I have a few questions, first how do you attach the coping and what too? Second, if the coping is slightly higher than the box then can you catch your skis on the coping easier? Third, if you have the coping level with the box does it make a difference?
All of this may be wrong - I'm just going off stuff I've read:
I've only hear of two ways of people attaching coping - for PVC you need to send a screw into the bottom of the pipe, then into the wood. You get access to the bottom of the pipe by first drilling a slightly larger hole in the surface to get a drill through to the base. The problem with this is if you crack the PVC after landing on it, there's a chance you're going to take your ski base right into a metal screw, bolt, etc. that may cause damage. To try and prevent this, you can inject the PVC pipe with expanding foam (not sure of the official name) that should help make it more solid. I've also seen people who have caulked metal coping onto the wood - basically gluing it - but I'm not sure this would work well with PVC.
The coping gets attached to 2x4's that are attached to the sides of the box. So if you have a box, you'll take two boards and run them flush against it, but 1" lower than the surface (depending on the width of the PVC) so that when you place the PVC on the edge, it raises just above the surface of the box. There's a few diagrams around that show how this should be set up, I'll see if I can find one.
I believe you have to have the coping above the surface, as one of it's purposes is to protect the edges of your surface (HDPE, Lexan, etc.) from chipping. If you have the coping level or lower than the top, there's no reason to put it on at all. There will always be a chance of your skis catching, unless you use metal coping.
Again - this is just stuff I've read - so if anyone sees something wrong, please point it out for me too. Thanks.
I just finished my 8' box using HDPE. I'm now wondering the same thing about coping. I was going to use pvc but isn't it still easy to catch edges on it? And is the upgrade to metal expensive? What diameter do most people use...