Don't Tell Me What I Can't Do-with Photographs
 

Considering I'm embarking on one of the largest rust repair projects known to man(or at least the W123), I've decided to chronicle it here with pictures. I bought the car in April, 2008 for $1300 with ~245,000 miles on it. Mechanically sound. We weren't really looking at the rust and didn't know much about it, but I've come to find it has done extensive damage. Nothing structural, from what I can tell (car doesn't fall apart on bumpy roads), but it's nearing it. I've got a Lincoln Promig 130 MIG welder, a door and a fender for metal, angle grinder with attachments, and POR-15 paint and epoxy. I've been told by just about everyone that this isn't cost-effective (I've come to terms with that) and I've been told it can't be done. We can think of this as an experiment and hope for anyone else working on a project like this.

SO FAR: Repaired rotted jack panel with rust-free donor, patched surrounding rotted rocker panel with 22 guage to keep out water (temporary) and painted and installed factory-new front right fender.

CURRENTLY: Hole in trunk/rear left wheel well. Lesson: cut out ALL rust affected metal before butt-welding.

CURRENTLY:

you can do it all.. just requires time and money

time, patience and money and itll be fine

This aint much to deal with really---search up thethread of the red 450sl the guy in england decided to fix the rust On!!

Do you have a link to the thread? I can'd find it.

Mann they git crust over there.........

Is it better/easier to cut out a lot of metal and just use one big patch, or keep as much original metal as possible and use lots of little patches (as I'm doing). I've cut out all the rust affected metal, but I just don't want to lose any more original metal/shape than I have to.

It all depends. On a visual surface area it's always easier/better to do the one big panel (less seams, welds and fills) but in a hidden area the little fills sometimes work a lot better because of the access problems.

Finished job.

Tried to use bondo to make the outside look pretty: fail (no pic). That's gonna be redone. Did have to use a little bondo to seal up a hole I couldn't weld. Everything was coated in POR-15 and undercoated.

NEXT JOB: driver's side floor pan.

How long have you been welding? It's hard to tell from pictures, but in the last one it looks like your weld is too cold.

I've been attempting to weld with a stick welder for about 8 months or so. Never really could, so I bought the MIG maybe a month ago. The jack point was my first project, this one, my second. I have no formal training. I think they might be too cold. For 14 gauge, it says to put it on setting "C" I had it on "B" cause I kept blowing holes in "C" probably cause I didn't cut enough rust-affected metal away. It's not structural, so I'm not gonna worry about it.

Where did you get that nice looking jack hole in the second picture of the first post?

What size wire were you using? For the thinner gauges I drop to the, I believe, .025" instead of using the .030" which is the standard wire.

Oh yeah, with THIS crowd, I show the pics AFTER I have done my grinding!:P

That jack hole was from a rust free texas donor. Another forum member purchased the whole corner to use in their welding project and that jack point was leftover. I'm using .035" flux cored wire-I have yet to accumulate enough money to afford a gas cylinder, I'll get there eventually. I didn't both to grind any of that down-it's mostly not visible and what is I'm going to finish with POR-15 epoxy putty.

Alright, took out the drivers seat to clean out, and originally intended to fix, but it looks like I'm going to need more than one day. It seems I need to remove a lot just to finish cleaning off all the rust. I want to remove that seat support thing in the second picture. I'll also need to remove those wires and vacuum tubes, should I cut and repair later, or disconnect at the source? Also, should I bother welding, or should I just repair with fiberglass and epoxy putty?

JEBalles,

As you know Ive just done this type of stuff. My advice would be to clear out the loose rust, POR-15 and then use epoxy putty. You also have your fuel lines in that area which are not helpful when welding.

The technique is:
1.) Coat with POR-15.
2.) Pain in fiberglass sheets with POR-15 to create form of sorts
3.) Put in the EPoxy putty
4.) Overcoat with POR-15's chasis coat black or similar.

I have the chassis coat black and the fiberglass for when the time comes.

