Rupesh Sawant wrote:

> Hi,
>    I want to make NH4F (Ammonium fluoride) in my lab for etching
> glass. The concentration of Ammonium Fluoride required is 40%.


I assume this is to buffer a solution containing HF.
Are you talking about semiconductor grade? Standard (non-semiconductor
grade) is fine for microfluidics and isn't expensive.
You could also consider using an aqueous solution with 2% conc. HF + 2%
conc. HNO3 instead. This gives very nice results for soda-lime glass.

Gareth