Working with acrylic panels

[flounderpounder225]

I thought I would put this out for those who may be interested.  I just sent Mark SR a Lexan Dash panel for his Osprey, I had an extra one that I was going to install on mine, but current one is OK, and he is redoing his gauge panel.  A couple tips when drilling these, either LEXAN or Plexiglass, using a "plastic Drill Bit" helps prevent cracking because of the different angle of  the flukes http://www.rplastics.com/plasticdrill.html  Also, I use a little rubbing alcohol as a cooling agent, like you would use cutting oil on a hard steel when drilling, this works very well when using the hole saw to cut the large holes.  Leave the protective paper coating on until finished working with the panel, or if drilling one that the paper has been removed, I would put the blue 3M painter's tape on both sides of the panel where drilling will be done, this helps prevent chipping as the bit/s exit the material.

[seabob4]

Good tip, Marc.  I remember at WC, we used tapered bits to drill into plexi...seemed to work, never cracked one!  

You also want to make your hole through the panel a "clearance" hole, where the threads of the screw don't come in contact with the panel, only the substrate below it...

[wingtime]

Solid advise Marc!  For working on acrylic aircraft windows I have a set of plastic only bit that are very similar to those. (you don't want to crack a $1000 window!)  There is also a way that you modify a old standard bit to drill into acrylic as well.  I'll have to look for the instructions on how to do it.  You basically want to make sure the bit does not grab the material and pull itself into it.  Also deburr any holes.  Polish the edges of the part with either very fine sand paper or even using a propane torch. (plastic guys actually use a hydrogen/oxy torch)

Edit:  Here's how to do it: http://acrylicsbydesign.blogspot.com/2010/10/how-to-modify-metal-working-drill-bit.html