- A measuring tape
- A square
- A saw (A table saw is recommended for cutting Plexiglas 1/4" or more in thickness. The blade should have a carbide blade with 40 teeth or more.)
- A sharp utility knife (Useful for 1/8" Plexiglas only. It can be scored and snapped along a hard straight edge.)
- Sandpaper (150 grit)
- Masking Tape and / or clamps to hold the pieces together as they dry.
- Methylene Chloride (sold as "Plaskolite" in hardware stores) or Silicone if you are gluing the Plexiglas directly to glass.
- A syringe (to use as an applicator for the glue because Methylene Chloride is a liquid) or a water color paintbrush.
- A heat strip made for working with acrylic, or a heat gun used for stripping paint (You only need this if you are planning on bending the acrylic.)
Acquiring Your Plexiglas
I bought the Plexiglas for my first project from Home Depot. There are several disadvantages to doing this. First, the selection is limited. Second, you can't get custom sizes, colors, or thicknesses. I have only seen sheets 1/8" in thickness. And third, it's more expensive. Alternatively, what you can do is purchase your Plexiglas from a local acrylic shop. They will cut the pieces for you (for a fee, of course) and they have a large selection of colors and thicknesses. Depending upon how much you are planning on working with acrylic, you might consider buying a sheet of the material and investing in a saw of your own. This is about the only way you will save money on this. Another bonus to getting your Plexiglas from an acrylic shop is that they usually have bargain bins that you can hunt through. The shop in my town sells these scraps for $3/lb. To find one in your town, look under "Plastics" in the Yellow Pages.
Depending upon what you want you want to do, I recommend your using 1/4" Plexiglas. My first project was done with 1/8" Plexiglas and it warped rather easily with time. Plus, it is more fragile and cracks easier.
First, you will need to make a plan of the project you want to build.
Second, your work area should either be wood, metal, or concrete. Paper or grass are not a good idea because they will adhere to your project.
Third, measure out the pieces and begin running them through the table saw. Leave the protective film on until you need to start gluing the pieces together. The film is helpful in marking the lines where you want to cut, as it "marks" better than the acrylic. Be sure to have the saw guard in place and don't stand behind the blade. You donít want to stand behind the blade if small pieces splinter off!
If you plan on drilling holes for bulkheads, or whatever other reason, it is best to drill the pieces before you glue them. I have more to say about drilling below.
Once the pieces have been cut and your holes drilled, set the pieces in place, and secure them with masking tape, wooden blocks, or C-clamps. Then use the syringe filled with glue, and touching the tip against the joint, gently squeeze until the liquid starts to ooze out. Then run the tip down the joint. As you do this, you will notice that the glue is drawn into the joint by capillary action. On this initial run, do as many of the joints as you can without moving the project. Skip over the parts you may have taped; you can go back over them after it sets up.
If any of your edges don't fit perfectly, position the project so that when the glue is applied, it will pool there. If this doesnít work, you can thicken the glue by mixing it with acrylic shavings.
It is best to glue both sides of your joints. Let the first side set up for a while (i.e., 20-30 minutes), then flip it around and do the opposite side. Be gentle as you do this because it is still very easy to pull the pieces apart. Do not remove any tape before 24 hours, when the joints have fully cured.
Do not spill any adhesive on any parts of the Plexiglas. The glue works by burning the acrylic. If you accidentally spill the glue, it will permanently scar your project.
Do not test the project for leaks until it has set for at least 24 hours.
You will find that Plexiglas is very easy to drill. But, you will want to go slow. Let the drill work through the acrylic. If you go too quickly, or if the acrylic is not supported on the other side, it may split or crack around the hole on the backside as the bit breaks through. I have found that drilling on top of wood is really helpful. I've also found that I get really clean holes if I switch sides once the point of my drill bit has pierced the other side.
Once you have drilled the hole, some residual material might be left around the hole. It is very HOT! Wait for it to cool before you try and remove it with a utensil.
In my opinion, a heat gun used for stripping paint ($25) works best when trying to bend acrylic. With a pencil, mark where you want to bend the Plexiglas. Place that line on an edge that you can bend it over. Then, with two people, one holding the heat gun and the other bending the acrylic, move the heat gun slowly, back and forth across the line. You won't have to heat both sides, just the outside. Stay far enough from the acrylic so that it doesn't melt or bubble. You can start out at 4 inches away and work your way towards the acrylic until you find a distance you find works best. When the Plexiglass gets soft, you will see it start to sag, but you will need to keep heating slowly. Don't rush this part. Gently, start bending the Plexiglas downward. When you get the desired bend, remove the heat, and hold it in place until it cools. If you want to speed this up you can either direct a fan on it, or drip water over the bent edge.
This is where the sand paper comes in handy. You can sand down any rough edges with the sand paper once it has fully cured. Do not sand any edges that will be glued. Sanding an edge will probably make it uneven and you will probably end up with a leak that will need repair.
Sealing the Joints:
I recommend using Methylene Chloride. Plaskolite is a name brand for this chemical. I used silicone on my first project, not knowing any better. Well, I soon learned that silicone does not stick to acrylic very well. Besides, let's say you've got a leak. If you want to fix it, it becomes next to impossible because you have buried the joint in silicone.
I mentioned that you could use a syringe as an applicator, but I actually prefer a watercolor paintbrush. I dip the brush in the methylene chloride and then run it along the joint. You can actually see the glue moving into the joint as you do this. I will continue to trace the joint until I can see that it has permeated the entire interface of the two pieces of acrylic.
It is imperative that you check for leaks before you assemble your setup. May I suggest that this is best done outside, that way you won't dump water on your floor.
Let's say you've finished the project, checked for leaks, and it LEAKS. Fine, it's an easy fix. Empty the water, dry the acrylic, and go back over the leaking area with the glue. It doesn't hurt to go over the spot several times if you like.