Question Summary
Does the gel cast residue from flax seed gel prove as a barrier for wudu?
Question Answer
In the Name of Allah, the Most Merciful and Compassionate
Water by its nature penetrates most things and reaches the smallest of areas. For this reason, products such as oils and lotions are not a barrier for wudu [Tahtawi/Shurunbulali, Hashiyat Maraqi al-Falah].
However, if the residue from the gel is very thick the water may not reach as this would have the ruling of things like paint or dough stuck under the nails, which are barriers for the water [Tahtawi/Shurunbulali, Hashiyat Maraqi al-Falah].
With that being said, the obligatory amount that one must wipe in order for the wudu to be valid is one fourth. So if after rinsing the gel the residue that remains would be little and it would be highly unlikely that one-fourth of the head would not get wet when wiping.
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani