VCarve

Mirror Frame

Learning to create intricately milled patterns into wooden projects has been something I've wanted to learn to do for a while, but I didn't have the right project in mind until this mirror frame idea started to take shape. As usual, this project had a lot of twists and turns as it came to life...

Mirror purchased on Craigslist

Finding and shaping the mirror

The first phase began with finding a piece of mirror that could be cut to shape. I wanted to try to emulate frames I had seen on Anthropology's website. In most of the frames I was using for inspiration, the mirror was cut into a rounded rectangle. I was able to locate a free mirror that was fairly large. It was a 1/4" thick piece of glass and figuring out how to cut it into the desired shape proved to be more difficult than expected. I went back to the local glass shop where I picked up the free mirror in the first place to find out more about how they cut glass in their shop. The technician told me that they score the glass freehand with a tool I could purchase online. They said it was simply a matter of creating a score line in the glass and applying pressure to the mirror on both side of the line while the glass is resting on a soft surface (they use carpeted workstations in their shop). I created a template in Adobe Illustrator and cut it with the laser cutter to attempt to make an accurate score line on both sides of the mirror. After scoring the mirror and setting it onto a carpetted surface we applied pressure to the glass with minimal luck. Eventually, we attempted to apply more force with gentle tapping from a rubber mallet and CRACK.... Broken mirror (not in the right place).

This led to attempting the same process on several other smaller pieces of thinner 1/8" glass with a similar result. It was much easier said than done. We also attempted to score the glass using a diamond drag bit on the CNC. This led to basically the same result. It scored the glass nicely, but it was very hard to crack the mirror along the line. I'll chalk this up to needing more practice, but I decided to move on to plan B. I decide to look for a piece of mirror for cheap on Craigslist. I was able to find a mirror locally that would allow me to design an updated frame around it.

Measuring the mirror and beginning to model in Fusion 360

I carefully measured the mirror and modeled it in Fusion 360. Once the mirror was sketched and extruded to 1/4" thickness, a rough stock was created around the mirror to allow for a substantial rabbet to be milled in the placeholder stock (this was refined later). Once the mirror and rabbet contours were designed, they were exported as DXF files and imported into VCarve for the design of the details to be milled into the front of the frame.

In retrospect, this whole project could probably have been designed in VCarve, which is where we eventually learned to create the intricate 3D patterns that make the frame look ornate. However, we wanted to flip-mill the frame so the backside could have a cutout for the mirror to drop in (this is called a rabbet). We had experience using a hold-down technique using bolts that are placed along a central axis, so the stock can be flipped with accuracy aligning the milling on the back with a second round of milling from the front.

Again, this could have been achieved in VCarve, but since it was familiar from making electric guitars using Fusion 360, I planned to use both pieces of software. This definitely added to the challenge of the project since all of the files needed to been carefully aligned to make sure everything was the same in terms of the stock as well as the orientation and location of the X|Y|Z home point for both the back (rabbet) and front mill work. If I were to do this project again, (and I do plan on making another frame using similar techniques in the future), I will try to make the whole project in VCarve.

Learning to use VCarve with 3D clipart

VCarve comes with a package of free 3D clip art files that can be used to create detailed carvings into a model. There were a variety of things we needed to learn about VCarve in order to use the included 3D files. Some of the biggest takeaways were learning that in VCarve you need to create a 0 Layer that is the baseline height where the bottom of any 3D elements will sit. Each 3D element is scaled in X, Y, and Z direction, so when you increase the horizontal size of an element, it also increased the vertical size in the Z direction. That said, you can also choose how much you want to scale the Z size of any element if you want it to be more or less prominently featured. VCarve has tools that allow creating rectangular patterns of elements, so I was able to create the details around the edge of the mirror by taking two small elements and mirroring them to make a small group. Then I patterned that group to make a long row of texture elements. The majority of the frame is made up of these small elements. Then there are several large 3D elements that are used in the bottom two corners as well as at the top "crown" of the mirror. I ended up purchasing a paid 3D model for the crown because I couldn't find exactly what I was looking for in the free 3D clip art files that were provided. VCarve has an online store called Design & Make where additional models can be purchased. The other important aspect of VCarve that I learned about and used regularly was the mirroring tool that includes an option to make a copy across the vertical or horizontal axis of symmetry. This allowed me to design one half of the mirror and reflect elements across the midline to create an exact duplicate on the other side.

