Just found an alternative to super glue for the painters tape hold down method that some of you might like.
Mix the following in a glass jar with metal top:
1 part acrylic scrap pieces
9 parts acetone
You can just eye it out roughly. Let it sit for 24-48 hours to fully dissolve.
It will create a liquid glue that can bond acrylic, pvc, abs, and some other materials.
I just tested it with painters tape to hold down some aluminum and it works well.
How long does it take to set up?
The superglue I use takes around 1 hour, the acrylic glue is very similar.
When the acrylic glue is applied in open air it dries much more quickly (almost instant for thin amounts). I haven’t tried anything like accelerator or letting it get tacky before pushing the pieces together yet.
Also should note that if you use the glue to stick together pieces of acrylic the acetone will slightly eat away at that plastic pieces, so the finish isn’t very nice cosmetically but not terrible either. The hold is very strong on acrylic. Stronger than super glue, rubber cement, and a random plastic glue I tried. I did scratch the acrylic to ensure it would hold well, still have quite a bit of testing to do.
I stand ready to be corrected by an adhesives chemist here but…
Cyanoacrylate glues, whilst they produce an acrylic like substance, have a fast chain reaction through the glue which causes them to set, triggered by the presence of water. This means you should get a fully cured glue area very quickly, with the bond being both mechanical and van der waals forces thanks to the surface of the CA glue conforming very closely to the glued objects. This bond will set up in seconds or minutes (esp if you use an accellerator to trigger the CA).
Oddly on clear plastics, CA glue will cloud the surface as it sets due to the reaction.
Here’s a quick read https://www.compoundchem.com/2015/10/15/superglue/
Acrylic can also be ‘solvent welded’ using a suitable solvent, commonly methylene chloride is used. I’ve only purchased commercial ‘solvent weld’ which is stated to be suitable for Acrylic. You can get these in super low viscosity plain solvents which flow into a tight joint as well as more viscous gels which are capable of filling some amount of gap or roughness. A big upside of these is that when well prepared you can get a glass-clear joint.
The solvent welds work (like Acetone) by being a solvent for the plastic (Acrylic in this case but others as well) and causing the two pieces of Acrylic being bonded to become one piece of Acrylic.
The downside is that these solvents need to evaporate out of the glue joint and then the joint needs to finish curing, which can commonly take 24 hours to reach full material strength.
A good trick, as you’ve found, is to mix up some acrylic shavings in the liquid solvent to create a cement-paste for gap filling and gluing, this can work quite well but be aware that, in addition to the drying out and curing times, the volume of the solvent (MEK or Acetone or whatever you’re using) is lost so the joint needs to be able to contract (as with wood glues) and you may still be left with voids where the solvent evaporated.
HTH
This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.