastwood cat. has a lap joint tool that makes a offset [about a 8th] to the piece that you are going to weld to. Practice is the best way to learn, mig with gas is easy, when you get the touch.

"Trim the replacement panel to fit along edges and around other stopping points."
I'll tell you what, I must be some ignorant moron, I have been doing this for 25 years, and don't have a clue what that line means! I assume making a butted seam, but I wouldn't stand on the witness stand and say it.

Anyway, I have to disagree with Allen. Lap welds under certain conditions are fine. I agree that butt welding is the way to go, but sometimes you have to lap weld just for the sake of convenience. It is much easier, so it would probably be the seam of choice for a beginer.

You can step the metal using a tool that Eastwood has (it is a vice grip what has a new jaw welded in)

One thing that I have to say is you probably won't need the whole patch panel, so plan on triming it down to just above the rust.

Go to http://www.autobodystore.com/cgi-bin/config.pl? and post this question, ask for Len (the site owner) to post his link to his "patch panel" page, it is very informative.

Allen, don't get me wrong, butt welding (and hammer welding) the patch is the "best" way to weld in the panel. But not the only way, sometimes you have to lap or it is just the "bestest-fastest" way on a particular project. http://www.camaros.net/forum/smile.gif

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Fan of anything that is interesting and moves human beings.
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
1948 Chevy PU with 401 Buick

? on the lap welds?? on the repair panel i received it has the top edge pre-lapped and the left and right edges with no lap. the way i look at it the lapped area is more so to get it lined up and started correctly to allow for a good butt weld in the other areas. is this correct?? the panels are the rear wheelhousings the quarter panel itself is great with the exception of the good old rusted out wheel houseing. cant see ripping off the quater when its nice and straight.

Hawaiian, your panel has a flange or step in it, not a "lap". The "lap" in "lap weld" refers to any weld that has one piece of metal "lapped" over the other.

I really don't think the way yours is set up means much other than "heres a start, have at it". I rarely use a patch panel as it comes, it is usually cut down quite a bit. Why cut that straight quarter any more than it needs? Your new panel should be just an inch or so above the rust, or where it is most convenient. For instance, if the rust was just an inch or two of the bottom of the 1/4 panel behind the wheel, you would have to go up much more than the inch I mentioned because of the fact that the trunk floor prevents you from getting behind the weld (on a first series that is). So you would need to go up above the floor.

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Fan of anything that is interesting and moves human beings.
1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
1948 Chevy PU with 401 Buick

MAHALO for the insight and setting me straingt was thinking about cutting the panel down but this will be my first try at this so ill do it like your stated. cut cout the rusted area +/- an inch and cut the panels down. Makes pretty good sence to me doing it that way. Also thanks for tuning me onto the correct terms on Lap VS Flanged .
Have a great weekend it.s a 3 day weekend here mondays a state holiday.
Again Thanks (Mahalo)

Thanks guys.

Looks like I've got to do a lot of work on the floors, so I think I'll get a MIG welder, practice on some scrap and then do little things, and things that won't show (like the floor pans). Maybe I'll try the quarters when I've had enough practice to feel comfortable. I'll try out the different types of joints, but the lap joint over the flange certainly sounds easiest. I'll just have to try and see.

--Brad

You definitely have your work cut out for you. Let me know how you do, I have a '73 Camaro I need to replace the same on. I got a great deal on a mig welder from Harbor Freight. You can weld with/without gas, just need to make sure you have the correct wire.

Make sure the wire is correct from reg wire to Flux wire. When you do switch thats not all you have to switch, on my welder you also have to reverse the terminals in side. Check your owners manuals and make sure you have all the electrical wires hooked up correctly as well Good to hear I am not the only one who will be welding this weekend http://www.camaros.net/forum/smile.gif

___ Jeff 68/69 RS's

Practice welding on scrap sheetmetal until you get the hang of it. It's not as easy as it seems unless you plan on using a lot of bondo to cover the warped panels.

Let me first say that "I am not a welder". I do have some projects in mind that require welding so I decided to sign up for night classes at a county college to learn the basics. I just wanted to respond to the issue of lap welding the floor pans. I thought this could create a ledge for debris and moisture to collect and promote rot. Isn't the preferred method a butt weld? Since this is one of my upcomming projects I am curious.

Hey Ray McCarthy,

That's why I butt weld almost everything and fully weld the panel unless it is factory spot welded or lapped.