Help!! Where to get acrylic

Sabic is open to the public, they sometimes have scrap/drop available that they'll let you dig through but I'm not sure if they allow that anymore.

They will cut pieces for you also but you typically have to pay for a full sheet + $15 minimum cut charge. I recommend asking for Arkema PMACS (clear cast acrylic with a plain brown paper mask) the "PMACS" is the generic-cast that is made by the Arkema company (which makes the brand Plexiglas). They list this in their system as "Plexiglas GP" (General Purpose, not sure if that's what it actually stands for...)

There is also the Plexiglas-G which is the higher grade, they list this as "GM" and it's the stuff that's guaranteed to be defect-free, but it's literally 99% the same as GP they just put a print on the mask and call is better. Also the guarantee is only valid until you cut it, then you have to buy $100k/year before they'll replace a bad sheet for you (so that follows with the Tommy Boy "I'll **** in a box and put a guarantee on it" philosophy, i.e. it's a worthless guarantee unless you feel like peeling off the mask and examining it completely, them somehow putting the mask back on to work with it without scratching the bejeesus out of it)

GP is my choice for sumps and frag tanks.

 

A sheet of 3/8" will run you around $200, 1/4" around $135-140. The thickness you will need depends on the dimensions of the tank you are wanting to make, the bracing layout, and your build technique.

There are a few mega-threads on the big boards that I chime in on related to fabrication techniques. There's definitely a way to do it wrong and there's a lot of misinformation out there. Just don't go by Joey the king of DIY's advice/method...

 

You could probably do 3/8" for that height and width, it would be a bit safer in the long run to use 3/8" all the way around as thickness is a contributing factor to strength and bowing. Basically the better the top euro, the less deflection and that means less effort removing algae => less propensity to scratch.

ideally you want a 3" euro and a 6" wide crossbrace every 24". So in the case of a square tank, that's a "+" or "X" brace (intersecting in the middle). 1.5" radius corners on all the cutouts, etc etc.

Having built many sumps/etc, I can tell you to plan for it to be more lik 47.5" on the OD, the 48x96 sheets may or may not have an extra overage, plus you have cutting blade losses etc.

 

You can probably get that a Regal (but you have to pay their $7 service charge), maybe Midland Plastics on Washington (in DSM)