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Warning....when installing sound deadening material beneath the sub-floors,

think twice before using expandable foam in a can. It will expand with

considerable force in a confined area. I completed this construction four

months ago, drilled numerous holes in the floors and injected foam. In due

time, the foam expanded and found its way out through the holes as I had

expected and about a week later, I filled the holes with micro. Four months

later and much to my surprise, I found a ball of foam about six inches in

diameter on the cockpit floor. Some of the origional foam had not completely

cured and over time, it expanded with enough force to rupture a small area of

2bid tape I had applied around the sub-floor. The bottom of the fuselage had

been wet sanded to 600 grit before being turned right side up and the force of

expanding foam had produced a visual distortion in the exterior surface. It

might have been only 2 or 3 mil and about the size of a slice of tomato. Noone

else will ever see it but I know it's there and will deal with it during final painting.



Just to be safe, fill the void between sub-floor and fuselage with rigid foam,

cut to size and shape and benefit from my mistake.



Angier Ames