Cutting acrylic

[her209]

Anyone have experience with cutting acrylic?

I want to cut out a piece of the top of an acrylic fish tank. I want it to look professional looking as if it came from the manufacturer that way so straight lines are a must. I have a circular saw already, but I'm thinking of buying this router to do the job except I'm unsure what kind of bit I'll need cut the acrylic properly without leaving much burring.

I also looked into this rotary tool except it looks like there's no speed adjustment.

 

[lozina]

cant you just score it using a brand new super sharp box cutter blade and a straight edge, then snap over the edge of a table?

 

[her209]

cant you just score it using a brand new super sharp box cutter blade and a straight edge, then snap over the edge of a table?

You can't exactly do that with an already assembled fish tank. Plus doing it that way doesn't always break cleanly.

 

[PottedMeat]

how thick is it?

i'd use the router + plain carbide trim bit

for straight cuts cut each side up against a guide or make a jig

 

[Markbnj]

Anyone have experience with cutting acrylic?

I want to cut out a piece of the top of an acrylic fish tank. I want it to look professional looking as if it came from the manufacturer that way so straight lines are a must. I have a circular saw already, but I'm thinking of buying this router to do the job except I'm unsure what kind of bit I'll need cut the acrylic properly without leaving much burring.

I also looked into this rotary tool except it looks like there's no speed adjustment.

I think we just used a jigsaw back in shop (a million years ago). Unfortunately that was the last time I cut plexiglass. Can't you deburr it after cutting?

 

[Jaepheth]

It'll tend to melt when cutting it with power tools.

I think the cheapest way would be a rotary tool:
cutting disc for a rough cut
sanding drum to refine
finish by hand with a rasp and sand paper


A router will probably be faster and look better if you have a template.
I'd try using just a straight 1/2 inch bit... maybe a beading bit; you'll want to experiment on scrap first.

 

[sdifox]

jigsaw

 

[waffleironhead]

I've cut it with a table saw before. The edge came kinda rough though. Could probably be sanded smooth.

 

[MadScientist]

Once upon a time when we had a small craft business I used a variable speed scroll saw with a medium/fine blade on slow speed to cut acrylic sheets.

The next best thing would be a variable speed jigsaw on slow speed. Place a piece of tape along the cut line so you don't scratch the piece.

Anything faster, i.e., a table saw or router, will melt the acrylic back together.

You will still need fine grit sandpaper to finish the edges smooth.

Scoring it with a box cutter blade and trying to snap it along the line over an edge will not work with acrylic.

 

[arkcom]

Single straight flute router bit. 1/8".

Anything faster, i.e., a table saw or router, will melt the acrylic back together.

Slow the rotation speed or move faster.

 

[waffleironhead]

Once upon a time when we had a small craft business I used a variable speed scroll saw with a medium/fine blade on slow speed to cut acrylic sheets.

The next best thing would be a variable speed jigsaw on slow speed. Place a piece of tape along the cut line so you don't scratch the piece.

Anything faster, i.e., a table saw or router, will melt the acrylic back together.

You will still need fine grit sandpaper to finish the edges smooth.

Scoring it with a box cutter blade and trying to snap it along the line over an edge will not work with acrylic.

Melt it back together? That just sounds kinda hard to believe. I'm not saying it doesn't happen, but typical saw blade kerf is what 3/16". That's a lot of room to have being fused back together.

Anyway op, they make specific blades for table saws to cut plastics.
http://www.rockler.com/freud-lu94m-industrial-plastic-saw-blades

 

[crashtech]

There is a special tool that you use to deeply score the material, then it will snap easily along the line:

 

[Leros]

I just cut some acrylic on my table saw with a 10" 180 tooth blade. It worked really well.

 

[EliteRetard]

Once you have it cut and relatively smooth (say 400 grit sandpaper) you can use a heat gun to "polish" it clear.

https://www.youtube.com/watch?v=kRCnVBM3R0c

You can practice on the scrap pieces you cut.

 

[lxskllr]

Once you have it cut and relatively smooth (say 400 grit sandpaper) you can use a heat gun to "polish" it clear.

https://www.youtube.com/watch?v=kRCnVBM3R0c

You can practice on the scrap pieces you cut.

I've used a hard Arkansas whetstone to polish plastic. Worked pretty well.

 

[EliteRetard]

I've used a hard Arkansas whetstone to polish plastic. Worked pretty well.

Yeah hand polishing can work well, but it's more laborious (unless you have a buffing wheel or something). Also, I think the heat polishing only works on acrylic. Anyway, just do one quick sand (medium grit) to knock off burs and larger grooves and whatnot and then hit it with a heat gun and it can provide pretty good results.

In the video they use a torch, and if you have one that can get hot enough you may not even need to do the sanding. They can melt and smooth rougher edges before the sides get to hot and discolor or burn etc. That's why you practice to figure out the distance from the piece and speed you need to move to get a good melt without the burn. I have successfully polished acrylic with a heat gun though so I know it can be done pretty easily.

 

[crashtech]

From a re-reading of the OP, I gather a rectangular hole is to be made in an existing top, which takes a bit more doing. I would still actually use the scoring tool method as part of the procedure, because very precise lines can be cut that way, but there must be some specialized mods to the procedure. First, drill holes in the corners of the desired rectangle, choosing a size that will yield the desired corner radius. Then use a hole saw to make a hole roughly in the center of the rectangle. Use an air saw, mini-hack, or small circular saw to cut four lines from the center hole out to the drilled corners. Finally, use the scoring tool shown above to deeply score lines that connect the outer edges of the four holes together into a nice rectangular shape with slightly radiused corners. At this point pliers may be used to snap the four pieces at the score lines. Care must be taken to bend the pieces away from the side that is scored. This may necessitate the use of highly angled pliers, or the ability to work from the other side of the piece. This technique will result in a very clean opening that will take a minimum of work to clean up.