Author Options:

Moldable, sandable substance to connect several pieces of plastic? Answered

I am attempting to connect several pieces of plastic and want to do it nice and smooth, so that when finished it looks like it is suppose to be like that. To that I end I would need to be able to mold, have it air dry, then be able to sand it smooth and paint it. I was thinking of using air dry modeling clay but I do not know how well that would integrate with plastic as well as being able to sand it. Any ideas?



Best Answer 8 years ago

JB Weld or a plastic-specific solvent cement would probably work.  You can "mold" the cement by creating a bridge of sorts out of clear packing tape.  Depending on the shape and thickness, you may need to do more than one application/pour of cement.  Once the cement has dried, peel off the tape and then sand.

Of course, you'll want to do a few test joints before trying it on the actual pieces.

You might be best with a "weld" - it depends upon the type of plastic and the size / shape of the joins you want to make.
More details?


Need about an 80ish degree angle that will be touching the plastic on the ends, each end has a surface area of 1 1/2" x 2". I am going to stop by Michael's/Lowe's later and look at the JB weld if they have it, and if not gonna go with jeff-o's suggestion of the plastic cement, Thanks to everyone for the help.

It does depend upon the plastic and the strength you want. For a weld on that I'd hold each piece in one hand near a blowlamp flame until they were liquid and gently press together, just a bit more than touching. I'd then have to keep them like that until the plastic cooled enough...


You're more likely to find JB Weld at hardware or auto parts stores.  I've never seen it at Michael's. 

IPS Corp sells a series of plastic cement through various distributors.  Use their guides to select the right adhesive for your plastic.


8 years ago

It depends, to a degree, on the type of plastic you are working with, but in general, I would say that JB Weld epoxy meets all your criteria.

Also, air dry modeling clay won't work at all.