Friend of mine couldn't buy replacement filter covers for his spa. His old covers had deteriorated and were old imperial measurements. I made the replacement covers in two halves because the platform on my printer wasn't big enough to do it in one print. I made a small joining block to give the glued edges some extra strength. I coated the two sides and joiner block with Tetra and stuck the complete cover in door clamps for 12 hours before he installed them. I made them in natural translucent ABS and he's very pleased with them - says the join cannot be seen under water and they look better than the originals which had lots of slots around the edges instead of my circles. His kids have trodden all over them last summer and they have withstood the weight and abuse. They've been in use almost a year now. We made the circles small enough to still stop rings and coins and simialr objects from being sucked through.