I have never had any problem, except for that one time I put Future over it. I use a small amount and a tooth pick to apply the glue. Do not put too much so as to cause a dome or bubble. You want it to be level or slightly concave. When it dries it has the look of glass. Don"t apply a second time as it will cause it to frost up. Applying too much will also cause it to frost up.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.