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document updated 2 months ago, on Feb 28, 2024

straight-edges

Advice on how to make cuts with a straight-edge and utility knife. This is really good advice: [1] [2]
- more background reading [1] [2] [3]
- loooottts of cutting tips, doing precision work and sometimes using a scalpel (YouTube playlist)
- there are a number of specialty blade-cutters when doing more precise cuts on thinner materials [2] [3] [4] [5]
- of course, people use rotary cutters with fabric and paper

Cutting specific types of materials:

1" foam — [1]
foam-core — [1] [2]
mat board — [1] [2]
EVA foam — [1]^†
drywall — score and snap
plywood — score and snap, score and snap
tile backer board — score and snap
sheet metal — [1] [2]
leather — [1]^†
fabric — [1] ⇐ there's some great advice in that video

† Look ma, no straight-edge!

My preferences for a straight-edge are:

material	Only steel is acceptable — aluminum is softer than a steel utility blade, so is liable to being scratched, allowing the blade to climb and travel over the straight-edge, posing a hazard to your fingers.
width	1½" or 2" wide are great. 1" is too narrow, as it doesn't give enough room for fingers to keep the straight-edge steady while avoiding risky situations.
thickness	I usually use stock flat bar at home stores, which often comes in ⅛" or 3⁄16" thickness.
anti-slip backing	I like some rubber / elastomer of varying thicknesses: 1⁄16" thick (often available with adhesive backing) 1⁄32" thick (often not available with adhesive) workout resistance bands — somewhere around 1⁄64", but your mileage may vary Thicker rubber can accommodate bumps and protrusions with ease, but feel like they would be less accurate due to the fact that the straight-edge can rock side-to-side. If possible, the rubber should be firm, especially for the thicker pieces. Note that you can put different types of rubber on each side of the straight-edge, which gives you a choice of which one you want to use for a cut. You can use CA glue for many types of elastomers (test this on a sample piece, however). But I had problems with the CA curing way too fast, after I spread it into a super-thin layer, before laying the rubber down.