Copper sheet should be part of every DIY’rs parts store:
ground plane – make flawless signal return ground path using bug-splat! type connection points.
shielding/lining chassis, sensitive high gain stages, transformers etc.
And make your own tube shields – commercial tube shields are perfectly useless thin .3mm aluminum. Roll a tube shield from this copper sheet, run a ground wire to chassis and you won’t believe the difference electrically and sonically.
This sheeting is 0.4+mm thick, the thickest that can be reasonably soldered by DIY’rs because copper is VERY effective conducting heat when in sheet form.
We will cut it with unfinished edges.