Best method for drilling acrylic?

[exnisstech]

I'm in the planning stages of replacing my RS reefer 300 and am thinking of having an acrylic tank built that will fit the stand then adding an external overflow so I can reuse the stand and sump. I've drilled glass a couple of times but never acrylic. What is the best way to drill acrylic? I've read of heating a pipe to using a wood hole saw but I would like recommendations from those of you with actual experience please.

 

[Biokabe]

I'm in the planning stages of replacing my RS reefer 300 and am thinking of having an acrylic tank built that will fit the stand then adding an external overflow so I can reuse the stand and sump. I've drilled glass a couple of times but never acrylic. What is the best way to drill acrylic? I've read of heating a pipe to using a wood hole saw but I would like recommendations from those of you with actual experience please.

The best way to do it is to have the tank builder do it.

I just went through this a couple months ago myself, and in hindsight I really wish that I had done it that way.

If you go down that route, decide on your overflow first, physically buy it, and measure the holes you need. Then provide that information to your builder and have them drill it to spec. If you want to do it yourself even so, I'll tag in @UncommonSense to add on to what I'll say.

First, tools. I used a hole saw, and that worked... fine. The big problem with a hole saw is that you cannot use the diamond-coated hole saws that most external overflow kits provide. They're designed to grind through glass, but all they really do on acrylic is clumsily melt the plastic. I drilled through two full batteries with a diamond saw and didn't even make it through 2mm of material.

So yes, you need a regular wooden saw, with a proper pilot bit (the other reason the diamond-coated saws aren't good). The next problem is heat. Cutting through the acrylic generates a lot of heat, and what tends to happen is you cut out some acrylic, it melts, and then it cools down over the teeth of the saw, so you can only cut for a little bit before your teeth are jammed up with melted acrylic. So you need water to keep the heat down and prevent melt, and you need to stop occasionally to clear out the teeth.

Other than that, resist the urge to press down on the drill as you cut. Let the saw do the cutting - you don't want to flex the acrylic. Go slow but not too slow. You also want a bit of torque - on my Ryobi 18v drill, I had the torque selector around setting 15.

Start from the back end, cut down about 50%-75% of the way through the material. Once you've done that, start the cut from the opposite side, using the pilot hole from your first cut to guide your cut through.

I got my tank from Tsunami, and they were great. If you have them apply a vinyl background to your tank, be aware that they actually sandwich the vinyl between the back wall of the tank and a very thin sheet of acrylic in front of it, so you don't need to worry about cutting the vinyl away when you drill.

I've heard that a step drill would also work, though I'm not sure I believe that for a hole the size of a bulkhead. You can find step drills thick enough for it, but they are expensive and unwieldy.

If you go for the Eshopps overflow, be aware that the provided drilling template might not play nice with the kind of hole saw you need. For the size I used, the holes of the template were 60mm (exactly), which is almost but not exactly 2 3/8". That makes the template basically impossible to use for an acrylic tank, but it's enough to just use it for a rough start. The bulkheads between your tank and the external box actually have a bit of play to them, so you don't need an exact fit for it to work.

 

[TenebraVos]

The King of DIY on YouTube is honestly incredibly helpful for a lot of these types of things and you will see how serious he takes all of his projects. Drilling Acrylic Video

 

[fishguy242]

I've used bimetal hole saws with acrylics up to 3/4 thick ,works ,but agree have manufacturer drill em
better safe than sorry...

 

[UncommonSense]

What is the best way to drill acrylic?

This may not necessarily be the best way, especially if you run a plastic fabrication shop with CNC tooling…. But, for us average joes working out of a garage with commonly available tools, here’s my process:

(This was specific to enlarging acrylic holes, though the notes therein pertain to fresh holes, too!)

Closed Loop Questions

Let me know if you’d like a few tricks on increasing the diameter of a hole-sawn hole accurately, or drilling acrylic in general! Please tell about the best method to drill holes in acrylic? I am an electrician by trade and have had to cut existing holes to larger sizes. But I have not had to...

www.reef2reef.com

@Biokabe Hit the nail on the head here!

