Drilling acrylic question

[euod]

I need to drill a 1.5" hole in a 1/2" thick acrylic tank and would like some suggestions how to do it,
Which drill bit?
Speed of drilling?
Should I cool with water?

Would like some experience feedback so I do not chip it. Thanks

 

[Coral reefer]

Take bulkhead to store, find hole saw that is exactly the same size as bulkhead, or just the tiniest bit larger. Go slow without pushing too hard, I've never used water while doing acrylic.

 

[Kensington Reefer]

What Mike said
Plus: high speed rotation, slow plunge

 

[aqua-nut]

Plus don't stop! Pull hole saw out of cut BEFORE you stop the drill. If you don't it could get stuck!!!

 

[gimmito]

Use a corded drill and not a battery one !

 

[neuro]

I have had to cut the hole from both sides in acrylic once. My goodness acrylic is sooo darned easy to drill compared to glass.

The acrylic will get hot.

 

[bondolo]

Letting things heat up is your enemy with acrylic. If you start to melt the plastic you're going to have a bad time.

 

[gimmito]

Hole saw kits from BRS or Harbor Freight work well and are expensive.

 

[rygh]

If it looks like it is melting, pull out drill, then stop, and wait for things to cool.
Water does help cool things, but not critical.
Do not push hard. It can shatter a bit as it comes through.
It sometimes works better to drill half way from each side, but if you do not drill straight,
it may not like up quite right.
If you are near Union City, I have quite a few different size hole saws.

 

[euod]

Thanks for the advices everyone. The predicament I get myself into. I really did not want to put more work or invetment into this project than I already have. I figure it is not like drilling wood and worry that I may have to do a ghetto patching if I screw it up.
I cannot use the drill bit for wood from Home depot?
I may take you on it Rygh. Thanks

 

[JAR]

wood bit works fine.

 

[JAR]

oh, and if you are worried about it just practice drilling a few holes in a scrap piece. of course you should secure it so it does not cut you to ribbons if it starts spinning

 

[Coral reefer]

Agree w jar, have used wood bits and metal bits w good results. And practice on a scrap is a great idea. Will ease your mind a lot.

 

[aqua-nut]

1.5" hole with wood bit? That's a BIG bit! I think most are referring to a hole saw. Anyone used a spade bit for this?

For small holes, <1/2", you can use a usual wood twist bit. It works better - less grab - if it's tip is ground for acrylic.

Two issues. Acrylic does not have the grain structure of wood so doesn't chip off like wood. Also there is a lot of heat generated and acrylic melts. Wood doesn't melt.

 

[euod]

Great idea. I will get some scraps at tap plastic and do a few dry run. Thanks

 

[Coral reefer]

For the record we are talking about hole saws or wood working on acrylic.

 

[aqua-nut]

For the record we are talking about hole saws or wood working on acrylic.

That's my impression.

Euod, make sure you clamp any test pieces down to a sturdy object. If the bit grabs it will want to spin the acrylic with amazing force! Wear eye protection!

 

[rygh]

Note : Best way to cut a big hole is with a router. Very clean cut.
But you need a template.

The heat causes two problems. It can melt around the bit, making a mess of course.
But it also damages the acrylic a little ways beyond the hole, weakening it slightly.
Not really a major concern, but be careful next to any joints, and do not over-tighten bulkheads.
I often double up the acrylic where I drill and put in a bulkhead.