For years these quarter panel has driven me nuts. I knew there were mounds of rust someone had fixed with bondo and that the putty had broken down

I went to yard and cut a replacement. I have a DEWALT 18VDC Sawzall and sometimes I think it could cut through a panzer tank!

TONIGHT I got all excited by this Forum and decided to fix it once and for all

I cut it open and I guess I was right, it was 99.9 % rotted steel

Evidence

More evidence.

Theres the killer DEWALT.Couldnt believe how tough it was.

A little day dreaming and fit up. It will take me some 3 days before I get a good fit up--lots of grinding, filing, and fit up

Thats my last pic. I dont think I have the ability or experience to butt weld.
Please HELP.

Thank you
Respectfully
Carrameow

I would recommend trying to find some pieces of fender metal that you can practice welding until you get it right. Only then do you want to start on your fender. You will need to get the rust/paint off of the sections that you are going to be welding too.

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Jim

If you are chicken, you could use Fusor 108B 2 part epoxy. That is my plan -I have one of those (worse) to do someday.

Rick

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

i have a lil bit of rust in that same spot.. i need to get some por-15 and just cover it up ... before it spreads

when you do decide to weld it , make MANY small tacks working your way around. if you start trying to run beads you will be banging your head. be prepared to do some hammering and pulling when done, more than likley the metal will warp. what size wire are you using?

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have no worries.....President Obama swears "If you like your gun, you can keep it

I agree use the recommended sized wire for whatever gauge steel that the fender is (I'm guessing around 18 ga). Practice, practice, practice. I'm a certified tig and mig welder and lots of very small tacks is the right way to do it. In a butt weld that size you may have a few hundred tacks with no bead. Butt welding old sheet metal is like painting in that your prep, and post work is much more time than the actual welding. Just a heads up, when you apply a weld the metal tends to be pulled up or shrink in that area. As you weld try to think about spreading out this controlled warpage to make your hammer and dolly (invest in a good set) work easier later. Also to clean up the area a good body file is the way to go. It takes forever but a grinder puts a lot of heat into the metal and can actually warp a panel worse than your weld (if it's a careful weld).

Good luck and kudos to keeping that baby rust free
Dan Ferrier

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'78 300D 85,000 original miles drive her daily

That looks familiar. I've got that project on my to do list too. I have the patch panel, but have yet to put saw to car. I second the tack suggestion. Also try using wet rags to keep the metal cool. If you don't want to do it your self you could take it to a pro. You have done the time consuming part.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

What size do you recommend? I have sevral sizes!!

i would go with .025 unless you have smaller . i would imagine thats the smallest wire your machine runs, as does mine. you can also buy stick on heat sink to get rid of some of the heat. as mentioned above with the rags.
belive me it will be very time consuming. you may also try in your practice welds turning up the gas flow a little. since you are not making structural welds you could probly weld a little cooler and have no side affects. (try it with some scrap first)

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have no worries.....President Obama swears "If you like your gun, you can keep it

Or he could also use what this guy used.
http://www.msdra.com/benzwagon.htm
Click the link then find the picture in the link below.
Read the comment he added on the 3M glue.
http://www.msdra.com/old/85lroutfix06.jpg

I think he said 3M glue?

Louis.

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Not always the smartest but certainly not dumb?

What sort of welder do you have? I know many manufacturers have manuals and tech sheets available online. I would go with the recommended size for 18 ga. The way I see it whoever built your welder knows way more about welding than you or I and so the data sheets are a good place to start.

I can try and help find some data if I know what kind (or size) welder you have. Good luck and make sure you post pictures when you're done!

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'78 300D 85,000 original miles drive her daily

Carrameow,
As most have said..practice.. practive.. practice. Mig welding is really the simplist form of welding once you get a technique down. You need to get use to working with a welding mask on while keeping everything lined up.
I have done a few restorations...The last one was the Austin Mini which I used nothing more than a Craftman Mig Welder with .030 Flux Wire (no gas) to do spot and bead welds.
Maiting surfaces have to be rust free...ground or filed shiny clean!
Old appliances like stoves, refrigerators, computer casings are a great source of 18 guage steel....and its actually better quality than whats used on the cars. I mention this because it looks like, in your pictures you will need to fabricate some new maiting surfaces / flanges for the new panel to weld to. Be creative!...don't be intimidated.... Steel is great to work with!

Grab a book from the Library on welding...you will probably learn more technique from a little reading than from a few tips on this board. I always give myself a refresher course and practice welding before I tackle a new project.

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FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K

Oh, the worst thing you could do is make it look like just standard old OEM Mercedes! C'mon, where be your style? Don't you wear your pants and your hat backward?

Then set a new heapo-thug style with pop rivits down the side......



Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles