Bumper Repair

[Seangbadee]

When I got my 95 E320, the impact strip was broken on the left side.

Did some fiberglass work to restore it, and I’m at the finishing stage.

I need some tips on how to finish this bumper. I used foam sealer to fill behind the impact strip. After it cured, I trimmed to shape and applied the fiberglass mat.

 

[nocfn]

good work sir!

 

[Seangbadee]

Thank you. Just spending free time productively.

 

[kwontumspeed]

Nice job. If you tear it up again, note that the new OE MB bumper strip is $100 (at least a few months ago) and may be easier just to buy that and rattle can it.

 

[mikeym]

When I got my 95 E320, the impact strip was broken on the left side.

Did some fiberglass work to restore it, and I’m at the finishing stage.

I need some tips on how to finish this bumper. I used foam sealer to fill behind the impact strip. After it cured, I trimmed to shape and applied the fiberglass mat.

View attachment 108381 View attachment 108382 View attachment 108383 View attachment 108384

Can you share the link to the fiberglass product that you used? I need to do the same to my car's rear bumper and those impact strips are NLA.

 

[Glen]

It looks good but I would suggest to anyone else doing this to alter the process a little.
For the foam backfill, I would isolate it from the actual bumper and impact strip with some plastic wrap so that it doesn't adhere to the bumper or impact strip. This is just a courtesy to you or someone else if the impact strip and foam are ever replaced with factory pieces.

And second, it appears you used a regular body filler to rebuild the impact strip. I suggest using a flexible filler like Evercoat Poly-Flex instead, It won't prevent stress cracks but should hold up better to minor impacts.

 

[Glen]

For finishing the bumper, I would sand the whole thing and seal with epoxy primer. Then a a high build polyester primer, block sand to 400 and base/clear it.

 

[Seangbadee]

It looks good but I would suggest to anyone else doing this to alter the process a little.
For the foam backfill, I would isolate it from the actual bumper and impact strip with some plastic wrap so that it doesn't adhere to the bumper or impact strip. This is just a courtesy to you or someone else if the impact strip and foam are ever replaced with factory pieces.

And second, it appears you used a regular body filler to rebuild the impact strip. I suggest using a flexible filler like Evercoat Poly-Flex instead, It won't prevent stress cracks but should hold up better to minor impacts.

I didn’t think of removing the entire impact strip, but you’re right. I used a plastic body filler but I’m not sure if it was ‘flexible.
I didn’t rebuild the entire missing left side, just the gaping hole between the two broken pieces.
I appreciate your comments. Thanks

 

[Seangbadee]

Can you share the link to the fiberglass product that you used? I need to do the same to my car's rear bumper and those impact strips are NLA.

I used the Bondo fiberglass mat (not cloth), and fiberglass resin all purchased at Walmart. I also purchased a plastic body filler. Another member suggested a particular brand which does make sense. It should be a flexible filler.

 

[Seangbadee]

For finishing the bumper, I would sand the whole thing and seal with epoxy primer. Then a a high build polyester primer, block sand to 400 and base/clear it.

Why epoxy primer? Would that go over the sanded base coat, or are you suggesting sanding the entire thing backdown to the primer?

 

[Glen]

Epoxy primers stick very well and seal the surface preventing any bleed through into the new paint. It basically gives you a uniform surface to work with. It can go over any scuffed old paint as long as it’s deglossed and clean.
The reason for the polyester primer over the epoxy is because the epoxy is harder to sand smooth.

 

[Seangbadee]

Nice job. If you tear it up again, note that the new OE MB bumper strip is $100 (at least a few months ago) and may be easier just to buy that and rattle can it.

Nice job. If you tear it up again, note that the new OE MB bumper strip is $100 (at least a few months ago) and may be easier just to buy that and rattle can it.

You’re right. It’s actually below 100, but I just wanted to have a ‘feel’ of the repair. I’ve got too much time on my hands !

