A
Anonymous
I had a slightly damaged center front bumper caused by sleeping police men, and since it happens to others too, I thought to write a small paper on repairing it. It's not difficult to do, and if you're a bit handy it's not more difficult than baking an apple pie.
For a good repair you first need to make moulds, which you use to reproduce the damaged areas. There comes the first trick. You start thinking about repair, if the damage already has been done, so you can't really take a mold of a damaged area. In that case you need a second one, which I had, with a damaged corner. You can also get one from another car, because you don't damage or ruin the bumper you take the mold from.
Items needed for the reapair:
Aceton for cleaning the tools,
rubber Gloves,
disk roller for pushing out enclosed air,
Polyester and hardener
glasfiber , I used 120gr keper and 240 gr uniform
carnauba wax
release gel.
gelcoat.
in order to make a mould you need to be able to take it off after the applied polyester with glassfiber has cured.
There for you need to wax the original at least 6 times.
Be sure to wax a much larger area then you need for the mould.
after you've done that you need to run out the edges, so the polyester doesn't run around the edge, and locks the mold, unable to get it of in one piece. I use some styling foamboard for this, but any cardboard will do. just fix it with tape.
Then you need to add some release gel. I applied it with a spunge, for a good smooth finish, this will be the outside result of the finished reair, so the smoother it is the less filler and sanding you need in the end. I hate sanding, so I make sure it is smooth like, ......
Let it dry for about 4 hours.
Then you can start, prepare some pieces of glassfiber and mix the chemicals. Apply the polyester with cheap brushes and dapp the glassfiber until it gets transparent.
For a bit strength you need to apply at least three layers of fibre and polyester. Use the special diskroller to roll away trapped airbubbles. This is very important, because trapped air when cured is a hole, which needs to be filled afterwards, or in worst case makes the mould unusable.
(The picture has been taken later in the process)
After the mould has cured, you can peel it of, thanks to the layers of wax and release agent.
Cut off the sharp edges, and you got a perfect mould which you can use several times.
Next step is preparing the damaged part, so cut out the damaged area, including small cracks, since it is broken fibre, and sand of the backside where you will put the repair. Also chamfer the edges, so you don't have a big step.
Now you need to wax the mould 6 times, and add release gel to it. Then place it on the damaged area.
apply a small film of gelcoat. This isn't essential, but it gives a smoother surface, You can get it in transparant or colorised.
Let this cure for about 8 hours to 24 hours depnding on the temperature.
Again prepare the same as for the mould, and apply it to the damaged area
After it is cured, remove the mould and admire the result in silence.
You will need to sand it smooth, since due to capilar effects, you will have some gelcoat between the mould and the bumper.
This could be avoided if you add a bit more release gel and place the mould when the gel is still wet.
After that send it of to the paintshop for finishing the piece
Finally two pictures of the corner area I made of the other bumper I had lying around.
For a good repair you first need to make moulds, which you use to reproduce the damaged areas. There comes the first trick. You start thinking about repair, if the damage already has been done, so you can't really take a mold of a damaged area. In that case you need a second one, which I had, with a damaged corner. You can also get one from another car, because you don't damage or ruin the bumper you take the mold from.
Items needed for the reapair:
Aceton for cleaning the tools,
rubber Gloves,
disk roller for pushing out enclosed air,
Polyester and hardener
glasfiber , I used 120gr keper and 240 gr uniform
carnauba wax
release gel.
gelcoat.
in order to make a mould you need to be able to take it off after the applied polyester with glassfiber has cured.
There for you need to wax the original at least 6 times.
Be sure to wax a much larger area then you need for the mould.
after you've done that you need to run out the edges, so the polyester doesn't run around the edge, and locks the mold, unable to get it of in one piece. I use some styling foamboard for this, but any cardboard will do. just fix it with tape.
Then you need to add some release gel. I applied it with a spunge, for a good smooth finish, this will be the outside result of the finished reair, so the smoother it is the less filler and sanding you need in the end. I hate sanding, so I make sure it is smooth like, ......
Let it dry for about 4 hours.
Then you can start, prepare some pieces of glassfiber and mix the chemicals. Apply the polyester with cheap brushes and dapp the glassfiber until it gets transparent.
For a bit strength you need to apply at least three layers of fibre and polyester. Use the special diskroller to roll away trapped airbubbles. This is very important, because trapped air when cured is a hole, which needs to be filled afterwards, or in worst case makes the mould unusable.
(The picture has been taken later in the process)
After the mould has cured, you can peel it of, thanks to the layers of wax and release agent.
Cut off the sharp edges, and you got a perfect mould which you can use several times.
Next step is preparing the damaged part, so cut out the damaged area, including small cracks, since it is broken fibre, and sand of the backside where you will put the repair. Also chamfer the edges, so you don't have a big step.
Now you need to wax the mould 6 times, and add release gel to it. Then place it on the damaged area.
apply a small film of gelcoat. This isn't essential, but it gives a smoother surface, You can get it in transparant or colorised.
Let this cure for about 8 hours to 24 hours depnding on the temperature.
Again prepare the same as for the mould, and apply it to the damaged area
After it is cured, remove the mould and admire the result in silence.
You will need to sand it smooth, since due to capilar effects, you will have some gelcoat between the mould and the bumper.
This could be avoided if you add a bit more release gel and place the mould when the gel is still wet.
After that send it of to the paintshop for finishing the piece
Finally two pictures of the corner area I made of the other bumper I had lying around.