The caveat is that you will not know how bad your issues are until you remove all the undercoat and the sound deadener to see the entire cancerous region. It could be really horrible.

dd

Has anyone torn out the interior of their w123? The rust has become bad enough that I'm beginning to look for rust free frames with bad drivetrains, but that's still expensive and I'd need an engine lift and everything, probably won't be doing that for a long time. In the mean time I need to tear out a lot of interior, mostly trim and carpeting to protect and prevent fires and I need room to clean out all the damn insulation. My front rocker/wheel well repair isn't going well. What about sandblasting?

Well, I've sort of finished the front rocker/wheel well. I worked about 3 days and it ended up being garbage. I'm getting really frustrated. End result looks ok, better than before. Poor paint job on the fender (and bloody trim wouldn't clip back on properly), and lower trip doesn't quite line up. The rocker is mostly epoxy putty to seal it, it looks really lumpy. I got really flustered when I kept finding more rust under the pedals in the floor, those are still open. I just got really lazy and that's what resulted in the putty fix. I've found what looks like a good recipient for my drivetrain: http://capecod.craigslist.org/cto/1267679462.html. Rust-free bodies are rare in N.E. I can't really afford this, but is it too good a deal to pass up, or do these come along periodically?

More pictures.

Well, I've discovered yet another hole in my floor under the pedal assembly. It doesn't appear to be structural based on the fact that a) I've been driving over some pretty rough roads for a while now and haven't had trouble and b) the sides of that structural pillar are not rusted, only the sheet metal. I plan to repair with fiberglass and epoxy putty.

Every, and I mean, EVERY bit of that floor pan is "structural". Unibody, remember?

POR15 and fiberglass is fine to patch holes but what you are working with needs to have metal welded/epoxied/riveted (I don't feel like going into that argument again) into place.

Think of your chassis as a cardboard match box (and in fact if you own a Yugo it's an even more apt simile). Pretty stable right? Now, slide the match tray out of it's cardboard shell. Squeeze the shell and what happens? When you remove the floorboard from the unibody equation you are doing the exact same thing. You can roll the empty shell down a flight of stairs (just like driving down a bumpy road) and it will flex and keep it's basic shape. Now, drop a book on the shell which is the equivalent of having a car crash into the side of you.

Hmmm. I see. I hadn't thought of an accident. How's this for a compromise: If I patch most of it with new metal welded in, but avoid areas that are problematic (i.e. fuel lines), and then patch said areas with fiberglass. I don't want to do a whole pan replacement or nothing (money and time issues with that).

I like the direction you were going with the alternative car - for $400; sounds like a great parts/body source. Assuming you can afford it, might be worth a look if it's close enough.

Yeah, I'd like that too, car sold for only 250 (didn't get to look at it). It would have been a pain to bring it home, though. I'd have to register it (shipping was 600 bucks). Although, my mom was NOT alright with having a parts car on our property, so it doesn't really matter. I'll have to do the swap after college. Until then, I'll continue fixing. I don't mind the work and it'll sound good in a college interview.

Under extracurricular activities: "I made a car with my bare hands.":D

The beginning of my floor pan repair, before and after. This should be the largest patch.

That's looking better! If you can find an old washing machine or dryer the sheet metal on them is just the thing for flat repairs. They are coated with GOOD enamel. Make a template of the hole you are filling, cut the piece from the sheet, grind back an inch of the paint and weld it into place. The enamel they use really holds the primer after you weld.

They are not so good for any bends because the enamel tends to crack at the bend.:(

I'm actually using a w123 door that came with the car purchase and I couldn't unload on anyone, figuring that'd be the best to use. I patched up most of the big holes and I'm finishing it with the POR-15 fiberglass that I'm not sure how to use. Advice?

Might want to take care of the rust in those most recent pictures. If you have to patch big holes of door dont you think its a waste of time and should locate another door?

But if you insist I would weld patch pieces of metal, smooth out with bondo and paint it.

The trick to using POR15 and fiberglass is to lay down a thick layer of POR15, let dry until tacky, lay the mesh across the hole, apply another layer of POR15. Let dry until tacky, lay another piece of fiberglass mesh at an opposing angle and let cure. Smooth in a thin layer of the POR15 putty, embed another layer of fiberglass mesh, let dry and sand smooth. Finish off with a coat of POR15 or any good primer and top coat.