 

[Seangbadee]

It looks good but I would suggest to anyone else doing this to alter the process a little.
For the foam backfill, I would isolate it from the actual bumper and impact strip with some plastic wrap so that it doesn't adhere to the bumper or impact strip. This is just a courtesy to you or someone else if the impact strip and foam are ever replaced with factory pieces.

And second, it appears you used a regular body filler to rebuild the impact strip. I suggest using a flexible filler like Evercoat Poly-Flex instead, It won't prevent stress cracks but should hold up better to minor impacts.

Poly flex is quite expensive especially for the little job that the bumper is. Any other suggestions?

 

[Glen]

Poly flex is quite expensive especially for the little job that the bumper is. Any other suggestions?

I've only ever use Poly-flex so no other suggestions. Since you've already done a nice job shaping, blending, and smoothing it, go ahead and finish it...and just be careful not to bump into anything

 

[Seangbadee]

I've only ever use Poly-flex so no other suggestions. Since you've already done a nice job shaping, blending, and smoothing it, go ahead and finish it...and just be careful not to bump into anything

I’ll try not to
Thank you

 

[Seangbadee]

Epoxy primers stick very well and seal the surface preventing any bleed through into the new paint. It basically gives you a uniform surface to work with. It can go over any scuffed old paint as long as it’s deglossed and clean.
The reason for the polyester primer over the epoxy is because the epoxy is harder to sand smooth.
[/QUOTe

Do you have any idea how many rattle cans will be required for the bumper?

 

[Glen]

Do you have any idea how many rattle cans will be required for the bumper?

I’m guessing about two cans of single stage should do it with some left over. For base/clear maybe one for base and probably 2 clear. YMMV.
If you do base/clear use a catalyzed clear so it will hold up better and be sure to wear a respirator.

 

[Seangbadee]

I’m guessing about two cans of single stage should do it with some left over. For base/clear maybe one for base and probably 2 clear. YMMV.
If you do base/clear use a catalyzed clear so it will hold up better and be sure to wear a respirator.

Thanks a bunch!

 

[Seangbadee]

I’m guessing about two cans of single stage should do it with some left over. For base/clear maybe one for base and probably 2 clear. YMMV.
If you do base/clear use a catalyzed clear so it will hold up better and be sure to wear a respirator.

I’m a stickler for doing things the right way. Took all the rigid filler off and I’m back down to fiberglass.
Now I’m off to using the ‘right’ materials! I’ve ordered the Evercoat poly flex, and Epoxy primer.
I made sure I got all the defined lines so I don’t have to overuse the filler

 

[LWB250]

I’m guessing about two cans of single stage should do it with some left over. For base/clear maybe one for base and probably 2 clear. YMMV.
If you do base/clear use a catalyzed clear so it will hold up better and be sure to wear a respirator.

I've done W140 bumpers with two, ideally three, so since the W124 bumper is smaller I would say two cans for single stage should do the trick.

Dan

 

[Seangbadee]

I've done W140 bumpers with two, ideally three, so since the W124 bumper is smaller I would say two cans for single stage should do the trick.

Dan

Thanks Dan

 

[Seangbadee]

I’m guessing about two cans of single stage should do it with some left over. For base/clear maybe one for base and probably 2 clear. YMMV.
If you do base/clear use a catalyzed clear so it will hold up better and be sure to wear a respirator.

So I’ve retraced my steps. I sanded the bumper down and used the Bondo body filler over the fiberglass only.
I used filler primer over the repaired area and sanded down with 320 grit.
The epoxy primer arrives tomorrow, and after that application I will use the polyester primer.
Do I still need the polyflex or would the primers suffice? If I need the polyflex, at what stage of this repair process should I apply it?

 

[Glen]

The poly flex would have replaced the body filler over the fiberglass. So at this point, keep moving forward...epoxy prime, polyester prime, block and paint.

