So I'm 16 and I bought a running, no rust, great body 1978 280z about a month ago. The worst part of this car was how bad the dash was cracked. I've stripped the whole interior and have the dash completely off also the dash components. On to the point, I've read other forums about beveling out cracks and putting great stuff foaming sealant. I've done all that, but I ran into a problem. After I sprayed foam into the cracks, the foam didn't seal the whole crack or didn't stick at all. Is there a way to make sure that the foam fills the cracks complete, so when I sand it down, the open cracks won't expose??