Question: how do you make a rfid blocker?
Answer: Step 1: Materials. All you need is: ... 
Step 2: Duct Tape. Lay down duct tape so that the strips overlap slightly and create a sheet. ... 
Step 3: Aluminum Foil. Lay the aluminum foil [carefully] onto your duct tape sheet. ... 
Step 4: Packing Tape. ... 
Step 5: Cut to Size. ... 
Step 6: Tape Edges. ... 
Step 7: Done!