Ah, poorly defined use of language, ok.
Abbreviation for Hillbilly Pumpkin
100% when I have them in the case they very much give off a alien vibe.
Takes about 5 months to grow to that point. They will grow towards a light source so one can get them to do all sorts of interesting shapes, patterns ect. Thus the Bonsai part of it.
Currently Reishi mushroom on oak sawdust leftover from a woodworking project.
Much easier to find a new piece of steel to use.
Like someone said above- the amount of heat required to fill those holes will most definitely warp your steel.
You could grind down any burr on the holes and let it be with the holes. Not sure if that would still suffice for your requirements though.