I agree with outlaw to an extent. If you are having problems removing it then I would think you are using too much, that I agree with. However, I dont see a problem adding a layer of 425 between the 2, or even between layers of SG. 425 doesnt contain anything that should prevent SG from bonding. This seems like a similar process that some like to use with zaino, adding a misting of z6 between coats.