If you take your time and are skimpy with the POR15 you'll never even notice the repair.

You will go through a stack of latex gloves and disposable brushes but what the heck! Much cheaper than skin replacement and a pint of the POR15 thinner/cleaner.:)

this is why it was recommended to me to purchase 1/2 a mercedes floor pan! they just sawed that carcass in half. it was up to me to cut appropriately and weld into place. there were a few other places that required patches, but for the most part, i welded 1 solid, rust free piece in and just did a few patches here and there to take care of the rest

i like por15 + fiberglass but make sure its in non-structural areas! and wear a vapor mask and vent the air out. that stuff is not good, unless you were a paint huffer in your previous teenage years :D

edit: it looks like your welds could be a little hotter. good that you are tacking, but it looks like you are not pulling or pushing your welds, just tacking. it's effective, but man, you must be getting tired tacking all the time, no? :)

my setting for the floor plan on my lincoln 120V welder was C + 4. easy to remember

For 14 gauge metal, the my Lincoln Pro-mig 135 calls for D-7, but I'm only using .025" wire, maybe that's an issue? How does wire feed speed affect a weld?

I'm fine tacking, as long as I'm not burning holes, which is usually what happens with pushing or pulling.

I think I might weld it all just because I'm better at that. I just can't seem to get the fiberglass to work well enough. I'm just going to make as big a patch as I can and finish it with littler patches.

JE,

Hows your repairs coming along? any new pics?

Haven't done any work over the winter- no time or space and it was damn cold. I should be starting again in the next few weeks. Floors first, then I'm getting replacement cut-outs of the front sections of the rocker panels from a rust-free donor. Do you happen to know the answer to the above question?

Which one? Wire feed? or any new pics?

Yes, how wire feed affects the weld. How about wire thickness? I've been using .025" and I don't think it was penetrating enough, so I bought some .030".

My next project is going to be rear passenger side. There's a long hole that started in the rocker-floor pan seam. It's about 2" wide and 1 1/2' long.

Well, we had some heavy rain and the Merce took on a little water when I drove through 10" of water, so I took out the carpets to let it dry... then i wanted to take out the back seat to see what was under there, and, well, I got a little carried away.

More pics.

Does anyone know a good way to get up the insulation on the front floor pans? I tried a heat gun, which is good for the stuff in the rear, but it just burned the front stuff.

I used a chisel and hammer to remove the undercoating. A good deal of it will come up in pretty big chunks.

Alright, I've learned that the welder is more of a feel thing. I'm using .035" solid wire because I though thicker wire would help penetration and lay down more material than the .025" I was using 16 gauge to patch and I was using the settings the welder recommended, but it just wasn't penetrating well enough, so I'm taking matters into my own hands. Higher heat-better penetration, as long as you're not blowing holes.

Now in the picture, I want to remove the front seat support (red) to ease the the patching of the hole underneath (green). I've been working on the hole circled in yellow. I also think the whole pan-rocker seam is infected, so I'm going to cut that whole thing out.

Does anyone know how difficult it is to take off the center console? And how bought that floor insulation? I'm really hoping someone has a good way to get that stuff up, cause it is busting my balls right now.

Alright, I've got two patches done, a fair amount of metal, the pan seems much more secure. I've still got to do that spot near the sub-frame mount.

I read that with using gas, the metal should be clean. I get it pretty clean, remove almost all the rust (I might be welding some rust-pitted metal, some rust could still be in the pits), and I spray on some water based degreaser, rinse it off and wipe it up. Cleaning is a pain in the ass, especially for painting. I've heard good things about POR-15's marine degreaser; does that require rinse? Does anyone have any other recommendations?

As for painting, I've decided to use this "rust destroyer" they have at the auto parts store. Relatively cheap and I think it's like what POR-15 has but separate. I used POR-15 before, but I like to spray, so i'm gonna do rust destroyer and then regs primer and paint. I wanted to get that weld-thru primer, but it was more than 30 bucks for a can! Is it really worth it? I'd only use it on spot and lap welds, but I do mostly butt welds.