 

[Seangbadee]

The poly flex would have replaced the body filler over the fiberglass. So at this point, keep moving forward...epoxy prime, polyester prime, block and paint.

Yes!!!
Thanks.

 

[Seangbadee]

I've done W140 bumpers with two, ideally three, so since the W124 bumper is smaller I would say two cans for single stage should do the trick.

Dan

2 cans did it!
Thanks

 

[LWB250]

Sean, those appear to be "Special Edition" wheels. Can you tell me if there is a black paint line at the joint between the spokes and the rim? I can't tell if there is on yours or if it's just the lighting.

I ask because I just sent a set in to be refinished for my E420 and I want them to be correct when they're done. They didn't have it originally, at least assuming mine weren't painted or refinished previously.

Thanks!

Dan

 

[Seangbadee]

Sean, those appear to be "Special Edition" wheels. Can you tell me if there is a black paint line at the joint between the spokes and the rim? I can't tell if there is on yours or if it's just the lighting.

I ask because I just sent a set in to be refinished for my E420 and I want them to be correct when they're done. They didn't have it originally, at least assuming mine weren't painted or refinished previously.

Thanks!

Dan

Let me check

 

[Seangbadee]

Let me check

I just took these pictures. I don’t see any black lines just some dirt.
I hope these help.
p.s
Checked the spare tire; no black lines.

 

[LWB250]

I just took these pictures. I don’t see any black lines just some dirt.
I hope these help.
p.s
Checked the spare tire; no black lines.

Thanks! I figured it was dirt, didn't want to sound like I was passing judgement on the condition of the wheels if that was the case.

Dan

 

[Seangbadee]

Thanks! I figured it was dirt, didn't want to sound like I was passing judgement on the condition of the wheels if that was the case.

Dan

Totally understood. That’s my ‘Project 2020’

 

[Seangbadee]

For finishing the bumper, I would sand the whole thing and seal with epoxy primer. Then a a high build polyester primer, block sand to 400 and base/clear it.

Glen:
What grit should I use to sand the epoxy primer before applying the polyester primer?
I’ve had the epoxy on for at least 72 hours.

 

[Glen]

Glen:
What grit should I use to sand the epoxy primer before applying the polyester primer?
I’ve had the epoxy on for at least 72 hours.

Do you have 3M scotch brite pads? if so, use the brown/purple one. If not, 320 grit paper.

 

[Seangbadee]

I will get some. Thank you.

 

[Seangbadee]

Glen:
What grit should I use to sand the epoxy primer before applying the polyester primer?
I’ve had the epoxy on for at least 72 hours.

After so many weeks of foot-dragging I decided to complete the bumper repair
Got some paint mixed at Finish Masters Inc. in Atlanta, and sprayed it on out of the can
Three coats of clear (1K), and the final product is shown below.
For comparison, there is the ‘before’ and ‘after’ pictures shown

 

[Glen]

What a great improvement. Nice job!

 

[Seangbadee]

Thanks for all the pointers; they really helped

 

[Trae]

Hi Glen and anyone else that has experience painting bumpers.

I have a rear bumper from my parts car that I am trying to paint and install on the E320 cabriolet.
The E320 is white and the bumper I sourced is 199 black/charcoal.

Found this on the internet, but wanted advice before starting this project.

 

[Glen]

Hi Trae,
Overall, I'd say that video is pretty good at describing what's involved. For the deeper nicks and scratches, I'd use a catalyzed glazing putty instead of the primer/filler he used because it's faster. So, clean, sand, one coat of primer as he did. Then use glazing putty to fill the deep nicks, sand again and then more primer. For primer, I personally like epoxy because it sticks to everything and is very durable but may not be convenient for a small job. Plus epoxy primers don't dry sand well so usually a standard primer is sprayed over epoxy...or you could go straight to a sealer. As he described, a sealer gives a uniform surface for the base coat and should seal and prevent any bleed through from lower layers. It's not absolutely necessary but helps when the new paint color is drastically different from the underlying paint. So, in your case it would be a good idea since you are putting a light over dark.

