cutting/routing acrylic

Andrew Butler

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As you can imagine most acrylic companies with laser/CNC capabilities are busy trying to get pieces cut for the current health situation so my 2 week wait (and great price) has long come and gone to the point I can't see it happening anytime soon, if at all this year.

I can wait the bigger out but was hoping to get a couple of smaller ones made to modify the Fluval Flex aquariums I've got, simply to make life more simple for my mum and also give me a smaller one to enjoy while my bigger one gets sorted. This was a quick fix for me - haha

I can get the panels cut to size online easily enough, although quite a lot more expensive.
What about cutting holes, slots or even the sheet itself?
I know @zozo linked me into the king of DIY before over something different where he uses a bench saw to cut the teeth which are never going to be square as a saw blade is round so not so keen on that for starters.
Given that it got me thinking about routing out some 3mm or 4mm slots into 5mm acrylic and ordering a bigger piece to simply cut to the sizes I need.

This then also leads me onto question cutting some teeth into a piece of 10mm acrylic also and if anyone has experience or wisdom to share.

*The router I have now doesn't have adjustable speed for anyone in the know.

I look forward to some input; I'm sure there will be different views!
Thanks
Andrew
 
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Does it need to specifically be Acrylic? I’ve done some machining on a variety of plastics over the years and avoid Acrylic like the plague because it breaks so easily. For clear plastics I used to use Polycarbonate but have also tried PETG. Polycarbonate was used in those NASA bubble helmets in the 1960’s because it’s virtually unbreakable. Also used in bullet proof “Glass”. It’s not optically quite as clear as Acrylic and it does scratch easier but is quite often supplied with a scratch resistant coating.
 

Andrew Butler

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Does it need to specifically be Acrylic? I’ve done some machining on a variety of plastics over the years and avoid Acrylic like the plague because it breaks so easily. For clear plastics I used to use Polycarbonate but have also tried PETG. Polycarbonate was used in those NASA bubble helmets in the 1960’s because it’s virtually unbreakable. Also used in bullet proof “Glass”. It’s not optically quite as clear as Acrylic and it does scratch easier but is quite often supplied with a scratch resistant coating.
Maybe to add it would need to be black to act as a partition between aquarium and built in filtration AIO (All In One) style.
Whether it's Perspex brand or another generic Acrylic I'm unsure if this makes any difference to machining.

From that you're saying no to machining it then?

There does seem to be 2 distinct answers wherever you look.
 
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No you can machine Acrylic just fine it just needs to be done with the right tools. Cutter speed must not be too high or the plastic melts. Tools need to be very sharp and in the case of Acrylic keep vibrations to a minimum.

I’ve just done a quick search and although there are lots of other plastics out there like ABS, Acetal, PVC, Polycarbonate and PETG most places only supply large sheets. Perversely the easiest to break - Acrylic is freely available cut to size!

This is a good site which tells you about the characteristics and machining of plastics.

https://www.directplastics.co.uk/acrylic-sheet
 

Andrew Butler

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Thanks for the input and link @Aqua sobriquet ;)
Acrylic is freely available cut to size!
When you start adding the smaller pieces up the cost soon ramps up from these places so just buying a larger sheet to cut and machine seems a better option financially and gives me the control to cut the bigger pieces first and if they go wrong they can be cut down to suit the smaller pieces. Probably not even half the price to do it myself and the places I have seen don't offer slots etc to be cut which is probably my biggest battle.
Cutter speed must not be too high or the plastic melts
This is something I have in mind for the slots; no longer having the tools I used to and just a small router with no speed control will probably rely just as much on letting the bit cool between cuts and making sure it is clean; experimentation is the only way forward here now and if it fails then back to the drawing board.

I'm currently on the fence about bonding it all together then siliconing it in place as one unit or trying to make all joints silicone, no experience of bonding acrylic but I guess offcuts would give me a chance to do so and learn. I think adding it as one unit is hopefully easier to silicone to the glass and once it's cured I can give the front/visible part a nice finish.

This is the chap on YouTube 'King of DIY' - he goes through a couple of builds where he machines the acrylic himself, maybe not quite as I'd like but I think I can hopefully improve upon the finish.
This video in particular shows one I was pointed in the direction of ages ago.

Below is a rough outline of what's planned for the smaller ones I'd like to build. I had a good price for making them all including bonded construction, shelving etc so I only needed to silicone them in place but as I say that's just not happening anytime soon.
IGNORE THE MEASUREMENTS!

*I also have the freedom to make something for the first chamber which could involve 2 things; a slide in box that I could put my foam in instead of ramming it in the box would have the flow directed into it; a little like the ones inTank make although note the link is just to give you an idea of the construction - how I'd make it work to direct all flow through it in C1 is something open to suggestion. (I do question whether this would cause vibration type noise?)
The other thing I'd thought of before in my bigger aquarium is something to sit inside C1 and give a skimming function yet at the same time leaving the front slots or comb open to any debris that might block it. Unsure if this makes any sense? Strangely enough inTank make something similar that's designed to sit inside the aquarium but would block off the front grill if any large debris was to hit the comb. inTank call it the ALL-IN-ONE SURFACE SKIMMER. I know this further complicates things with the first 'complication' I'm adding to the design with the above slide in/out box.

As always open to suggestions, ideas and honest opinion.
Thanks
Andrew
Flex -outline.jpg
 
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This is the guy on YouTube I like.


