View Full Version : Any Advice, Acrylic Adhesives?

Steve Crawford
07-25-2014, 12:23 PM
Pardon the alliteration and I'm sure this has been asked before, but I cant find the answer easily, so thought I'd ask. What is the best adhesive for sticking clear cast acrylic together?

David Somers
07-25-2014, 12:40 PM

Check with Tap Plastics web site. If you are in their site and search for Glue Acrylic they will give you some videos on using various adhesives on acrylic and how to do it. Typically you use a solvent rather than an adhesive on acrylic. Weldon is one of the solvent/cements used. It has a number of formulations depending on your need and the materials. TAP has a lot of information on it.

Hope that helps.


walter hofmann
07-25-2014, 2:25 PM
hi there
take a few little pieces of the acrylic and dissolve then in aceton till its like suppy.that's the easiest and cheapest glue for acrylic and much cheaper

Michael Reilly
07-26-2014, 12:06 AM
There is Weldon 3 and Weldon 4... I forget which is which. Both are water thin, one is fast set, one is slow. The slow set uses pure acrylic solvent which I believe is not flammable and not carcinogenic. It won't leave white spots (blushing) if dripped ont he material and allowed to dry without touching it. It's less likely to cause crazing (stress fractures along the laser cut edge). But it is important that pieces be held in place for several minutes to set. The other version of the glue sets within 30seconds, is flammable and carcinogenic. Neither of these are gap filling so it's important that the joint be smooth and flat.

Weldon 16 is a thicker liquid that comes in a tube. It's somewhat gap filling. It sets slowly.

Acrylite (acrylic manufacturer) makes similar versions. They also have one called "Bright" which is similar in consistency to the Weldon 16 but is UV curing. It is very clear and hardens strongly. It seems more prone to crazing, but it's very strong and gap filling.

There is also a 2-part epoxy that requires mixing before application. This is also gap filling and super strong. It's used in aquarium manufacture.

These all fall in the category of solvent glues... meaning they soften the acrylic to create a better bond. But that's also what allows crazing to occur. Crazing occurs because the laser dramatically heats the immediate material around the cut. This creates an imbalance in the stresses in the material. The only way to release the imbalance is by annealing the plastic... slowly heating it up to a specific temperature and then slowly cooling it. This isn't really practical for most of us. Extruded acrylic is far more likely to craze than cast acrylic.

Steve Crawford
07-28-2014, 6:01 AM
Thanks guys... some good advice and food for thought.

Keith Colson
07-28-2014, 6:45 AM
Hi Steve

FYI Weldon is extremely strong as it chemically melts/welds the plastic together, so if you make a mistake it will not wipe off cleanly. Epoxy is much cleaner to work with but not as strong. If you have a good supply of syringes you can use the really runny weld on 4. See this video for how to apply.

https://www.youtube.com/watch?v=hT6Ow_cBTps (http://www.youtube.com/watch?v=hT6Ow_cBTps)