Microscale Krystal Klear is identical to canopy glue. A form of white glue that dries clear. I consider it to be an essential tool in my "arsenal".
It is sold to be used as window glazing (it dries clear). I've been using it as a basic adhesive in all kinds of applications for a couple of decades (most likely longer) and it has never "let go" on me. I -rarely- use it for window glazing. If the KK is 'thick' the window has a certain "coke bottle glass" appearance. If the sides/edges of the window are thick (think Athearn caboose for an example) the thick lens appearance is unavoidable - if the edges are thin (think brass) then it can be almost discernible from more traditional forms of glazing. I often/almost always use it when attaching something to a surface that is painted (it dries clear). It does take a long time to dry/set up. The thicker it is the longer that takes. It will skin over in a short amount of time (an hour or two). The rest of the drying occurs thru the evaporation thru the skin (which remains "flexible"). It will not "pick up moisture from the air and let go". At least not enough to matter. It forms a "fillet" (note spelling) when used where two parts are joined at 90 degree angles. And adds considerable strength in these applications (think cab shades). Keeping the part correctly aligned/oriented - while the KK dries - can be a challenge. It 'shrinks' as it dries and will rarely form a thick layer between the two parts. If you soak the joint in water for 30 minutes or so - you can cause it to let go and you will be able to rework the joint. By soak I am including just laying the model on its side and putting a drop or two of water on it with an eye dropper. KK does not "craze" painted surfaces like CA/ACC. KK is paintable and does not form hard/'shiny' surfaces that paint/stains show when you apply them over it on something like a wood trestle.
Places where I use KK that you may not have thought about are:
To attach/reattach a brass part to a painted brass model - such as a small detail part with a brass 'nipple' that goes thru a hole in the frame/shell. To hold wiring in place so it doesn't "get into the drive" This can be difficult unless you can figure out how to hold the wires in place while the KK dries. What I do is to grab the wires with a strategically placed set of cross lock tweezers. (I often use other products for this one.) Installing 0402 LEDs inside a headlight, class light, or markers. The KK holds them in place - and forms a lens for the light to shine thru. I often/usually paint the inside of the detail part with "Old Silver" or other such color. Installing LEDs inside a Tomar car drum head. Installing parts that have a mechanical advantage where the KK only holds them in place - such as a small piece of brass 'bracing' that keeps the gear box in a brass loco from rotating (I file a notch for the strength and just use the KK to hold it there). Attaching glazing (actual glass or clear plastic sheet)to the inside of passenger cars and/or cabeese. Building wood structures. I -rarely- complete a model I'm working on without using KK somewhere or other.
I'm "just an old guy who plays with trains" (ask my wife) ... so the fact that KK takes more time to dry/set is of less importance to me. If Microscale ever stops selling it - I'll just switch to canopy glue. - Jim B.
