A while back, I was using solvent to glue up acrylic boxes.
The trick was to get one drop of Methylene Chloride (causes cancer in California) at the junction of two pieces of plastic to form a right angle.
I came up with a design, to what I refer to as a “Capillary Dropper”.
The dropper must serve two functions, #1 dispense only one drop at a time, #2 place that drop at a precise location.
Below are images that describe what is necessary to make one of these droppers.
Note: the larger the diameter of the capillary rod, the more liquid will be dispensed (up to a point).
I find a rod diameter of .026” in a syringe needle with a diameter of .039 works best for one drop at a time application.
Capillary rod diameter:
Straight pin, .026"
Pin with yellow ball on end, .026" <-----<<< best for one drop at a time
Sewing needle, .035" <-----<<< best for almost a continual flow at a seam
I will follow up later with “Attaching a PCB inside a plastic case without drilling through the project box itself”.