Ok, not gonna happen, esp in a junglePortable Medieval forge, so you can get an idea of the size/bulk of it.
Think the biggest thing will be the supply of coal or charcoal that would be needed to do major repairs.
I don't agree with this. By collecting the above info, the forge seems to be required to do a repair for heavier metals: the table has a column named "Repairability".You can, of course, houserule however you'd like. But RAW it’s the same set of tools and just a different DC between the two checks. A5E.tools even links to the Materials page for reference.
So, for Splint Mail/Armor, repairs might be fairly easy depending on what was damaged.I don't agree with this. By collecting the above info, the forge seems to be required to do a repair for heavier metals: the table has a column named "Repairability".
Maintenance thus appears to be for minor things (greasing, fixing small dents, repairing latches etc) and wouldn't require a forge, but a failed check means that the small repair was botched and the item is now damaged
It's a good idea. My main point with this post was to figure out RAW and its gaps/flaws.Why not allow the players to set up a sufficiently hot fire with a Survival skill check, or Arcane skill check if using magic, and then have the character making a smithing tool proficiency roll? If the conditions are poor, impose disadvantage on the roll. But I would lead into the "Rule of Cool" and allow the characters a chance of doing it, if that's what the players want to do to have fun in your session. You could still require that they fix it properly when back in town, giving it the Flaw property (i.e., so it breaks again on a critical hit against the person wearing the armor) in the meantime if they don't roll sufficiently high on the skill checks.