I just picked up my idea of a 'deal' $200 for an aero front bumper matching my pepper white, with the lower grill.

http://chicago.craigslist.org/chc/pts/2979854038.html

*But, all that glimmers is not gold. The bumper has been cracked in about 3 spots noticeable by the pink filler. Now I've got 4.5 years dealer experience as a mercedes and audi technician so I never shy away from a challenge, but body man- I am not.

So here's where we are. I've recently ordered 2 cans of pepper white spray paint from here:

http://www.automotivetouchup.com/cho.../buypaint.aspx

Luckily for me the chap I bought it from did not own a mini; rather, he worked at a body shop. I figure this is where he acquired the bumper. He assured me the cracks were repaired with a flexible plastic bonding agent, NOT bondo which I know believe would crack apart on a flexible bumper. Basic prep has been done in the sense that the cracks are filled and sanded smooth.

I need to:
-Clean and lightly scuff all surfaces of the bumper.
-Primer whole bumper, re-sand and paint, multiple coats with light sanding in between.

If anyone has experience with painting and would like to give me any advice, much would be appreciated. I've read about 'adhesion promoters', 'anti-dust coating', and not sure about the grit of sand paper I should be using between coats of primer, basecoat and clear coats??
Advice?

 

Mine would be talk to your local mini dealer, find out who does their work. have them paint it. prob be about another 200 and you'll be happy with the results. spray canning it.. something that big and flat it's going to be very difficult to get a good look. even if you get all the conditions perfect, u still need to clear coat it and with no practice that is reallly not easy..

here is a thread with some basics..https://www.northamericanmotoring.co...-pictures.html

i would use the 320 grit, clean with distilled water, dry with ?, use a tac cloth, spray with the adhesion promoter, primer, sand, paint, then follow the steps in the thread for sanding painting sanding. the clear coat is best in thicker layers but not so much that it runs. if the paint or clear coat runs you can sand it but don't rely on that. do all of that in a garage NOT outside. proper ventilation a plus just maybe it will come out to your approval or save yourself a huge headache and have a pro do it..

there is somone on the site with capt in their name who give you advice but the best advice for a piece that big is let someone do it that does it for a living. the people your dealer recommends do this all the time.. & Good Luck!!!

 

Thanks! I appreciate the tips. I'll be avoiding the body shop as I'd always like to try a DIY before shelling out cash. Worst case scenario it turns out bad, sand it down and then bring it to the body shop to have them paint. Best case scenario, it looks fine after prep, prime, paint and clear and I saved a load of dough.

I'm also considering filling in the center grille and having the bumper flat in that portion. I believe some people refer to it as ''shaved'' or ''smoothed''. Either way, all I know is that I've hated that pointless center grill since '02 when I first saw these cars.

I've decided to turn this into a bit of a show as I go. I'll be posting pics as I modify the bumper to fill in the center grill area and as I prep and paint. I hope to help shed light to anyone else attempting this type of project if all goes well. If all goes bad, then I hope my posts and pics will discourage anyone else from tying this themselves

 

Good luck bud, sounds like fun!

 

Ah Yes Act_04 I saw a thread you posted in just a week ago and clicked your link in your sig. Great looking R53! So clean with the middle grill filled in!

 

Thanks. Sadly I cannot offer any words of wisdom because I have never done this myself. I had planned to fill in the lower grill area on my non-aero bumper since it's just lying around, but have never done it.

 

Since you're attempting this DIY and will be installing the front bumper, please keep me updated as to the fitting of your front bumper. I installed my front aero bumper and could do a better job fitting it a bit better. I'm not a body nor mechanic so I can't figure out what to adjust to fix some of that gap.

I may bring it to a body shop one day when I'm not lazy

 

MrCooperS- I haven't fitted the bumper yet, but when I do I'll be likely fiddling with the adjustment screws to get it to sit right. I'll let you know when that time comes.

 

Time for an update of actual progress. Lots has been learned through trial and error primarily.

Start with the Before:



There were slight imperfections on the bumper noticeable by the pink bondo-looking areas. I hate the center grille's on the gen 1's and always thought the best looking part of the GP was its lack of the center grille. So the project begins...

Dremel 543 cut off wheel for plastics: (works GREAT!)



I cut from the rear of the bumper flush against the back of the bumper itself to remove the recessed center grille mounting area:





From there I cut out the 'recessing' lip around the edge of the piece I had just cut out, so that that center cut out strip would be flat and flush:



From there I wanted to reuse this center strip and reglue it back to the bumper flush to help 'fill in' that center grille area:



I reglued that strip in using Bondo Bumper Repair. Works EXCELLENT. It is specifically for bumper cracks. It is strong and flexible and sandable, thus making it the perfect product for gluing in that center strip flush to the bumper.



A couple pics to show the epoxying of the center strip in place:

 

Once the Bumper Repair Epoxy was cured I felt I was 1/2 way there with the center grille removal. The first process was to remove that center recessed mounting location, cut flush and reglue so now the only recessed portion was the rectangular strip down the center that would have to be filled in with some sort of filler.

I could have cut out this center recessed rectangle and attempted gluing that part flush to the center strip/bumper however I left it be for stability/reinforcement.

