Poly(methylmethacrylate) also known as acrylic or by its various commercial
names, come clear and other colors. It's notoriously hard to cut, particularly by hand.
Due to its glossy and brittle nature, it
tends to scratch easily, crack, break and show every mistake. But there are a few
methods to solve this issue, this is how I cut acrylic sheet by hand.
Hi guys, this is Cosador, Jonathan here. So, I want to cut a piece of acrylic sheet, but let's
say I don't have a jigsaw, circular saw, or table saw but I really want a good finish.
There's a few things that I need to think about, first, preparation then
cutting and afterwards finishing the new edge. Let's start with preparation, when I
work with acrylic and generally work with recycled sheets and a new sheet
comes with protective adhesive paper which prevents scratching and is easily
drawn on without affecting the sheet below. However, when dealing with recycled
sheets it's best to use masking tape in areas where there are complex cuts and
to conserve masking tape, cover the rest in clean paper without any print on it.
I'm using baking paper but anything you have on hand is good enough.
Okay, let's start with the scoring method. For this I'm going to need a rigid straight edge,
I'm using rectangular tube, I need two clamps, a flat surface to work from there
has rigid edges to clamp on to, and a knife or scoring blade. I measure and mark
exactly where I want the cut to be. I line up the rectangular tube with the
mark and I clamp either end to the bench. I run the blade across the acrylic next
to the straight edge, scoring it with each pass. I want to be firm when scoring
the acrylic but gentle enough that the blade doesn't deviate from where I
wanted to go. I flip the sheet and I line up the rectangular tube with the
score marks and re-clamp then I score this side of the acrylic sheet.
Now, I must snap the piece of acrylic sheet and it's important that I
get an even force across the score mark. If I try to break the acrylic sheet from
the short side, the force will not be even, however if I use the larger side
the force will be distributed and I will have more leverage.
So, I rotate and clamp it, lining up the score mark with the edge of the bench,
I push downward, it snaps and it's done. The result is an uncontrolled break
center, which is shown by the higher and lower points in the break. While it's
mostly glossy, it does have some stress fractures and this would take work if I
wanted to finish it, but it was quick and easy and I didn't require a saw.
On to the hand saw method, this method is almost identical to how I made long
straight cuts in another video, but there are a few differences and you'll need to
watch that one if you want to know how to make it jig and more specific skills.
For this I'm going to need the handsaw jig, a sacrificial piece of timber,
4 clamps and a hand saw. I place the sacrificial sheet onto the bench,
I place the acrylic on top and I place the jig on top of the acrylic. I measure
the acrylic and double check placement of the jig, then I align the cut just off
the edge of the table and I clamp the sacrificial sheet the acrylic and the
jig together, then I clamp the jig to the table on either side. I pass the saw
into the jig, I cut very gently and smoothly through the acrylic sheet and
the sacrificial piece of timber.
I remove the clamps and it's done
I did this with two different saws, one finer than the other for comparison.
The result is a cut with teeth marks and with the finest or the teeth marks are
more shallow which will be much easier to finish over the other.
Now, the coping saw method. Coping saws are great for wind cuts aren't straight.
So I'm going to cut a rounded corner on this sheet. For this I'm going to need
some clamps, a small piece of timber and a coping saw. I put the acrylic sheet on
the workbench, with the cut line close to the edge of the bench for support.
I place timber on top and I clamp it to the bench. I cut with the coping saw, I
come in a little after the start of the line, I cut slowly and I keep the blade
90 degrees to the sheet. It's okay if the blade doesn't meet up with the line, but
I mustn't go over it. I adjust the rotation of the coping saw as I follow
the line until I have reached the other side and the cut is done.
The parts that I have missed will be dealt with when finishing the edge so continue watching.
Now, I need to finish these cuts, there's two parts to finishing first sanding
then polishing. Let's start with sanding straight cuts, I'm going to need a couple
of straight pieces of timber, some clamps, a small block of timber to be used as
the sanding block and various grits of sandpaper rough to fine.
First, I put down one of the straight pieces of timber, I line up the cut edge
with the edges of the timber, then I put the other piece of timber and
I clamp them into a sandwich.
This is a basic jig to assist the sandpaper to remain at a 90 degree angle.
I wrap the rough sandpaper around the
makeshift sanding block and I sand the edge in long strokes.
Once a finer surface has been achieved, I graduate to a finer sandpaper and I
repeat the process until I have a rough matte finish.
Now for curved cuts, I will
do this one without a jig, but extra care must be taken. Like when I cut the
rounded corner, I put the cut edge as close to the edge of the bench as
possible, I place timber on top and I clamp it to
the bench. I start sanding with the rougher sandpaper and I pay attention
that the sanding block is 90 degrees to the acrylic, I sand off any parts that
are trouble with and I get close up to the line. I graduate to finer sand papers
until I have a rough matte finish and that's it sanding complete.
okay, last step, polishing. I'm going to need a rag and some creme cleanser or abrasive
kitchen and bathroom paste cleanser as a buffing compound. On straight edges, I put
some paste cleanser on a rag and I begin to polish the edge with small strokes
followed by longer strokes, I move along the edge until the edge appears polished
or satisfactory for its intended use. On curved edges, I put some paste cleanser
on a rag, I wrap the rag around a sanding block and then I buff the rounded edge
as evenly as possible until the edge appears polished
and it's done!
This only takes a few minutes to polish but leaves a great finish particularly for something
that's done by hand.
Cutting acrylic definitely has it's challenges, but the skills that can be gained
through the exercise are well worth it and if it was useful to you, please like and subscribe, if you would
like me to make something else just drop a comment below, and remember guys
Break It Til You Make It!
and I'll see you next time.