What do you use to cut thick plastic card?

[Emperor's Furor]

I've tried using scissors, modelling knife, Stanley knife but I find it really difficult, can anyone suggest something to make precision bits? For example I want to expand a Storm Raven to make it in a Storm Eagle so want to make the body bigger which means it needs to be precise.

[Brother-Chaplain Kage]

You score the plastic first and then break it away from the main piece. I use a metal ruler and a hobby knife, but you don't actually use the blade edge - flip it over and use the top side of the tip to score the plastic along the straight edge. Depending on how thick the plastic is, you might need to score it several times, and then you can cleanly snap it along that line.

[LutherMax]

^ what he said. If the edge isn't 90 degrees you can sand it down.

[Subtle Discord]

How thick is 'thick'? The score-and-snap method is very effective, but it can struggle if the shape is even modestly complex; it can be prone to ripping corners and other tight forms if you're trying for really sharp/clean detail.

 

I personally use nothing but a No.11 razor/scalpel blade for everything I cut, and I can surprise even myself just how clean and accurate I can get if I take my time. For anything upto 1mm thick the blade is perfect and you just need to be patient while cutting 0.75mm or 1.0mm; once the shape is lightly cut in the plastic, just keep cutting the lines several times with modest force until it gives, taking care to get into the corners for clean shapes. It will take time and care if you want really clean shapes. More force will cut faster, but the pieces will likely be less accurate. I routinely cut shapes down to the 1/10 of a millimeter in accuracy with no real problem, if I'm willing to take the time.

 

I find as soon as you get over 1mm, it just becomes a complete pain to cut polystyrene with a blade. The cut is so deep in the material that there is much more friction the deeper you go. The only solution I've found is to be patient and slowly cut your way through with a fresh blade. It will take considerably more time and require more care to get clean shapes if they are complex, there's just no way around it. I tend to keep shapes very simple at these thicknesses, and use thinner sheets that are much easier to cut, to add detail on top.