I started out using a tube of Bondo 930 Glazing Putty. This stuff is flexible enough not to crack, dries strong and is sandable. Be careful though, the first tube I bought ended up being rock solid.



I used this glaze to fill in the cracks or 'seams' around the center strip that was glued in. The glaze is strong enough to fill in the small holes where the grille's mounting tabs would have gone through. However, I would recommend using some mesh for support of any holes being filled:



Since 1 of my 2 tubes ended up being garbage I took a 20 minute drive back to O'Reilly's. They returned it just fine but they were now out of stock of the UV 930 Glaze. I also cleaned them out of their Bumper Repair Epoxy They only had 2 tubes of each in stock.

I would recommend anyone attempting this to buy everything in bulk online. Probably 4 tubes of the black epoxy Bumper Repair stuff and 4 tubes of the 930 UV Glaze should be okay. The more the merrier so you don't run out.

Since I was in a pinch I tried out this Bondo 801 Spot Putty. Bad mistake. I tried to use it to fill in the center rectangle but it clearly says on the back not to apply heavily or in anything other than thin layers or else it will crack DOH!



It all cracked up like expected:



Now I was really in a pinch. I needed something to fill in that center rectangle that would be liquid enough to also fill in all the cracks of the putty. I tried out the regular Bondo body filler. I read everywhere online that it would crack on a bumper...so I don't know what the heck I was thinking besides desperation.



Oh well... here goes:



I then sanded everything down with a sanding block and sheets of 150 and 220 paper *DRY. Don't attempt to wetsand, it doesn't work as well on the 930 glaze or Bumper repair epoxy as what dry sanding does.

In hindsight I should've sanded up to about 400 and ensured that I got all my imperfections out before painting. 150 was really too rough before paint as all its grooves showed up in the primer, only to be sanded out later...

 

Finally moving on to paint I sprayed the bumper with 3 or 4 coats of grey primer / filler. Nothing special there. I didn't end up using any adhesion promoter as I wasn't really painting any areas of bare plastic.

Hindsight is 20/20. What I should have done is either never used that Bondo 801 red putty or the regular Bondo body filler. The cracking inevitably showed through and cracked the layers of paint. Can't tell by the pictures:



And base coat:



So 2 problems I encountered here: I should have sanded everything down enough to put a final layer of the Bondo 930 glaze over the top of everything to prevent any of the body filler cracking to work its way up to the paint. Another thing, before painting I really should have used a large 4-6" sanding wheel on a rotary wheel to really grind down everything smooth. I feel areas of the bumper that raise due to fillers/epoxy.

All in all I ended up sanding down the entire center portion again after painting with basecoat due to cracking. I really picked away at the bondo and red glaze 801 putty (The primary culprit of cracking) and refilled those areas with fresh Bumper repair epoxy. Everything got a good dry sanding of 150, 220 and finally 400 grit.


With no more cracking I went back to a couple layers of primer followed by wet sanding of 400 after first coat and 600 wet sand thereafter.



I don't have pictures any further yet but I went ahead and applied about 4 coats of base color sanding with 600 between the first couple and working up to 800 wet sand in between the final coats.

I now need to apply the clear coat and then tape off the black trim around the edges and repaint those areas with flat black. Not sure whether to use clear coat after spraying the flat black or not...


All in all it looks much better now but I can still notice imperfections mainly areas that raise due to epoxy. Again If I were to do all over again I would sand totally smooth using a sanding wheel to ensure that everything is totally flat and even... something a sanding block couldn't fix.

More to come as I progress. I will be back down to the garage in about 2 weekends to hopefully finish up the painting so long as there are no more surprise cracks.. Then I'll post pics of mounting and the final product.

 

cool, i have a cooper S bumper i've been "thinking" about working on. that dremel tool is exactly what i was looking for cutting out my mid grille

 

rustyeuro, That bit worked wonders. I think I got totally ripped off at my local true value, $31 Now I see that cut off wheel should've been more like half that price.

I mainly wanted something that was going to *cut* the plastic though and not melt it and this did exactly that. Cut through the plastic very nicely without any awful burnt plastic or melting.

 

Keep us posted on how that holds up. That's a lot of bondo for a bumper. They tend to flex quite a bit. Ideally it's best to plastic weld ABS plastic on it then use little amounts of filler to smooth out any imperfections.

 

Evasive- can you confirm that the bumper material is indeed ABS?? I looked for stampings on the the backside of the bumper and although I saw part numbers and other jumbled letters I did not see ABS anywhere on it.

I even tried to use the recessed 'lip' that I cut off the center strip along with a soldering iron with a flat tip to try to melt/fuse the center strip back on to the bumper from the back side but the meltings would dry too quickly and did NOT want to stick to the bumper even though it was all the same material...

 

Pretty sure they're ABS. Below is a description of the rear bumper on out motoring.

http://www.outmotoring.com/mini-coop...ar_bumper.html

I've welded plastics before back in my old VW days and used the tool below. It plugs in an air compressor and blows hot air to fuse the plastics together.

http://www.outmotoring.com/mini-coop...ar_bumper.html

 

Man that is a lot of bondo man. The front bumper flex's so much that I can't see how it won't deform or crack. You may want to get a professional opinion from a local shop before you spend money painting it and it all comes apart.