I mentioned a while ago I would take some pics and post a bit of a write up on this so here goes. Please note that this is done with a non Urethane bumper off a Nissan pathfinder, there is no plastic welding involved and the techniques used here are much the same on a Urethane bar but you need to be a little more carefull. Also this is a car yard repair so I am a little less picky with the work - they dont give us a lot of money for this stuff. First pics of the damage, sorry about the crappy phone shots but it was all I First I use a heat gun and gently heat the damaged areas so I can manipulate it closer to the original shape. I do this in stages - that is I dont try and push the bad dents out in one go nor the large areas. first I will try and do the deep gouges with a large plastic screwdriver handle or similar then the larger shallow dents with a dolly or similar this is done until I am happy that the damage is relieved as much as is practical and then I sand with 180 grit or similar (I dont use anything coarser as it causes the plastic to get very fluffy and harder to prep) Here you can see there was previous damage that had cracked and had to be repaired as well. once we are happy all loose paint etc is removed and the bar has been sanded enough the filler comes out in this case UPOL's dolphin glaze. this product is suitable to put over scuffed paint as well so it makes feathering the edges out easier. I also sand this with 180 (although if I need to get a lot off to start with I may hit with 80 quickly) to get this sort of result and then we send it off to get primed This bar was damaged in 4 seperate locations so we primed the whole bar.
Nice. The front bar I have could do with a bit of tweaking where it meets the guard just below the head light. So if I loosen the bolts i can push on it in the right spot and it matches the guard perfectly. but when I nip the bolts back up and take the pressure off it moves and creates a step between the two. How thick can I go with body filler on urethane.
I would not normally use filler to fix something like that, rather try and find why its not lining up, something must be in the wrong place to be causing the mismatch it may be your bar (slightly warped from a hit) or the guard is slightly in the wrong place or similar. As a rule building an edge up with filler is too easy to have chip and look like crap. but in the end it may be unavoidable. my hybrid bumper has bog on the uerthane some of it is up to ~ 3mm thick in this case I used 80 grit to make sure it was quite rough. this bumper took a good low speed (10kph or so) into the leg of my engine crane and flexed it in enough to damage my radiator overflow but did not crack any filler was as close as 20 cm.