Designing the cut profile in Illustrator

VCarve has a really nice feature which allows users to create vector outlines of all of the 3D clip art files in a design. This creates a boundary of all of the clip art that can be exported as a DXF and imported into other tools like Adobe Illustrator. I exported the clip art vector outlines along with the outer boarder of the frame stock (for alignment purposes) and brought the DXF into Illustrator to create a profile of the outside and inside of the frame to be cut. I selected the vector outlines from the 3D art and offset each shape by about 3/8" of an inch. I had planned to use a round-over bit to soften the edge of the frame so I wanted a buffer around the milled clip art so there would be room for the round-over bit.

Once I had offset each of the vector shapes, I added some rectangles and contours created with the Curvature tool to refine the overall shape of the mirror. Finally, I used the Shape Builder tool to combine the elements that would make up the final profile and removed any parts of the design that wouldn't be included in the profile cut. Ultimately, this technique creaed an overly complex contour with way too many anchor points. When I exported the profile and tried to work with it in Fusion 360, it brough the program to a halt. Eventually, I developed a better technique were I only offset specific elements of the clip art (mostly in the top and bottom corners of the frame) and added only necessary additional anchors using the Curveture tool to make a much less complex profile. Fortunately, I had some issues when milling the first design, so I had an opportunity to use this better technique when I recreated the frame a second time.

Manufacturing the frame

Once the frame cut profile was finalized, it was brought back into VCarve to be used for cutting out the frame and for applying the round-over around the edges of the frame. I also brought the profile into Fusion 360 to confirm that the cutting profile wouldn't intersect the rabbet. This proved quite difficult with the first version of the profile becuase it was too complex. Fusion 360 took over an hour to process simply adjustments to the DXF. This was resolved in the second version where the contour was simplified.

The setup for milling the frame was fairly complex. First the frame was created with oversized pieces. I used a domino joiner to construct the frame from four pieces of 3/4" thick poplar.

Once the frame stock was created, I needed a way to mount and align it to the CNC table. I created a small rectangular block that was milled in place on the CNC table to notch into the right size of the frame. This allowed me to have a known box point to use as the origin point for Fusion 360. Using this box point, I was able to drill two mounting holes along the vertical axis of symmetry. These holes allow the frame to be flipped from back to front and provide a method for keeping everything aligned. The X|Y offset distance from the corner of the rectangular jig used for drilling the holes is then used to change the origin point for future milling steps to the top alignment mounting hole.

Overall, the first attempt at milling the frame went fairly well. The biggest challenge / problem was holding down the frame. Carpet tape is something we have been exploring as an alternative method for keeping parts affixed to the CNC table. The carpet tape worked well for milling the back rabbet. However, during the extended milling of the front VCarve details, the carpet table failed to hold down the wood and it slightly came off the table. The proved to be a major issue as various part of the frame were milled to different depths due to the frame coming off the table. Typically we would have used the mouting holes at the top of the bottom of the piece to hold down the stock, but there wasn't much room around the bolt holes, and we were concerned about hitting them with a bit or tool holder.

The good news was this mistake gave me a second opportunity to refine the design and milling process and ultimately produced a better result and some excellent learning opportunities! The first version of the frame also gave me a chance to see the frame in real life and get a better feel for the proportions of the frame. I decided that the next frame needed to be a bit thicker / more substantial and the crown at the top need to be enlarged to make it look better proportionally.

First attempt at milling the frame. Note the lines in the frame from the stock detaching from the table during milling.

Redesign and milling frame v2

The initial contour created in Illustrator was unnecessarily complicated with way too many anchor points. This led to a variety of issues later in the design process when importing the DXF of the contour lines into Fusion 360. For the second version of the frame, I manually created most of the contour with the Curvature tool and only used offset lines from the imported vector shapes when necessary. This created a much smoother process for the rest of the CAD / CAM work.

