covered wagon,
A little info to help since you mentioned there being "lead" and/or flakes. There is absolutely NO lead at all in either Astro Foil or Reflectix.
TECHNICAL DATA for Astro Foil:
Thickness: 5/16" (8mm) nominal
Weight: 1.25 oz/sq ft
Puncture Resistance: 66 lbs/sq in
R-Value* properly installed: 15 down as in attic install, 7.31 laid horizontal from roll as on sidewall, 5.4 laid vertical from roll as on sidewall
Reflectance: 0.03-0.04
Degradation: 0.96-0.97
Fungi Resistant Astro-Foil 0.02
2 layers of sealed Polyethylene air bubbles forming a air bulle cushion with 99.9% pure aluminum foil on either side. It's impervious to moisture and air currents and is an ideal convection barrier
What Astro Foil does:
It reflects heat - keeps buildings warm in Winter and cool in Summer.
It stops air infiltration - seals drafty buildings.
It acts as a vapor barrier.
It is strong, light weight, clean and does not degrade over time.
This info is from the Astro Foil web page.
Reflectix web page states much of the same but with lower R-values.
Proper installation has a min of 3/4" of dead air space on either side with the foil sealed tightly to the mounting surface on all edges (360 degrees). The dead air space on both sides can be filled with fiberglass insulation for an additional R-value sandwich.
Basically states that stopping or preventing air currents/airflow is ultra important for maximum effective insulation R-values.
Enough said!