Cutting flexiglass

[Vince2005]

I need to cut some hole in the case window for the tubing that conncets to my dual heatercore and I was wondering what would cut flexiglass the best?

[Ugly n Grey]

a drill bit larger than the hose or a dremel works wonders....

[+Torm+]

Normal drillbits for metal will probably crack your plexiglass window. The problem is that such drillbits are too sharp and drill very fast thru the plexi but at the same time "yanking"/pulling material from around the bit (instead of cutting) making for a nasty hole in the plexi.

Best option is to use special bits for plexi. If you cant get that a very dull old drill bit may work, "Grinding" its way thru the material. Watch out for heat related problems then tho - the bit may melt a hole in the plastic instead.
Another trick that may work is to use some strong adhesive tape on both sides before you drill - the tape supporting the plexi a bit. A good way of making a new metal drill bit dull fast is to drill concrete with it before you use it on plexi.

If you need a big hole (for large tubing) start with a small drill bit and work your way up. Alternatively drill a small hole then use a routing bit on a dremel and work the hole till its the size you want. Make sure you use the dremel at lowest speed to avoid melting.

I've drilled in plexi a lot and using non plexi drill and get good results is very difficult.

[Ugly n Grey]

I've drilled hols in plexi lots with standard bits... just use a slower RPM on your drill.... avoid melting it but there is no need for special bits..

[[XC] leviathan18]

take a normal bit put it on your dremmel and use the lowest rpm possible you can spill some water so it wont melt

[+Torm+]

Dunno what kindo drill bits you guys are using, but anytime ive tried using a normal steel drill bit on plexi - drilling any hole larger than 5mm and I get a severly ugly looking hole in the plexi. The moement the drill bit touches the plexi it is like it grabs hold of the bit and yanks it through the plexi really fast.
Maybe if you manage to drill really really slow it would work (i have no drill that goes THAT slow).

[SamHughe]

I found couple of plexi sheets in the dumbster this evening. Tomorrow I'm getting a 120mm drill bit and cutting some holes on them. I need it for my fan duct project. I'll let you know how it'll turn out.

[Vince2005]

I drilled part of it then tried using a hack saw to cut the rest and it snaped the piece I should have drilled all of it.

[Tulatin]

Holesaw but make sure it's either clamped down TIGHT. Alternately, just use lexan and go nuts on the poor sheet, watching it NOT break :)

[SamHughe]

DO NOT USE THIS THING!
http://img11.imageshack.us/img11/6670/plexi0019oe.jpg

It won't work. Trust me, I know it! :D

[Navig]

As mentioned, larger drill bits have a tendency to grab and wreak havok. If you mask, and the hole is nowhere near an edge, usually you can get away with it if you are careful and experienced. If you are anywhere near an edge, there is a good chance the whole corner will snap off or a break will extend right to that edge.

Holesaws work great if you take your time. Go slow so as to not melt the plastic, pause frequently to clear way debris.

Here is my holesaw working thru the wimpiest of materials 1/8in plexi.

http://img.photobucket.com/albums/v363/navig/holemade.jpg

navig

[mvagusta]

the first few holes i cut with a holesaw werent too good, but doesnt take too long to get the hang of it and make neat holes.