The rubber mats arrived. If I were to do it again, I’d shorten the width of the top plywood sheet by 5cm for bars with slim collars.
First layer of coating. Unfortunately the coating also makes the impurities in the wood more prominent. But I knew that it wasn’t quality wood anyway, and other than that the top sheet has a nice pattern.
First shot at a DIY lifting platform. I used five sheets of 2.50m x 1.25m plywood (9mm thick, birch) and a lot of 16mm wood screws. I was afraid the 1.25m might actually be too wide, but it seems ideal for a (primarily) deadlift platform. The usual approach is to also glue the (alternating) layers of plywood together, which would probably be a lot more durable - fewer air pockets and all - but I decided to go with screws only, because this platform doesn’t have to last forever and this way I might be able to reuse the wood should I rebase my garage gym, moving the 2.5m x 2.5m platform would be neigh impossible.
Now I just need some sealer for the top layer and rubber mats for the sides… and I hope the screws will suffice.
The price for this varies greatly with wood quality, wood thickness and so on, but costs a fraction of a “professional” lifting platform.