Repairing my shortened rear bumper

[straight6pwr]

wow looks very nice! excellent work, and i think you owe 80s book guy a thank you.

[Jand3rson]

Just got finished primering the bumper and trim after finishing up all the repair work. There were still some air bubbles and low spots after the last application of plastic epoxy, so used filler and pot putty to fill and even them out. After that was all fixed, I cleaned the whole surface thoroughly with acetone, then plastic cleaner/prep, then put on 3 light coats of adhesion promoter, and then 4 coats of high build primer.

Here's how everything came out after the last coat of primer. See any seams? No, you don't.

[Jand3rson]

Got some more sanding done and realized I'd been taking a lot of actual material out of the surrounding bumper plastic as well, and made some low spots, so I'm going to have to skim some more in there to get it leveled out again. No biggie though, I'd rather use this stuff than Bondo.

I fucking hate Bondo.

[Jand3rson]

Did some more work today, got the plastic epoxy from yesterday sanded down to level.

Borrowed an orbital sander from Andrew, made short work of taking everything down:








As you can see from the pics tho, this stuff tends to make some air bubbles as it's drying, so I did a small skim coat over the top of all 4 of the seams to fill them:

[Jand3rson]

Yah, I know about plastic welding, I just don't have access to one. I used this for repairing the broken corner of my front bumper, and it worked amazingly well.

The book does cover modern plastic welding, it's a really awesome book. I would definitely recommend picking it up if you do any kind of plastic work like this.

[straight6pwr]

I wasn't sure something like this was even possible.

did you know you can 'weld' plastic, which is probably the way i would have went for this project. it chemically melts the two pieces of plastic together, essentially creating one piece that is as strong as the original.

however, this way is very acceptable as well. looking forward to progress! does that book even cover modern plastic welding? circa 1985?

[Holland]

I wasn't sure something like this was even possible.

[kamotors]

body work can be fun, I had lots of fun rebuilding my car last year.

[Jand3rson]

I really like doing this sort of thing, so I have a good time with it.

[Holland]

Awesome. looks like fun.

[Jand3rson]

Since I've got my car torn apart in all kinds of different ways, I figured it was about time to fix my shortened rear bumper. We did an awesome job on the backside of them, using fiberglass to bond the sections back together, but on the frontside, we didn't use the right method, and the seams cracked through to the paint. We simply filled the gap in the seam with epoxy, and there was nothing really holding the 2 parts together in the front.

About this time last year, I picked up an AWESOME book:



So what I did it stripped an area about 2" each direction away from the seams back down to bare plastic, then used an orbital to get the surface level. Then I used an air-tool with a sanding head to grind a v-channel out on top of the seam. I also drilled several small holes along the inside of the channel for the plastic epoxy to settle into, creating more holding strength by kind of stitching the 2 parts together:





Here's the top of the bumper, where I did the same thing:




Also did the same for the bumper trim, and this is with the first application of plastic epoxy, I'll probably have to do a little more filling once I get it smoothed out: