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Looking to see the best way in repairing this crack on the OEM lip.
Did some research and was thinking:
1. Sand down the finish around the crack
2. Remove the rivets from the bracket
3. Reinforce with hot staples from the back
4. Apply epoxy adhesive (JB Weld plastic bonder? bumper weld? 3M bumper repair kit?), not sure what type of plastic the lip is though. It was ">PPE<" stamped.
5. Dremel a ridge on the from of the lip and apply flexible body filler. Maybe USC Flexible Glaze or 3M EZ sand?
6. Sand, paint.
I do stuff like this at work all the time. I actually have to repair my AP2 lip in two places. The steps are pretty simple:
1. Drill a hole at the top of the crack to prevent it from spreading. This is SUPER important. If you don't, you run the risk of the crack spreading. It only has to be a small hole.
2. Sand the area so it's course. I would use like an 80 grit on the front and back about 2-3 inches around the area.
3. Use a plastic welder from the back. That will help keep it together structurally. (We don't use these on aircraft, just fiberglass, but this is a great tool you can use on car bumpers.)
4. Buy fiberglass patches and cut 2 layers: small and medium. This is just to reinforce the lip, the plastic weld is doing most of the work. Dab some resin onto the lip with a brush and lay the fiberglass over it. Dab resin over the fiberglass and lay the second layer on it. Dab more resin on the top layer.
5. Use a dremel to make a slight V-groove on the crack at the front. Shallow, like 1-2mm at most. The resin needs a place to rest rather than just going over the top of a flat surface.
6. Since it's near a mounting hole, I'd do a layer of fiberglass over the front. This will help reinforce it a bit more. Pull the fiberglass taut across the groove. Same method as above.
7. Add body filler over the repair.
8. Sand smooth and paint.
Take your time and make sure each layer dries completely before moving onto the next step. That means give the plastic welds time to cool, so like 30 minutes, and make sure the fiberglass is cured before sanding. If it's polyester resin, I'd give it like 24 hours to cure. If you use epoxy resin, that stuff takes like 48 hours to cure but is stronger. Good luck!
I do stuff like this at work all the time. I actually have to repair my AP2 lip in two places. The steps are pretty simple:
1. Drill a hole at the top of the crack to prevent it from spreading. This is SUPER important. If you don't, you run the risk of the crack spreading. It only has to be a small hole.
2. Sand the area so it's course. I would use like an 80 grit on the front and back about 2-3 inches around the area.
3. Use a plastic welder from the back. That will help keep it together structurally. (We don't use these on aircraft, just fiberglass, but this is a great tool you can use on car bumpers.)
4. Buy fiberglass patches and cut 2 layers: small and medium. This is just to reinforce the lip, the plastic weld is doing most of the work. Dab some resin onto the lip with a brush and lay the fiberglass over it. Dab resin over the fiberglass and lay the second layer on it. Dab more resin on the top layer.
5. Use a dremel to make a slight V-groove on the crack at the front. Shallow, like 1-2mm at most. The resin needs a place to rest rather than just going over the top of a flat surface.
6. Since it's near a mounting hole, I'd do a layer of fiberglass over the front. This will help reinforce it a bit more. Pull the fiberglass taut across the groove. Same method as above.
7. Add body filler over the repair.
8. Sand smooth and paint.
Take your time and make sure each layer dries completely before moving onto the next step. That means give the plastic welds time to cool, so like 30 minutes, and make sure the fiberglass is cured before sanding. If it's polyester resin, I'd give it like 24 hours to cure. If you use epoxy resin, that stuff takes like 48 hours to cure but is stronger. Good luck!
Thanks for the detailed response. I'm not able to pinpoint the type of plastic used on the lip so would something like
for the front? Would using fiberglass in the front still allow for easy sanding (mostly concerned about the visible curved area) or should I just place a layer near the mounting hole to reinforce the rivet?
Reinforce rear/backside (after 80grit scuff) with patches smothered in JB or 3M bumper repair epoxy. It's unseen, so use as much JB/epoxy and patches as you'd like. Plastic weld sucks imo (it just cracks, it's thin and super brittle). Patches in backside will give plenty/extra strength and more thickness.
For the front, fill crack (after sanding it down flat or with slight V groove) w/ 3M bumper repair epoxy, sand down. Then finish with filler/primer/sand until smooth.
25146960]Thanks for the detailed response. I'm not able to pinpoint the type of plastic used on the lip so would something like JB Bumper Weld be sufficient for the backside and USC Flexible Glaze for the front? Would using fiberglass in the front still allow for easy sanding (mostly concerned about the visible curved area) or should I just place a layer near the mounting hole to reinforce the rivet?
yes, you can still sand the fiberglass smooth. It won’t be perfect but it’ll be close. It’ll take some work but you can do it. The goal is to reinforce the plastic.
If you want, use three layers on the back and then use a filler on the front. The three layers will be pretty strong. I’d still make the V-groove to allow somewhere for the epoxy to sit. If not, it’ll just rest over the crack and not actually support it.
The plastic weld and fiberglass will be strong in conjunction with one another so the lack of a layer on the front won’t detriment the repair. I WOULD however fiberglass the front where it broke near the tab. That is necessary to reinforce the tab, unfortunately. It needs to extend out some to reinforce past the bend in the lip. This is mandatory otherwise the tab area will crack again.
I wouldn’t do this without the plastic welding and fiberglass though. It’ll just crack again.
Edit: OEM bumpers are usually made from polypropolene.
Last edited by MaintenanceObsessed; Feb 6, 2026 at 06:31 PM.
Getting started on the front lip repair and repaint. The lip came tied at the fracture point. Structurally not too bad The lip is pretty light and rigid. No wonder it cracks easy. Some clear coat burn. Unfortunately it's close to the mounting tabs Small hole to prevent the crack from spreading Put some foil tape to reinforce the crack. Ended up drilling out the rivets to see how close the crack was to the mounting area. Looks like someone else tried to repair the area with a welder. Sanded with 120 grit. Made a shallow bevel to see the crack clearer. Hot staple time Impressively they provide a lot of strength. Little to not flex. I clipped off the ends and ground it down with a dremel. Sanded the finish off and made a "U" groove to start adding epoxy fiberglass.
Advice for repairing OEM AP1 lip
