Welding Acrylic

Acrylic is one of the best materials to use on a laser cutter because of its versatility, transparency, and ease of cutting/etching. However, acrylic is notoriously difficult to bond with glues and other adhesives in a clean fashion and scratches easily when trying to remove unsightly residue. Welding acrylic is easy to do with the right materials and can create incredibly strong bonds with little to no residue left over.

Acrylic objects can be held together with adhesives such as Goop or sealed with various caulk products. However, for a solid bond that is as strong as the material itself, a chemical weld is the easiest method for bonding. Welding two acrylic parts essentially joins them together as a single piece and forms an incredibly strong bond. Acrylic cement works by dissolving the plastic of the objects to be bonded, then as the solvent evaporates the two objects essentially form together as a single object.

You'll need some acrylic cement (I recommend TAP Plastics and a syringe to apply it to the objects.

WARNING: Acrylic cement is a flammable solvent. Wear safety glasses, prevent any skin exposure (wear rubber gloves), and avoid any heat/flame sources.

1. Pour some of the acrylic cement into the syringe. Use a funnel if possible, or for small jobs use the syringe itself to draw out a small amount of the fluid.

2. Hold or clamp the pieces to be bonded as tightly as possible. The cement will flow into the bond via capillary action, so the tighter they are held together the stronger the bond will be.

3. Hold the syringe upright to prevent any fluid from leaking out. If some of the cement leaks on to your objects, the best solution is to leave it alone and don't try to clean it up, if the spill is not disturbed before the solvent evaporates it should return back to normal without cleaning.

4. If using a squeeze-bottle syringe, before applying the cement, squeeze a bit of air out of the syringe while holding it upright then let it release right before turning it over. As it draws air in it will prevent the cement from dripping from the syringe before it is in place.

5. Place the tip of the syringe right at the junction of the two objects to be bonded and either wait for the cement to begin to flow or give the syringe a light squeeze to start it flowing. You should be able to see the fluid flow between the two parts, the thinner the fluid level the stronger the bond will be.

6. Drag the syringe along the two parts applying the cement along the entire bond surface. When finished, return any unused cement to the container and clean out the syringe with water immediately.

7. The bond will be strong within about 10 minutes, but will not be fully cured for about a week or two. Allow the solvent to evaporate completely before testing its full strength.

There's a very nice video describing this process from TAP Plastics.