what is front bumper made of?

**ghostdunks** · 07-06-2008

anyone know what type of material the front bumper is made of? eg. is it fibreglass, or just some type of plastic?

reason why i ask is that I managed(stupidly) to drive too far forward while parking in a spot, and managed hit a concrete block and cracked the front bumper a bit. Seeing as its on the underside, I'm not too worried about it, but just want to do a quick DIY repair on it to make sure the crack doesn't get worse. Will probably replace the bumper later, but for now, just need to make sure it doesn't get worse. If anyone has any ideas or products they recommend, would appreciate it as well

oh, its for a 2005 SLK280

**etyu** · 07-06-2008

Sorry to hear Ghostdunks. For sure it's not fiberglass, it's plastic. Most body shops may be able to mend the crack from the inside surface.

bobsquad7 · 07-06-2008

The bumper is an injection molded semi-rigid plastic.
Go to your local body shop-paint supply store & get a product called Duramix 4040 (aprox $35.00) and a roll of reinforcing mesh ($5.00). (O'Reily's Auto Parts carries it in their paint dept) Also get a dual tube applicator gun ($ ?) - like a caulk gun but has twin plungers. (You may be able to borrow one of these from the store - or a paint & body shop)
Prep the inside of the cover in the cracked/torn area with an 80 grit sanding disc. Rough-up an area a couple inches either side of the crack.
Cut & apply a piece or two of mesh to the area & spread an even thin layer of the Duramix over the mesh. For maximum strength, apply 3 or 4 additional layers of mesh & Dura.
This stuff set's up in a couple of minutes (or less - in warm weather) so get everything layed out & be prepared to work fast.
Also, wear Nitrile gloves or plan on "wearing" the Duramix on your fingers for a week until it wears off. Laquer thinner won't even desolve it once it sets.

**SLKCop** · 07-07-2008

Quote:

Originally Posted by bobsquad7

The bumper is an injection molded semi-rigid plastic.
Go to your local body shop-paint supply store & get a product called Duramix 4040 (aprox $35.00) and a roll of reinforcing mesh ($5.00). (O'Reily's Auto Parts carries it in their paint dept) Also get a dual tube applicator gun ($ ?) - like a caulk gun but has twin plungers. (You may be able to borrow one of these from the store - or a paint & body shop)
Prep the inside of the cover in the cracked/torn area with an 80 grit sanding disc. Rough-up an area a couple inches either side of the crack.
Cut & apply a piece or two of mesh to the area & spread an even thin layer of the Duramix over the mesh. For maximum strength, apply 3 or 4 additional layers of mesh & Dura.
This stuff set's up in a couple of minutes (or less - in warm weather) so get everything layed out & be prepared to work fast.
Also, wear Nitrile gloves or plan on "wearing" the Duramix on your fingers for a week until it wears off. Laquer thinner won't even desolve it once it sets.

Great description.....sounds like you've done that before!

**ghostdunks** · 07-07-2008

thanks for the suggestions guys, I might give it a go later. I've heard good things about the Duramix stuff as well(made by 3M I believe) so that sounds like the right thing to use.

Might as well learn to do it myself, I can see myself doing this more than once

Now, got to figure out an easy way of taking the bumper off so I can fix it properly.

**etyu** · 07-07-2008

IIRC, someone in Canada was able to remove the front bumpers while putting in an aftermarket HID. It was stevenlau.

**ghostdunks** · 07-08-2008

yeah I remember his post as well, I used it a fair bit while putting in my own aftermarket HIDs

**Dolebludger** · 07-08-2008

Where exactly is the crack on the front bumper? Is it on the rear-most part of that part of the bumper that tucks underneath the car? If so, this is a rather common problem. I got a very small crack there myself, in the same way. Fortunately, to see it, one had to lay down on the pavement and crawl under the front, face up. I didn't want the crack spreading further, so I cut a small, short strip of sheet aluminum and secured it to the back (inside) surface of the area of the crack with JB Weld. When this was dry, I masked the area while leaving only about 1'4" of area around the crack exposed. I sprayed the crack with some aerosol touch-up paint a local auto paint supplier mixes and sells, and polished it down with a fine polish when dry. If the crack on your bumper is in this obscure area, this may work for you.

**ghostdunks** · 07-22-2008

Yeah, the crack "starts" where it tucks under the car but it ends somewhat high. Its not that noticeable but like I said, just want to stop it from getting worse.

