Using Bondo for plastic repairs?

[netrate]

Looking for some experience in using Bondo to repair the attached piece of plastic.

Right now the 2 pieces of plastic are held in place with aluminum AND a backing of plastic from a $ store tub.
I wanted to get the basic Bondo kit and fill in the gaps between them (sand smooth and paint).
I went to my local auto reseller and of course, both people working the desk had "no experience" with bondo, BUT understood the concept.

A couple of questions :
1) I believe bondo is a filler - will it adhere to the edges of the plastic and the backing piece?
2) If it adheres to the plastic on either sides of the two pieces, WHEN DRY, will this be strong enough that I can remove the aluminum backing/supports?

PICTURE OF PART :

bondo hosted at ImgBB

Image bondo hosted in ImgBB

ibb.co

BONDO (GENERIC):

General PDP Template

www.canadiantire.ca

 

[Alaskan]

Bondo might adhere to the plastic if you sand it rough enough (80 grit sandpaper) and clean it thoroughly with denatured alcohol. This will be needed give the bondo enough "tooth" to hold on to. Bondo has no strength or structural value. It is a flimsy surface filler/smoother that is light weight and very brittle and cannot be applied in thickness. The aluminum will still be needed to retain strength and structural integrity.

Not sure from the photo but that appears to be a fender. I would just buy a new one. You will spend hours on this as that will take considerable work to look half decent and hold together. It will never be as strong or look good.

 

[netrate]

Thanks for the suggestion.

 

[rich c]

Bondo peals right off the hand squeegee used to apply it. It will flake off your part as soon as it flexes a bit. Get a professional product from an automotive finishing supply that is used to repair plastic car bumpers.

 

[netrate]

Great advice, I appreciate that.

 

[6zfshdb]

I doubt Bondo will adhere to that plastic very well. Bondo is also quite rigid and will crack if flexed much.

I use this product from JB Weld:

Amazon.com

You can sand, shape and paint it but it's expensive to fill in large areas.

I agree with @Alaskan above though. It might be cheaper in the long run to buy a new fender.

 

[netrate]

I am looking into the parts right now. The issue will always be shipping- it is expensive, and if the part is not correct, I am stuck, so I am trying to suss that out now.

 

[Merle Nelson]

I knew an old timer ("hick") that used bond with less hardener to repair radiator leaks. Always stayed a little soft and pliable. Held and worked on tubes with fins swept to one side.

If bond or special plastic repair product, drill holes in plastic both sides?

 

[retiredNH]

Having used bondo in the past, I can confidently say it will do what you want at first, but probably fail with time because it's a filler material, not a structural material. It's designed for relatively rigid automotive panels. What it certainly won't do is replace the backing/supports.

But heck, it's cheap, and if you have any kind of power sander and a manual sanding block, it won't be hard to apply and smooth out. If/when it fails, you've learned, and order the right part or do without a pretty looking fender. IF it works, you've saved a bit.
What's not to like?

 

[netrate]

Great response