CA is like crazy glue for wood, thick fills gaps and drys slower, med is just that, between the two grades and drys a bit faster, thin soaks in fast and sets quick and will "run" meaning if you apply some to a area it will soak in along a seam and glue that seam rapidly. CA is a great adhesive although there are many types of glues and knowing where to use them is important experience counts in where to apply the right glue and where. epoxy ,titebond or elmers wood glue, or CA they all have there uses.