Bumper and Bonnet

A

Aeroadster

Member
Hi everyone, I currently have an aero front bumper which has a crack on the side. My dad thinks it can be repaired with a plastic welder but needs to know what plastic material the bumper is made from, i.e. is it ABS, PVC, PP, Polyurethane, thermoplastic/thermosetting etc...

The other option is to put an M bumper on but I'm unsure of what parts are mandatory to retrofit. I think I have the standard undertray with the aero bumper, so will need the M undertray? Also, I think I've read somewhere that different arch liners are required as they are different from the bottom left and right corners where the bumper attaches on to them?

I'm also interested in replacing the bonnet with an M bonnet. I believe these have different bonnet catches/locks to standard bonnets? The car is a 3.0i pre-facelift. Will this be possible?

Any help is greatly appreciated.

Thanks.
 
Aeroadster said:
I'm also interested in replacing the bonnet with an M bonnet. I believe these have different bonnet catches/locks to standard bonnets? The car is a 3.0i pre-facelift. Will this be possible?
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My understanding is pre-facelift have a single catch at the front; facelift have a catch on each side. So I guess that means an awful lot of work to accomodate an M bonnet.
Quite happy to be corrected though, as my son fancies doing it with his zed too.
 
So just tried ABS plastic welding rods with a hot air plastic welder. It does not seem to stick to the bumper - it just melts with bubbles and makes a mess that you can easily just pull off. I prepped the cracks up properly; sanded to remove any coatings to expose plastic and then thoroughly cleaned with isopropyl alcohol. I tried PP welding rods too, but they didn't seem to bond either...

I cant seem to find any writing on the back side of the bumper which should indicate what type of plastic material the bumper is made from...
 
I'ts PP or PE. (My guess is PP)
There must be stampings inside the bumper that say so.
Are you sure your heat transfer in the base material is ok?
Plastic welding is a real artform

It's certainly not ABS or PVC.
If that was the case, glueing (with an aceton/mek/solvent based glue) would be an option ;)
But alas the bumper material from modern cars is always completely solvent inert.
 
GuidoK said:
I'ts PP or PE. (My guess is PP)
There must be stampings inside the bumper that say so.
Are you sure your heat transfer in the base material is ok?
Plastic welding is a real artform

It's certainly not ABS or PVC.
If that was the case, glueing (with an aceton/mek/solvent based glue) would be an option ;)
But alas the bumper material from modern cars is always completely solvent inert.
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Thanks for your reply. The bit of plastic which has the stampings is missing at the very bottom of the bumper beneath the centre grille. I could only make out the part number. Searched the part number but it doesn't state the bumper material. Heat transfer seems ok, I try to heat both the base material and welding rod (pendulum technique) and gently apply downwards pressure on the rod to give better rod penetration/adhesion to the base material. I have tried ABS, PVC, PP and PE to no avail. I will try some TPO plastic rods....

Thanks.
 
I managed to find a picture of the stampings...

20190810_221914.jpg

I'm assuming >PUR GF20< is the identification code of the plastic and the material used to manufacture the bumper?

I'm guessing this also stands for Polyurethane Resin with a 20% Glass Fibre mix?

Does anyone know if this can be repaired/plastic welded? As I think this may be a cross linked thermosetting plastic which may not reshape/melt upon heating...

Any help is greatly appreciated :thumbsup:
 
^thats a surprise. it would mean the aerobumper is different than the stock and m bumper.
First of all check with a soldering iron if its actually a thermoplast; PU is thermosetting.

I have seen aerobumpers repaired (a friend of mine had one with a tear in it), but I dont know what they used.
It was done by a professional shop.
If its really PU, thus thermosetting, welding of course becomes impossible... so you have to resort to some kind of glueing, probably with a mat or gitter in there.
(that surface texture sure doesn't look like PP though)
 
I've repaired many cracked bumpers over the years just by heating the area up and basically melting the crack together, cool off with water sand down usually with a mini DA and a skim off filler and then the usual steps to repair and paint
 
Aeroadster said:
I managed to find a picture of the stampings...

20190810_221914.jpg

I'm assuming >PUR GF20< is the identification code of the plastic and the material used to manufacture the bumper?

I'm guessing this also stands for Polyurethane Resin with a 20% Glass Fibre mix?

Does anyone know if this can be repaired/plastic welded? As I think this may be a cross linked thermosetting plastic which may not reshape/melt upon heating...

Any help is greatly appreciated :thumbsup:
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I think you didn't managed to find a pic. Somebody took it form his bumper for you because you were "interested in buying it". Meaning that the seller had to remove his lower grill so you can have the information you were searching for. The point is, you could at least have answered the PM, or directly asking for that part of the bumper...
Good luck with your fix, and let's hope you're not going to have to buy another bumper :wink:
 
SloanRH4 said:
Aeroadster said:
I managed to find a picture of the stampings...

20190810_221914.jpg

I'm assuming >PUR GF20< is the identification code of the plastic and the material used to manufacture the bumper?

I'm guessing this also stands for Polyurethane Resin with a 20% Glass Fibre mix?

Does anyone know if this can be repaired/plastic welded? As I think this may be a cross linked thermosetting plastic which may not reshape/melt upon heating...

Any help is greatly appreciated :thumbsup:
Click to expand...
I think you didn't managed to find a pic. Somebody took it form his bumper for you because you were "interested in buying it". Meaning that the seller had to remove his lower grill so you can have the information you were searching for. The point is, you could at least have answered the PM, or directly asking for that part of the bumper...
Good luck with your fix, and let's hope you're not going to have to buy another bumper :wink:
Click to expand...

My mistake, I do apologise. I did say I showed interest in buying the bumper but I wasn't 100% on it after I realised you were overseas. Hence why I just asked for the number. Sorry if I was unclear at the time and I am happy to remove the picture if you don't want it on here. PM replied to.

Thanks :thumbsup:
 
Hi, yes I tried plastic welding it but only with PP, ABS and PVC rods, which are obviously the wrong plastics to use. I then later found that it's a thermosetting, which cannot be plastic welded, so it went in the bin lol.
 
Aeroadster said:
SloanRH4 said:
Aeroadster said:
I managed to find a picture of the stampings...

20190810_221914.jpg

I'm assuming >PUR GF20< is the identification code of the plastic and the material used to manufacture the bumper?

I'm guessing this also stands for Polyurethane Resin with a 20% Glass Fibre mix?

Does anyone know if this can be repaired/plastic welded? As I think this may be a cross linked thermosetting plastic which may not reshape/melt upon heating...

Any help is greatly appreciated :thumbsup:
Click to expand...
I think you didn't managed to find a pic. Somebody took it form his bumper for you because you were "interested in buying it". Meaning that the seller had to remove his lower grill so you can have the information you were searching for. The point is, you could at least have answered the PM, or directly asking for that part of the bumper...
Good luck with your fix, and let's hope you're not going to have to buy another bumper :wink:
Click to expand...

My mistake, I do apologise. I did say I showed interest in buying the bumper but I wasn't 100% on it after I realised you were overseas. Hence why I just asked for the number. Sorry if I was unclear at the time and I am happy to remove the picture if you don't want it on here. PM replied to.

Thanks :thumbsup:
Click to expand...
I don't mind the picture, I'm ok with it. It's just I think you weren't interested at all at the time writing the PM...
Anyhow, it's all ok now and I'm also interested in the thread, since my bumper, as you could see it's not in perfect shape either. Maybe it's not fixable "with heat", some chemical binding should be available. I'll have to search about it, since I also thought it was ABS.
 
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