Re: Seat upholstery question
In our upholstery shop, we use NEW burlap and then thread NEW piano wire through it to replicate the original GM spring covering. The piano wire is in there to help distribute the weight evenly over the springs. As Ben mentioned, do not use the original 50-year-old wire again, since it could break and poke through the new upholstery. As added insurance, we also install a thin automotive carpet or similar fiber material between the burlap and the seat foam. You'll never see it, and when looking at the seat from the bottom, all you see is nice clean springs and new burlap. Make sure the piano wire runs from side-to-side over the seat springs, not front-to-rear.
These happen to be '70 Chevelle buckets, and the customer wanted everything underneath painted Satin black.....
When I works, I works hard.
When I sits, I sits loose.
When I thinks, I falls asleep.
The '68 L79 Malibu survivor as found in Nov. 2014, in my profile pic.