Glueing Plastic to Plastic

I live in an apartment and we have a microwave built into, but over the oven. I accidentally bumped into the corner of it one day, right where the door hinges are, and a good size piece of plastic broke off and landed on the counter. I picked up the piece and it was a triangle shape, but otherwise fit perfectly where it had broken off from the microwave door.

I pride myself on being able to repair things so I got some ‘crazy glue’ and tried to glue the piece back on. No dice. It simple slipped off and fell onto the counter. I could stand there and hold it for 5 minutes, but as soon as I let go it would fall on off as if the glue wasn’t even there.

I then went down to the local hardware store and bought some special adhesive designed to glue plastic to anything… including plastic. It was thicker than the crazy glue so I thought it would adhere, but it also just slipped off. Again, I tried to hold it for 5 minutes but it didn’t adhere at all… not even a little.

So is there some new kind of easily breakable plastic and you can’t glue back together? What am I doing wrong? :confused: Any advice?

I guess it’s spelled gluing these days…

I have had very good luck with two-part epoxy made for plastic. Any decent hardware store should have it. It is usually packaged in a gizmo that looks like a syringe but has two output tubes. Example.

Did you try Duco Cement?

Crazy glue is incredibly weak in shear strength, so it’s not surprising it couldn’t hold the weight of the plastic.

Okay… I will try epoxy this weekend. Stay tuned!

You can also tape it with masking tape so you won’t have to hold it yourself.

Make sure the surfaces to be glued are absolutely clean and free of grease. You might want to use rubbing alcohol to get the grease off.

That said, I had a handle break off of my microwave a while back and I never was able to fix it, even after degreasing the surfaces and using two-part epoxy. It would support its own weight but kept breaking off when I tried to open the door.

Some plastics are very difficult to glue. Delrin and acetal are two I can think of offhand that are generally impossible to glue back together. But those two are normally used for things like gears and bushings rather than appliance doors.

You could try to find a glue called “Plastic Surgery” - it claims to be able to glue almost any kind of plastic together. My guess is the door is either some type of PVC or ABS.

Try polystyrene cement (poly cement). You can find it in modelling/craft shops.

Gorilla Glue?

Used to be a product I used when building miniatures and models that fused plastic to plastic via a chemical thermal reaction marketed under the name Weld-On. It’s not fun stuff to work with, but it will actually melt the plastic where applied in a manner that you can spread across the seams and when it dries sand and scrape to make a really decent fix.

It’s amazing how many things I learned building Warhammer 40k minis as a kid.

Same stuff.

If this won’t do it, give up.
It will glue almost anything except “low surface energy” plastics (LDPE, HDPE and Teflon).

If the plastic is PVC or ABS, you could use multipurpose pipe cement used for socket welding plastic pipe.

nit: Delrin is a trade name for acetal, like Lexan is a trade name for polycarbonate, and Plexiglass for Acrylic.

Excellent. If you choose to go this route, make sure that you get a real hair brush and not a plastic one, otherwise after a few dips in the jar you’ll realize that you just have a soft stick in your hand.

BRAINSSSSSSSSSSS!!! are also good for making them stick together.

score both surfaces to be bonded
put some zap a gap on both sides
wait a minute for the glue to become somewhat tacky
attach the piece and use a piece of tape to hold it in place
take off the tape when it is cured

i am an architecture student and build plexiglass models a lot.

Note: The spam post that revived this zombie has been removed.

I was going to suggest that. I have had good luck with it. It still won’t do polyethylene or polypropylene. Any hardware or home center has it next to their plastic pipe fittings.