— wood hole saw with centering bit!

— water cooling to prevent acrylic from melting and “grabbing” the hole saw… — you want to cut through via teeth shaving chips, not grind or melt through!

— always use your drill’s slip clutch! (The collar behind the spinning chuck, usually labeled with numbers; requires the drill to be set to the screw symbol. 10-15lbs should suffice!)

— clear the gullets of the hole saw’s teeth every 10-20 seconds of cutting, removing wadded up plastic chips. (Plastic chips in tooth gullets can be all but avoided if you drill a small hole right inside the rim of your target hole sawn hole; this gives the plastic chips a place to evacuate to!)

— you can make your own drill guide from a 2x4, or plywood easily, just use the same hole saw to poke your desired holes in it!

— as stated above, don’t drill the entire way through from one side of the acrylic if possible… finishing the hole sawn hole from the other side through the same centering bit hole will make a much cleaner hole rim! (I used 2ft of extensions on a hole saw to finish each of the four bulkhead holes in the bottom of my acrylic hexagon’s welded in circular island overflow, for example!)

 

[exnisstech]

Thanks all. If I go this route maybe I'll see if the builder will send a couple of scrap pieces that I can practice on.
I agree having the builder do it would be best. Problems is my brain works in visual touchy feely way. I can't measure and lay things out on paper with any confidence that it will line up correctly. I can follow plans but not lay them out. If I have everything here I can figure it out going back and forth with a tape measure. Crude but it works for me.

 

[UncommonSense]

If I go this route maybe I'll see if the builder will send a couple of scrap pieces that I can practice on.

If you have any local plastic fabrication shops, I’d recommend stopping by one or two to enquire about pillaging their off-cut bin for test scraps, and/or enquiring about the cost of having them do the drilling!

I agree having the builder do it would be best. Problems is my brain works in visual touchy feely way. I can't measure and lay things out on paper with any confidence that it will line up correctly.

This is honestly the best way… even when you do layout in CAD at full scale, it’s amazing how many things can’t fit in reality, particularly when tolerances are tight!

If I have everything here I can figure it out going back and forth with a tape measure. Crude but it works for me.

There’s a few little tricks to make your life easier, too! (For example, drilling 1/8” oversized so any drill alignment or hole centering error on a dual-hole overflow doesn’t lead to the overflow not fitting at all!)

— one of the big traps is overflow weir height; the operating water level will be appreciably higher than the bottom of weir teeth, so there’s a bit of either educated guessing, or tedious math involved there!

 

[fishguy242]

I used a few drops of dish soap mixed in lube water and a ring to contain if possible
keep saw cool !!

 

[UncommonSense]

I used a few drops of dish soap mixed in lube water and a ring to contain if possible
keep saw cool !!

I’ve had my best luck just working outside and running a garden hose on the cut area! — you might recall the mounds of acrylic chips this process produces!

I’m a big fan of evacuating chips from the cut as effectively as possible, minimizing clogging, and re-cut of chips! (Treating it a bit like a machining process, essentially!)

 

[Red_Beard]

I’ve had my best luck just working outside and running a garden hose on the cut area! — you might recall the mounds of acrylic chips this process produces!

I’m a big fan of evacuating chips from the cut as effectively as possible, minimizing clogging, and re-cut of chips! (Treating it a bit like a machining process, essentially!)

Definitely. The biggest problems are heat and clogged teeth. Keep it cool and clean and it is really pretty easy.

 

[Rob A]

Harbor Freight step drill and go slow so you don't melt the acrylic I do it all the time it isn't as hard as it seems . A small spray bottle of water helps with dissipating the heat but going slow is the way.

 

[exnisstech]

Harbor Freight step drill and go slow so you don't melt the acrylic I do it all the time it isn't as hard as it seems . A small spray bottle of water helps with dissipating the heat but going slow is the way.

I have step drills that work great on thinner acrylic. I don't think they would work well on thicker material unless one can be found that has the max size equal to the hole size needed. I'm talking bulkhead holes also which would be a very large step drill.

