The most difficult problem here is holding the piece steady. A vacuum chuck works well for this. Most silica aerogel is destroyed by contact with liquids. Rapid changes in ambient pressure can cause the aerogel to shatter as gases try to enter or escape the pore network. Use care when placing aerogels under high vacuum.
Many people ask if there are any hazards associated with handling silica aerogel.
Working with aerogel with your bare hands can have a slight desiccating effect on the skin. This is due to the absorbance of moisture and oils from the skin into the pores of the aerogel. This is more of a nuisance than a hazard and can be avoided by wearing gloves. Cutting and shaping aerogels usually produces a cloud of fine dust. Nevertheless, it is a good precaution to work in a fume hood or wear a good respirator to avoid inhalation of the aerogel dust.