For shaped pieces, I've been welding on a rough patch in places and then hammering and grinding to fit. Does anyone have a better way? My way is frustrating, time consuming, and not that good. Also, I'm looking at my last patch, and I think I'm going to have to redo a fair amount. Welds are too cold--not enough penetration, and that fiberglass is terrible. Paint isn't holding on too well either.

I could really use the feedback here.

Pic #1: rusted metal cut out

Pic #2: Patched metal

Pic #3: Rust destroyer

That is quite a project. Keep at it.
For non-flat panels, try using a crowned body hammer and a sand bag as the support. Take a small ( 1' square +/-) piece of scrap and just practice beating it on the sand bag, and seeing what comes up. After you do that, you might get a feel for what shapes you can hammer. Realize that as you beat the steel, it gets thinner, which means that the same metal must now occupy more space, so it curves.
For straight bends, a brake is the proper tool. Harbor Freight has a little one that might be all you need. Or, you could use a 2X4 and clamp the metal to it, and fold it over to whatever angle you need.
Keep posting pictures. They help me appreciate my rust-free car, and I'm down in MD!

man, that looks alot like my project. school keeps getting in the way, but its time for the metal to go back in. As far as stripping the car out, my car has the steering wheel and headliner in place. Most all of the panels and parts are removable by screws and bolts. It probably took me 20-30 hours to strip my car out over a month of work after school. Stripping off the front end took a lot less time and was much easier lol.
Andrew

Yeah, school and rain for me. I wish I had enough space in the garage to work.

Weld penetration isn't so much about the wire thickness, it's more about the power setting on the welder. 025" wire is best for auto body stuff, you can weld thinner stuff with it without burning through. Using 035 requires more heat to melt it in properly, so burn through is more likely to be an issue. If you feel you aren't getting enough pentration either inch back the wire feed slightly or up the power a bit. Tack the edges of the repair section in every 2 inches or so to start with, then add short welds in between each tack, and repeat until you have it seam-welded. Doing small bits at a time reduces heat build up and distortion and burn through. If you have to bridge a burn through area, drop the power one notch, up the wire feed so that it barely melts in and flick the trigger rapidly to give small quick bursts of wire. When you have the hole filled with what looks like bird droppings, correct your power/feed setting for normal welding and go over what you just did to smooth it out.

Oh, and practice on some scrap stuff, and experiment with turning the wire feed knob slowly while welding(NOT the power knob, you'll hurt the welder)and you will also get to recognize the sound of a good weld being laid down. I clean my areas to be welded with a bit of paint thinner to degrease it. Just make sure it's dry and the thinner is capped and well away before hitting the welder. Have a fire extinguisher at your elbow when welding. Enjoy! Welding is great fun when you get the hang of it.:D

Oh, and your car is worth doing, I have saved far worse machines from the crusher:) Here in Northern Ontario, rust is quite severe. Guys from down south wouldn't look twice at stuff we consider do-able up here.

I usually make a cereal box cardboard template before ever cutting any metal. It's so much easier to rough it in cardboard, then fine tune it with a pair of scissors. Then just trace your pattern onto metal and it will fit first time, no grinding req'd.

I'm doing the cereal box cardboard technique, but I still end up needing to do some grinding, especially if the patch is shaped. With my car, I figure I know everything about it already and it's good to learn how to do this type of repair in this climate because I'd have to end up doing it on any car I own.

As for the welding, I'm hesitant to go back to the .025" because I let it unwind some and now it jams. Such a pain in the ass. NEVER LET THE WIRE SPOOL UNWIND. I fooled around a bit with the settings and .035" with setting C-4 (wire feed is dialed, but heat is notched) like bob said seems to work pretty well. I'm gonna try that hole filling technique, that's a good idea.

More pics

Pic #1: passenger side front floor pan--no insulation

Pic #2: driver's side front floor pan--no insulation, for some reason, much more rust than passengers side

Pic #3: hole in DS tunnel

Pic #4: hole with seat support to be replaced

Pic #5: parking brake cable guide, repaired, to be replaced

Pic #6: prepped hole for patch

For the rust under the pedals, I'm thinking of taking off the rear section of the frame rail. As you can see in pic #7, the front section is spot welded to the front section right underneath the pedal cluster. Good idea?