Acrylic Experts?

[JPierceMT]

I have been contemplating building my own sump and have a couple of acrylic questions. Does anybody know the differences between cast and extruded? I know some people say cast is better for bigger tanks but some people still use extruded. I have been looking at acrylite FF (extruded I think) and Acrylite GP (cell-cast). Anybody have any ideas on differences? Any ideas? Thanks!

[scubadude]

Does anybody know the differences between cast and extruded? I know some people say cast is better for bigger tanks but some people still use extruded. I have been looking at acrylite FF (extruded I think) and Acrylite GP (cell-cast). Anybody have any ideas on differences? Any ideas? Thanks!

Cast is much stronger and I think its less apt to crack/craze....but its also more expensive usually. I always build tanks using cast and use extruded for things like sumps.

[JPierceMT]

Thanks for that, sounds good.
Josh

[Amp2020]

For sumps less than 18" tall. I usually go with the cheapest acrylic possible. Here in VA I search all the acrylic dealers and find who has droped(left over scrap that has already been paid for) pieces of 1/4"( or they call it .220") acrylic in sizes that I can use. Very cheap this way. Usually only costs me $10.00 for a sump with three baffles and pump return chamber. I do get crazing and lots of bubbles in and around the joints but its a shallow sump that no one is going to see. Plus it doesn't hold much pressure like a taller tank. The bubbles might be reduced if I used the pin method but I don't like spending more than 30 minutes making one. Last one took an hour to build but I had lots of baffles to instal plus drilling.

Here's a tip. If you've ever seen anyone flame polish the edges of acrylic. You might do what I did and assume that it will give you a much better edge to bond with. Don't, this method basically tempers the edges and after touching a solvent like weldon 4. The whole edge will craze out of control. Makes it look bad and might casue it to weaken at the joint.