Update on this. Having a lot of trouble sourcing the 3M Duramix(renamed to Automix I believe) in Australia, from automotive stores we have around here(such as Autobarn, Supacheap Auto, etc...). They have stuff like "Plastic Weld" or "JB Weld" instead. Going to try and find some specialised paint & panel beating supply shop and see if they supply it instead,

Failing that, I was thinking of the following. Use either "Plastic Weld" or "JB Weld" to glue the crack together, then on the hidden side of the bumper, reinforce the repair by using a fibreglass repair kit to add some reinforcement behind the crack. Then sand the repaired crack on the front side, and just paint it over. Anyone see any problems with that approach?

I've never worked with fibreglass before, so not sure if it'll adhere to the back of the bumper, etc...how strong it'll be, etc..

bobsquad7 · 07-22-2008

I don't know how compatible fiberglass cloth/resin or JB Weld would be with the bumper cover material.
If you can't find Duramix at a pro body shop supply, try sending 3M an email requesting a source in Au.
The "mesh" that most pro body shops use is available from home builder or lumber stores. It's also used to reinforce sheet rock (wall board) joints, . . .comes in a roll of aprox 100 feet and costs around $5.00 US.
I don't believe fiberglass resin or JB weld would be flexable enough - not as pliable as the bumper.

07-06-2008	#1 (permalink)
ghostdunks Elite SLK World Member Join Date: Feb 2007 Location: Melbourne, Australia Vehicle: SLK280 Posts: 208 Country: Thanks: 5 Thanked 3 Times in 2 Posts	what is front bumper made of? anyone know what type of material the front bumper is made of? eg. is it fibreglass, or just some type of plastic? reason why i ask is that I managed(stupidly) to drive too far forward while parking in a spot, and managed hit a concrete block and cracked the front bumper a bit. Seeing as its on the underside, I'm not too worried about it, but just want to do a quick DIY repair on it to make sure the crack doesn't get worse. Will probably replace the bumper later, but for now, just need to make sure it doesn't get worse. If anyone has any ideas or products they recommend, would appreciate it as well oh, its for a 2005 SLK280
	http://www.slkworld.com/

07-06-2008	#2 (permalink)
etyu Founding Member #2 / Ambassador Of Good Will Join Date: Jun 2006 Location: Orange County, CA Vehicle: 2008 SLK 55 Posts: 5,164 Country: Thanks: 385 Thanked 249 Times in 145 Posts	Sorry to hear Ghostdunks. For sure it's not fiberglass, it's plastic. Most body shops may be able to mend the crack from the inside surface. __________________ *Eddy* To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Pewter/Beige, PIII package, Airscarf, Hands-Free Communication System, Lighting package Designo Black Leather Cover on e-brake handle, ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Bill T), SmartTop v1.0, Kleyman 3BFM (NoRegret Custom), Green Air Filters, *Mod. R170 ant.* EuroClear sidemarkers w/PIAA PlasmaIon lamps, chromed front & rear turn indicator lamps, PIAA SuperPlasmaGTX front parking lamps, HyperWhite license plate lamps ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Scott), bilateral rear fog lamps enabled.

07-07-2008	#6 (permalink)
etyu Founding Member #2 / Ambassador Of Good Will Join Date: Jun 2006 Location: Orange County, CA Vehicle: 2008 SLK 55 Posts: 5,164 Country: Thanks: 385 Thanked 249 Times in 145 Posts	IIRC, someone in Canada was able to remove the front bumpers while putting in an aftermarket HID. It was stevenlau. __________________ *Eddy* To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Pewter/Beige, PIII package, Airscarf, Hands-Free Communication System, Lighting package Designo Black Leather Cover on e-brake handle, ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Bill T), SmartTop v1.0, Kleyman 3BFM (NoRegret Custom), Green Air Filters, *Mod. R170 ant.* EuroClear sidemarkers w/PIAA PlasmaIon lamps, chromed front & rear turn indicator lamps, PIAA SuperPlasmaGTX front parking lamps, HyperWhite license plate lamps ( To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts. Scott), bilateral rear fog lamps enabled. Last edited by etyu; 07-07-2008 at 02:03 PM. Reason: revised info

07-08-2008	#8 (permalink)
Dolebludger Elite SLK World Member Join Date: Feb 2008 Location: Yukon, OK Vehicle: '07 SLK 280; '04 C 320, '01 Honda S 2000, '98 Ford Ranger truck. Posts: 470 Country: Thanks: 38 Thanked 70 Times in 45 Posts	Where exactly is the crack on the front bumper? Is it on the rear-most part of that part of the bumper that tucks underneath the car? If so, this is a rather common problem. I got a very small crack there myself, in the same way. Fortunately, to see it, one had to lay down on the pavement and crawl under the front, face up. I didn't want the crack spreading further, so I cut a small, short strip of sheet aluminum and secured it to the back (inside) surface of the area of the crack with JB Weld. When this was dry, I masked the area while leaving only about 1'4" of area around the crack exposed. I sprayed the crack with some aerosol touch-up paint a local auto paint supplier mixes and sells, and polished it down with a fine polish when dry. If the crack on your bumper is in this obscure area, this may work for you. __________________ The SLK -- What the SL was supposed to be.

