Repairing Polyporpylene

Juce-
As I said, I don't think the original design was weak or bad in any way. I think someone applied 1,000 ft. lbs. of torque where 2 ft. lbs. is called for. If I can get a repair that is even 3/4 strength of the original it should be plenty.
 
I would make a knurled insert with a larger diameter and melt it into the air box. The trick is to heat the insert by placing it on the tip of an electric soldering iron and hold it on the hole. Push down gently and as the insert heats up it will sink in. Stop pushing when it gets flush.
 
Tozguy said:
Forget any kind of glue unless you work for NASA. The hole could be welded up with pp and tapped but this would only return things to the orignal weak design.
Inserts are the way to go, what about Riv-nuts?
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+1 on the riv nut.... perfect application for it.
 
None I can see. Riv nuts need a through hole. They work great in sheet metal. not sure about molded blind holes.
 
That poly looks like it's not very deep, so it looks just like a thick piece of sheet metal. Rivnuts come in different lengths, so in my opinion, stick it in, pull the trigger and let it set.
 
Sorry, the picture is misleading.
The "post" (the inner part of the air box where the insert goes) is as deep as the insert (8.7mm) and about 8-10mm in diameter. The box itself is about 2.5mm-3mm where there are no features, ribs, posts, etc. The insert measures 8.6mm long and 6.75mm in diameter.
 
The way this broke out makes me think that this is some sort of filled PP. The symbol PP M 25, leads me to think that it is indeed a filled Polypropylene perhaps to improve its stiffness. My experience with trying to weld filled PP hasn't worked out well.

As others have stated if you can get behind it and make a flanged bushing so it can't pull through may be a good choice. May want to pin it to resist rotation.

David
 
Groundhog said:
RJ,
We did a lot of plastic welding at the ski areas.
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Hey, that's exactly what I was going to suggest: a p-tex candle (hotmelt repair). I can look out a window and see snowcapped
mountains from here, but in Salina, Kansas, it'd be less than easy to locate such an item.

Riv-nut with washers as appropriate, and maybe some filler (hotmelt glue would be good) is an ugly solution, but should work.
 
whitmore,
You'd be right. not much p-tex around here! I've got an old pair of Dynastar 207 GS skis I could scrape to get a little! Found polypropylene filler rod at Harbor Freight though.
I worked at Crystal in the 80s, just for 1 season. Sure miss the mountains!
 
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