What you will need to do is create a silicone mould of the head you want enlarged. Pour the HydroSpan 100 and let it sit in a compression chamber for about 1 hour. Remove the object and let it cure for 24 hours. Then take the casted HydroSpan item and let it soak in water for about 1 week and it will grow. It will keep its size when done soaking. Then recast the enlarged size item in a new silicone mould for a final resin casting. The HydroSpan cast item is only to enlarge an item to be recast in a larger size. It is not a workable final casted part.