Water glass by any name can seal cracks better than failed head gaskets I believe. There is no way to estimate how long it will last though.

Some engines have never developed a similar problem again. It is in my opinion for engines not worth spending money on. I think the silica fuses to glas in the presence of combustion temperatures.

I would not trust a car going long distances with this fix myself. On the road issues are too expensive now to chance. It could easily cost you the car is one risk if it let go far from home. For the same reason I would try to locate a number 17 head or higher if a number 14 failed.. .