 

[Freenow54]

I'm in the planning stages of replacing my RS reefer 300 and am thinking of having an acrylic tank built that will fit the stand then adding an external overflow so I can reuse the stand and sump. I've drilled glass a couple of times but never acrylic. What is the best way to drill acrylic? I've read of heating a pipe to using a wood hole saw but I would like recommendations from those of you with actual experience please.

I cannot speak to that . I am going through quit an experience to drill my glass one. I have had a lot of help. and $$$$. So I decided to look for a 10 gallon to practice on , and a sump. While I was looking I saw my exact Tank already drilled for $100 Canadian more. I have about $ 600 into this project so far

 

[exnisstech]

I cannot speak to that . I am going through quit an experience to drill my glass one. I have had a lot of help. and $$$$. So I decided to look for a 10 gallon to practice on , and a sump. While I was looking I saw my exact Tank already drilled for $100 Canadian more. I have about $ 600 into this project so far

I drilled glass and it went so well I bought smaller bits and drilled some wine bottles for my Gal to put lights in for crafts. Acrylic seems like it would be easier but what I think isn't always correct lol. I'm also getting a quote with the manufacturer drilling it to see if it's worth the risk. I'm not sure I have the nerve to drill a new $1500 tank.

 

[UncommonSense]

I drilled glass and it went so well I bought smaller bits and drilled some wine bottles for my Gal to put lights in for crafts. Acrylic seems like it would be easier but what I think isn't always correct lol. I'm also getting a quote with the manufacturer drilling it to see if it's worth the risk. I'm not sure I have the nerve to drill a new $1500 tank.

I think acrylic is honestly easier than glass!

I have piles of acrylic slugs of various sizes around from past projects… I’m thinking of welding some together to serve as thick acrylic “rods” for skimmer stand legs at this point!

 

[Freenow54]

I think acrylic is honestly easier than glass!

I have piles of acrylic slugs of various sizes around from past projects… I’m thinking of welding some together to serve as thick acrylic “rods” for skimmer stand legs at this point!

Do you have to be careful not to melt it ?

 

[UncommonSense]

Do you have to be careful not to melt it ?

Yes, you run water cooling on the wood or bimetal hole saw, trying to minimize heating of the hole saw, and surrounding acrylic!

If done correctly, you can cut dozens of holes in a row without the hole saw getting past warm to the touch!

 

[air_run]

The best way, as above, let the builder do it. For DIY...route the hole.

I've been in the sign industry (CNC/Fabrication end) for a over 26 years. The best way to cut acrylic is to route it, not drill it. At least a hole the size we use bulkheads for anyway. Not that a hole saw bit will not work but, it's crude and risks stressing the acrylic. Remember acrylic is a lot harder and more brittle than lexan or poly and you do not want to create a stress crack. Drilling acrylic should be left to small holes mainly using drill bits specific for acrylic (or sharp step bits) as they do not allow chipped edges or blow out on the back side.

I would make a hole template for all the holes of out of MDF or the like, clamp or secure it to your work piece to use as a guide and route the hole with a router bit with a bearing guide. Do passes no more than the diameter of the bit. Holes will be smooth as butter.

 

[exnisstech]

The best way, as above, let the builder do it. For DIY...route the hole.

I've been in the sign industry (CNC/Fabrication end) for a over 26 years. The best way to cut acrylic is to route it, not drill it. At least a hole the size we use bulkheads for anyway. Not that a hole saw bit will not work but, it's crude and risks stressing the acrylic. Remember acrylic is a lot harder and more brittle than lexan or poly and you do not want to create a stress crack. Drilling acrylic should be left to small holes mainly using drill bits specific for acrylic (or sharp step bits) as they do not allow chipped edges or blow out on the back side.

I would make a hole template for all the holes of out of MDF or the like, clamp or secure it to your work piece to use as a guide and route the hole with a router bit with a bearing guide. Do passes no more than the diameter of the bit. Holes will be smooth as butter.

I remember reading about using a router but it's been a while and and I had forgotten about it until you mentioned it.