Preparing to Shorten My Front Bumper Cover

[tektic]

Ok, So I have this bumper cover from a vr4 that's kinda mangled there's a crack on the bottom. It's missing the tabs in the corners.
I want to bring it back to life as a sleeker slightly redesigned version of its former self.

Goals are to :
1. Fix holes and cracks
2. Remove the remaining slats from in front of intercooler but then mold the plastic smooth so it doesn't look cut
3. Shorten about 2-3 inches but retain the fender liners and tabs that secure them.
4. retain some of the foam because People can't park in Manhattan
5. cover front opening with a stainless steel screen or other protective mesh
6. I might also cover the fog light holes haven't decided yet

I saw 2 shortening threads on here but neither went in to much detail about the front bumper. Oh I have a ggsx front bumper support and foam as well as the original ggsx bumper that I will be cannibalizing to get this project done. Does anyone know if the bumper support and foam is different than that of the VR4?

If anyone has had good experience with a flexible bumper filler I would like to hear about it. I'm going to try welding cracks using pieces of the ggsx bumper. I still think I'm going to need filler on the front. I have seen a few products but just their advertisements so I don't want to pick just by hype.

For the shortening I was leaning toward slicing the bumper strait down by the back of the corner lens taking out the desired amount of material then welding it back together so the original wheel edge will remain. then add a spacer to where it would bolt to the bumper support. Or possibly cut and remount the whole mounting tab. I don't know how feasible this will be as I have never worked in this medium before. I'll see how the repair goes first. For now I'm just trying to get experiences or feedback from anyone who has attempted a similar mod. I'm sure a few of you with the jdm bumpers had to do some repairs before paint.

Edit: Porche forum link

 

[G]

click

 

[curtis]

When I did the rear one on mine I just kept triming and pushing it in to the desired depth then where the ends went into the wheel well had to be cut. What you need to do is measure the distance on top then made a jig so you can cut the same distance around the radius. A small piece of wood with two holes will work and one sharpie marker as a marker and one as a guide on the edge. Tape everything well then mark and then cut with a jigsaw and clean up with a new half round file, dremel, die grinder with cartridge roll etc. You can look up my aluminum rear bumper thread in the how to section.

As for filler a few zip lock bags with spray foam inside may work. I use aluminum c channel to support the top then with it bolted down didn't sag so didn't use any foam around the rear bumper.

 

[tektic]

Bumper bully might be an answer for some, but where I park I have come back to my car a half a parking spot away from where I left it. I want to know I did everything possible to keep from having to do it again.

Foam in the bag sound like a better plan than cutting the stock ggsx foam. I used the same trick with bath tub installations.

Curtis did you add the tabs back on for the fender liners to connect? I'd like to try to avoid a raw cut edge if at all possible. I'd really like to try to take the space out from the middle and mend the two pieces back together. Did you consider this method?

Photoshop mock up cuz its too cold out and I board:

 

[89Mirageman]

A few years ago when I was taking autobody classes some guys came out and showed us some products made by U-Pol, one which was flexible bumper repair stuff. The stuff worked really well, much like regular body filler except it was more like the stock urethane once it cured. I'd look into something like that. It would look more professional if you put the tabs back on the part you cut off for the fender liners IMO like you mentioned.

 

[curtis]

No fender liner in the back and its even with the inside sheetmetal. When I attack the car again and do the build I'll just place clear tape over the metal and then fill with urethane or something and blend it in but it really isn't noticeable as it is.

 

[tektic]

u-pol 7061 is what I saw. I was between that stuff and the stuff that comes in the caulk tube size from urethane supply. I'm sure either will work just fine. I'm going to try to get some ss screen tomorrow and start the repairs. I don't know if I even have room to shorten this bumper with my ets core under there.

 

[tektic]

ok well today was an epic Fail. I tried a few different ways to melt and weld the crack in the bottom with no luck.
The bumper material gets hot and turns to a rubbery ash. It does no melt and flow. It skips that step and goes right to burn as far as I can tell. unless it's just too hot. I tried a soldering iron a heat gun and a torch i could not get the scrap pieces of bumper or the vr4 bumper to melt.

I'm going to do more research on flexible plastic fillers. As this seems like the only option now.

EDIT: I gave it another try with a soldering iron and it did melt but the two bumpers are different plastics. I couldn't find any markings on it does anyone know what type of plastic this is?

Edit2: Found PUR on the back. That means this bumper is made from polyurethane. This also means it does not melt and if a plastic welder is used it is used like brazing rod to adhere the pieces together.

 

[theevozero]

I just finished doing this to my front bumper and it turned out pretty good. I used some sort of body shop urethane epoxy(dont ask me what it is, my paint guy gave it to me), recycled fender, recycled bumper, rivets and body filler for blemished and sanding marks. The epoxy I used is very similar to the plastic the bumper is made from, so it can flex and not crack.

*edit* that flimsy piece below the mouth of the bumper has not been secured yet(obviously), I made brackets to pull it back into place.

 

[tektic]

Looks good. I need names though!

I'm looking at 3M Flexible Parts Repair Kit 05896 now. It's like $65 for 13oz.
I have to fill in a bunch of little spots I think that will be enough.

 

[curtis]

click me.... My buddy has one of these and have used it a bunch .... it will work. No I can't borrow it and mail it to you. Hard enough to get it when I need it. I would have to see it again but seems like urethane is like 325 degrees. Your probably double or triple beyond that temp today.

 

[tektic]

Lol, not even for like only a day?

Urethane doesn't melt it just burns. They have a setting but its like using a hot glue gun. It melts the media between the pieces. After coffee I'm going to the autobody supply shop. Their always dicks in there when I ask questions, but I don't know of any other place to get polyurethane adheasive in the quantity I need localy.

 

[89Mirageman]

Have you searched Youtube for bumper repair? Seems like I remember seeing a lot of nice videos on the subject.

 

[tektic]

for hours... Every one of them uses like 15 products a video though, or a $1500 welder. If I need $500 in supplies or buy a welder I rather try to find a good condition bumper and be done with it. I need to do this for around $100 plus paint, or it's just not worth it.

 

[89Mirageman]

Gotcha and I agree most of this stuff is very overpriced if you only plan to use it once.

 

[theevozero]

The main ingredients I used were made by 3M. PN: 04240 is a 2 part plastic welder epoxy and its a semi rigid. I used this on the sheet metal and flat plastic pieces, to help hold it together and give it some rigidity. The other is PN: 05887 also a 2 part epoxy, this one is flexable and has a 24 hour cure time. I used this on the outside surface of the bumper, the parts that would be painted to avoid visible cracking. The most important part is the adhesive promoter, still 3M product, PN: 05907 and it comes in a spray can. Would you like to know more?

 

[theevozero]

 

[tektic]

That's a nice job. I bought a sem quick set 50 or something like that. I fixed my crack on the bottom and remaid the tabs in the corners. It took a long Damn time to trim the foam backing and stuff it in the bumper cover. Wish I had another set of hands. I need this bumper on to get this car inspected, so I think the fabrication has to wait untill I'm ready to paint the whole car. I'd love to chop the bumper now but the condition of the rest of thebody doesn't warrent more work without addressing everything.

There's a 2 inch hole saw hole in the pqssanger side I still have to patch but after that its just getting a light sanding and some white rustolium. Unless someone knows a rattle can color that matches summit white better.?