Acrylic Sump Cover How Thick To Not Warp?

[LarryS]

I'm going to buy and cut some acrylic for a 20g long sump. Want to be sure I buy it thick enough to not warp (as experience tells me that 1/8" thick will warp!). I'll probably do this in 3 sections so that I can slide a section over another to expose an opening without having to actually remove the cover except when necessary to gain full access.

20g L dimensions are: 30" x 12"

Hoping someone has already done this and can share their experience.

 

[LarryS]

bump... anyone?

 

[BillD]

Are you going to span the 12" width or the 30" length? 1/4" should be sufficient .

 

[LarryS]

Are you going to span the 12" width or the 30" length? 1/4" should be sufficient .

The 30" length will be 2 or 3 sections tbd after the skimmer is plumbed. Not one 30" x 12" but not clear yet how long is the longest piece.

What surprised me about the 1/8" scraps I had on hand is that they warp and sag with spans as small as 12" x 4" and 7.75" x 13" (on a 5g RO/DI reservoir).

I'm hoping 1/4" will work but really would like to know for sure before I buy and cut it.