7685147030 COVER, FRONT SPOILER - Plastic welding repair

Its on the bottom of the Prius, just behind the front bumper. The thing that gets worn away rubbing tire stop in parking lots.

The bottom of the panel has this molded into it:
76851-47030-A
>PP+E/P-TD20<

PP+E/P (I found out) is "polypropylene blended with ethylene/propylene"

I "guessed" that a rod designed for PP would work.

I was doing some other work & had this cover off. I noticed that all of the wear points were _very_ worn. The 4 main wear points were barely hanging by a thread. I like Mendel's approach using epoxy & screening but thought I would try something different. After a little research I decided to plastic weld & use Harbor Freight plastic welding rod as filler. I had a 40W chisel point soldering iron around & used that for heat. For this size job no temperature controller was needed. The 40W iron was slow going but kept me from melting through the cover.

With the cover removed I first washed it with soap & water. After drying I got it in the sun (S FL, 80° today) to slightly warm the plastic. I then cleaned the area to be filled with alcohol & let that dry.

The plastic welding is the same as metal welding. You need to make sure the base plastic gets melted also. I tack welded the towers in position, then ran a full bead around the base of each "tower", followed by another 1 or 2 beads to add filler & strength. I could tell after the first bead on the first tower that this was going to come out well. It almost seemed too easy

I think the welding rods were $6 after the 20% coupon discount.


40W soldering iron & PP welding rod


Finished welds after 3 passes.
I used <3 of the green PP rods.
The welding probably took 45 minutes as I was enjoying the ease at which the welding was going.

 

Yes, but no pics Before starting I had removed all of the "fuzz" plastic that collected on the edges where the cover was worn through. The backside, where I added the green filler, ended up quite thick. When I inspecting the other side I could see the green filler rod peeking through the crack at all four towers. I used the soldering iron to smooth over & round the remaining black plastic edges. The end result is, from the bottom, one would be hard pressed to notice anything was repaired.

Small Correction: The soldering iron used (shown in pic) is really a 50W iron (checked using a kill-a- watt).