So, latex is squiggly. It moves around, it stretches, it’s a huge pain in the ass to actually get it to do anything. It makes cutting thin strips, like trim, pretty hard.
I, personally, tend to order pre-cut trim a lot of the time (Radical Rubber does it, and you can purchase it from them or from resellers who carry Radical sheeting), but that only really works in common colours like black and transparent natural, and if I plan ahead to know that I need trim, which to be honest I mostly only do when it’s part of the design on the outside of the garment — and even then, the trim only comes in so many different thicknesses, and it doesn’t match when you’re using non-Radical colours sometimes, sometimes dye-lots are slightly different …
Basically, I wind up spending a lot of time cutting my own trim.
Lucky for you, I have a pretty simple trick for it!
I illustrated this with a 1/2″ piece of trim that I had already cut, that I’ll be cutting into 1/4″ trim, but obviously this will work for any piece of latex with a flat edge that you want to cut trim from.
What you can see in the picture is a piece of latex where I’ve cleaned and glued the bottom, waited for it to dry, and then adhered it to the edge of my clean plastic ruler. (To clean the ruler, just give it a gentle scrub with your cloth and some thinner, wait for it to dry, voila! If it’s really dirty, you might have to break out the Windex and give your ruler a scrub.)
I’m using what’s generally called a Quilting Ruler, but can also be referred to by its measurements (which would make this a 24″x6″ Ruler). I basically never use any other ruler anymore (except for occasionally my French Curve, and even then, to be honest with you, I do a lot of eyeballing on curves instead of using it). It’s great for making sure things are square, saves a lot of time in marking distances and seam allowances, and it’s also amazing for cutting latex trim. You absolutely want one of these if you sew, pattern draft, do foam, basically anything that involves measurements.
You can see in the photo that I’ve lined the flat edge of the latex up to the 1/4″ mark all the way along, and I’ve pressed it down with my fingers. Generally this is enough to get it to adhere, but sometimes I also give it a (careful and gentle) roll with my roller, to make sure it’s really on there. The rest of the latex is just hanging off the edge.
Flip this over, so that the latex is on the bottom, stuck to the ruler, and now sandwiched between your ruler and your cutting mat. This is going to hold the latex in place while you cut along it.
I had to take the hand holding the ruler away to take this photo — press down against the ruler firmly to hold it in place, and then use the edge of the ruler to guide your rotary cutter.
This is where I think it’s important to note the quality if your ruler; you want a thick one for this. Mine is nearly 1/4″ thick by itself. This makes it hard to knick it with your rotary cutter — I wound up throwing out my last quilting ruler because the edge wasn’t straight anymore because of all of the time I’d knicked it with my rotary cutter while trying to do this.
Flip it back over, pull your trim off, and voila! There’s your trim! Clean off the bottom again, gently, maybe reapply glue if you find that you need to, and you have perfect trim, every time!