For this second frame, I took fixed of the aesthetic issues that I noticed after the first frame was milled. In particular, I increased the scale of the crown at the top of the frame and adjusted the size and placement of many of the other 3D clip art elements in VCarve. I also kept the stock as thick as possible starting with the 1" poplar. I was able to gain about 1/8" in overall thickness leading to a thicker rabbet and a more durable and substantial looking frame.

Another area for improvement was the method of holding down the frame on the CNC table. For this second attempt at milling the frame, I used a combination of many of the techniques I experimented with in the first attempt. The biggest change was a switch to painter tape on the table and frame with CA (Super) glue holding them together. This is an old standby technique and it works very well. In addition to the glue and tape, we also used the bolt holes down the vertical axis of symmetry to aid in flip milling the frame. I also added vinyl nails around applied with a nail gun to hold down the perimeter of the frame. This combination of hold down techniques worked perfectly.

One mistake that was made in the second frame was not leaving enough space around the edge of the 3D clip art shapes. This made it impossible to use the round-over bit without hitting parts of the 3D milled elements. Ultimately, the issue was subtle and I'm probably the only person who will ever notice the issue. It only really was a problem at the bottom left and right corners of the frame.

Finishing

Their were several steps to get the project to completion. The mirror itself had several large scratches in the back of the glass where the mirror material was applied. I found a mirror paint that was available in a spray paint and was able to partially fix some of the stratches in the mirror. The scratches are still visable but definitely improved with the mirror paint.

Before painting the frame, I needed to find a way to sand the frame to remove some of the marks and wood residue leftover after milling. I tried hand sanding with sand paper but it didn't really get the frame to the state I was looking for. I eventually tried using a Dremel rotary tool with a small grinding bit and that worked really well to clean up the frame and get it ready for painting.

To finish the mirror, I used a bright shiny gold paint and applied several coats over the course of two days. The paint went on easily and really made the frame pop. I am very pleased with the results.

I decided to create a thin wooden panel that would fit on the back of the glass to hold the mirror in place as well as adding more rigidity and strength to the final assembled frame. I bought a piece of 1/4" baltic birch plywood and cut it out with a 60 degree v-bit to create a chamfered edge. I painted the back panel black and it worked very well to finish up the back side of the frame.

Packing and shipping

Sometime when you think a project is finished, it is just the beginning of the next project... I took the framed mirror to the FedEx store to see what it would cost to have them package and ship it to NYC. After taking measurements including height, length, width, and weight of the frame including estimates for the size and weight of the packaging they would likely use, I was quoted a price of $120 in materials + $400 in shipping fees. After absorbing the sticker shock and stopping back a smaller local packing/shipping store, I decided I would need to build my own packaging. The local shipper told that I could likely ship the package to NYC via UPS for around $150 if I kept the weight of the entire package under 50lbs (the mirror weighed 21 lbs on its own) and the size of the box under 57" x 29" x 5".

With that information in mind, I set out to design my own custom container for the mirror. At first, I was considering building some kind of wooden crate, but that seemed like it was going to be quite heavy and expensive to construct. Then I thought about milling styrofoam to make a custom container for the frame. Many packages like TVs come in boxes with styrofoam holding the TV safely inside the box and that was the inspiration for this idea. It ended up working very well to mill custom foam pieces for the front and back of the mirror.

It was probably not necessary, but to add additional strength, I also inlayed strips of pine into the back of each piece of foam. I also learned a lesson about super glue and styrofoam. DO NOT MIX these two materials. I tried gluing the pine into the foam and it quickly started to melt the foam. Fortunately I noticed this issue quickly and removed the pine and used GA glue accelerator to harden the glue before too much of the styrofoam melted.

Once the two foam pieces were milled and reinforced I put the mirror inside and taped the two halves together. Then I took two large cardboard boxes and cut them open to give me the longest pieces of cardboard to work with. I proceeded to fold and cut the cardboard around the foam to create a custom box. It ended up working very well and I am proud to report I was well under the weight I was shooting for. The final package was 37 lbs. Total cost to ship was $150 including insurance. The box made it to NYC safe and sound and the mirror is now hanging in it's new happy home.

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