Advice? Acrylic sheets in DSM?

Regal Plastics in Clive/WDM is about the only place you'll find 3/8". They can cut to size but their prices suck.

How much do you need?

 

I googled that and got nothing

 

Regal will rough cut it for you and they will say "they will be square" but that's relative - for a sump you need it really square, and rough cut is weldable but I wouldn't do it. If you want to build it yourself I can have the parts cut for you on a CNC, then at least you won't have to worry about squaring or prepping the edges. Then you just have to have the workspace/tools to do the bonding and flush trimming

 

I get all my acrylic from Sabic. But when you say they polish the edges, exactly what do you mean? You should not "polish" an edge before you bond it. If "polish" means machine buffing of flame polishing. Only a very good table saw cut (like a panel saw) or a routed edge should be used. Even then, a good panel saw will not always yield a top quality edge, nor will it be truly square, and that is critical.

I order my stock from Sabic and piggyback it on to an order for a local sign company that has the CNC. So if you want to go down this road let me know.

 

If you have a few baffles you could probably get away with 1/4", but the incremental cost of 3/8" is really negligible, especially when you are only paying for the material used. A full sheet of 1/4" is about $130 and 3/8" is about $175