 

[Trae]

Thanks Glenn!

 

[LWB250]

Good info, Glen. Thanks! I've got a bumper paint job in my future, so this is good to know.

 

[albdentist]

Just thought I’d add a paint system that worked well for my project. I felt to match the color, both bumpers, sills and cladding all had to be painted.

The Spray Max rattle can worked well enough however using an air compressor would have been an improvement: more control and consistency...
The clear coat uses a hardener where a nozel on the bottom of the can is compressed...after which one has 38 hrs to empty the can...

So far the front bumper has held up well...

 

[Glen]

Mario,
Do you think one can is enough to get two wet coats on a bumper?

 

[Seangbadee]

To be on the safe side, I would suggest getting 3 cans. Ideally 2 cans should do the job, but better to err on the side of having too much rather than too little.

 

[gsxr]

Can we buy SprayMax rattle cans online, in MB color codes? Anyone have recommended vendors/brands in USA for online orders?

I need to buy a few cans in various colors for smaller stuff (headlight trim panels, etc). This is the place I was leaning towards, since TowerPaint appears to be gone. They are

1993 Mercedes-Benz (All Models) Colors of Touch Up Paint

Touch Up Paint for your 1993 Mercedes-Benz (All Models)

www.automotivetouchup.com

Prices in screenshot below:

 

[albdentist]

Glen, two cans for the front bumper, three for the rear... one tends to run out of propellant in the can ! There is a bit of a learning curve: even when the cans are preheated in a tub of hot water, towards the bottom 1/4 of the can the spray starts “spitting”. The spray is no longer reliably even. The clear coat seams better, one can per bumper.

Dave, I went to a local auto paint retailer, the paint used in this system is shot into the can with the recipe from a database...

I found it very difficult to match standard colors...

 

[mikeym]

Time to tackle the crack in the rear bumper in quarantine 2021... What do you guys recommend for patching it?

1) Bonda fiberglass mat + Resin
2) poly-flex
3) some sort of epoxy/hardener ( https://www.3m.com/3M/en_US/company...5+8711413+3293241076&preselect=8711351&rt=rud )

or something else....

 

[gsxr]

Have you read this thread yet?

Polyurethane (PUR) bumper repair | Body Shop

Most 80's/90's Mercedes have their bumpers in Polyurethane, afaik (PUR for w126 and Pc/PBT for w124). I did some research on internet and found an US company, Polyvance who has very convincing vids on youtube. Their technology is based on melting a special rod (R01) at 300C and keeping cold the...

www.500eboard.co

 

[mikeym]

Have you read this thread yet?

Polyurethane (PUR) bumper repair | Body Shop

Most 80's/90's Mercedes have their bumpers in Polyurethane, afaik (PUR for w126 and Pc/PBT for w124). I did some research on internet and found an US company, Polyvance who has very convincing vids on youtube. Their technology is based on melting a special rod (R01) at 300C and keeping cold the...

www.500eboard.co

that missed my search! Will take a read, Thx!

 

[Glen]

Time to tackle the crack in the rear bumper in quarantine 2021... What do you guys recommend for patching it?

1) Bonda fiberglass mat + Resin
2) poly-flex
3) some sort of epoxy/hardener ( https://www.3m.com/3M/en_US/company...5+8711413+3293241076&preselect=8711351&rt=rud )

or something else....

You need the strength of either 1 or 3 on the back side. Or another option is plastic welding.
Poly-flex is used on the front side to smooth it out and prep it for paint.

 

[khomer2]

Polyvance fiberflex rods are the way to go with PC PBT (Xenoy) for the w124 bumper covers as well as many of our era plastics.
You can also use the scrap bumper cover pieces of the same to melt down and piece them as needed - just sand off the primer and paint.