Tag Archives: MDF

24: Transfer Tape

Most suppliers I use for laserable materials ship those materials with transfer tape applied to either one or both sides.  I didn’t really learn to appreciate this until I made a bulk order of melamine-coated MDF from a large home improvement chain; they don’t assume you’re going to be firing a laser at their product so they ship the boards without that kind of protection. I did some lazy-bones “research” and determined that my own roll of transfer tape was too expensive, so I tried to use the material without any. Unfortunately, the MDF is 1/8″, too thick to cut with a laser without some serious scorching. That scorching meant surfaces too damaged to be presentable, so I sorted the stacks of MDF to the back of my materials pile and left it to collect dust.

The roll of transfer tape, medium tack!, and one set of numerals.
The roll of transfer tape, medium tack!, and one set of numerals.

Jen, awesomeness incarnate, did some proper actual research and discovered the right roll of tape at the right price. Our very first very own transfer tape roll arrived, and it was glorious. I pulled out some gray melamine MDF and whipped up a design I’d been thinking about for a while: a number pad. I’ve been a little obsessed with Clarendon lately thanks to some flyer design at work, and its numerals fit so well! Design finished, I applied some transfer tape to both sides, totally overdoing it by using a brayer and everything, and left one section without tape so I could show off the difference.

The top surface, where white is tape, gray is melamine, and yellow is unacceptable!
The top surface, where white is tape, gray is melamine, and yellow is unacceptable!

I use a manual air assist solution with my laser, which means I hook up an air compressor though an accessory that funnels said air through the laser’s path. This prevents a lot of scorching when cutting any materials, but is almost essential when cutting thicker woods as the heat can build up and wood can actually catch on fire if you’re not paying attention. For all it’s worth, it still can’t completely prevent scorched edges. With the air assist active during the entire cut, I cut four sets of numerals, one completely nude. The transfer tape did its job, shielding the melamine surfaces front and back from the laser’s super crazy heat.

Cleaning off all of the resin from the material's back surface is awful. Go transfer tape!
Cleaning off all of the resin from the material’s back surface is awful. Go transfer tape!

The back surface in particular is a mess. The air assist does a great job of pushing all of the heat downward as the laser lases, keeping the surface mostly clean. However,  the somewhat dirty downdraft cutting table—that’s the metal honeycomb pattern you’re seeing—and all that air being pushed around means the back face gets pretty grimy. It’s a huge pain cleaning that much sticky woodish residue off of any surface, let alone one with many curved edges that you don’t want to get wet.

Look at all of those messy bits of mess.  Thankfully, it's all lifted away with the transfer tape.
Look at all of those messy bits of mess. Thankfully, it’s all lifted away with the transfer tape.

That’s not the half of it, though! When I’m removing the cut pieces from the remaining material, every charred edge is full of soot that adheres to the nearest finger, tool and surface. It’s so much happier a process when I don’t have to daintily handle each piece while wiping down the sides to avoid dirtying the surfaces. With the transfer tape applied, I just brush the soot away, care not where it mars the taped surface, and then peel it all away!

The biggest issue, though, isn’t just a matter of inconvenience when finishing laser-cut products. Even after all of the cleaning is done, the laser just does too much damage to the tapeless surface. It might not be a big deal to some people, but the kind of surface damage seen below drives me crazy, so I couldn’t think of selling that to someone else (via Abecediary on Etsy).

The number three here and his twin show off the difference between a taped surface (left) and an untaped surface (right).
The number three here and his twin show off the difference between a taped surface (left) and an untaped surface (right).

There are so many ways to use transfer tape beyond protecting a material’s surface from the laser beam’s blast. I’ve used transfer paper in the past to etch various designs into acrylic surfaces to prevent discoloration, even if that can mean hundreds of tiny little paper Tetris pieces to peel. I have yet to laser-cut vinyl, so I’m not really that knowledgeable when it comes to using transfer tape to keep discrete vinyl bits aligned properly when applying them to something. Those are just two examples; if you’ve worked with transfer tape before—with lasers or otherwise—let me know in the comments below and share your own examples!

The final piece, full of implied maths.
The final piece, full of implied maths.

08: 3D Etching

This week I decided to give 3D etching another shot. I have just once before played around with the 3D settings available on our laser, but I haven’t really explored the process until now.

Normally, the laser interprets shades of grey by preparing a halftone map and etching that at whatever singular power I have set. With the 3D feature enabled, the firmware will adjust the power of the laser depending on the darkness of the grey: white is ignored, black is etched at your selected power. Because of this, all you really need is a depth map and you can 3D etch straight away.Just remember: white is shallow and black is deep!

ABCD 3D
The Abecediary logo with the core etched away

Back when I first tried it out, I just used some sample depth maps available in Google’s image search, but this time I created my own typography-themed art. I had to use Photoshop to create some raster effects to create the sloping edges I wanted because there isn’t an easy way to create shape-burst gradients in Illustrator, but this wasn’t a problem because, while the laser won’t cut anything that isn’t proper vector data, it’ll etch even raster graphics with impunity.

ABCD Layout
The blurry edges are where the 3D happens.

I often use the simple Abecediary logo as a sample design when testing new materials. Even though the white melamine-coated MDF I used wasn’t a new material to me, I felt it appropriate, so I created a black version with a white inner glow. The thin red line is the vector cut that created the final shape of the letters after I hollowed out the core. Because I etched five passes at a fairly strong power, the finished piece had too steep a slope; you can hardly see that it was a slope and not just a really deep etch, but it’s there! I swear!

Etaoin in MDF
The whole piece; the depth is hard to capture without appropriate lighting.
Etaoin in MDF
The slight lip on the edge was made by skipping a few lighter levels of grey.

The second piece, ETAOIN SHRDLU, was based on a fun part of newspaper lore and set in Colonna. It was etched opposite the ABCD: the letters were left untouched while the outer space was etched away. I chose a thicker gradient stroke so that the slope would be gentler. I also only etched the bitmap four times. The contrast between the white letters and the resulting grain of the MDF’s innards is profound. It almost looks like the letters are sitting in a bed of sand that has settled over years.

Etaoin in Black
The black acrylic Shrdlu is a little hard to read without the right light reflected!

The final piece was cut from quarter-inch black acrylic. For fun, I created an offset path so that the letters would be cut out more tightly than the MDF version’s square border. Even with six passes at full power (and half-speed) the etch didn’t quite reach half-way through the material.  The result is a little hard to read (maybe I should have used a capped material!) but certainly looks neat.

Etaoin in MDF
The slight lip on the edge was made by skipping a few lighter levels of grey.

The amount of passes necessary to create a good 3D look takes a lot of time, but there’s a whole lot more that can be done than just beveling the edges of pretty type faces. I’ll definitely be playing more with the 3D mode as we go on.

Etaoin in MDF
The sand blows away, revealing pure white type!