Welcome to the forum, it’s good to hear from a fellow armor modeler. I’ve always made my own vision blocks, with mixed results. The first ones were made by taping the openings on one side and pouring clear epoxy in on the other opening. I did this with a M-48 driver hatch.
Since then, I’ve saved any clear sprue, flat clear plastic or any other clear plastic that that looks useful.
For open vision blocks, I cut what ever clear plastic works best to shape the block and use Elmer’s glue to install it. Elmer’s glue is not very strong(ask me how I know this), but is good for non structual parts and doesn’t craze the part.
For non open vision blocks, I paint the “glass” part black and paint clear gloss over the black. A harder way to do it is use very thin clear plastic, such as from the sprue that comes with wind shields for military vehicles or clear plastic page dividers. Again, paint the “glass” area black, then cut the plastic into pieces that will fit the the “glass” and use the Elmer’s or any other glue made for clear parts. I know these are not easy to do. Hopefully someone can help find abetter source. Happy modelling.
To replicate armoured glass I am using rainbow tape, which I found on Amazon.
There are lots of differend types available, but the two on the right does only work for this.
Most times I use the blue/green tape, but the red/yellow looks good either.
One of the last things I do on a build is to paint the vision blocks silver, cut a suitable piece of tape and stick it on. Depending on the angle of view the tape changes its color and looks very effective like armoured glass!
There are also numerous companies that make various periscopes in either clear plastic or resin. It just may take a bit of searching to find exactly what you want. Here is a sample of what is available.
ancoron109: I disagree with your suggestion for this question. The rainbow tape is good for modernized glass with anti-laser treatment. WW2 era glass had no such treatment.
If the periscope or vision block is open I use MicroScale Krystal Klear for WW2 subjects. On modern armour I have painted the vision block with Tamiya Chrome Silver and then applied Tamiya Clear Green, Red, Blue or a mix of all as appropriate.
OK, if you want clear vision blocks on your model it is completely up to you. But vision blocks on German tanks in WW2 consist of multible layers of thick glass. Looking from inside these are clear, also if removed! However, looking from the outside they appear in a very dark shade of blue, sometimes even green. If you ever had the chance to see a real thing in a museum you know what I am talking about.
If you really want an authentic look paint the block in a dark blue (XF-17 works good), then dry-brush with a lighter blue (if you like additional with a green) and put a small dot of very light gray into one corner. Finally a coat of PVA, Pledge or whatever gloss varnish is at hand.
I do it all in one with the tape …