That the ski has been waxed will make getting the surfaces you plan to glue the ptex to that much more difficult. Use a wax remover (a spefic type of liquid solvent) to clean the ski. If the edge isn't broken, you'll be better off using screws to hold it in rather than cutting it out to replace with an edge segment. Cheaper, too. Tiny screws will help hold the edge in place when you epoxy it. You can dremel the heads of the screws down once everything has set. You are looking for lateral strength from the screws, so the heads can be pretty thin. They'll need to be to accept the layer of ptex over them.
I wouldn't use a dremel to cut the ptex. Use a guide and a very sharp box cutter or knife to cut the base area you talk about. Be sure the guide can be used to cut the patch as well or you'll have a hard time getting them to mate. Use a separate patch for the hole in the middle. You may need to chisel or lift the ptex from the ski. Or it might just pull off once you get a handle on it.
In a nutshell:
- cut and remove ptex
- clean ski to remove wax
- dry fit the edge and screws
- epoxy the edge and final fit the edge and screws
- cut the patches and dry fit them; you should have not space between the patch and the base if possible
- epoxy and clamp the patches
- use a ptex candle for the rest of the base repairs
Clamps and metal sheets will hold the parts while the epoxy sets.
Use a good long curing epoxy.
These are pictures of my first edge and base patch repair:
Patch cut to expose damaged edge. I had started one hole in the edge for a screw.
Screws in place and epoxy set. Screw heads dremeled to allow for overlaying ptex.
The finished work. As I said, it is hard to get the edge to line up. You can see where it is skinnier because it bulged at that location and was ground down during side edge tuning. The patch is practically seamless which will help it to resist being pulled out. It took a fair amount of scraping and grinding to make the ptex flush with the original ptex as well. I started with a metal scraper to remove the gross excess, then finished with a belt and stone grind.
This was a virtually brand new ski and the customer insisted on keeping the original edge. I think in the long run it is a good idea, but as you can see it had been badly damaged prior to the repair. It was nigh impossible to get the damaged area to match the natural line of the edge without the surrounding edge being pushed inside the natural line, thus unable to be filed. It is a trade off. I marked this edge to be the outside edge for the customer.
BTW, this was the second repair to the ski. The edge hadn't been screwed in before and a simple square cut had been done to expose the edge by peeling back the original ptex rather than patching it. The ptex repair and as well as the edge repair had failed when I did this repair.