Bumper fix

Recently our lovely little Freelander was rudely assaulted by an old MR2, the un-insured hit and run driver must have taken most of the front corner off his red MOT failure (reg K531CBO, if found inform Bedfordshire police) before speeding off into the night.
This left our car with a ten inch gash in the rear bumper. Now normally the simplest fix is to buy a second hand item and bolt it on, but this car is still new enough for spares to be pricey, and also I really didn’t feel like spending another afternoon away from my family fitting the damn thing.
So it was time to try a spot of plastic welding, this may sound complicated but actually it is no more difficult than most other ‘normal’ DIY jobs.
Firstly I should point out this only works on thermoplastic bumpers, they are the more flexible ones. Harder glass filled nylon or fibre glass GRP bumpers need gluing instead.
Thermoplastics can be melted and reformed, so the basic principal is to get the damaged part of the bumper hot enough that it can be re shaped back into something approximating the original profile, then get the split hot enough to melt and flow back together again.
A word of warning; heat guns can melt more than just the bumper, it is vital to ensure that fuel lines and wiring etc. are not going to get hot during the operation. The second safety point is that the plastic will be scolding hot, so don’t touch it!
Back to our Landy, to do this job I used an ordinary DIY style heat gun, usually used for stripping paint of windowsills. Moving the heat gently across the whole damaged area softens the plastic enough for the creases to be eased out by running the rounded handle of a screwdriver along the inside, working each section a little at a time so as not to create further distortions.
Unfortunately the plastic has stretched in the collision, so some material has to be removed from the split area. I did this by heating a large flat blade screwdriver with the heat gun and running the tip through the split whilst waiving the heat gun over the plastic, its a bit like soldering or gas welding, the hot tip ensures the edges of the split melt and can then join together.
Once the joint is complete and the bulges and creases are smoothed out, there is a surplus of material around the joint. This has a smooth surface which does not fit in well with the textured surface of the original, to get a rough approximation I pressed a course weave cloth against the joint whilst it was still pliable.
In my case I just wanted the split strong and safe again so I only spent a few minuets on it, but if you take your time and gradually work the material into the original shape you can get an invisible mend, saving a fortune on parts and workshop time.

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