Watch some of his videos and it may give you some ideas or an insight into the process.
 

jaypeecee

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Hi Folks,

Very useful thread. If I do any more work with plastic alternatives to glass, I shall refer to this. I will probably try polycarbonate next time as acrylic is not the most stable material in a warm, humid environment. I have several pieces of flat acrylic sheet that would make good fruit bowls when they get anywhere near my tanks! :lol:

JPC
 
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I was surprised to learn many years ago that most if not all plastics absorb moisture. I’ve seen instructions that say Acrylic should be dried before bending.
 

zozo

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I've used a Dremel tool with a router kit to make some smaller acrylic projects. And it actually worked pretty well. Acrylic that easily breaks is the Extruded version XT® readily available at any hardware store. This you should avoid using. For smooth cutting you need the Cell Cast GS® version and indeed as stated above sharp router bits and proper RPM.

I've used this
Knipsel.JPG


and this
Knipsel1.JPG


In quite a few occasions on acrylic, since it is much smaller and lighter tool it gives you a lot more control on small projects and lighter materials.

Going at it with its big brother, needs a tad more practise..

An old saying "Proper tools, is half the battle" :)
 
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I tried to cut some Acrylic with a jigsaw many years ago - big mistake. A hacksaw works fine though if you’re cutting small pieces. I generally gave up using it though. I did need to make some frontsight elements many years ago though and I used to cut the Acrylic into 1” squares with a hacksaw and then used double sided tape to hold them while I turned them on a lathe. I have also cut slots into pipe on my milling machine and that worked ok. The pipe did end up being very fragile though so not worth doing in the end.
 

jaypeecee

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Acrylic that easily breaks is the Extruded version XT® readily available at any hardware store. This you should avoid using. For smooth cutting you need the Cell Cast GS® version and indeed as stated above sharp router bits and proper RPM.

Hi @zozo

Now that's what I call useful!

JPC :clap:
 

zozo

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'Perspex' branding is mainly cast isn't it? (pay a small premium)

I'm not sure scientifically it all is PMMA or Acrylate for short, Perspex® and Plexiglas® are among many others registered tradenames.

It depends per region where what is available and in many cases if the label doesn't specify the production type, Extruded (XT) or GS (Cast) than it most likely is the cheapest variety and XT. The extrusion process causes lots of internal tension and stress.

And as soon as you start cutting you'll notice it cracks and chips easily. Sheet materials also warp out of shape at rather low temperatures.

GS is cast and with this releases its tension and stress and there for a tougher and more solid product.

In my region, i can only get Cell Cast Acrylic at specialized stores and still ask to play safe. Regular hardware stores don't have it and most employees working there never heard about it. For them its all Plexiglass...
 
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foxfish

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Andrew, if you just want that one small component perhaps you could just get one made on a 3d printer?

I am always cutting Perspex for various projects like router templates, it does crack sometimes but if you hold it firmly in a vice or such like and use a fine blade hack saw it should not be to difficult.
A fine diamond blade in a coping saw (ceramic cutting blade) works if you can keep the piece clamped firm near the cutting edge.
I use masking tape, mark out the shape onto the tape and cut in on my band saw, you do get a bit of furring on the edge but it just comes of and then you can add a little flame over the cut edge.
Drilling small holes is easy on thick Perspex but not on thin material but you can heat your drill bit and it just glides through. Drilling free hand can cause the most issues but with a drill stand it is pretty easy.
Cold acrylic is a no no but when it is warm it is far less likely to crack.
Overall it is not an easy product to work with.
 

Andrew Butler

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*UNFINISHED*

Overall it is not an easy product to work with.
:banghead: - Trying to find the best solution.
I have a PVC sheet product which is too thin so thought I'd have a go at bonding two together but it's simply not happening despite the correct adhesive, there's just not enough time to work with it.
Andrew, if you just want that one small component perhaps you could just get one made on a 3d printer?
Strangely I had an email yesterday evening from the company who were originally making it for me and have pointed towards a probable 2 week time window now which is now making me think more towards that, all laser cut and assembled if I want. :sorry:

I'm still thinking some kind of intank type insert added to C1 to keep the foam in mainly and hopefully reduce mess which I think can only be measured once it's all together so that leads me onto maybe order it all (assembled/unassembled) and then as for the intank style inserts have a go at making them.I have a table saw
 

Andrew Butler

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So to surmise I can (hopefully) get all of the sheets laser cut with slots/combs, assembled and delivered for less that I'd be paying for the Perspex alone.
I doubt any of what I say next will make any sense but I can always hope.........

I am still thinking about making some kind of insert for C1; maybe even C2 instead of eggcrate if I find it easy enough going.
This is the kind of thing intank make just for a rough visual but foam could be cut and gently slid in, instead of ramming it all in for the mechanical filtration!
I've followed it with a VERY CRUDE sketch of what I'm trying to explain with regards the suspended intank type basket that could slot into C1.
The red being a supporting rim on all 4 sides of C1 and the green would be a basket that slid down and supported buy the red rim if this makes sense?
Assuming any of that made sense then I welcome suggestions or ideas, I'm sure this one sounds silly enough as it it!
(I can already think of a problem :banghead:)

intank design.jpg

rough intank c1.jpg

Some kind of internal skimmer into C1 so it takes more water from the surface than it does now, yet allows the main weir combs to get a little blocked if this makes any sense?
A kind of reverse to what intank make to fit on the inside of the aquarium instead of hidden in the filtration section (finally an idea I've had that someone else has already employed :woot:)
https://intankaquatics.com/intank-all-in-one-surface-skimmer/

intank skimmer.jpg
 
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