I've been toying with the idea of building an enclosure out of plexiglass or lexan. My main concern is that it will crack or craze(microcracks) in the winter. I live in Saskatoon so it can get down to about -40 and acrylic sheet contracts quite a bit in the cold, not to mention gets brittle. Has anyone done something like this?

And also how thick does it have to be?

 

lexan will never crack......well, maybe after 8-10 years....even with the constant vibration and coldness.
i've never built an enclosure but work with the 2 plastics all the time.

I'm sure some other people on the site will tell you some tips and precautions while working with plexiglass/lexan.

 

I honestly don't know.... BUT... I can probably point you in the right direction.

Do a search for Gately Audio on google... they do some very nice enclosures with plexi.

I'm sure if you email him/them your questions they'll be able to answer everything for you

 

ive built some lexan/acrylic, into my system, and it had no problems all winter, i didn't use it for a box, but it was covering everything and im constantly throwing things on top of it and it has been fine.

 

I've had a large 3/4" thick plexi (acrylic) window in a sub box when I lived in Sask that I would beat on with my system (pair of 12s) and never worried about cracking. And it never did. Best thing to do though is pre-drill your holes for screws that are larger than the body of the screw including the flutes. In other words, you don't want the screw gripping the acrylic. Let it grip the wood that the acrylic is sitting on (or in). Even better, use T-nuts or the like. If the entire thing is going to be plexi, then you'll have to use a plastic solvent type of product that fuses the edges together in order to eliminate the look of bolts or screws.

 

the best thing to use is methyll cloride, It will bond the plastics together better then anything, but doesn't work so will with lexan. The stuff I use is called weld 45(comes with a special gun)That's the next best thing but I don't think it drys clear.

 

Thanks a lot for all your help.

What I was originally intending was to build a full acrylic box and chemical weld the joints. - because it's pretty easy to do and will look good. How do I attach the speaker to the box? Can I just put the screws into the acrylic? Or would I need to drill a hole straight through and put something on the other side to screw into.

 

you could screw the sub into the acrylic but make sure u predrill the holes relatively large, i have had lots of problems with my plastics cracking or spider webbing when my holes weren't big enough, id say screw it in by hand so you can tell when something is about to go wrong.