Cutting gaskets from EVA foam with a diode-LASER

One of the great things about having a CNC machine is that we can make very professional looking projects whenever we want to. So sometimes we’ll want to add those nice details that make a project stand out. Things like, for example, gaskets between parts. Recently I had a need to cut a couple of 50 mm square gaskets for a 3D printed extractor project, for which I chose to use commonly available EVA foam sheet. So I thought I’d write a quick post to let you know how that went with my diode-LASER and whether EVA foam is useful for low-power LASER-cutting on a CNC router.

As you can see from the photo above, my 5W diode-LASER module cut right through the sheet easily with the power set to 25% and a feed rate of 200 mm/min. I’ve cut EVA in the past with a 1500 mW LASER module too, so those settings sound quite comparable and show that low-power LASER’s cut EVA well. At those settings I didn’t find any burning of the foam, and the shape came out pretty much as planned with just a little shrinkage at the edges. Plus, as the photo below shows of the MDF sheet I cut the EVA foam on, the LASER energy left after it had passed through the sheet was small: although probably I could have used a lower LASER-power just as well.

A photo of the laser cut EVA foam gasket together with a photo of the limited damage to the underlying MDF sheet

If you decide to LASER-cut some EVA too, please remember to use lots of ventilation as the fumes are unpleasant: given the small amounts of fumes you’re likely to create you may be tempted to skip the ventilation, but be warned that there have been reports of some EVA foam containing chlorine, which could make the fumes quite hazardous. So please make sure the foam you use is safe for LASER-cutting and use plenty of ventilation just in case 🙂

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Spring loaded detail/finger sanders for finishing CNC projects

Sandpaper, as well as sanding blocks and detailing sponges, are essential for all CNC projects. They let us remove flaws, smooth surfaces and prepare materials for finishing with a variety of coatings. For many projects though, especially the small ones, they can be too big and bulky and can indiscriminately remove small, often fragile, details, as well as changing shaped edges away from what we so carefully designed.

So, for newcomers to CNC work, I thought I’d add this short post to quickly mention my experiences with spring-loaded detail/finger sanders. Mine is shown in the photo above and it’s simply a plastic finger with a continuous band of replaceable sandpaper around the outside. They come in many sizes, the one here being 20mm wide, although 10mm and 30mm ones are common. They also cost just a few pounds: try searching for something like ‘finger sander spring loaded’ on eBay or Amazon to see what I mean.

One of the most exciting things about finger sanders is the variety of sanding points. To start with there’s a long flat zone at the bottom, allowing sanding of large areas and straightening of cut edges. There’s also a narrow area at the front which allows for getting the sandpaper into tight places and around curves. Plus the rest of it has compound curves that can be very useful too. And when the paper starts to get worn where you need it, just push the pointy front end inward to slacken the sandpaper so you can rotate it around the edge. Personally I find them very useful as you can see in my photo of a Darth Vader routing project below.

A detail finger sander with a walnut routed Darth Vader

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