Discouraging finding ... should I learn to weld? - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 07-09-2009, 01:52 AM

I went to touch up some of the surface body rust on my 240D today and pulled the bumper off and found what's pictured below. I knew I had a lot of rust, but this is much worse than I thought. There are also a couple holes above the rear bumper that I'm guessing will reveal similar underlying disaster. I realize that on this forum a lot of guys will tell me it's a part car. I like it, I've put a lot of work into it and it's structurally pretty solid. And I don't need anyone else to tell me I'm an idiot for buying/working on this car. So, next answer.

-Since this area will be covered by the bumper cover, I thought about using a fiberglass patch, as in POR15's powermesh, along with POR15, good filler and enamel. Waste of time? Decent stop-gap?
-I thought about learning to weld. My 300D also desperately needs a little rocker panel work. This 240D has other areas that could use patching. And it seems like a good skill to have. That said, I've always been scared to try, mainly because of not knowing what equipment to buy and not having anyone to help me learn. Should I take a class? Or can I just pick up some decent equipment, follow safety guidelines and play around? All my other "skills" I've learned through trial and error (woodwork, painting, sanding, etc.) but are admittedly less intimidating. Is it easy to pick up or am I right to be apprehensive?
Here's the damage ... either way I'm replacing the brackets that hold the side bumper trim in place. They were shot.

amosfella · #2 07-09-2009, 03:24 AM

Welding is a bit more difficult a skill to pick up. Most guys that do it have gone through about a year's worth of courses and 4 years of apprenticeship. Example, if you hold the rod or wire feed too long in one area, you will create a lump that you will have to grind out... If you set the power settings too high, you'll blow holes through the panel, and if you set too low, you'll not get a decent amount of penetration, so it could fall apart later...
if you're bound and determined to learn to weld, don't start on your car. Find some scrap steel somewhere, and work at it, and learn to weld at different angles once you have learned the basics...
As for a welder, lincoln makes a really good little portable wire feed welder. My friend has one, and he can get proper penetration on 1/4 inch thick steel, and it runs on household ac. If you're buying one, don't cheap out. The cheap models have poor power regulation, and other problems. The last think you want is to be finishing your final weld and have a power flare, causing a blowthrough...
Oh, you'll need a grinder if you intend to weld. Avoid TIG welders until you learn how to weld with a stick welder... The type you want is called a MIG.

http://www.mylincolnelectric.com/Catalog/equipmentdatasheet.aspx?p=59618
You might be able to barter the price down in a shop that's having a slow year....
have fun, and post pics...

amosfella · #3 07-09-2009, 03:26 AM

btw, I picked up welding really easily... Then again, I have a fast learning curve for such things...

Dee8go · #4 07-09-2009, 12:20 PM

I've done gas welding, but new tried arc welding. I'd like to learn, though.

Chad300tdt · #5 07-09-2009, 12:39 PM

Learning to weld is a great idea and a skill you'll definitely use, but for the damage in the pic, I'd just get a replacement fender from a parts car.

Dee8go · #6 07-09-2009, 01:58 PM

Mine is all on my rear quarter panels, so I would need to weld the donor pieces on to the car. I've never tried welding anything as thin as car body material.

BodhiBenz1987 · #7 07-09-2009, 03:15 PM

Quote:

Originally Posted by Chad300tdt

Learning to weld is a great idea and a skill you'll definitely use, but for the damage in the pic, I'd just get a replacement fender from a parts car.

I thought of that ... this may sound like a dumb question, but what exactly constitutes the fender in the front? I looks like it wraps all the way under the bumper (I don't see a seam) and is one with the strips under the headlights. On my 124 the fenders are very obvious panels ending at the side of the headlight.

Chad300tdt · #8 07-09-2009, 03:21 PM

Quote:

Originally Posted by BodhiBenz1987

I thought of that ... this may sound like a dumb question, but what exactly constitutes the fender in the front? I looks like it wraps all the way under the bumper (I don't see a seam) and is one with the strips under the headlights. On my 124 the fenders are very obvious panels ending at the side of the headlight.

