|Rover 800 Plastic Bumper Repair (Soldering ABS Plastic!).|
Car: 1999 Rover 800 820 Auto Fastback
Colour: Charcoal Grey / Black
Although we had attempted to repair this rear bumper on a previous occasion, the previous repair was just done from the inside of the bumper, trying not to ruin the look of the paintwork on the outside. Subsequent knocks by yet more careless drivers had since caused the split in the bumper to re-open! (we should of perhaps soldered it right through in the first place!). Plus this time the bumper was really hanging loose at the brackets on the sides of the car!
Again by the time we got round to repairing the rear bumper the split had continued to open wider and wider and was getting more and more obvious.
This time we wanted to do a proper repair and we were considering buying a plastic welding device, but any of those that seemed even half decent were priced from £60 upwards, which we did not want to spend!
After watching a couple of repair videos on youtube we then realised that we had a better quality soldering iron than that which we had used the previous time, and should perhaps give welding with a soldering iron another go!
The welding devices come with plastic rods to melt into and reinforce the existing plastic. With these ABS bumpers we would need some more ABS plastic too! Luckily we had kept the piece of door trim that we had bought from the scrap yard when we required the replacement chrome strip for the rear passenger door, and so we could use this ABS if we needed some.
The rear bumper is back to having an open wound!
Using strong tape the gap in the bumper was closed up so that we could begin to weld parts of it.
To keep the two sides of the split level, a hammer was wedged under the boot lid to begin with.
The paint was scraped off wherever we were going to melt the plastic.
After using a soldering iron (with a cutting knife type tip) to join the parts either side of the silver tape, the tape was then peeled back, and the paint was again scraped ready for more soldering to begin.
The two sides of the crack were joined by melting the plastic on either side of the crack with a soldering iron, whilst melting in more ABS where needed.
The bumper was now easily strong enough for the second piece of tape to be removed.
Although most of the crack had now been welded together using extra ABS where needed, (you can see the strip of ABS on ground)(it's a piece of door trim with the paint sanded off!), the end part of the crack was a small problem.
The far end of the crack was not level and was too tight to move into a level position, and so the soldering iron was run through the crack to open it up, allowing it to then be levelled.
The far end of the crack was soldered up the best, this was because we had soldered it through the full thickness of the bumper, and so this part was back to full strength.
We then went back along the crack repair again, this time going deep with the soldering iron all the way along the crack adding in a lot more ABS as we went. The bumper now looks and feels far more solid than when we started.
To the right of the rear bumper was another crack. Although this did not look too bad, it was another weak spot in need of a repair.
Here the bumper was sliced through its depth with the soldering iron.
Running the soldering iron through the opened crack to heat up the plastic, whilst melting in more plastic as needed, soon had this side filled.
After the soldering was finished the repair was sanded down flat.
This repair was sanded down too.
At this point the bumper was removed from the vehicle, so that the new rear bumper brackets could be fitted to the car.
With the bumper off the car, the crack repairs were masked and a small amount of flexible isopon bumper filler (rather than car body filler) was added.
The tape was removed so that the area could be sanded flat once more, and more isopon bumper filler was added as required.
More filler was added this side too.
With a small block and some fine wet & dry paper used wet, it did not take long to get a better finish than originally expected!
We thought because the bumper wound had been open for so long that it had changed shape and would still have an obvious bulge or ripples when repaired, but this was not the case. It is amazing how plastic bumpers can spring back to their original shape!
The bumper was masked off with some newspaper, ready for priming.
The repairs were primed using ordinary primer, because we had run out of plastic primer! ..but this should not cause us too much of a problem as it is only a small area being painted, and most of the primer is being painted onto existing paint, rather than just on to plastic.
With the newspaper removed, the bumper repair was looking good.
A tiny bit more filler and primer may be required before the bumper receives it's top coats, but that was not going to get done at this time, because we needed the car back on the road!
With the new rear bumper brackets fitted on the car, the back bumper was refitted so that the car could now continue to be used.
The rest of the painting would have to wait for another day!