This page offers a guide on how to make Copper Bars in My Time at Sandrock. There are a few ways to get Copper Bars and this page will detail each of the different ways you could obtain them.
Making Copper Bars in the Furnace
Firstly, Copper Bar can be made with x3 Copper Ore in a furnace. Copper Ore is the most abundant ore in the mines. It can be found on the first level of the Abandoned Ruins and you’ll be able to get hundreds of the stuff in no time. You’ll get the most Copper Ore from mining big Copper Crystals found in the mines, but you’ll also get some ore from clearing the blue-brown debris that blocks your path.
Obtaining Copper Bars from Recycling Copper Scraps
You could also obtain Copper Bars from recycling Copper Scraps in the recycler. Copper Scraps can be obtained from Junk Piles found in the Eufaula Salvage Yard - or you can purchase Copper Scraps from the Eufaula Salvage Shop as well. Given that materials dropped from a Recycler are random, you may have to recycle more or less Copper Scraps depending on your luck.
Purchasing Copper Bars
And finally, if you really don’t want to do any of the work, you could just purchase Copper Bars from Hammertime! They cost around 25 Gols, depending on the price fluctuation.