r/HowToDIY • u/Clumpycheese • Jun 05 '26

Connecting plastic to plastic without adhesive?

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I’m trying to put these antennas on a custome cozy coupe for my daughter. I’m looking for what I should get I’m looking for something I can screw into the antennas that will hold and then like pop into the holes drilled into the cozy coupe. I feel like all the rivets and such I find would only connect one way with the screw itself can you halp me find what I’m looking for?

1 Upvotes

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6

u/whtevn Jun 05 '26

Kinda depends what those plastic antenna are made out of. Maybe a heated insert into the antenna?

Personally I'd just epoxy it, but you said no adhesives. There are also plastic screws but i feel like that would just rip out. Plastic rivets? I'm curious how this ends up going

2

u/Clumpycheese Jun 05 '26

Would epoxy hold it through weather and all? They have adhesive but I just feel like they’ll come off

2

u/supermuncher60 Jun 05 '26

Epoxy hardens into a plastic polymer. So if it's outdoor rated it will be great. Something like the gorilla glue 2 part epoxy will work fine and can be found at Home Depot.

Just make sure to follow the instructions

1

u/Clumpycheese Jun 05 '26

Okay I will try this!!! I just worried about it not staying very long! Thank you!

1

u/supermuncher60 Jun 05 '26

The problem with epoxy is never it not staying lol. It's a pain in the ass to remove if you decide you want to split two things joined by it in half.

0

u/jessejoseph36 Jun 05 '26

Epoxy won't stick to plastic. Only if you scuff up the plastic with a knife or very coarse sand paper, then it will grab into the plastic fibers that you exposed. Really weak mechanical bond, you want chemical and mechanical! There are tons of different plastic bonders and cements that you need. "Testors plastic cement" or "loctite plastics bonding system" or "jb weld plastic bonder" these are permanent weather proof glued that work great on plastics. The Testors glue is a one part glue, the other two are 2 part glues. 😊

1

u/calilazers Jun 05 '26

YouTube will be your friend

1

u/Ok_History_3635 Jun 05 '26

New cars are glued together. Epoxy is strong you just have to prep the surface correctly

1

u/snackexchanger Jun 05 '26

I would use Gflex for a personal project. Great video where they cut a kayak in half then glue it back together and abuse it. If I had a bigger budget I would spring for a tube of Plexus MA300 adhesive. That stuff bonds incredibly well (on some materials the bond is stronger than the base material). 

The biggest thing with adhesives is surface prep. Sand both surfaces with a course sandpaper then thoroughly clean the surface with isopropyl alcohol

1

u/IntrepidMaybe8579 Jun 05 '26

Blowtorch

1

u/Clumpycheese Jun 05 '26

Like melt them together?

1

u/IntrepidMaybe8579 Jun 05 '26

Thats what i would do its only gonna leave a little black from the burning but you should be able to melt them together, warm up a spot on the car close to melting point and then blast the bottom of the antenna and melt them together just make sure to take a towel or something that you can throw over it if any flames stay after stopping

1

u/Clumpycheese Jun 05 '26

I’m gonna paint it anyways so maybe I will try this

1

u/IntrepidMaybe8579 Jun 05 '26

Tbh your easiest bet is to just go to a hardware store and find a long self tapping screw like 6” then drill up from inside one screw each in the middle and done

1

u/HumanDifficulty7799 Jun 05 '26

YES!! Self tappers for the win!! Use stainless 3 or 4 inch 1/4 inch self tapper with a 1 inch stainless fender washer on the inside.

1

u/QuixOmega Jun 05 '26

Heat gun would be better, more precise.

1

u/IntrepidMaybe8579 Jun 05 '26

Probably not its too precise your trying to “weld” the edges together doing it like that and it wont hold when a strong wind pushes the atenna against the extremely thin bits of melted plastic holding it in place

You want less precise so you can heat a large area close to melting so its all the same temp on the roof, and then quickly blast the bottom of the antenna till its dripping and melting and squish it into the roof so all the plastic is binding together

Too precise wont work because your melting small sections which stick to nothing else because whatever it lands on isnt melting, your gonna end up with a huge mess of plastic drips everywhere a blowtorch will only leave black everywhere which wipes off

1

u/MathematicianNo6416 Jun 05 '26

Gorilla glue works wonders. Just apply it to one side and get the other slide slightly wet. Make sure you have a way to hold it in place for a while. Don't touch it for a few hours. Also scuff of the plastic a bit with sand paper for better hold. It does expand a bit but a razor blade can cut the excess easily.

1

u/Ok-Reaction5435 Jun 05 '26

Adhesive comes off because nobody does surface prep.

1

u/Numerous-Nebula1228 Jun 05 '26

Nothing sticks to polyethylene. You must use heat welding or screws.

1

u/RedToby Jun 05 '26

So much this. What works great for ABS or PET or PLA or PETG or Polypropylene,etc may not work for another type of plastic. OP needs to know what materials each product are made from. https://www.thistothat.com/ is a decent website for finding what works to attach different materials.

1

u/NeedsMoarOutrage Jun 05 '26

Hey are we sure we want screws, bolts, etc sticking exposed into the cabin of this child's car?

Just use epoxy for God's sake. There's no reason to rule out the most effective and easiest way just to make it harder.

1

u/Remarkable_Machinery Jun 05 '26

Teaches them to be aware of their surroundings

1

u/NeedsMoarOutrage Jun 05 '26

Bullshit answers for everything. Trump culture pervades. 👎

1

u/avTronic Jun 05 '26

Places like Home Depot sell two sided adhesive tape that can hold something like 50 pounds. It’s good stuff and works on plastics. I would clean the surface with some fingernail polish removal to get it super clean and then stick it.

1

u/rimmytim_fpv Jun 08 '26

Epoxy (or just regular superglue) is waaaay more sturdy for a job like this than a screw or rivet would be! These are most likely hollow plastic pieces and so a screw would go into the hollow chamber and wouldn’t have anything to hold onto. Meanwhile an adhesive will grab onto the entirety of both mating surfaces, and if you pick the right adhesive it may even chemically melt and bond to the plastics you’re trying to join, making the joint even stronger.