How to strengthen packaging plastics for greeblies or to use as prop parts.


Active Member
Hi all, I have gotten some interesting plastic packaging in an item that I bought recently and thought it would be brilliant if I could strengthen them to use as outdoor props.

I would ideally like it as strong as fiberglass so wanted to ask you amazing lot what I should do.

Would I bushe the inside with epoxy resing and fi erglass or just fiberglass... I think the latter will cause it to melt so really need some help here.

I see cool packaging all the time and think how it would make cool. Sic fi wall dressings etc.

Any help is much appreciated.

Thanks all, Craig


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It depends on what plastic was used. Some plastics are formulated in a way that almost nothing will stick to them. With some others you can't glue them easily.

Epoxy gets warm when it cures so that could warp the material. It would need to be brushed on thin. And "fiberglass" isn't a material by itself. It's a combination of resin and glass fibers. The resin most commonly used is stinky polyester, but you can also use epoxy.

So, the safest bet might be to brush on a thin layer of epoxy and then add some thin fiberglass cloth.
You might be able to CK the plastic type. Most have a recycling code stamped somewhere. It's that little triangle with 2 or 3 letters in the center. PP for polypropylene, ect. If it's Polystyrene or acrylic you can paint and finish it like any model. But like Charles said paint will not stick to some plastic, like the aforementioned polypropylene. Not without a lot of prep and fancy paints. You might be able to beef it up from the inside with spray foam, but ck it in a small area first. Urethane foam might attack it. Especially if it's thin, which most packaging is. Good luck.
I have wanted to go to junk car lots. Behind bumper there are odd vent like shapes-also on trailers reefers. Plastic air wedges under trailers can fit photon torp like cargo pods atop cars.
Plaster would be the easiest answer to your quest (y) As for packaging made out of heat formed paper pulp; your best bet is to spray it with a clear mat varnish to seal it and then make a plaster mold;)
Another vote for Plaster of Paris..
Or if you want to use it outside as a building block/ wall etc I've used cement and it looks great with plants etc..

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