I found a great DIY that shows how to swap your front fender.

http://dieselgiant.com/mercedes_front_fender_rr.htm

BodhiBenz1987 · #9 07-09-2009, 03:28 PM

Cool, that actually doesn't look that bad. I'm going to do some ghetto fiberglass tomorrow to hold me over for a while, but if I can find a nice pair of fenders, that would probably be an easy way to go. And with my painting skills, they will match perfectly.

Chad300tdt · #10 07-09-2009, 03:36 PM

Quote:

Originally Posted by BodhiBenz1987

Cool, that actually doesn't look that bad. I'm going to do some ghetto fiberglass tomorrow to hold me over for a while, but if I can find a nice pair of fenders, that would probably be an easy way to go. And with my painting skills, they will match perfectly.

I think the hardest part of a fender swap is getting the strips just above and below the bumper to align while putting the fender back on. Study how it looks before you remove it otherwise you may end up struggling a little.

If you haven't seen my repair threads, here's some ideas for non-structural rust repair areas.

http://www.peachparts.com//shopforum/showthread.php?t=231360
http://www.peachparts.com//shopforum/showthread.php?t=202295

BodhiBenz1987 · #11 07-09-2009, 06:43 PM

Wow Chad, you did an awesome job. I would be thrilled if I could end up with something that looks like that! Can you tell me more about how to use rivets? Sheet metal and JB Weld might be something I could do. Thanks for the links ... I feel much more optimistic now that I've seen someone else dive in and come out alive!

barry123400 · #12 07-12-2009, 12:24 PM

What suprised me was how easy it was to get the hang of mig wire welding years ago. I already could stick weld but the wire feed was a walk in the park by comparison.

Just have a friend to guide you initially. Actually it is about the only sane method of welding on older car metal gauges in my opinion.

In your case though there is no sane alternative over a solid junk yard replacement fender. Yes the bottom of the fender does wrap around quite a ways.

JEBalles · #13 07-14-2009, 09:57 AM

Quote:

Originally Posted by barry123400

What suprised me was how easy it was to get the hang of mig wire welding years ago. I already could stick weld but the wire feed was a walk in the park by comparison.

Just have a friend to guide you initially. Actually it is about the only sane method of welding on older car metal gauges in my opinion.

In your case though there is no sane alternative over a solid junk yard replacement fender. Yes the bottom of the fender does wrap around quite a ways.

X2 or you could pay the big bucks for a factory new fender from the dealer. Definitely get a good lincoln or hobart MIG (not fluxcore) 110v or 220v (110v is just easier to use at home). it's a good skill and relatively easy to pick up (not stick) you will need a grinder.

BodhiBenz1987 · #14 07-17-2009, 11:14 PM

I've been working really hard on this all week long and thought I'd post what I've got so far. Even though the long-term solution would be replace the fenders, I decided to play around with them a bit and see if I can at least make it look decent. After POR15 mania, I patched the bottom part with fiberglass, then JB Welded a strip of scrap metal behind it bridging the intact areas of the fender for support in the destroyed area. Around the fiberglass and metal "beam" I built up pourable putty, POR Putty and filler and then sanded it as best I could. As you can see in the pics, I didn't bother prettying up the area where the bumper will cover. I shot it with DuPont paint with my $15 gun and it didn't come out perfect, but it certainly looks better then picture No. 1 (keep in mind what the bumper will hide). I actually sprayed it again after the last pic, and it came out better blending-wise, but with runs.

I hope in the next areas my painting skills improve (I have plenty to practice on!).

79Mercy · #15 07-18-2009, 12:08 AM

WOW, that looks really good. You should be proud of yourself. You really got the body smooth near the side marker light.

just continue like that and paint the whole car, LOL....