Reptile & Amphibian Forums

Any instructions on how I can drill acrylic ( plexi ) without cracking it?
Bought a new cage that needs to have barrel bolts or locks put on the doors.
I'm getting tired of chasing a burm through the house.
Chris? Any ideas?
I have a pretty good idea of how to go about drilling it...but I wanna be sure...I only have one chance to do it right.

Bob

I hate drilling acrylic, but I've found that starting with a small titanium bit is the way to go. Even then the material has a tendency to craze (many microscopis cracks).

Now I just solvent weld hinges onto the acrylic and then screw those into the face of the cage. A bit more expensive but I'll never drill acrylic again... hopefully.
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Current snakes:

0.2 Gonyosoma oxycephala - (Silver/Yellow)

3.3 Gonyosoma oxycephala - (Green)

2.1 Gonyosoma janseni - (Black)

3.3 Gonyosoma janseni - (Black & Tan)

Burmaboy,

The key is remembering several things. I've been using and drilling plexi for years and I still get cracks even with the precautions I'll mention. However, it is rare that I will crack plexi when drilling it these days.

First you start with a sharp drill bit. You may even want to purchase a brand new bit. Chris suggested Titanium, which is good but for drilling plexi it's really no better than a regular high speed steel bit. Titanium and cobalt bits have their strength in heat dissapation which is important in drilling metals. If they're good quality they may also hold their edges longer than high speed steel. Just don't buy the really cheapo bits. And by the way, there are some cheapo brands of titanium and cobalt bits. For good quality look for Bosch if you can find them. Most are made in Switzerland or Germany and tend to be very high quality.

Secondly, you'll need to drill your holes on a very firm and stable surface. I usually use a piece of scrap plywood or some other thick, stable, and firm piece of wood and I just place the whole thing on the floor [no workbench - live in an apartment]. You're going to drill through the plexi and into the board underneath, so make sure you don't mind drilling into the board.

Thirdly, the drilling. Make your mark with a Sharpie permanent marker or some similar marker. Start slowly with the bit, just enough to score the plexi so you get a small divit and so the bit doesn't walk across the surface. If it starts to walk, stop immediately and use a sharp nail or the point of a sharp knife to kind of twirl in the middle of the mark in order to get a very tiny crater in the surface of the plexi. Place your bit back on this little crater/mark and start over. Again, go slowly [lower rpms] until the bit makes its own divit, at which point you increase the speed to the maximum, the whole time keeping your hand firmly [VERY FIRMLY] pressing down the plexi onto the board during the drilling process. Don't force the drill, in fact let the weight of the drill bring it down through the plexi. Once it goes through you'll be able to feel it and you'll get some sawdust/shavings as the bit cuts into the wood. Keep downward pressure on the plexi and your finger on the trigger [continued high rpms] and at the same time ease the bit back out while it's turning, taking care to keep it from twisting to one side or the other.

Finally, I've found the cracks almost always come from too much force, using a dull bit that requires too much force to cut effectively, not holding the plexi down firmly - as it will be grabbed during the last bit of the cut by the bit and will be jerked upwards which usually causes the crack - and allowing the bit to be moved/tilted because the drill is not kept in perfect alignment while removing it from the hole. Obviously this seems much more complicated than simply gluing hinges/hasps or something to the plexi as Chris mentioned. If you have that option I would try that, however with a cage housing a burm, I would go for the more secure screwed and bolted in method. Like I said before, I still crack/break pieces but I just grumble, put it in my scrap pile for later use somewhere else, and just get a fresh piece resolving not to do whatever it was I just did that resulted in breaking the last piece. Good luck.
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Matt Campbell
Animal Keeper, Small Mammal/Reptile House
Lincoln Park Zoo Chicago, Illinois

Assistant Curator
Wildlife Discovery Center at Elawa Farm
Lake Forest, Illinois

You guys had me all nervous! It was a piece of cake. Just used a good bradpoint bit...no walking...cut at high speed...barely any pressure. Just as I remember drilling it so many times.
I've been reading the posts here about drilling acrylic, and sheesh...I got all nervous for nothing!Oak is harder to drill...believe me, I have tons of broken drill bits to prove it.
Thanks for the help guys...
Hey...need any plexi drilled? I'm offering!

BOB