a Glass Clear material???

I am looking for a Glass Clear material that can be used as a
grout/joint(?) for a mosaic. The mosaic is made of small glass tiles so
the material has to adhere to glass,(and wood).
I have tried with an acrylic paste but it does not adhere very well to
the glass, and during evaporation it looses to much volume, and it
looks pretty yellowish and not transparent enough.
Does anyone here knows of a good tranparent product that might be a
solution.
(if available in europe, that would be a help too)
Thanks alot,
rasmus