Part 5 - resin or vacuum forming?
The visor for the helmet is in a number of sections. All of these are twice the size of my print area. This means I have two options. One, I print a set of former pucks (as suggested by CMDR Antonia) and vacuum form some plastic over them to make the visor. Two, I print the visor model in translucent resin. This comes with several issues, the main one being size - I will have to half all the parts then weld them after printing. Another issue is resin is transparent, but a little cloudy; fine for "glass" statues, but not much use for an optically transparent visor. To fix this you need to sand and polish the resin to a clear finish.
To test this I first had to buy some translucent resin. I then chose a small "glass" model I could print and test to see how hard or easy it would be to get transparent. This was the result.
With some painted caps and little alcohol ink, the results were excellent.
Having proved the concept, I went on to halve the front visor model and add some pin holes for alignment, so it would be easier to assemble.
I set it printing and came back twelve hours later...