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07-06-2008	#3 (permalink)
bobsquad7 SLK World Member Join Date: Apr 2008 Location: OKC, Ok Vehicle: slk350 Other Toys: R1200GS, Freightliner Class-8-RV conversion Posts: 33 Country: Thanks: 0 Thanked 12 Times in 5 Posts	The bumper is an injection molded semi-rigid plastic. Go to your local body shop-paint supply store & get a product called Duramix 4040 (aprox $35.00) and a roll of reinforcing mesh ($5.00). (O'Reily's Auto Parts carries it in their paint dept) Also get a dual tube applicator gun ($ ?) - like a caulk gun but has twin plungers. (You may be able to borrow one of these from the store - or a paint & body shop) Prep the inside of the cover in the cracked/torn area with an 80 grit sanding disc. Rough-up an area a couple inches either side of the crack. Cut & apply a piece or two of mesh to the area & spread an even thin layer of the Duramix over the mesh. For maximum strength, apply 3 or 4 additional layers of mesh & Dura. This stuff set's up in a couple of minutes (or less - in warm weather) so get everything layed out & be prepared to work fast. Also, wear Nitrile gloves or plan on "wearing" the Duramix on your fingers for a week until it wears off. Laquer thinner won't even desolve it once it sets.

07-07-2008	#5 (permalink)
ghostdunks Elite SLK World Member Join Date: Feb 2007 Location: Melbourne, Australia Vehicle: SLK280 Posts: 208 Country: Thanks: 5 Thanked 3 Times in 2 Posts	thanks for the suggestions guys, I might give it a go later. I've heard good things about the Duramix stuff as well(made by 3M I believe) so that sounds like the right thing to use. Might as well learn to do it myself, I can see myself doing this more than once Now, got to figure out an easy way of taking the bumper off so I can fix it properly.

07-08-2008	#7 (permalink)
ghostdunks Elite SLK World Member Join Date: Feb 2007 Location: Melbourne, Australia Vehicle: SLK280 Posts: 208 Country: Thanks: 5 Thanked 3 Times in 2 Posts	yeah I remember his post as well, I used it a fair bit while putting in my own aftermarket HIDs

07-22-2008	#9 (permalink)
ghostdunks Elite SLK World Member Join Date: Feb 2007 Location: Melbourne, Australia Vehicle: SLK280 Posts: 208 Country: Thanks: 5 Thanked 3 Times in 2 Posts	Yeah, the crack "starts" where it tucks under the car but it ends somewhat high. Its not that noticeable but like I said, just want to stop it from getting worse. Update on this. Having a lot of trouble sourcing the 3M Duramix(renamed to Automix I believe) in Australia, from automotive stores we have around here(such as Autobarn, Supacheap Auto, etc...). They have stuff like "Plastic Weld" or "JB Weld" instead. Going to try and find some specialised paint & panel beating supply shop and see if they supply it instead, Failing that, I was thinking of the following. Use either "Plastic Weld" or "JB Weld" to glue the crack together, then on the hidden side of the bumper, reinforce the repair by using a fibreglass repair kit to add some reinforcement behind the crack. Then sand the repaired crack on the front side, and just paint it over. Anyone see any problems with that approach? I've never worked with fibreglass before, so not sure if it'll adhere to the back of the bumper, etc...how strong it'll be, etc..

07-22-2008	#10 (permalink)
bobsquad7 SLK World Member Join Date: Apr 2008 Location: OKC, Ok Vehicle: slk350 Other Toys: R1200GS, Freightliner Class-8-RV conversion Posts: 33 Country: Thanks: 0 Thanked 12 Times in 5 Posts	I don't know how compatible fiberglass cloth/resin or JB Weld would be with the bumper cover material. If you can't find Duramix at a pro body shop supply, try sending 3M an email requesting a source in Au. The "mesh" that most pro body shops use is available from home builder or lumber stores. It's also used to reinforce sheet rock (wall board) joints, . . .comes in a roll of aprox 100 feet and costs around $5.00 US. I don't believe fiberglass resin or JB weld would be flexable enough - not as pliable as the bumper.

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