I am researching using acrylic sheet, either two, or one combined with MDF board, or something, to make ‘bespoke’ wall frames for some painted fabric African art.
Never used either, so I was looking at some recommendations/best practices from
vendors, and the consensus seems to be
Does that sound about right, in your experience? 
Any more tips/gotchas etc. appreciated.
drilling Acrylic is tricky and different if you have either cast or extruded.
cast acrylic is harder and less likely to crack during drilling, extruded is more prone to crazing\cracking during drilling.
I do it a couple of ways, if you have double sick tape, put it on a board of MDF and stick the acrylic to it then drill it at a slower RPM, you can use a bar of soap on the bit to wax it and it will drill nice. the reason to tape down is that a normal twist drill likes to grab as it breaks thru and thats when the cracking chipping happens, the backer stops that.
you can also grind a slight flat on the drill, taking off the curl at the tip the causes the grab, with this the drill scraps the the hole and you usually dont need a backer.
I also make up a spray bottle of water and dawn dish soap and use that as a lub when drilling deep holes into acrylic almost polishes the hole and keeps the drill and palstic cool so you do not get crazing.
An old Model Maker guy I worked for taught me this trick way back in 1986 and have used it eversense and have showed many, paying it forward.
or if you have a laser cutter even better
Asking out of curiosity and for the sake of conversation.
Is water jet cutting an option? Local automotive (safety, tempered, etc) glass and acrylic uses water jet for holes or special shapes.
Is water jet more/less prone to crazing?
water jet is another good option, just that shit gets wet and possible scratches if protective cover is off, most cast acrylic has paper mask.
edit Laser gives a nice polished edge
AFAIK, local shop that sells acrylic sheets, amongst other things, is using
either laser or water jet to cut them to size, depending on the thickness.
I have a few designs in mind, and I even asked Deepseek to come up with one
It’s the usual juggle with various constraints, like budget, part availability, my DIY
skills etc.
Thanks @len_1962, quite a few tips there
If you are using TAP Acrylic Drill Bits, leave them sharp as is. TAP does recommend oversize holes and the use of gaskets to allow for thermal expansion, but do note that thermal expansion issues only occur when you mount acrylic sheets in a frame made of a different material. If your construction is all acrylic, you can make tight holes without gasketing.
Dwight
cheaper to just grind the flat on the front edge of regular twist drill works the same as the ones ground for plastic, also better for blind holes becuse they have a flater tip.
as a model maker I have cut tons of acrylic parts and the home made drills have never failed me in 40 years.
I generally agree with you. I’ve been successfully sharpening/modifying drill bits for years. But I’ve also found that some people are not so conversant with cutter geometry (note that I’m just an amateur in the game myself), so for many the option of buying a ready made bit is worth the money. I won’t fault them for it. Baffling as it is to me, not everyone finds making the required tooling as fun as making things with the resulting tools.
We have a CNC router and do acrylic sometimes, we have found single flute carbide end mills (Onsrud O-Flute series) with a high helix angle usually work the best. Not sure if you could drill with them in a drill press though.
