Does anyone know if I can apply Blackfire Wet Diamond Sealant onto my windshield? Will it provide any water beading/rain repelling benefits? Or will it make my windshield a smeared mess?

 

its designed for paint. use it on paint.

use something that is designed for glass.

 

i used FS UPP on my windows and windshield. its works great. i could go months without reapplying it. just prep the windshield properly making sure its super clean, (clay, polish a little and then apply the sealant) it works wonders.

 

It is perfectly fine to apply a sealant/wax on a glass. It is actually recommended after claying it.