How to cut out rusted areas - Jeep CJ-8 Scrambler Forums

BLennon · #1 10-27-2009, 11:16 PM

This is probably a simple question... What is the best way to cut out the rusted sections of my scrambler that I'm planning on replacing with new sheet metal? These include a small part of a rocker panel, a few areas under the seats, and the bed. Are there multiple good ways? Because I might not have access to the best way.
Thanks for any advice

Randyzzz · #2 10-27-2009, 11:43 PM

I prefer an air body saw. They have extreme accuracy, don't use heat (or warp the metal) you can get them into corners, and they will cut sharp curves.

bigred1969 · #3 10-30-2009, 03:08 PM

A related question for those of you who have used replacement panels, do you recommend using butt welds or use a flange and overlap the sheet metal?

kohldad · #4 10-30-2009, 03:47 PM

Stephanie prefers a plasma cutter, it's still her favorite tool.

When you cut out, figure on going about 1" out from the obvious rust area. This should put you into clean metal. If you don't get to clean metal, you will waste more time trying to weld half rusted metal than you can imagine.

I prefer butt welds but have found that to get the best weld with the smoothest finish, you need to leave a 1/16" gap between the plates. This gives the weld a place to go yet allow you to grind almost smooth. If done right, you can weld in a new piece, have very little to grind away, yet have a tough joint.

I dislike over lapping replacement panels since it give the moisture a place to sneak into that can't be painted. IMHO, kind of defeates the purpose.

JeepScrambler · #5 10-30-2009, 03:48 PM

I always use butt welds, mainly because when done properly, it gives a finished look and you cannot tell a patch was ever installed. Plus, it does not allow another place for water and junk to get in and rust to start, like what can occur when using a flange if it isn't properly sealed. I always weld both sides of the butt weld joint and then grind/smooth the welds down till you cannot even tell a repair panel was installed. A butt weld does require a lot more time to get everything to fit right and to clean up the welds, but IMO, it is worth it in the end. I'm sure others do it differently but that is how I do my rust repair!

BOBCAT · #6 10-30-2009, 03:52 PM

Quote:

Originally Posted by bigred1969

A related question for those of you who have used replacement panels, do you recommend using butt welds or use a flange and overlap the sheet metal?

Kent, I sent you a PM.

Don

jeffs396 · #7 10-31-2009, 12:06 AM

Hey Bobby, you can use a high-speed die grinder with a thin cut-off wheel with great results also...I cut these ovals on the curved quarters of my HHR, just take your time! Butt welds for me also

BLennon · #8 10-31-2009, 12:24 AM

Thanks a lot for the help guys. I'm putting all my plans together on paper and in my head now and am planning on starting the grinding and stripping on paint and rust next week. I'm going to get it painted silver and hopefully it will look like a new jeep in about a month or so. I'll post pics and all the details when i'm done.

Bobby

idiot magnet · #9 11-07-2009, 07:21 AM

Quote:

Originally Posted by BLennon

Thanks a lot for the help guys. I'm putting all my plans together on paper and in my head now and am planning on starting the grinding and stripping on paint and rust next week. I'm going to get it painted silver and hopefully it will look like a new jeep in about a month or so. I'll post pics and all the details when i'm done.

Bobby

Harbor Freight has butt weld clamps that will leave a gap of 1/16" which is ideal for butt welding and they come in a package of 4 or 8. (I also grind those down to be a bit thinner if ned be) I've been restoring old Mustangs for years and using butt welds is the standard practice for all the floor, 1/4 panels, trunk floors etc. repairs to make them look like they just came from the factory. There are some tricks and one is using sheet metal screws to fasten down the replacement section then using a thin cut off wheel you cut the section you don't want plus extra to get to the good metal. Then using the new section that was cut at the same time as you cut out your old rusted piece, which will match the hole perfectly along with the correct size gap for a butt weld. Then clamp in place and use your mig to weld up the panel starting with spot welds that are 4 inches apart then add a spot weld between each of those keeping the heat to a minimum and continue around the patch panel until the gap is completely filled then grind your weld down and voila you have a repaired panel. Try out some test pieces so you get the welder set up just right, since you don't want any blow thru which is a pain to correct. Use a flapper disc for the final step for a nice even and smooth finish.
Good luck.

Alaska CJ8 · #10 11-12-2009, 08:26 PM

Awesome advice Bobby. Lot's of good ideas. I am about to embark on resurrecting a rust heap '82.

I am debating whether or not to take the body off the frame. I know all the repairs will be better if I do.

How much effort is it to remove the body and to re-install it?

I have a shop and can install an overhead lift. Seems like the body should weigh around 1000#?

BLennon · #11 11-12-2009, 08:41 PM

I'm not much help on that one. I don't have the space or experience to do it myself but have seen others do it and it seems to be worth the extra time and effort. I'm sure others here are experts on it.

CBRogers · #12 11-13-2009, 06:49 AM

Quote:

Originally Posted by Alaska CJ8

Awesome advice Bobby. Lot's of good ideas. I am about to embark on resurrecting a rust heap '82.

I am debating whether or not to take the body off the frame. I know all the repairs will be better if I do.

How much effort is it to remove the body and to re-install it?

I have a shop and can install an overhead lift. Seems like the body should weigh around 1000#?

There are only 10 ? Bolts. But it all depends on how easy they are to come out.

Once you get all of the extra junk off of the body it is only in the 250-400 pound range. 4 guys can easily move the tub of a scrambler. I have done it several times. You can set up saw horses with cross boards and lift one end at a time by you self and then roll frame out if you have too.

Once body is off of the frame, make some sort of cart to roll it around on. It will make it much easier to do body work and get to stuff as needed. Also if you can get a few buddies to help you can flip it over to do work on its side or bottom as required.

Carl

Pepper · #13 11-13-2009, 07:55 AM

If you pull the body, you can use a couple engine stands to make a rotisserie. I googled it and found this:
http://www.raysmg.com/rays_mg_midget_rotisserie.htm

Pepper · #14 11-13-2009, 07:59 AM

Here's another good one:

http://forums.hybridz.org/showthread.php?t=152566

Alaska CJ8 · #15 11-13-2009, 10:56 AM

Thanks for the tips. I have never done a car rebuild. I have built small wooden boats and have restored fiberglass boats but this is all new to me.

I'll head out and see about making a frame rotisserie.