I got an old workbench with a top made by a pair of railway sleepers (I assume this is timber). It was very old and sticky with paint stains and not very plane at all, so I tried to use a router and a planning jig to make it nicer to use.
I've almost completed the process and it only needs a last router pass to be "almost as new" but it has a few big holes (about 10cm/4 inches long, see picture below) that I would like to try to fill to avoid them being always filled with sawdust or trapping screws and other small things that like disappearing in holes. I'm also concerned that since they are close to the edges the outer part may break away and make an even bigger hole.
I heard about something called "liquid wood", but also of "epoxy glaze" and some peoples seems to use wood glue mixed with sawdust, but I have no idea which of those solutions (or another one) would be the best in this use case.
I don't want to have a "mirror finish" (this is a workbench, and I'm planning to use it) but I'd appreciate if it could still look good.
My questions are:
- Which product can I use to fill those holes
- Should I fill the holes before the last router pass or should I finish with the router and fill the holes later (then presumably sand whatever I put in the holes)
- Extra question: My router has variable speed (6000 to 26000 RPM); what would be the recommended speed to use in this case for a better looking finish (I'm using a 1 inch diameter router bit like this one and I'm removing about 3-5 mm at a time)
I should add I'm pretty new with routers or woodwork in general so feel free to add anything that seems obvious to you.